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Contents
Internet
Sites on Fish Diseases
57
Fish diseases constitute one of the most important problems and challenges
confronting fish culturists. Fish diseases do not occur as a single caused
event but are the end result of interactions of the disease, the fish and
the environment.
This annotated bibliography is prepared to highlight some of the latest research done in this field, to assist fish health and fishery biologists in information gathering. Articles included in this bibliography cover the period from 1995 to
2002. They are arranged alphabetically by author last name.
Furthermore, a list of some very useful internet sites related to the
topic, freely available, is provided at the end of the document.
Articles
The following is a list of bibliographic citations
related to Fish Diseases arranged alphabetically by first author. Abstracts
are provided . Information was retrieved from ASFA database.
Bacterial diseases control in fish farming], Symposium sur la Maitrise des maladies bacteriennes en pisciculture, Nantes (France), 29 May 1996, Piscic.-Fr.-Eau-Vive-Etang-Saumatre-Mar. Paris-France Federation-Francaise-d'-Aquaculture 1996 no. 125, 76 pp This French symposia offers an overview of the bacterial diseases control (freshwater and marine fish): ecopathology, epidemiology, diagnosis, therapy, disease control, aquaculture products, veterinary drugs (development, legislation and EEC perspectives). Solutions from countries such as USA, Japan and Norway are also presented and discussed. All the papers are analysed separately. Daniel,-P. [Diagnosis of bacterial diseases of farmed fish. An overview],Bacterial-diseases-control-in-fish-farming.-MAITRISE-DES-MALADIES-BACTERIENNES-EN-PISCICULTURE. Paris-France Federation-Francaise-d'-Aquaculture 1996 no. 125 no. 125, pp. 25-32 The author reviews the diagnostic methods of fish bacterial diseases: epidemiology, clinical and anatomo-pathological diagnostic, etiology and complementary assays are described. [Epidemiology of bacterial diseases of farmed fish. An overview] Fan,-Haiping; Xu,-Juaner; Huang,-Xiaofeng Investigation and control for the bacterial diseases of cultured eels in Fujian Province,Trans.-Oceanol.-Limnol.-Haiyang-Huzhao-Tongbao 1996 no. 2, pp. 66-70 The bacterial diseases of cultured eels in Fujian Province were investigated from November, 1993 to June, 1995. 8 spieces of bacterial diseases were observed during the research. This paper presents the epizoology, diagnosis and control methods for these diseases. Kusuda,-R.; Salati,- , Major bacterial diseases affecting mariculture in Japan F.ANNU.-REV.-FISH-DIS. 1993 vol. 3, pp. 69-85 With the development of intensive fish culture practices in Japan, bacterial and viral diseases spread and caused serious problems for culturists. The most important bacterial diseases affecting mariculture of yellowtail, sea bream, and flounder in Japan are caused by Enterococcus seriolicida, Pasteurella piscicida, Vibrio anguillarum, Nocardia kampachi, and Edwardsiella tarda. Characteristics of these pathogens and efforts to control them via chemotherapeutic and immunological methods are reviewed. (DBO) Muroga,-K.,Viral and bacterial diseases in larval and juvenile marine fish and shellfish: A review,FISH-PATHOL. 1995 vol. 30, no. 1, pp. 71-85 In Japan, seed production techniques have been developed for about 80 species of marine fish and shellfish. However, mass mortalities due to infectious and non-infectious diseases have often occurred in larvae and juveniles reared in hatcheries. Among these problems the viral and bacterial diseases are reviewed in this paper. Since around the middle of 1980's some new viral diseases such as viral epidermal hyperplasia (herpesvirus infection) in the Japanese flounder, viral ascites (birnavirus) in yellowtail, viral nervous necrosis (VNN) (nodavirus) in striped jack and some other fishes, and baculoviral mid-gut gland necrosis (BMN) in kuruma prawn have been reported. It was demonstrated that the selection of virus-free spawners based on the diagnosis by polymerase chain reaction (PCR) could serve as a control measure against vertical transmission of the pathogen in striped jack. Vibriosis, pasteurellosis, gliding bacterial infection and other bacterial diseases have occurred in various marine fishes during their juvenile stages. On the other hand, larval fish most frequently develop intestinal infections represented by bacterial enteritis with Vibrio sp. INFL in the Japanese flounder. Live foods contaminated with pathogenic bacteria have been suspected to serve as an important source of these intestinal infections. Ogbulie,-J.N.; Okpokwasili,-G.C,.Efficacy of chemotherapeutic agents in controlling bacterial diseases of cultured fish,Journal-of-Aquaculture-in-the-Tropics [J-Aquacult-Trop] 1998 vol. 13, no. 4, pp. 285-292 Sensitivity patterns of 74 genera of bacterial isolates from pond culture systems as well as from diseased and apparently healthy fish, to chemotherapeutic agents were evaluated. Results showed that bacterial isolates from culture systems and fish samples were resistant to flumequine, erythromycin, furazolidone, streptomycin and nitrofuranthoin, but sensitive to amikacin, kanamycin, tobramycin, neomycin and polymyxin B sulphate at low concentrations. The MIC and MBC assays showed amikacin, tobramycin and neomycin to be effective in eliciting both bacteriostatic and bactericidal effects at low concentrations on the bacterial isolates. Strunjak-Perovic,-I.; Hacmanjek,-M.; Coz-Rakovac,-R.; Teskeredzic,-E.; Teskeredzic,-Z.; Topic-Popovic,-N. Bacterial diseases in sea fish, Ribarstvo 1995 vol. 55, no. 4, pp. 147-160 With the development of marine fish culture, interest in fish health is also increasing. The major reason for this is the fact that the diseases, or rather the mortality that occurs in such controlled cultures, cause great economic losses. By growing large quantities of fish in rather small spaces, natural conditions are changed, so the fish is more sensitive and prone to infection agents (viruses, bacteria, parasites). A large fish density in the culturing process accelerates spreading of the diseases, but also enables better perception of them. In wild populations, sick specimens very quickly become predator's prey, which makes it difficult to note any pathological changes in such fish. There are many articles on viral, bacterial and parasitic diseases nowadays, but this work deals exclusively with bacterial diseases that occur under controlled sea culture conditions (vibriosis, furunculosis, pasteurellosis, nocardiosis, mycobacteriosis, edwardsiellosis, yersiniosis, and diseases caused by bacteria of the genera Flexibacter, Pseudomonas, Aeromonas, Streptococcus and bacterial nephritis). Yet, the knowledge on these diseases vary, depending on whether a fish species is being cultured for a long period of time or whether it is only being introduced in controlled culture. Ogbulie,-J.N.; Okpokwasili,-G.C.,,Haematological and histological responses of Clarias gariepinus and Heterobranchus bidorsalis to some acterial diseases in Rivers State, Nigeria, Journal-of-the-National-Science-Foundation-of-Sri-Lanka [J-Natl-Sci-Found-Sri-Lanka] 1999 vol. 27, no. 1, pp. 1-16 Bacteriological evaluation of various diseases of Clarias gariepinus and Heterobranchus bidorsalis showed higher bacterial colonisation of the diseased than the apparently healthy fish. Identification showed the isolation of Aeromonas hydrophila, Pseudomonas sp., Salmonella sp., Vibrio sp., Bacteriodes sp., Clostridium sp., Campylobacter jejuni, Yersina enterocolitica, Bacillus sp., Aeromonas sp. and gram positive anaerobic cocci from apparently healthy fish while Pseudomonas fluorescencs, Flavobacterium sp., Flexibacter sp. and Aeromonas sp. were isolated in addition to the above genera from diseased fish samples. Haematological evaluation of diseased and apparently healthy C. gariepinus and H. bidorsalis indicated a significant difference (p<0.5) in the PCV, WBC, ESR and Hb of diseased and apparently healthy fish. Characteristic differences were observed in the histology of affected tissues of diseased fish. These results are indicative of these bacteria in disease aetiology. Palanisamy,-V.,Preliminary studies on bacterial diseases associated with penaeid larvicultures .Fish-Bull-Dep-Fish-Malays; Buletin-Perikanan-Jabatan-Perikanan-Malays 1993 no. 84, 15 pp Studies on diseases of bacterial origin were carried out in larval cultures in a penaeid hatchery at the National Prawn Fry Production and Research Centre of Malaysia. Detailed occular observations, light-microscopy, bacteriology by API 20 E System, histopathology and staining techniques were carried out to determine the pathogens and related symptoms. Results showed that bacteria were the main pathogens in larvicultures causing frequent larval mortality. Main diagnostic symptoms were external and internal necrosis. The causative agents of external necrosis were Myxobacterium spp., Aeromonas sp., Pseudomonas sp., and Vibrio spp. The genus Leucothrix, non-pathogenic and peritrichous in nature, was found to cause surface fouling of gills and other external organs. Internal necrosis of larvae led to destruction of internal organs, especially the mid-gut gland, resulting in serious mortality of larvae. Main species of bacteria associated with internal necrosis were Vibrio spp., Pseudomonas spp. and Aeromonas spp. Protozoea, mysis and early postlarval stages were found to be more prone to bacterial pathogens. Strict hygiene practices, water treatment measures and temporary cessation of hatchery operation were found to reduce serious outbreaks of bacterial disease problems. Observation also showed that larvicultures with bacterial infection can be treated with prophylactic levels of antibiotics like furazolidone, oxytetracycline and chloramphenicol. Pasco,-L.,[Fish bacterial diseases control: the French SNGTV Aquaculture Commission proposals] Bacterial-diseases-control-in-fish-farming.-MAITRISE-DES-MALADIES-BACTERIENNES-EN-PISCICULTURE. Paris-France Federation-Francaise-d'-Aquaculture 1996 no. 125 no. 125, pp. 62-66 The propositions of the French SNGTV Aquaculture Commission are presented and discussed: - present state of fish bacteriosis control (vaccination, curative therapy); - weaknesses: bacterial resistances, diseases evolution, administration of drugs, European context,...; - propositions to manage therapy problems (vaccines, antibiotics). Vigneulle,-M [Bacterial diseases of farmed fish],Bacterial-diseases-control-in-fish-farming.-MAITRISE-DES-MALADIES-BACTERIENNES-EN-PISCICULTURE. Paris-France Federation-Francaise-d'-Aquaculture 1996 no. 125 no. 125, pp. 12-15 The author reviews fish bacterial diseases in freshwater
(furunculosis / Aeromonas salmonicida; enteric redmouth disease - ERD /
Yersinia ruckeri; bacterial cold water disease - BCWD / Flavobacterium
psychrophilum; bacterial kidney disease - BKD / Renibacterium salmoninarum),
and marine culture (vibriosis / Vibrio anguillarum; Pasteurella disease
/ Pasteurella piscida).
California case spotlights aquaculture drug approval crisis,FISH-FARM.-NEWS 1997 vol. 5, p. 1 The need to secure broader federal approval of drugs for use in aquaculture was dramatically illustrated late in September when a California fish farmer was sentenced on criminal charges of improper use of a widely utilized pesticide. Mike Saylor of Dutchman Creek Fish Farm was sentenced to six months house arrest, a $1,750 fine, and three years probation by a US district court judge on Sept. 30 in a plea bargain agreement on charges that he illegally used trichlorfon - also called Masoten or Dylox - to control gill flukes on goldfish. The charge, along with two other misdemeanor violations of bird protection laws, were filed after US Fish and Wildlife Service (USFWS) agents came onto Saylor's farm, apparently looking for evidence of illegal bird depredation activity, in June 1996. The case has raised alarm in the fish farming industry and spurred many - including other farmers, veterinarians, the National Aquaculture Association (NAA), and Saylor's US congressman - to come out in support of Saylor and in opposition to the hard line USFWS took against him. Choi,-M.-S.; Park,-K.-H.; Choi,-S.-H.,Drug resistance and R plasmids in Edwardsiella tarda from cultured-eel,Fish-Sci-Res 1995 no. 11, pp. 141-150 A total 41 strains of Edwardsiella tarda were isolated from cultured eels and examined for drug resistance, distribution and transferabilities of R plasmids. All isolates were multiple-resistant to drugs (at least 4 among 13 drugs) and mostly restricted to LM (41 strains), SD (41 strains), CH (39 strains), SF(38 strains), CP (37 strains), PM (37 strains), OT (36 strains), SM (29 strains), OA (29 strains), AM (28 strains), KM (7 strains), GM (6 strains), AK (6 strains) and EF (2 strains). Twenty five different drug resistant patterns were observed, the most frequently encountered pattern was LM-SD-CH-SF-CP-PM-OT-SM-OA (8 strains, 20%) followed by LM-SD-CH-SF-CP-PM-SM-OA (5 strains, 12%). In transfer experiment, transferable R plasmids were carried in 39 of 41 resistant strains, indicating that most isolates carried conjugally transferable R plasmids related to multiple drugs. The most frequently observed transferable R plasmids were SD-SF-CP-CH-LM-PM-AM (4 strains), SD-CP-CH-LM-PM-AM-OT (3 strains), SD-SF-CP-CH-LM-PM (3 strains) and SD-SF (3 strains). These results suggest that the chemotherapy of edwardsiellosis is extremely difficult due to the acquisition of multi-drug resistance to wide range of antibacterials. Furthermore it seems that high levels of various chemotherapeutics have already been introduced to eel culture. Erdal,-J.I.,New drug treatment hits sealice when they are most vulnerable,FISH-FARM.-INT. 1997 vol. 24, no. 2, vp Lepsidon is the trade name for a novel veterinary drug under development for the control of sealice in salmonid farming. It contains diflubenzuron, which belongs to the Insect Growth Regulator (IGR) group of substances, and is administered as a medicated pellet. An oral treatment against sealice (Lepeotheirus salmonis and Caligus elongatus Nordmann) has been chosen for at least two reasons: First, the drug specifically targets sealice on the fish, without unnecessary distribution to surrounding water. The parent drug and its metabolites will predominantly be excreted in faeces and deposited by sedimentation into the sediment layer beneath the farm, where it is eliminated through degradation. The second benefit of using an oral treatment method is that the practical limitations with bath treatments, in having to use tarpaulin skirts in large sea cage systems, are avoided. Getchell,-R.,Data required for new drug approval,FISH-FARM.-NEWS 1996 vol. 4, vp The Food and Drug Administration (FDA) has recognized the scarcity of approved drugs for the aquaculture industry and has made special provisions to facilitate drug-approval efforts. These include increased flexibility and interspecies data extrapolation, which can be especially helpful in the case of drugs that are already approved for major species like cows, chickens, dogs, and cats. Hawkins,-L.; Hariharan,-H.; Whitman,-K.; Johnson,-G.; Bryenton,-J.,Drug resistance of atypical Aeromonas salmonicida from Atlantic salmon and rainbow trout in Newfoundland,Proceedings-of-the-Contributed-Papers,-Aquaculture-Canada-'-97. Waddy,-S.L.;Frechette,-M.-eds. 1997 no. 97-2 pp. 39-41 Antimicrobial drug resistance patterns of atypical isolates of Aeromonas salmonicida from Atlantic salmon Salmo salar, or rainbow trout Oncorhynchus mykiss, from sites in Newfoundland were determined by disk diffusion assay. There was no resistance against chloramphenicol, kanamycin, nalidixic acid, neomycin or nitrofurantoin, but isolates resistant to erythromycin were found at 3 sites. Oxytetracycline-resistant strains reached 61% in 1995. Resistance to sulphamethoxazole-trimethoprim reached 52%, and a similar trend occurred with ormetoprim-sulfadimethoxine. Simultaneous resistance to the potentiated sulphonamides and oxytetracycline was common at some sites. Enrofloxacin appears to be the most promising drug, since all 72 isolates tested during 1995 were fully susceptible to the drug. MacMillan,-J.R.,,Drug development for use by the aquaculture industry: The producers' perspectiv USAVeterinary-and-Human-Toxicology [Vet-Hum-Toxicol] 1998 vol. 40, pp. 7-8 US commercial aquaculture industries are committed to producing safe, wholesome, high quality products. To do this economically, they strive to optimize production conditions, environmental quality, and animal health. Their challenge is to produce a product demanded by the consumer where demand is created by competitive pricing, quality, and palatability. There are considerable obstacles to this effort. The availability of federally approved drugs and water treatments, while widely recognized as a critical need, is only one of many impediments. Others include environmental quality, effluent and waste management, water volume restrictions, fish disease regulations, feed costs, bird depredation, diseases of unknown etiology, foreign competition, and community perceptions. In spite of these difficulties, aquaculture has developed and continues to grow. Shrimp drug attacks vibrio,Fish-Farming-International [Fish-Farm-Int] 1999 vol. 26, no. 2, p. 14 BACTERIAL disease remains a significant problem for shrimp farmers, in particular infections caused by the vibrio species. Fortunately a wide range of drugs (antibiotic and antibacterial) are available to farmers to prevent and treat infection. However, incorrect drug application is not only wasteful, but also results in more serious problems such as bacterial resistance and drug residue in shrimp after harvest. Antibiotics taken from animal and even human health fields have been used in shrimp aquaculture, often with little knowledge about appropriate application for aquaculture. Wang,-Fangguo; Wu,-Youlu; Chen,-Quanzhe,A study on PVP-I drug treatment for diseases of cultural prawn,Donghai-Mar.-Sci.-Donghai-Haiyang 1995 vol. 13, no. 2, pp. 16-20 In this paper is reported a test of the PVP-1 drug treatment
for diseases of Penaeus chinensis and P. penicillatus. The result shows
that 15 mg/dm super(3) of PVP-I is efficient for killing bacteria in the
seawater, and that 0.3 mg/dm super(3) of PVP-I can promote ecdysis of Penaeus
chinensis and P. penicillatus. during the period of prevalent prawn disease.
Anderson,-I.G.; Norton,-J.H.,Diseases of barramundi in aquaculture,AUSTASIA-AQUACULT. 1991 vol. 5, no. 8, pp. 21-23 The intensive hatchery and cage culture technology used to breed and rear barramundi have much to do with the number of diseases that have been diagnosed by regional veterinary diagnostic laboratories in Queensland. High densities facilitate pathogen (eg. bacteria, parasite) spread from fish to fish. Also, given the dependence on the farmer for nutritional and environmental needs, barramundi will be stressed -- and therefore more susceptible to infectious disease -- where such care is not the best (DBO). Anders,-K.; Landwuest,-C.-von,[Fish diseases in the North Sea],Texte Berlin-FRG Umweltbundesamt 1996 no. 57, 557 pp In 1991 and 1992 methods of biological effect monitoring were employed to investigate the state of the North Sea and of estuaries tributary to the North Sea. Investigations focussed on dab (Limanda limanda) in the North Sea and on flounder (Platichthys flesus) in estuaries. Investigations on biological effects comprehended activity of mixed function momooxygenases (MFO) and tests for lysosomal stability in liver samples, epidemiology of external fish diseases, and malformation rates of fish embryos. Concentrations of selected organochlorines, heavy metals, and arsenic were determined in fish parallel to investigations on biological effects. Among other areas, severe biological effects occurred in the Ekofisk oilfield, off the Northeast coast of England, and in the estuary of the River Elbe. The combined application of several methods of biological effect monitoring made it possible to register the effects of different influencing anthropogenic factors. These included pollution effects, especially of organochlorines, but sometimes also the effects of fishing activities and of deepening of waterways in estuaries. The occurrence of significantly elevated biological effects should lead to a reduction of contaminant emissions following the precautionary principle or to a reduction of fishing activities or waterway deepening in estuaries. Arkoosh,-M.R.; Casillas,-E.; Clemons,-E.; Kagley,-A.N.; Olson,-R.; Reno,-P.; Stein,-J.E.,Effect of pollution on fish diseases: Potential impacts on salmonid populations,Journal-of-Aquatic-Animal-Health 1998 vol. 10, no. 2, pp. 182-190 Anthropogenic factors have contributed to the precipitous decline of wild Pacific salmon stocks, although the mechanisms and processes at work are largely unknown. Pollution may be one of these factors. Sediments in estuaries are known to act as repositories for contaminants, and estuaries are important habitats for ocean- and river-migrating salmon. We have shown that juvenile salmon Oncorhynchus spp. and their prey bioaccumulate chlorinated hydrocarbons and aromatic hydrocarbons--important classes of toxic xenobiotics. Furthermore, we have shown that exposure to these pollutants can lead to immunosuppression and increased disease susceptibility in juvenile salmon. Whether pollution influences natural disease outbreaks in host populations, including salmon, is currently unknown. It is postulated that the occurrence of disease depends on the interaction of the host, the environment, and the pathogen. Absence of pathogens would reduce the potential for adverse environments to influence disease outbreaks. However, a recent reconnaissance survey of juvenile chinook salmon Oncorhynchus tshawytscha from Oregon coastal rivers revealed that pathogens were an integral component in all systems studied, although the prevalence of the pathogens varied. Furthermore, recent studies of natural fish populations have demonstrated that infectious-disease-induced mortality can significantly reduce the size of the host population. By creating adverse environments (e.g., polluted estuaries) which alter the susceptibility of the host to pathogens that are integral and ubiquitous components of the habitat, pollution increases the probability of disease-related impacts on fish populations. Bylund,-G.,-Loennstroem,-L.-G.-(eds,Diseases and parasites of flounder (Platichthys flesus) in the Baltic Sea,PUBL.-BALT.-MAR.-BIOL. AABO-FINLAND INST.-PARASITOLOGY,-AABO-AKADEMI 1994 no. 15, 147 pp A summary is provided of a workshop held in Finland to compile and discuss the present knowledge of flounder Platichthys flesus diseases and to explore and develop the possibilities for using flounder diseases as biomarkers in the Baltic Sea. It includes 20 individual presentations as well as summary statements from group discussions covering the following topics: lymphocystis-disease, skin ulcers, liver neoplasias and new methodologies for studying the potential relationship between prevalence of various diseases and exposure to environmental contaminants. Castric,-J., Viral diseases in fish mariculture,Bull.-Eur.-Assoc.-Fish-Pathol. 1997 vol. 17, no. 6, pp. 220-228 Viral diseases in maricultured fish species constitute a limiting factor to the development of this promising industry, mainly because of the high losses they cause in larvae and juveniles. The viruses associated with those diseases can be tentatively grouped in ten families. All countries practising fish farming and all cultivated species in seawater are concerned. If some viral diseases have direct economical consequences on the fish production, some others, due to agents of lower virulence, can decrease the resistance of fish to secondary infections or lead to clinical signs during stress or under bad environmental conditions. In numerous cases, the viruses can be transmitted by the spawners or by cultivated infected fish, but the presence of wild latently infected carriers must be considered in the open sea where sanitary measures are hardly applied. Das,-M.K.Fish diseases and their control in inland open water,Fisheries-enhancement-of-small-reservoirs-and-floodplain-lakes-in-India Sugunan,-V.V.-(ed.); Sinha,-M.-(ed.) Barrackpore-India CIFRI 1997 no. 75, pp. 231-236 Flood plain lakes and small reservoirs in India are increasingly used for enhancing fish production during the last few years. New methods of fish culture are being widely used to increase fish yield with the use of fertilizers on a limited scale. All these practices influence the environmental and parasitological factors in these culture areas and consequently various fish disease epizootics are encounted. Common fish diseases recorded in lakes where enhancement practices like stocking and fertilization are undertaken are discussed and include the following: ulcerative dropsy; columnaris disease; trichodiniasis; white gill spot; dactylogyrosis; argulosis; and epizootic ulcerative syndrome. Fish diseases encountered in reservoirs are also examined: ligulosis; black spot disease; isoparorchiosis; ergasilosis. Quarantine and fish health certification are considered briefly. Hedrick,-R.P.,Relationships of the host, pathogen, and environment: Implications for diseases of cultured and wild fish populations, Journal-of-Aquatic-Animal-Health 1998 vol. 10, no. 2, pp. 107-111 Many effects of diseases on cultured fish are known; they are less clear in wild fish populations. Cultured fish represent captive populations that can be subjected to intense scrutiny with an increasing range of diverse and powerful tools. Disease represents a spectrum from acute mortality to rather benign or inconsequential syndromes, all sharing the common feature of a deviation from the normal structure or function of the host. Understanding these deviations among cultured and wild fish populations and balancing their implications against ecological, economic, and political concerns are challenges for both fish health scientists and fisheries managers. The severity of a given disease is dependent on the interaction of numerous variables of the host, the parasite, and the environment. To understand diseases and their impacts on fish populations, we must know which variables are important, how we measure them, and finally how we assess the results of our measurements. We have perhaps been most successful with variables associated with the pathogen. We often can more easily isolate and scrutinize the pathogen than either the host or the environment. The host variables of importance (for which we lack considerable knowledge) include actions of the immune system in general and specifically the influence of genetics and nutrition on host resistance-susceptibility to disease. Lastly, the contribution of the environment, a nebulous term encompassing everything other than the host and pathogen, is only partly appreciated. While we can measure certain physical and chemical parameters of the environment, we have a poor understanding of the biological-ecological variables that influence host-pathogen interactions. Ultimately, diseases of wild fish must be considered in the context of these complex interactions including numerous physical, chemical, biological, and ecological parameters, which may yet be discovered as integral parts of the aquatic habitat. Liu,-Hui; Wu,-Yiping; Gao,-Shangde; Zhang,-Zhinan,Studies on chlorophyll-a and some other facts in the shrimp pond before the outbreak of the shrimp diseases,J-Ocean-Univ-Qingdao; Qingdao-Haiyang-Daxue-Xuebao 1998 vol. 28, no. 3, pp. 377-382 The total amount of the chlorophyll-a, phaeophytin, chlorophyll-a contents of sizefractionated phytoplankton and the influence of nutrients on the growth of phytoplankton, which were sampled from two shrimp ponds in Jinkou, Jimo, were studied from May to August 1994 before and after the outbreak of the shrimp disease. The contents of chlorophyll-a were decreasing during the investigation, from 46.98mg/m super(3) to 1.501mg/m super(3), and from 25.54mg/m super(3) to 3.30mg/m super(3), but the contents of phaeophytin was increasing at same time. Nanophytoplankton (2-20 mu m) is the most important part which makes up the total phytoplankton in both shrimp ponds, 74.3% and 68.4%, picophytoplankton (2-0.45 mu m) 20.4% and 27.5%, microphytoplankton (>20 mu m) 5.5% and 4.2% respectively. During the investigation the contents of DIN did not exceed the threshold of eutrophication, but the contents of DIP exceed the threshold of eutrophication almost from May. Manera,-M.; Biavati,-S.; Marcato,-P.S.,[Skin diseases of fish],Laguna 1996 no. 2, pp. 12-25 The integument of teleosts, as well as their gills, is the most exposed to environmental hazards. An understanding of the mechanism responding to pathogen attack is crucial for a correct diagnosis and as well as description of the pathologies which may affect them. Plumb,-J.A.,Overview of Warmwater Fish Diseases,Journal-of-Applied-Aquaculture [J-Appl-Aquacult] 1999 vol. 9, no. 2, pp. 1-10 Infectious diseases are among the most serious constraints to warmwater aquaculture. During the past 30 years, reported fish diseases in the southeastern United States have increased greatly; much of which was due to expansion and intensification of aquaculture, especially in the channel catfish industry. Viruses, bacteria, water molds, protozoa, helminths, and crustacea induce disease in warmwater fishes. While some of these are obligate pathogens, most are opportunistic facultative organisms that produce disease when fish health is compromised by injury or environmental stressors. The preferred method of controlling infectious diseases in warmwater aquaculture is by using "best management practices" that include improving and controlling the environment, handling and transporting fish properly, stocking at reasonable densities, using proper quantities of high quality feeds, using legal drugs judiciously, and vaccinating when effective products are available. Shariff,-M.,Impact of diseases on aquaculture in the Asia-Pacific region as exemplified by epizootic ulcerative syndrome (EUS),J-Appl-Ichthyol; Z-Angew-Ichthyol 1998 vol. 14, no. 3-4, pp. 139-144 . Traditional production systems rely on extensive management
regimes that involve low stocking densities and input levels. In recent
years, however, the aquaculture industry has evolved into a major force
in the regional aquatic economy. As a consequence, a major structural change
has occurred, leading to capital intensive production systems with high
stocking densities and high operating costs. While this structural change
has enabled many Asian countries to increase their aquaculture production
multifold, it has not been without environmental and socio-economic impacts;
among the most important are increasing fish health issues. Fish diseases
are the major risk factor in commercial aquaculture, with millions of dollars
lost annually. There is a tendency for epizootic outbreaks to spread to
other areas; lack of knowledge on the aetiology and spread of these fish
diseases requires much research. A case in point is epizootic ulcerative
syndrome (EUS). Despite regional collaborative research efforts from Australia
to India over the last 6 years, scientists have still not been able to
establish the primary factor behind this disease. As this example shows,
the lack of knowledge in fish health remains a major constraint in the
development of the regional aquaculture industry. This paper identifies
long-term measures that producing countries must implement to ensure the
sustainability of the industry. These include quarantine systems to prevent
the spread of exotic pathogens, together with diagnostic services. There
is also an urgent need to improve husbandry techniques to reduce fish stress,
and to train operating personnel adequately.
Ach,-J.J.; Gaikowski,-M.P.; Howe,-G.E.; Schreier,-T.M., Evaluation of the toxicity and efficacy of hydrogen peroxide treatments on eggs of warm- and coolwater fishes, AQUACULTURE 1998 vol. 165, no. 1-2, pp. 11-25 The use of hydrogen peroxide in aquaculture is growing and there is a need to develop fundamental guidelines to effectively treat diseased fish. The safety (toxicity) of hydrogen peroxide treatments was determined on eggs of representative warm- and coolwater fish species. Eggs of northern pike (Esox lucius), walleye (Stizostedion vitreum), yellow perch (Perca flavescens), white sucker (Catostomus commersoni), lake sturgeon (Acipenser fulvescens), paddlefish (Polyodon spathula), common carp (Cyprinus carpio), and channel catfish (Ictalurus punctatus) were cultured in egg jars or aquaria. Treatments were initiated with non-eyed eggs and continued until all viable eggs had hatched. Eggs were treated daily for 15 min Monday through Friday with either 0, 500, 1000, 3000, or 6000 mu l l -1 of hydrogen peroxide. For all species, the mean percent hatch was greater in eggs treated with 1000 mu l l -1 hydrogen peroxide for 15 min than in the untreated controls. Common carp, lake sturgeon, and paddlefish were the least sensitive to hydrogen peroxide with percent hatch ranging from 40 to 48% in the 6000 mu l l -1 hydrogen peroxide treatment. . Alfred-Ockiya,-J.F.; Akeodi,-J., Comparative study of fungal infestation of three traditionally smoked-dried freshwater fishes in Rivers State,J-Aquat-Sci 1998 vol. 13, pp. 41-43 Samples of 3 species of traditionally smoked-dried freshwater fishes (grey catfish Chrysichthys nigrodigitatus, mud catfish Clarias gariepinus and snake-head Parachanna obscura) were obtained from Port Harcourt fish market in Nigeria and examined for fungal infestation. All fish species showed signs of fungal infestation after incubation for three days on Potatoes Dextrose Agar (PDA) medium. Fungi isolated and identified included Aspergillus sp., Rhizopus sp., Fusarium sp. and Mucor sp. Five fungal species were identified on C.nigrodigitatus, 4 and 2 fungal species were identified on P.obscura and on C.gariepinus, respectively. Barnes,-M.E.; Ewing,-D.E.; Cordes,-R.J.; Young,-G.L., Observations on hydrogen peroxide control of Saprolegnia spp. during rainbow trout egg incubation, PROG.-FISH-CULT. 1998 vol. 60, no. 1, pp. 67-70 Daily treatments of 250, 500, and 1,000 mg hydrogen peroxide/L for 15 min were evaluated for fungal control on incubating eggs from two strains of rainbow trout Oncorhynchus mykiss. Observed infection rates and egg clumping were extensive enough in incubator trays receiving treatments of 250 or 500 mg hydrogen peroxide/L to make egg and fry handling difficult. The 1,000 mg/L treatment provided fungal control similar to daily formalin treatments of 1,667 mg/L for 15 min. Despite the differences in infection rates and clumping, egg survival was not affected by any of the treatments used. Barnes,-M.E.; Cordes,-R.J.; Sayler,-W.A., Use of formalin during incubation of eyed eggs of inland fall chinook salmon, PROG.-FISH-CULT. 1997 vol. 59, no. 4, pp. 303-306 The influence of daily formalin treatments on eyed egg
and fry mortality was evaluated during the incubation of eyed eggs of inland
fall chinook salmon Oncorhynchus tshawytscha. A 3-5% increase in survival
was observed in trays of eggs treated with formalin at 1,667 mg/L for 15
min daily from egg eye-up until just before hatch compared with incubation
trays from which dead eggs were manually removed to control Saprolegnia.
Egg survival in trays receiving both daily formalin treatments and manual
egg removal did not differ significantly from those trays receiving only
formalin treatments. Significant reductions in mortality were observed
prehatch when formalin was used, and there was no difference in mortality
from hatch to fry swim-up. Both formalin treatments and the hand-picking
of dead eggs adequately controlled visible fungal development from egg
eye-up to hatching.
Blazer,-V.S.; Vogelbein,-W.K.; Densmore,-C.L.; May,-E.B.; Lilley,-J.H.; Zwerner,-D.E. Aphanomyces as a Cause of Ulcerative Skin Lesions of Menhaden from Chesapeake Bay Tributaries,Journal-of-Aquatic-Animal-Health [J-Aquat-Anim-Health] 1999 vol. 11, no. 4, pp. 340-349 During the summer and fall of 1997, an unusually high prevalence of skin lesions in fishes from Chesapeake Bay tributaries as well as two fish kills in the Pocomoke River stimulated significant public concern. Atlantic menhaden Brevoortia tyrannus were the most frequent target of the acute fish kills and displayed skin lesions that were attributed to the presence of the toxic dinoflagellate Pfiesteria piscicida. Hence, the penetrating skin ulcers so commonly found in this species are now widely viewed by the general public and some scientists as Pfiesteria-related and to be caused by exposure to Pfiesteria toxin. We examined, histologically, 121 menhaden with these ulcers collected from both Maryland and Virginia waters of the Chesapeake Bay in 1997 and 31 from the Pocomoke and Wicomico rivers in 1998. All of the deeply penetrating ulcers, as well as raised lesions (with or without eroded epithelium), were characterized by deeply penetrating fungal hyphae surrounded by chronic, granulomatous inflammation. These lesions had an appearance identical or similar to epizootic ulcerative syndrome (EUS), an ulcerative mycotic syndrome of fishes in other parts of the world caused by the fungal pathogen Aphanomyces invadans. They were also identical to ulcerative mycosis of menhaden previously reported along the Atlantic coast of the USA as associated with Aphanomyces spp. In 1998, using methods for isolation of A. invadans, we were able to culture from affected menhaden an Aphanomyces sp. that by preliminary tests is similar or identical to A. invadans. We believe these findings suggest that factors other than Pfiesteria toxin need to be considered as the cause or initiator of these lesions. Cerenius,-L.; Schmid,-I.; Hoffmann,-R.; Soederhaell,-K..Crayfish plague epizootics in Germany--classification of two German isolates of the crayfish plague fungus Aphanomyces astaci by random amplification of polymorphic DNAOidtmann,-B.,Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1999 vol. 35, no. 3, pp. 235-238 Following 2 outbreaks of crayfish plague in southern Germany,
the causative agent, the oomycete fungus Aphanomyces astaci, was isolated
from the diseased Astacus astacus. The identity of the 2 strains was confirmed
using established techniques, such as physiology, spore production and
the fact that the isolated strains were highly virulent for A. astacus
in infection experiments. The relationship between these German strains
and other A. astaci strains was investigated using randomly amplified polymorphic
DNA-polymerase chain reaction (RAPD-PCR). The German strains were found
to be closely related to a strain that had been isolated from Pacifastacus
leniusculus from Lake Tahoe, USA.
Cooray,-R.; Morein,-B.; Holmberg,-M.; Hellstroem,-A.; Haerdig,-J..; Mattsson,-R.; Gunnarsson,-A.; B Screening for microorganisms associated with M74 disease syndrome in sea-run Baltic salmon (Salmo salar),Ambio 1999 vol. 28, no. 1, pp. 77-81 A broad screening approach was taken, using conventional methods for isolating and identifying fungi, bacteria, and viruses. The selection of tissue sites to be isolated was based on histopathological findings. Bartonella spp., which are known to be associated with inflammatory cardiac diseases in other animals, were not found to be associated with coronary arterial lesions in sea-run Baltic salmon (Salmo salar). From the gastrointestinal (GI) tract of adult sea-run Baltic salmon, we were able to isolate Aeromonas sobria, Pseudomonas putrefaciens, Pseudomonas spp., A. Hydrophila and Hafnia alvei, all of which can produce vitamin B sub(2). P. Putrefaciens and Pseudomonas spp. isolated from the GI tract also produce small amounts of vitamin B sub(3). Furthermore, it was found that chemotheraputic treatment of spawning salmon with formalin seems to disturb the symbiotic GI-flora. Glenn,-D.W.,III; Tiersch,-T.R., An alternative egg-incubation jar,PROG.-FISH-CULT. 1997 vol. 59, no. 3, pp. 253-255 Inexpensive hatching and incubation jars have been constructed in the past from polyvinyl chloride fittings or plastic bottles. Most cost less than $50 each, but contain numerous parts. The incubation jar described in this report was easy to assemble, recyclable, and cost about US$2.50. It took about 10 min to construct and 24 h for the sealant to cure before use. Eggs of common carp Cyprinus carpio in quantities of 2,000-80,000 were hatched in these jars by adjusting water flow. The small size (2.3-L volume) provided separation of many treatments in a confined area. Guandalini,-E.; Draisci,-R.; Macri,-A.; Cecilia,-A.M.; Mantovani,-A. What future for malachite green in aquaculture? Assessment of the available data, of the question still open and analytical method,Riv-Ital-Acquacolt 1998 vol. 33, no. 2, pp. 99-119 Malachite green (MG) is among the most debated compounds used in aquaculture. In fact, MG shows remarkable potential usefulness, such as efficacy against important protozoan and fungal infections and limited costs; however, considerable concerns, together with insufficient information, remain about the persistence of residues in fish tissues as well as on MG toxicity and ecotoxicity. The discrepancies between results of different studies (concerning either safety and residues) offer further ground to concern; the general term MG comprises different chemical forms of the substance (oxalate and chlorate salt, carbinol, leukobase). The following critical points must be clarified in order to adequately assess the risks for the consumers: the actual composition of the substance, including impurities; effects on immune function; reproductive toxicity, and mainly the genotoxic and carcinogenic potential. As regards the assessment of residue depletion and environmental impact, further studies are needed which should take into account the real usage patterns of MG and follow standard experimental protocols. In conclusion, the available information is fully inadequate; thus, the presence of MG residues in edible fish tissues cannot be allowed. However, some use of MG might be considered, similar to that authorized in USA since 1993. Such use should be strictly limited to eggs and fry of some species and performed under the control of the veterinary services; obviously this should be a transient measure, waiting for new compounds showing both a comparable efficacy and lower levels of concern for the consumers. An analytical method for tissue residues, presented in ISO format, is enclosed in an appendix. Holst,-J.C.; Salvanes,-A.G.V.; Johansen,-T., Feeding, Ichthyophonus sp. infection, distribution and growth history of Norwegian spring-spawning herring in summer, J.-FISH-BIOL. 1997 vol. 50, no. 3, pp. 652-664 After its collapse in the late 1960s, 1991 was the first
year of systematic herring (Clupea harengus) investigations after the Norwegian
Sea stock returned to the traditional summer-feeding areas. Of 11 prey
groups three dominated the diet; Calanus finmarchicus, Parathemisto spp.
and Sebastes spp. There was a high prevalence of Ichthyophonus sp. at stations
in the central and western parts of the Norwegian Sea where the cpue was
low. This suggests that infected individuals were unable to return from
the feeding to the wintering area of the Norwegian fjords. Highest cpue
were recorded between 68-73 degree N and 5-15 degree E. Age groups 2, 3
and 8 were most frequently caught and age group 8 (the 1983 year class)
dominated the samples. Herring occurred in dense concentrations where C.
finmarchicus dominated diet. 0-group fish dominated diet at stations along
the coast from 66-73 degree N and out to c. 300 km off the coast. Mature
herring overlapped in distribution with 0-group fish and Sebastes spp.
contributed largely to herring diet in this area. The first rich year-class
after the collapse, the 1983 year class, had a faster growth than rich
year classes from past herring periods, but slower than poor ones.
Khan,-M.H.; Marshall,-L.; Thompson,-K.D.; Lilley,-J.H ,Susceptibility of five fish species (Nile tilapia, rosy barb, rainbow trout, stickleback and roach) to intramuscular injection with the oomycete fish pathogen, Aphanomyces invadans,Bull-Eur-Assoc-Fish-Pathol 1998 vol. 18, no. 6, pp. 192-197 Tilapia (Oreochromis niloticus), rosy barb (Puntius schwanenfeldi), rainbow trout (Oncorhynchus mykiss), roach (Rutilus rutilus) and stickleback (Gasterosteus aculeatus) were challenged with Aphanomyces invadans, the Oomycete fungus considered to be the causative agent of epizootic ulcerative syndrome (EUS). At least 16 fish of each species were injected intramuscularly with 1-15 x 10 super(3) zoospores of A. invadans, kept at 11-24 degree C depending on species, and periodically sampled for histology and immunohistochemistry using anti-A. invadans polyclonal antiserum. Most tilapia remained healthy throughout the experiment with no significant histopathological changes, except for two tilapia, which died on day 20 and 21 post-injection (p.i.) showing invasive fungal growth and typical EUS-type lesions. All rosy barbs rapidly developed clinical signs of EUS. Fungus was seen in histological sections by day 7 p.i. In addition, all fish died by day 22 p.i. Rainbow trout also demonstrated signs of fungal growth and the progressive development of lesions, but these occurred at a slower rate than in the rosy barbs. The sticklebacks remained clinically and histologically normal, except for two fish, which died on day 13 p.i. with fungal infection of the integument and peritioneal cavity. However, this is believed to have been a secondary non-invasive fungus. Most roach displayed some scale loss and mild histological changes, but two roach sampled on days 25 and 35 p.i., showed typical EUS histopathology with fungal hyphae associated with muscle necrosis and a granulomatous inflammatory response. Kitancharoen,-N.; Yamamoto,-Atsushi; Hatai,-Kishio, Effects of Sodium Chloride, Hydrogen Peroxide and Malachite Green on Fungal Infection in Rainbow Trout Eggs,Biocontrol-Science [Biocontrol-Sci] 1998 vol. 3, no. 2, pp. 113-115 Two chemicals, sodium chloride and hydrogen peroxide were investigated for their efficacies as fungal control agents and compared with malachite green, fungal a control agent commonly used in hatcheries. No significant differences in results were seen between treatment with 1000 mu g/ml hydrogen peroxide and that with 2 mu g/ml malachite green in terms of the number of eggs infected and the hatching rate. When compared with the other two chemicals, sodium chloride at 25 ppt showed less effectiveness for fungal control. Lehmann,-J.; Mock,-D.; Schaefer,-W. Swim bladder infection of farmed Atlantic salmon (Salmo salar L.) by a fungus: a case report,Bull-Eur-Assoc-Fish-Pathol 1999 vol. 19, no. 2, pp. 83-84 This is a report of a seldom observed swim bladder fungal
infection of farmed young Atlantic salmons with severe clinical symptoms
of diseased fishes, but with low mortality relating to the total stock.
The fungus, diagnosed in the wall of the swim bladder, possibly belongs
to the species Paecilomyces farinosus, already described in 1989 as pathogen
for salmon in Scotland and Norway or to the genus Phoma, also known as
a swim bladder pathogen in salmonids.
Lopez-Doriga,-M.V.; Martinez,-J.L., Ultrastructure of fish cells involved in cellular defences against Saprolegnia infections: Evidence of non-leucocytic nature, Dis.-Aquat.-Org. 1998 vol. 32, no. 2, pp. 111-117 Fish cells attached to hyphae were observed in brown trout Salmo trutta L. infected with Saprolegnia parasitica. Earlier studies with light microscopy indicated that these cells were lymphocytes and neutrophils and that they were involved in the defence mechanisms against Saprolegnia infections. However, using electron microscopy, we found these attached cells did not show leucocytic characteristics, but instead shared some ultrastructural features with filament-containing cells. The presence of a dense mass of cytoplasmic filaments precludes the leucocytic nature of these cells. How these cells could be involved in cellular defences against fungi is discussed. Pottinger,-T.G.; Day,-J.G., A Saprolegnia parasitica challenge system for rainbow trout: Assessment of Pyceze as an anti-fungal agent for both fish and ova,Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1999 vol. 36, no. 2, pp. 129-141 A reproducible Saprolegnia parasitica spore delivery system
was developed and demonstrated to be effective in providing a sustained
spore challenge for up to 10 d. Treatment of rainbow trout with slow-release
intraperitoneal implants containing cortisol resulted in chronically elevated
blood cortisol levels and rendered the fish susceptible to infection by
S. parasitica when exposed to the spore challenge. Sham-implanted fish
were not susceptible to infection. Bronopol (2-bromo-2- nitro-propane-1,3-diol),
formulated as Pyceze, was effective in protecting predisposed fish from
infection by S. parasitica when administered as a daily bath-flush treatment
at concentrations of 15 mg l super(-1) and greater. Pyceze was also demonstrated
to protect fertilised rainbow trout ova from S. parasitica challenge when
administered as a daily bath/flush treatment at concentrations of between
30 and 100 mg l super(-1). Pyceze appears to qualify as a safe and effective
replacement for malachite green and formalin in the prevention of fungal
infections in the aquaculture environment.
Qureshi,-T.A.; Chauhan,-R.; Prasad,-Y.; Mastan,-S.A.. Effect of certain drugs on pathogenic fungi isolated from EUS affected fishes,Journal-of-Ecotoxicology-and-Environmental-Monitoring [J-Ecotoxicol-Environ-Monitoring] 1998 vol. 8, no. 1, pp. 15-22 In vitro studies were conducted to test the fungicidal effect of six chemicals viz. Dettol, Formalin, Malachite green, Potassium chromate, Potassium permangnate and Sodium salicylate on five fish pathogenic fungi viz. Achlya prolifera, Aphanomyces sp.Dictyuchus monosporus, Saprolegnia ferax and S.parasitica. All the six drugs tested exhibited positive fungicidal effects. On the basis of duration of survival of fishes in different drugs, it is recommended that except Sodium salicylate, the rest of the chemicals can be used for short term treatment only. Souheil,-H.; Vey,-A.; Thuet,-P.; Trilles,-J.P., Pathogenic and toxic effects of Fusarium oxysporum (Schlecht.) on survival and osmoregulatory capacity of Penaeus japonicus (Bate) Aquaculture 1999 vol. 178, no. 3-4, pp. 209-224 A gill-blackening disease in Penaeus japonicus was caused by Fusarium oxysporum, now considered for the first time to be a parasite of this shrimp. Two different isolates of a strain of F. oxysporum, I sub(1) and I sub(2), have been used in our experiments. In I sub(2) treated for 3 days with antibiotics, sporulation and growth were inhibited compared to I sub(1) treated for only 3 h. The pathogenic effect of F. oxysporum is dose- and isolate-dependent. With isolate I sub(1), all inoculated animals died within 14 days and their gills were covered in black patches, although they showed no signs of reduced behavioural activity. In contrast, with isolate I sub(2), all animals died later within 22 days and gill lesions produced were limited but, nevertheless, the behaviour activity of the animals was significantly reduced. Moulting or exposure to low salinities increased animal mortality. In juvenile animals, infection by F. oxysporum resulted in a significant decrease in their hypo-osmoregulatory capacity (hypo-OC) in seawater and in their hyper-osmoregulatory in diluted medium. Injections of crude filtrates from shake cultures of the fungus showed that molecules greater than 6-8 kDa caused a significant decrease in the hypo-OC and are likely to be responsible for the toxic effects of this fungus on these animals. Suzuki,-Y.; Otaka,-T.; Sato,-S.; Hou,-Y.Y.; Aida,-K., Reproduction related immunoglobulin changes in rainbow trout, Fish-Physiology-and-Biochemistry 1997 vol. 17, no. 1-6, pp. 415-421 . AB: Annual changes in plasma immunoglobulin (IgM) levels were investigated in three strains of rainbow trout Oncorhynchus mykiss which have different spawning periods, i.e., September-October, November-December, and January, reared under constant water temperature and natural day length. Plasma IgM levels decreased during the spawning season in all strains tested. The IgM changes became reversed in response to significant increases in plasma testosterone (T) and estradiol-17 beta in females and T and 11-ketotestosterone in males. Though the IgM decline showed a connection with suppressed immunocompetence, since many mature fish caught fungal diseases, no clear differences were observed in the plasma IgM levels between infected and noninfected fish during the spawning season. Incidentally, plasma IgM levels in infection prone fish were higher than in noninfection prone fish prior to the spawning season, whereas coincident differences in the plasma steroid levels were observed. Immature fish reared under lower water temperatures showed lower IgM levels. The effect of water temperature may have to be considered when analyzing the defense mechanism during the spawning season in rainbow trout. Taylor,-S.K.; Williams,-E.S.; Pier,-A.C.; Mills,-K.W.; Bock,-M.D Mucormycotic dermatitis in captive adult Wyoming toads.,Journal-of-Wildlife-Diseases [J-Wildl-Dis] 1999 vol. 35, no. 1, pp. 70-74 During late May 1995, 50 adult captive endangered Wyoming toads (Bufo baxteri) were brought out of hibernation. Approximately 3 to 10 days after hibernation emergence, all toads were hormonally induced to breed, and paired. Each pair was placed in their own breeding tank. Four toads developed clinical signs of disease which included lethargy and multiple (4 to 12) small (2 mm) raised hyperemic nodules with white fuzzy caps on the ventral skin. The condition progressively worsened until death occurred, within 3 to 6 days. Mycotic dermatitis caused by Mucor sp. was diagnosed in the four toads through histology and isolation of the organism. This is the first case report of a Mucor sp. causing a fatal dermatitis in an amphibian without significant inflammatory response and without systemic involvement. Vishwanath,-T.S.; Mohan,-C.V.; Shankar,-K.M., Epizootic Ulcerative Syndrome (EUS), associated with a fungal pathogen, in Indian fishes: histopathology -- `a cause for invasiveness',AQUACULTURE 1998 vol. 165, no. 1-2, pp. 1-9 A highly invasive fungus is associated with Epizootic Ulcerative Syndrome (EUS) in Indian fishes. The fungal invasion and associated pathology is not confined to the region of dermal ulcers. The fungus invades and proliferates in tissues away from the site of dermal ulcers and even penetrates across the vertebral septum to the contra-lateral side. The fungus readily invades the body cavity and produces mycotic granulomas in all the visceral organs. The invasive ability of the fungus is further demonstrated by its presence in the gizzard, spinal cord and intermuscular bones. The invasive nature of the fungus and associated tissue necrosis observed in a wide range of fresh and brackishwater fish hosts during natural epizootics present a plausible explanation for its high virulence and possible importance in defining the primary etiology of EUS. Vishwanath,-T.S.; Mohan,-C.V.; Shankar,-K.M., Mycotic granulomatosis and seasonality are the consistent features of epizootic ulcerative syndrome (EUS) in fresh and brackishwater fish of Karnataka, India, Asian-Fish.-Sci. 1997 vol. 10, no. 2, pp. 149-154 Histopathological investigations carried out between 1992 and 1994 on a large number of fresh and brackishwater fish of Karnataka, India, have confirmed that the ulcerative syndrome sweeping through Karnataka since 1991 is the devastating epizootic ulcerative syndrome (EUS). The 2 key diagnostic features of EUS, namely, oomycete involvement and proliferative mycotic granulomatosis, have been consistently demonstrated in all affected fresh and brackishwater fishes of Karnataka. Interestingly, Indian major carps and tilapia present in these affected water bodies were refractory to EUS. Mycotic granulomatosis and seasonality have been identified as the key features of this syndrome. Ali,-M.A., Henneguya ghaffari sp. n. (Myxozoa: Myxosporea), infecting the Nile perch Lates niloticus (Teleostei: Centropomidae), Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] Inter-Research 1999 vol. 38, no. 3, pp. 225-230 Light microscopical description is presented for a new myxozoan species, Henneguya ghaffari, which infects the Nile perch Lates niloticus (Linnaeus, 1758) in Lake Wadi El-Raiyan in Egypt. The spore is characterized by a triangular thickening at the base of the caudal processes. The relatively long caudal processes run adherent to each other for two-thirds of their length, then bifurcate to very fine processes. Prevalence of infection was 34.6% and peaked during winter and early spring. The infection was concentrated along the intestinal tract, and in severe cases gills and gill rakers were also infected. Histology revealed that, in contrast to findings of previously published works on related species, intralamellar plasmodia did not develop inside the blood capillaries of the gills. Intestinal plasmodia were very pathogenic due to their large number and size. These plasmodia caused atrophy of the muscularis layer, and replaced and distended the submucosal and mucosal layers. The validity of some Henneguya species in Africa is discussed. Almeida,-M.; Berthe,-F.; Thebault,-A.; Dinis,-M.T, Whole clam culture as a quantitative diagnostic procedure of Perkinsus atlanticus (Apicomplexa, Perkinsea) in clams Ruditapes decussatus, Aquaculture 1999 vol. 177, no. 1-4, pp. 325-332 The protozoan parasite Perkinsus atlanticus (Azevedo, 1989) causes severe losses among cultured clams, Ruditapes decussatus. This parasite is routinely diagnosed by means of histology or incubation of gills in fluid thioglycollate medium. However, in order to develop models of experimental reproduction of the disease, a procedure for infection intensity evaluation was required. Thus, a diagnostic method has been developed, based on the culture of all clam tissues in fluid thioglycollate medium, followed by sodium hydroxide lysis, and iodine staining of the parasites on cellulose filters. This method was compared with histology. Results suggest that histology is not sensitive enough to detect low levels of infection. The whole-clam culture technique allows detection of low levels or early infection of clams by P. atlanticus. Moreover, this method provides a quantification of infection intensity as number of parasites per gramme wet weight tissue. Athanassopoulou,-F., A case report of Pleistophora sp. infection in cultured sea bream (Sparus aurata L.) in Greece,Bull.-Eur.-Assoc.-Fish-Pathol. 1998 vol. 18, no. 1, pp. 19-21 Pleistophora sp. infection invading the skeletal muscles of cultured sea bream (mean weight 75g) in cages from Greece is described for the first time. The overall prevalence of the infection in the farm was 10.5% and daily mortalities were 0.2%. In feed treatment of fish with fumagillin 15 mg/Kg/fish for three weeks proved successful in lowering the mortalities but histological lesions due to the parasite were still present after 60 days post-diagnosis. Bucke,-D., Cataracts in farmed fish- a multidisciplinary intiative for scientific progress: histological techniques for teleost eyes ,Bull-Eur-Assoc-Fish-Pathol 1998 vol. 18, no. 4, pp. 121-123 An EC FAIR PL97-3963 programme on "Cataracts in farmed
fish" involving 16 partners with multidisciplinary skills has commenced.
The main objectives are to collate and disseminate knowledge on occurrence
and causation of cataracts in farmed fish and to initiate further research
to prevent and control the disease. As part of this programme detailed
instructions for making histological sections from teleost eyes are presented.
Carrasquero-Verde,-J.R., Role of associated bacteria in Heterosigma carterae toxicity to salmonids, Aquatic-Toxicology [Aquat-Toxicol] 1999 vol. 45, no. 1, pp. 19-34 This paper addresses the role of heterotrophic bacteria in Heterosigma carterae toxicity to salmonids. The experiments performed in this study showed that under the tested conditions, H. carterae is toxic to salmonids only when bacteria were present in the culture. The culture conditions used consisted of: an enriched seawater medium; and either 16L:8D photoperiod or 24 of continuous illumination. When the experiments were performed under these conditions, but in the absence of bacteria, H. carterae was not toxic to salmonids. In the absence of the algae, neither the associated bacteria nor the supernatant of a centrifuged H. carterae culture was toxic to salmonids. The experiments presented here demonstrate that toxicity can be induced in an initially axenic non-toxic H. carterae culture. This toxicity can be achieved through the introduction of the associated bacteria from a toxic H. carterae culture, or by the addition of Vibrio natriegens or Alteromanas haloplanktis (non-toxic marine bacteria). The histological analyses of fish gills suggested that the toxic mechanism might work through the disruption of fish gill lamellae (capillary epithelium separation). Further work is recommended. Constantino,-F.; de-Ocampo,-A.A.; Garcia-Marquez,-L.J., Dermal fibroma in goldfish, Carassius auratus (L.), Journal-of-Fish-Diseases [J-Fish-Dis] 1999 vol. 22, no. 3, pp. 223-226 The tumour, which was located in front of the dorsal fin and posterior to the cranium, was white, 1 x 1.5 cm, firm and well-delineated with a rough indented surface. The cut surface of the mass showed a smooth, firm, homogeneous, white and well-circumscribed tumour, covered with normal epithelium. One half of the tumour was fixed with buffered formalin, processed routinely for histological examination, and stained with haematoxylin and eosin, and Masson trichrome stains. The other half of the tissue was trimmed into 1-mm cubes, fixed in glutaraldehyde and processed for transmission electron microscopy. Sections were stained with uranyl acetate and lead citrate. Microscopically, the tumour examination confirmed a tissue covered with normal epidermis, consisting of a poorly vascularized nodule and extended deep into the dermis. Neoplastic cells were spindle-shaped, with hyperchromasia, with round to ovoid nuclei. There were few mitotic figures. Diggles,-B.K.; Carson,-J.; Hine,-P.M.; Hickman,-R.W.; Tait,-M.J., Vibrio species associated with mortalities in hatchery-reared turbot (Colistium nudipinnis) and brill (C. guntheri) in New Zealand Aquaculture 2000 vol. 183, no. 1-2, pp. 1-12 Studies were conducted to determine the cause of the acute mortality of juvenile turbot Colistium nudipinnis and brill, C. guntheri in an experimental rearing facility. Gross signs of disease included loss of appetite, erratic swimming, distended abdomens caused by an accumulation of clear fluid in the stomach and intestines, and haemorrhagic lesions on the underside and bases of the fins. Histological examination of the liver and kidney showed focal areas of necrosis and extensive haemorrhaging. Other lesions included necrosis and sloughing of the mucosa of the stomach and intestine, and sparse vacuolation in the brain and spinal chord. Bacteria isolated from the liver, kidney, and spleen included Vibrio splendidus I, and V. campbellii-like variants. Examination of the liver, kidney, and brain by electron microscopy failed to detect the presence of viral particles and samples of brain were negative against anti-SJNNV rabbit serum. It appears that the mortalities were due to infection by opportunist bacteria in fish predisposed by a combination of adverse factors including an acute period of poor water quality and perhaps an inadequate diet. Diamant,-A., Fish-to-fish transmission of a marine myxosporean,DIS.-AQUAT.-ORG. 1997 vol. 30, no. 2, pp. 99-105 Fish-to-fish transmission of the marine myxosporean Myxidium leei was experimentally demonstrated in sea bream Sparus aurata L. A group of specific-pathogen-free (SPF) fish of similar to 11 g each were placed in a wire-mesh cage immersed in a tank holding infected fish. A second group was placed in a tank receiving water discharged from another tank holding diseased fish. After 9 wk, the fish were sacrificed and 12 of the 38 (31.6%) test fish from the mesh cage were found to harbor trophozoites, sporoblasts and spores in the posterior gut epithelium, as was readily diagnosed by standard paraffin histology. Of the fish exposed to water discharge, 10 out of 30 (33.3%) showed similar infection. None of the fish examined displayed any proliferative stages of the parasites in the blood, spleen, kidney, liver or gill samples. All of 100 control fish examined remained uninfected. A third group of SPF fish was fed once daily for 7 d on pieces of freshly dissected M. leei-infected gut, after which the fish were maintained on a commercial pellet diet for a further 4 wk. Control fish in this experiment were fed only commercial pellets for 5 wk. The fish were sacrificed after 5 wk, and 4 out of 30 test fish (13%) were found to be infected. All control fish remained uninfected. Examination of the water sampled from all tanks in which infected fish were held revealed presence of exfoliated gut tissue and mucus casts containing trophozoites, sporoblasts and spores of M. leei. Examination of existing potential intermediate hosts yielded definitively negative results for actinosporeans. It is suggested that M. leei is transmitted between fish by ingestion of excretions from infected fish. The results reveal that sharing facilities with diseased fish as well as exposure to contaminated water is a route for parasite transmission. In general contrast to the freshwater myxosporeans studied to date, the present study of a marine species provides evidence that direct transmission can take place without need for actinosporean development in an alternate (oligochaete) host. It is suggested that this may be a model for the development of other marine myxosporeans as well. Docker,-M.F.; Devlin,-R.H.; Richard,-J.; Khattra,-J.; Kent,-M.L., Sensitive and specific polymerase chain reaction assay for detection of Loma salmonae (Microsporea), DIS.-AQUAT.-ORG. 1997 vol. 29, no. 1, pp. 41-48 Ribosomal DNA sequence of the microsporidian parasite Loma salmonae, including portions of the small subunit (SSU), large subunit (LSU), and internal transcribed spacer regions (ITS), was determined. Based on L. salmonae-specific regions of sequence, a polymerase chain reaction (PCR) assay was developed for detection of this parasite in chinook salmon Oncorhynchus tshawytscha. The specificity of the assay was verified by the lack of amplification with DNA from 3 other microsporidians that parasitize fishes in British Columbia, Canada. A dilution study assessed the sensitivity of the test, showing that the PCR product (derived from multiple copies of rDNA per cell) was routinely detected from as few as 0.01 spores per 50 mu l reaction (or 40 spores/g of infected gill tissue). The assay detected L. salmonae infections in the gills, kidneys, and ovaries of broodstock females from a seawater netpen on Vancouver Island, British Columbia, and infections in these organs were confirmed by histology. This is the first report of L. salmonae infections in ovarian tissue. Although neither PCR nor histology detected L. salmonae within the eggs themselves, it is possible that the progeny of infected females may become exposed to the parasite through contaminated ovarian fluid. Escher,-M.; Wahli,-T.; Buettner,-S.; Meier,-W.; Burkhardt-Holm,-P., The effect of sewage plant effluent on brown trout (Salmo trutta fario): a cage experiment, Aquatic-Sciences [Aquat-Sci] 1999 vol. 61, no. 2, pp. 93-110 The objective of the present study was to elucidate the influence of treated wastewater from a sewage plant on the state of health of brown trout (Salmo trutta fario). Trout were kept in two cages in a moderately polluted river at a site where a sewage plant discharges. River water only flowed through one cage (river water only (RWO) trout), while treated sewage water was added to the river water (final concentration 5%) in a second cage (river and wastewater (RWW) trout). As a reference, fish were kept in tap water (tap water reference (TWR) trout). After 66 days the mortality rate in group RWW was 87%, in group RWO 29% and in group TWR 0%. In RWW and RWO trout the infectious agent of furunculosis (A. salmonicida) and additionally in RWW another bacterial species (A. hydrophila) were isolated. Parasites were found in fish from both cages, whereby there were differences in species composition and degree of infestation between the two groups. Only in RWW trout were ulcerations of the upper and lower jaw found, together with significantly more severe Hasson,-K.W.; Lightner,-D.V.; Mari,-J.; Bonami,-J.R.; Poulos,-B.T.; Mohney,-L.L.; Redman,-R.M.; Brock,-J.A., The geographic distribution of Taura Syndrome Virus (TSV) in the Americas: determination by histopathology and in situ hybridization using TSV-specific cDNA probes, Aquaculture 1999 vol. 171, no. 1-2, pp. 13-26 Representative archived Litopenaeus vannamei samples (117 total), originating from 13 different countries and collected between 1992 to 1996, were analyzed by in situ hybridization to verify the presence of Taura Syndrome Virus (TSV) within pathodiagnostic acute phase TS histological lesions. The in situ assay results showed that TSV was present in one or more representative samples analyzed from each country (76 of 117 samples or 65%), thus, confirming the original histological diagnosis of TSV infection. The false negative in situ hybridization results, obtained for 35% of the samples assayed (41 in total), were attributed to over-fixation with Davidson's AFA (acetic acid, formaldehyde, alcohol) solution and consequent acid hydrolysis of TSV genomic RNA within pathodiagnostic TSV lesions. The collective findings of this disease survey assisted in documenting the spread and current distribution of TSV over a 5-year period and definitively established the presence of TSV within TS diseased shrimp originating from Ecuador when and where the disease was first recognized in 1992. These findings further strengthen the existing evidence that TS has a viral, not a toxic, etiology and indicate that either a single TSV strain, or very similar strains of the same virus, are responsible for the TSV panzootic that has been expanding in the Americas since 1992. Hodneland,-K.; Karlsbakk,-E.; Skagen,-D.W., Ichthyophonus hoferi in the Norwegian spring spawning herring (Clupea harengus L.) 1. Evaluation of examination methods, IFM-RAPP. 1997 no. 3, 32 pp Since the original discovery of Ichthyophonus hoferi infections in Norwegian spring spawning herring (Clupea harengus L.) in 1991, Russian researchers have reported prevalences at, or close to 100%. These prevalences were based on the examination of herring for clinical signs of ichthyophonosis, and the presence of "small spores" in kidney and other organs. Such high prevalences are incompatible with previous findings on the longevity and severity of experimental infections in herring, concluding that the infection is fatal in a time span of less than a year. A carrier status of all herring are thus indicated if the prevalences receive support. We set out to verify the high prevalences reported, and particularly the nature of the "small spores". Using culturing methods, histology for light and transmission electron microscopy we failed to confirm the Ichthyophonus aetiology of these "spores", and, together with critical evaluation of clinical signs, can not confirm such high prevalence values. We describe an examination method based on external and internal macroscopical signs of Ichthyophonus infection. Thus, we avoid the laborious microscopical or histological examinations which only allow limited sample sizes. We report prevalences below 6% in the wintering area in Tysfjorden-Ofoten (overall 2.9%, weighed according to acoustic abundance measurements 2.6%), and below 6% in commercial catches from the spawning area off More (overall 2.8%). Masoumian,-M.; Pazooki,-J., Myxosporean parasites from Mesopotamian part of Iran,Iran-J-Fish-Sci 1999 vol. 1, no. 1, pp. 35-46 A survey on myxosporean parasites of freshwater fishes from the Mesopotamian part of Iran (Khuzestan Province) was carried out. Some 280 individuals belonging to 14 different species were examined during a period extending from 1994 to 1997. In this study, the prevalence of myxosporean parasites, spore morphology, plasmodial development, the infective site, and characteristics of the cyst location were investigated using histological methods. The collected parasites were as follows: Myxobolus persicus, M. karuni, M. bulbocordis, M. nodulointestinalis, M. iranicus, M. mesopotamiae, M. shadgani, M. sharpeyi, M. molnari and M. mokayed. Barbus sharpeyi and B. grypus, economically important fishes, were infected by six and four myxosporean parasites respectivelly. All of the studied cases of infection were observed in natural waters. Mitchell,-A.J.; Goodwin,-A.E., Evidence that Enteric Septicemia of Catfish (ESC) was Present in Arkansas by the Late 1960s: New Insights into the Epidemiology of ESC, Journal-of-Aquatic-Animal-Health [J-Aquat-Anim-Health] 1999 vol. 11, no. 2, pp. 175-178 Enteric septicemia of catfish (ESC), a disease of channel
catfish Ictalurus punctatus, was first reported in 1979 based on isolates
obtained from 1976 through 1978. Channel catfish that had been preserved
in 1970, labeled "nutritional cranial spot," and stored at the Stuttgart
National Aquaculture Research Center were tested with Gram stains, histology,
and immunohistochemistry to demonstrate that the specimens were actually
infected by Edwardsiella ictaluri (the causative agent of ESC). A reexamination
of catfish disease case records has indicated that ESC might have been
present in Arkansas in 1969. Investigation of these old records and specimens
has led to insights on the discovery and epidemiology of the disease.
Miyazaki,-T.; Goto,-K.; Kobayashi,-T.; Kageyama,-T.; Miyata,-M., Mass mortalities associated with a virus disease in Japanese pearl oysters Pinctada fucata martensii, Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1999 vol. 37, no. 1, pp. 1-12 The annual mortality of cultured Japanese pearl oysters Pinctada fucata martensii in all western regions of Japan was over 400 million in both 1996 and 1997. The main pathological signs of the diseased oysters were atrophy in the adductor muscle, the mantle lobe and the body accompanied by a yellowish to brown coloration. Histological studies revealed necrosis and degeneration of muscle fibers of the adductor, pallial and foot musculatures as well as the cardiac muscle. Electron microscopy revealed the presence of small round virions approximately 30 nm in diameter within intrasarcoplasmic inclusion bodies in necrotized muscle fibers of the adductor and pallial musculatures, and the heart. The causative virus was isolated and cultured in EK-1 (eel kidney) and EPC (epithelioma papilosum cyprini) fish cell lines. Marked mortalities occurred in pearl oysters that had been experimentally inoculated with the cultured virus; these oyster displayed the same pathological signs of the disease as oysters in natural infections. These results indicate that a previously undescribed virus caused the mass mortalities in cultured pearl oysters. Pietrock,-M.; Krueger,-R., (Larval triaenophorosis of juvenile river perch (Perca fluviatilis) of the mesotrophic lake Grosser Vaetersee), Diseases-of-aquatic-organisms-Krankheiten-der-aquatischen-Organismen Wedekind,-H.-(ed.) Gross-Glienicke-FRG Institut-fuer-Binnenfischerei 1999 pp. 13-20 Prior to biomanipulation of the mesotrophic lake Grosser
Vaetersee (Germany), baseline data have been collected on the interactions
between aquatic organisms occupying different positions within the food
web. Fish parasitological studies were integrated into these investigations
to elucidate the impact of qualitative and quantitative changes in the
zooplankton community on parasite infection. Of particular interest was
the pseudophyllid cestode Triaenophorus nodulosus, which uses cyclopoidid
copepods as the first intermediate host, percid and other fishes as the
second intermediate host, and esocidae as final hosts. The present paper
describes our findings concerning ecological and pathological aspects of
infection in perch, Perca fluviatilis. Examination of 260 juvenile fish
between June 1997 and July 1998 showed that plerocercoids of T. nodulosus
commonly infected the liver, with a prevalence of 49.6 % and intensity
of infection ranged from 1 to 8, with a mean of 1.7. The hepatosomatic
index was significantly lower in infected than in uninfected fish. Histology
revealed mild to severe pathological changes in the liver of infected perch
comprising cirrhosis, necrotic foci, atrophy of hepatocytes, and decreased
glycogen and lipid. We could therefore anticipate that if biomanipulation
resulted in increased abundance of cyclopoidid copepods, or other suitable
alternative first intermediate hosts, this would lead to increased T. nodulosus
infection in perch with associated liver pathology, and compromised health.
Rajendran,-K.V.; Vijayan,-K.K.; Santiago,-T.C.; Krol,-R.M., Experimental host range and histopathology of white spot syndrome virus (WSSV) infection in shrimp, prawns, crabs and lobsters from India, Journal-of-Fish-Diseases [J-Fish-Dis] 1999 vol. 22, no. 3, pp. 183-191 Experimental studies were conducted by injecting or feeding white spot syndrome virus (WSSV) derived from infected shrimp, Penaeus monodon (Fabricius), collected from the south-east coast of India, to five species of shrimp, two species of freshwater prawns, four species of crabs and three species of lobsters. All species examined were susceptible to the virus. Experimental infections in the shrimp had the same clinical symptoms and histopathological characteristics as in naturally infected P. monodon. A cumulative mortality of 100% was observed within 5-7 days in shrimp injected with WSSV and 7-9 days in shrimp fed with infected tissue. Two species of mud crab, Scylla sp., survived the infection for 30 days without any clinical symptoms. All three species of lobsters, Panulirus sp., and the freshwater prawn, Macrobrachium rosenbergii (De Man), survived the infection for 70 days without clinical symptoms. However, bioassay and histology using healthy P. monodon revealed that crabs, prawns and lobsters may act as asymptomatic carriers/reservoir hosts of WSSV. This is the first report to suggest the carrier/reservoir capacity of these hosts through histological and bioassay evidences. Ultrastructural details of the virus in experimentally infected shrimp, P. vannamei, (Boone), were also studied. Real,-F.A.; Oros,-J.; Acosta,-F.; Acosta,-B.; Santana,-P.; Deniz,-S., Pasteurellosis of gilthead seabream (Sparus aurata) in Gran Canaria Island, Spain, Bull-Eur-Assoc-Fish-Pathol 1997 vol. 17, no. 5, pp. 153-157 In this report we describe the first epizootic pasteurellosis in gilthead seabream cultured in a fish farm located in South Gran Canaria (Spain), beginning in January 1996. Isolates from moribund fish conformed to Pasteurella piscicida biochemically and serologically. The measures which applied to control the disease an the epidemiological hypothesis of the source of this outbreak are also discussed. Rodriguez,-H.; Soto,-M.; Arias,-C.; Estevez,-J., A case of disseminated haemic sarcoma in Cerastoderma (=Cardium) Glaucum Poiret, 1789 collected from Ria de Vigo (NW Spain), Bull-Eur-Assoc-Fish-Pathol 1997 vol. 17, no. 3/4, pp. 88-90 A case of a disseminated sarcoma of possible haemolytic origin in Cardium glaucum off the Ria de Vigo (NW coast of Spain) is reported in this work. On the basis of the morphological characteristics of the neoplastic cells and their distribution in the tissues we propose an haemocytic origin. Finally, we suggest a polyfactorial aetiology. Ruby; Sheela,-R.; Muralimanohar,-B.; Sundararaj,-A.; Selvaraj,-D.; Chidambaram,-P.; Mohan,-A.C.; Ravishankar,-B., Infectious hypodermal and haematopoietic necrosis virus (IHHNV) in cultured Penaeus monodon in Tamil Nadu, India, Indian-J-Fish 1998 vol. 45, no. 2, pp. 183-186 During June - July, 1995, a severe epizootic epidemic with heavy mortality occurred in cultured Penaeus monodon near Chidambaram, Tamil Nadu, India. The clinical symptoms and gross lesions observed resembled infectious hypodermal and haematopoietic necrosis virus (IHHNV) disease. Histological examination of the affected shrimp revealed prominent Cowdry type-A eosinophilic intranuclear inclusions within chromatin marginated and hypertrophied microscopy sections of gills revealed intranuclear inclusions and paracrystalline arrays of icosahedral IHHNV particles in the cytoplasm. This is perhaps the first conclusive evidence IHHNV in cultured P.mondon in Tamil Nadu, India. Sano,-M.; Sato,-J.; Yokoyama,-H., Occurrence of beko disease caused by Microsporidium seriolae (Microspora) in hatchery-reared juvenile yellowtail, Fish-Pathology [Fish-Pathol] 1998 vol. 33, no. 1, pp. 11-16 Hatchery-produced juvenile yellowtail Seriola quinqueradiata were transferred from an indoor tank to sea netpens on June 20, June 30, July 10 and July 31, 1995 (4 groups), and each group was monitored at about 10 day intervals for Microsporidium seriolae, the causative agent of beko disease. Water temperature gradually increased during the study period, ranging from 20.8 to 30.2 degree C. In the first 3 fish groups, almost all fish were found to be infected. However, prevalence of infection in the last fish group was much lower than in the other groups. Groups which were transferred later attained their maximum prevalence of infection within a shorter period. Furthermore, we investigated the effects of water temperature and fish size on the development of M. seriolae in juvenile yellowtail. Two different fish size classes (average body weight 0.3 g and 22.0 g) were infected with M. seriolae to a similar extent. In the histological examination, the development of M. seriolae and host recovery were accelerated in fish reared at 25 degree C compared to those kept at 20 degree C. Steinhagen,-D.; Bunnajirakul,-S.; Kiesecker,-I.; Schuberth,-H.J.; Scharsack,-J.; Hetzel,-U.; Koerting,-W., (Immunological and histological investigations on carp with blood parasite infestation), Diseases-of-aquatic-organisms-Krankheiten-der-aquatischen-Organismen Wedekind,-H.-(ed.) Gross-Glienicke-FRG Institut-fuer-Binnenfischerei 1999 pp. 32-39 Hatchery populations of common carp (Cyprinus carpio) and tench (Tinca tinca) are frequently infected with the blood flagellate Trypanoplasma borreli, the cause of sleeping sickness of carp. Affected fish harbour large numbers of parasites in the peripheral blood and show on anaemia and pale gills. When necropsied these carp display an enlarged spleen and a swollen kidney with petechial haemorrhages. In histological investigations a generalized endovasculitis and an congestion of blood capillaries by masses of mononuclear cells and trypanoplasma could be seen. In liver, spleen and kidney of moribund fishes focal haemorrhages and necroses were seen. In the excretory tissue of the kidney, a glomerulonephritis and a tubulonecrosis occured. In laboratory infections of carp with the T. borreli the appearance of kidney changes was investigated during the course of the development of the parasite. The carp were infected with the parasite by an i.m. injection of 5,000 Trypanoplama cells. In weekly intervals carp were killed and tissue samples were taken for histology. Additionally, cell suspensions were prepared from pronephors and spleen and examined by means of a flow cytometer. To label proliferating cells in situ, the carp were injected with a BRDU-solution 5 h pior to sampling. The nucelotid analogue BRDU is incorporated into the DNA of dividing cells and can be envisualized by means of immunocytochemistry. In the first week post injection (PI) of the parasite, an infiltration of mononuclear cells into pronephros and kidney was observed. This resulted in an increase in the proportion of renal interstitial tissue, which already was visible in histological preparations. This increase of interstitial tissue was mainly induced by an increase in the proportion of proliferating cells. Stephen,-C.; Ribble,-C.S., Mortality surveys as a tool for studying marine anaemia in seapen-reared chinook salmon, Oncorhynchus tshawytscha (Walbaum), AQUACULT.-RES. 1997 vol. 28, no. 4, pp. 265-269 Because of their rapid autolysis and post mortem contamination, the examination of dead seapen salmon has been considered of limited value for investigating disease in farmed salmon. Marine anaemia is a recently described plasmacytoid leukemia of farmed salmon that is diagnosed primarily by histological findings. The objectives of this study were to determine if marine anaemia could be reliably diagnosed in dead fish under commercial conditions and to identify the factors that affect the quality of data that are derived from mortality surveys. Surface moribund fish and dead salmon were recovered from four adjacent pens on 31 farm visits to commercial salmon farms over a 6-month period. Mortality surveys provided six times as many fish for gross pathological diagnosis and three times as many fish for reliable histological diagnosis of marine anaemia than did surveys of surface moribund salmon. The interval between recovery of dead fish from a pen most strongly influenced the quality of information derived from the mortality surveys. Mortality surveys proved to be more sensitive to finding the disease than did surface morbidity surveys. The results demonstrated that mortality surveys can provide reliable information, which can generate new insights not only into the impact and epidemiology of marine anaemia, but also for other fatal diseases of seapen salmon. Tatsuo; Takeda,-Masaei; Chiba,-Akira; Oka,-Shunya, Remarkable papillomas in white sturgeons, Acipenser transmontanus, reared in an aquarium, Ichthyological-Research [Ichthyol-Res] 1999 vol. 46, no. 2, pp. 107-114 Papillomatous growths on the ventral surface of the body and paired fins of the white sturgeon, Acipenser transmontanus Richardson, were described histologically with the aid of light and electron microscopy. Contrary to the usual state of intact squamous epithelium being equipped with microridges, no such surface structures were apparent in the papillomatous tissue. The growths appeared to be an aberrant elevations of proliferated dermal tissue, which sustains the hyperplastic Malpighian layer consisting of the stratum spinosum (prickle cell layer) and s.basale. Many intercellular bridges were found, constructed from prominent projections, with distinct desmosomes and many tonofilaments. The likely causative agent was mechanical irritation between the small aquarium tank and growing sturgeon, since no viral and/or parasitic inclusion bodies were encountered in the cells. Taylor,-S.K.; Williams,-E.S.; Pier,-A.C.; Mills,-K.W.; Bock,-M.D., Mucormycotic dermatitis in captive adult Wyoming toads, Journal-of-Wildlife-Diseases [J-Wildl-Dis] 1999 vol. 35, no. 1, pp. 70-74 During late May 1995, 50 adult captive endangered Wyoming toads (Bufo baxteri) were brought out of hibernation. Approximately 3 to 10 days after hibernation emergence, all toads were hormonally induced to breed, and paired. Each pair was placed in their own breeding tank. Four toads developed clinical signs of disease which included lethargy and multiple (4 to 12) small (2 mm) raised hyperemic nodules with white fuzzy caps on the ventral skin. The condition progressively worsened until death occurred, within 3 to 6 days. Mycotic dermatitis caused by Mucor sp. was diagnosed in the four toads through histology and isolation of the organism. This is the first case report of a Mucor sp. causing a fatal dermatitis in an amphibian without significant inflammatory response and without systemic involvement. Thompson,-K.G.; Nehring,-R.B.; Bowden,-D.C.; Wygant,-T., Field Exposure of Seven Species or Subspecies of Salmonids to Myxobolus cerebralis in the Colorado River, Middle Park, Colorado Journal-of-Aquatic-Animal-Health [J-Aquat-Anim-Health] 1999 vol. 11, no. 4, pp. 312-329 Recent failures in recruitment of rainbow trout Oncorhynchus mykiss in the Colorado River in Middle Park, Colorado, USA, led to studies of the effect of the myxosporean parasite Myxobolus cerebralis, the causative agent of whirling disease, on the wild trout fishery in the river. During 1995-1996 and 1996-1997, we conducted field exposures of sentinel fish to examine the vulnerability of seven species or subspecies of salmonids exposed to the parasite in the Colorado River. During 1995-1996, brook trout Salvelinus fontinalis and Colorado River cutthroat trout O. clarki pleuriticus experienced 85% or higher mortality within 4 months of exposure. Groups of fish introduced at greater mean weight or later in the summer tended to survive better than others, but mortality often was severe among these groups during the second summer. By April 1996, dead fish or sacrificed fish representing seven groups were shown by histology to contain mature M. cerebralis spores. During 1996-1997, three groups of cutthroat trout O. clarki spp. experienced poorer survival than brown trout Salmo trutta and rainbow trout introduced at similar weights. Snake River cutthroat trout O. c. bouvieri introduced in July survived well and developed fewer M. cerebralis spores (prevalence and mean concentration) than any group except brown trout. Rainbow trout parented by fish that recruited after M. cerebralis was established in the drainage developed significantly fewer myxospores than those parented by fish that recruited before establishment of M. cerebralis (P less than or equal to 0.0001), but survival was not different between these groups (87% versus 89%, respectively). The poor performance of parasitized brook trout and cutthroat trout suggests that establishment of M. cerebralis in high-country streams may have serious consequences for these species. Usheva,-L.N.; Odintsova,-N.A., Hyperplastic growth of mucous cells in the mantle of the mussel Modiolus kurilensis from a heavily polluted area of Amursky Bay, Sea of Japan, Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1998 vol. 33, no. 3, pp. 235-238 The histology of an external mantle growth in 1 of 500
Modiolus kurilensis from a heavily polluted area of Amursky Bay, Sea of
Japan, was described. The growth consisted of subepithelial basophilic
mucous cells containing glucosaminoglycans, eosinophilic large-granular
cells with proteins and neutral polysaccharides, and mixed (acid + neutral
mucopolysaccharides) cell types. Some subepithelial eosinophilic and basophilic
gland cells were dividing and seemed to be the source of tumor growth.
The mitotic index of growth cells reached 0.5% on some growth sections;
however, many mitoses were pycnotic. The emergence of the tumor on the
mussel mantle is probably related to a compensatory or regenerative hyperplasia
of subepithelial mucous cells.
Viswanath,-T.S.; Mohan,-C.V.; Shankar,-K.M., Clinical and histopathological characterization of different types of lesions associated with Epizootic Ulcerative Syndrome (EUS J.-AQUACULT.-TROP. 1997 vol. 12, no. 1, pp. 35-42 Using clinical and histological features, the present paper has classified and characterized three distinct types of EUS lesions. Type 1 lesion appeared as tiny red spots on the body surface and showed inflammatory changes and fungal involvement to be confined to the epidermis. Type 2 lesion appeared as dark raised areas on the body surface and histologically showed fungal involvement and granulomatous response in the epidermis, dermis, and skeletal musculature. Skin and scales were relatively intact in these lesions. Type 3 lesions occurred as open dermal ulcers on the body surface. Histologically these lesions showed mycotic granulomatous response and massive necrotic changes associated with fungal invasion in the integument and skeletal musculture. Clinical and histological evidence also suggested that fungus is involved from a very early stage and the early lesions (Type 1) progress over a period of time to develop into advanced dermal ulcerative lesions (Type 3), which are the characteristic features of EUS. Watermann,-B.; Ide,-I.; Liebe,-S., (Diseases of blue mussel (Mytilus edulis) at the East-Frisian coast) Diseases-of-aquatic-organisms-Krankheiten-der-aquatischen-Organismen Wedekind,-H.-(ed.) Gross-Glienicke-FRG Institut-fuer-Binnenfischerei 1999 pp. 177-187 Between 1994 and 1997 roughly 200 mussels were collected
from musselbeds and coastal enforcements along the East-Frisian coast between
Emden and Cuxhaven. A variety of infectious, non-infectious diseases and
parasitic infestations were recorded. Histological sections revealed the
presence of protozoan symbionts, like ciliates, and parasites like trematode
as well as nematode larvae and Mytilicola. Inflammation processes as haemocyte
infiltrations and granulocytomas were present in the mid-gut gland, mucosa
of the intestine and the storage tissue. Preliminary bacteriological investigations
revealed the presence of Vibrio and Pseudomonas in internal organs.
Abelli,-L.; Picchietti,-S.; Romano,-N.; Mastrolia,-L.; Scapigliati,-G. Immunohistochemistry of gut-associated lymphoid tissue of the sea bass Dicentrarchus labrax (L.),FISH-SHELLFISH-IMMUNOL. 1997 vol. 7, no. 4, pp. 235-245 Histology revealed scattered lymphoid cells at all levels of the digestive tract of the sea bass Dicentrarchus labrax (L.), notably in the mucosa and submucosa. Immunohistochemistry with monoclonal antibodies against T cells (DLT15) and immunoglobulin-bearing cells (DLIg3 and DLIg13) demonstrated the presence of a gut-associated lymphoid tissue. Quantitative analysis showed that the concentration of DLT15-positive cells largely exceeded that of Ig-bearing cells, while the number and the distribution of DLIg3- and DLIg13-immunoreactive cells were superimposable. An apparent gradient in the number of lymphoid cells was present, concentrating them towards the anus. This suggests that, as in other fish species, the posterior gut acquired higher immunological relevance. Alikin,-Y.S.; Shchelkunov,-I.S.; Shchelkunova,-T.I.; Kupinskaya,-O.A.; Masycheva,-V.I.; Klimenko,-V.P.; Fadina,-V.A. Prophylactic treatment of viral diseases in fish using native RNA linked to soluble and corpuscular carriers, J.-FISH-BIOL. 1996 vol. 49, no. 2, pp. 195-205 The potential of double- (ds) and single-stranded (ss) yeast RNA preparations for protection of carp Cyprinus carpio against experimental infection with Rhabdovirus carpio, the infectious agent of spring viraemia of carp, was studied. Prophylactic intraperitoneal injection of fish with dsRNA proved efficient while ssRNA had a much smaller effect. The protective effect of yeast dsRNA in 1-year-old carp lasted for at least 3 weeks. The efficacy of the preparations decreased considerably if they were administered by the bath method. Both insoluble and soluble carriers for dsRNA were studied to increase the preparation efficacy. Screening of the preparations revealed the importance of DEAE-groups on the carriers. Their biological efficiency is confirmed by the method of phagocytosis of the mouse peritoneal macrophages. Ardelli,-B.F.; Woo,-P.T.K. The therapeutic use of isometamidium chloride against Cryptobia salmositica in rainbow trout Oncorhynchus mykiss, Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1999 vol. 37, no. 3, pp. 195-203 Rainbow trout Oncorhynchus mykiss injected intramuscularly with isometamidium
chloride (0.01 or 0.1 mg/kg) at 3 wk post-infection and given a booster
2 wk later had significantly lower parasitaemias than infected controls.
Packed cell volume increased after treatment and remained higher than in
infected controls. The concentration of isometamidium in plasma was highest
at 2 wk after injection and then declined. An intramuscular dose of 1.0
mg/kg of isometamidium chloride-at 1, 2 and 3 wk postinfection (preclinical)
significantly reduced the parasitaernia in rainbow trout 2 wk after treatment.
A booster at 9 wk postinfection (chronic disease phase) reduced the parasitaemia
further in all fish. The packed cell volume in these fish was higher than
in infected controls. Treatment at 5, 6, and 7 wk postinfection (acute
disease) had no effects and parasitaernias in treated fish were higher
than in infected controls; also, anti-Cryptobia salmositica antibodies
and titres of complement-fixing antibody were higher in these than in infected
controls. Incubation of immune plasma or complement with isometamidium
for 3 h did not affect the lytic titres of complement-fixing antibodies
nor rainbow trout complement.
Baldwin,-T.J.; Collins,-L.A.; Newton,-J.C., Antigens of Edwardsiella ictaluri recognised by serum antibodies from naturally infected channel catfish, FISH-SHELLFISH-IMMUNOL. 1997 vol. 7, no. 4, pp. 261-271 Immunogenicity of whole cell lysates of Edwardsiella ictaluri and bacterial fractions enriched for outer membrane proteins (OMP), flagella and lipopolysaccharide (LPS) was examined using pooled convalescent sera from channel catfish (Ictalurus punctatus) that had survived a natural infection with E. ictaluri. Bacterial components were separated by gel electrophoresis; proteins were stained with Coomassie brilliant blue and LPS were stained with silver. Thirty-eight proteins were identified in whole-cell preparations (apparent molecular masses of 108 kDa to 14 kDa). Thirteen proteins were identified in OMP preparations (apparent molecular masses of 84 kDa to 16 kDa). Two flagellar proteins (apparent molecular masses of 45 kDa and 37 kDa) were identified. Low and medium molecular mass LPS were seen on purified LPS preparations. Immunogenicity was evaluated by indirect staining following transfer of bacterial antigens to filter paper. Lipopolysaccharide and the 39 kDa OMP were strongly recognised by antibodies in pooled sera from channel catfish naturally infected with E. ictaluri. One flagellar protein (37 kDa), nine OMP, and five unidentified proteins seen on whole cell preparations stained less strongly. Balfry,-S.K.; Shariff,-M.; Iwama,-G.K. Strain differences in non-specific immunity of tilapia Oreochromis niloticus following challenge with Vibrio parahaemolyticus, DIS.-AQUAT.-ORG. 1997 vol. 30, no. 1, pp. 77-80 Red and black strains of tilapia Oreochromis niloticus were compared
for differences in non-specific immunity. Communally reared, naive fish
were challenged with the bacterium Vibrio parahaemolyticus. Serum lysozyme,
phagocyte activity and differential leucocyte numbers were examined in
pre-challenge and post-challenge fish. The percent cumulative mortality
in the 2 strains were not significantly different. There was a significant
effect of strain on serum lysozyme activity and phagocyte activity. Phagocyte
activity increased significantly following the disease challenge. Lymphocyte
numbers decreased significantly in the post-challenge sample, while thrombocytes,
neutrophils, and monocytes remained unchanged. This study provides the
first report of strain differences in non-specific immunity in tilapia.
Bang,-Jong-Deuk; Kim,-Jin-Woo; Lee,-Saeng-Dong; Park,-Su-Il; Chun,-Sae-Gyu; Jeong,-Choon-Soo; Park,-Jeong-Woo, DIS.-AQUAT.-ORG. 1996 vol. 26, no. 3, pp. 197-203 Antisera obtained from flounder Paralichthys olivaceus immunized with Edwardsiella tarda were fractionated using Sephacryl S-300 gel filtration. The flounder was found to contain various sizes of immunoglobulins (Igs) ranging from <200 to >700 kDa. These Igs were combined into 3 pools according to molecular weight; pool I consisted of high molecular weight (HMW) Igs of >700 kDa, pools II and III consisted of low molecular weight (LMW) Igs of 230 to 700 kDa (pool II) and <230 kDa (pool III). After being further purified by hydroxyapatite column chromatography and isoelectric focusing, HMW Ig in pool I and LMW Ig in pool III were compared with each other by SDS-PAGE under reducing conditions. They were found to be composed of 1 size of heavy chain and 2 sizes of light chain. While HMW Ig in pool I contained 68 kDa H chains and 22 kDa and 24 kDa L chains, LMW Ig in pool III contained 69 kDa H chains and 22 kDa and 26 kDa L chains. A set of 5 monoclonal antibodies (MAbs) against HMW Igs was prepared. The reactivities of these MAbs with Igs in the 3 pools were determined by enzyme linked immunosorbent assay (ELISA) and dot immunoassay. All 5 MAbs reacted strongly only to the HMW Igs. Results suggest that flounder Igs comprise LMW Igs as well as HMW Igs and the physicochemical and antigenical characteristics of LMW Igs are different from those of HMW Igs. Belotsky,-S.; Tinman,-S.; Shirak,-A.; Bejerano,-I.; Levy,-R.S.; Avtalion,-R.R., Spontaneous and stimulated chemiluminescence responses of blood leukocytes from healthy and infected tilapia,Israeli-Journal-of-Aquaculture; Bamidgeh [Isr-J-Aquacult; Bamidgeh] 1998 vol. 50, no. 2, pp. 67-72 A bimodal distribution in the spontaneous chemiluminescence (SpCL) measurements in naive tilapia leads us to divide the fish into low and high responder groups. Because of the homogeneity in both differential phagocyte cell counts and stimulation indexes, it is suggested that differences between the responder groups are due to innate intrinsic factors. Difference between these two groups is also displayed, in a less significant manner, in zymosan stimulated chemiluminescence (zStCL) that showed a weak linear regression factor (R super(2)=0.4756). In naive tilapia, Streptococcus difficile bacterin-stimulated chemiluminescence (bStCL) values were much lower than those obtained in zStCL. When sibling fish were infected with live S. difficile bacteria, a spectacular increase in bStCL values, with a high stimulation index of 42, was displayed on day 6 after infection. The SpCL and bStCL values increased considerably in diseased fish which displayed a serious symptomatology on day 36 after infection. However, fish that developed resistance to the disease showed lowered values in both SpCL and bStCL. The implication of these findings in the in vivo production of reactive oxygen radicals by phagocytic cells and their connection to resistance and susceptibility to disease are discussed in comparison to mammals. Boesen,-H.T.; Pedersen,-K.; Koch,-C.; Larsen,-J.L., Immune response of rainbow trout (Oncorhynchus mykiss) to antigenic preparations from Vibrio anguillarum serogroup O1, Fish-Shellfish-Immunol. 1997 vol. 7, no. 8, pp. 543-553 The humoral and cellular immune responses of rainbow trout were investigated following injection with formalin-killed Vibrio anguillarum in Freund's incomplete adjuvant (FIA) in terms of reactivity towards different antigen preparations of the bacterium. Vaccinated fish were compared with control fish that had been injected only with FIA. The antigen preparations used for the comparative studies were formalin-killed bacteria, extracellular products (ECP), outer membrane proteins (OMP) and cytoplasmic membrane proteins (CMP). Humoral antibody as measured by ELISA was detected with all antigen preparations. As evaluated by ELISPOT and by proliferation assays, leucocytes isolated from vaccinated fish reacted most strongly with the OMP preparation. This observation suggests the existence of undefined potent antigenic components among these proteins. In proliferation assays, the tested antigen preparations contained components that were mitogenic to cell cultures from unvaccinated fish. However, in terms of antibodies measured by ELISA and ELISPOT techniques, only vaccinated fish reacted with the V. anguillarum preparations. Bowser,-P.R.; Earnest-Koons,-K.A.; Wooster,-G.A.; LaPierre,-L.A.; Holzschu,-D.L.; Casey,-J.W. Experimental transmission of discrete epidermal hyperplasia in walleyes, J.-Aquat.-Anim.-Health 1998 vol. 10, no. 3, pp. 282-286 Two related retroviruses, designated walleye epidermal hyperplasia virus type 1 (WEHV1) and type 2 (WEHV2), have been identified in discrete epidermal hyperplasia skin lesions from adult walleyes Stizostedion vitreum. A transmission experiment was conducted in an effort to provide evidence for a viral etiology and to develop a model for pathogenesis studies. Cell-free filtrates derived from discrete epidermal hyperplasia lesions and known to harbor WEHV1 and WEHV2 were injected into young-of-the-year (age-0) walleyes. Discrete epidermal hyperplasia developed in 97% of walleyes inoculated with lesion filtrates; whereas those injected with a cell-free filtrate of normal walleye skin did not develop lesions. The presence of WEHV1 or WEHV2 was detected by polymerase chain reaction (PCR) assay. Amplified DNA products from the PCR assays indicated the presence of viral sequences in 100% and 69% of the skin lesions for WEHV2 and WEHV1, respectively. Bowser,-P.R.; Wooster,-G.A.; Getchell,-R.G., Transmission of Walleye Dermal Sarcoma and Lymphocystis via Waterborne Exposure, Journal-of-Aquatic-Animal-Health [J-Aquat-Anim-Health] 1999 vol. 11, no. 2, pp. 158-161 A study was conducted to determine if walleye dermal sarcoma could be
experimentally transmitted by waterborne exposure of tumor-free walleyes
Stizostedion vitreum to tumor-positive walleyes by cohabitation. Uninfected
walleyes were placed in a common raceway with tumor-positive fish for either
5 or 15 d. Direct contact between the two groups of fish was prevented
by two screen barriers. The exposed fish were then maintained in the laboratory
for a total of 20 weeks. Walleye dermal sarcoma developed in 89% and 71%
of the fish exposed for 5 and 15 d, respectively. There was no significant
difference (P > 0.05) in incidence of tumors between the two groups of
fish exposed for different lengths of time.
Buchmann,-K., Binding and lethal effect of complement from Oncorhynchus mykiss on Gyrodactylus derjavini (Platyhelminthes: Monogenea), AF: Department of Veterinary Microbiology, Section of Fish Diseases, Royal Veterinary and Agricultural University, 13 Buelowsvej, DK-1870 Frederiksberg C, Denmark, Dis.-Aquat.-Org. 1998 vol. 32, no. 3, pp. 195-200 A lethal effect of rainbow trout Oncorhynchus mykiss plasma containing intact complement factors on Gyrodactylus derjavini was demonstrated. It was associated with binding of complement factor C3 to certain carbohydrate-rich parasite structures. Parasites were exposed in vitro to plasma from rainbow trout. Untreated plasma from infected and uninfected fish showed lethal effects on the parasites within 1 h, whereas prior heat inactivation of complement prevented any parasite killing. Inhibition of the classical pathway by EGTA (ethyleneglycol-tetraacetic acid) treatment of plasma did not prevent the killing. It was shown by immuno-cytochemical assays that C3 bound directly to certain parasite structures (cephalic gland openings, parasite body, hamulus sheath). In contrast, no immunoglobulin binding was detected on the parasites. Lectin-binding assays indicated mannose-rich regions in the cephalic gland openings and lactose derivatives in the hamulus sheath. Galactose derivatives showed a general distribution in the glycocalyx. Thus, the antibody-independent plasma effect on the gyrodactylids are ascribed to the alternative complement pathway, and it is suggested that some carbohydrate epitopes on the parasites are involved in the C3 activation. Cain,-K.D.; LaPatra,-S.E.; Baldwin,-T.J.; Shewmaker,-B.; Jones,-J.; Ristow,-S.S., Characterization of mucosal immunity in rainbow trout Oncorhynchus mykiss challenged with infectious hematopoietic necrosis virus: Identification of antiviral activity, DIS.-AQUAT.-ORG. 1996 vol. 27, no. 3, pp. 161-172 Cutaneous and lower gastrointestinal (GI) tract mucus of rainbow trout Oncorhynchus mykiss were evaluated for immunological responses following exposure to infectious hematopoietic necrosis virus (IHNV). Juvenile rainbow trout (mean weight 5.4 g) were infected with IHNV (isolate 220-90) by waterborne exposure to 10 super(4) plaque forming units (pfu)/ml or by an injection challenge of 10 super(4) pfu/fish. Cutaneous mucus and lower GI tract washings were analyzed for virus neutralizing activity (antiviral activity) using a complement-dependent neutralization procedure. Antiviral activity was primarily detected in the GI tract and was highest in mock infected fish (not exposed to virus). This activity decreased rapidly over time in fish challenged by the injection route. Specific antibodies were not detected in cutaneous mucus or GI tract washings by ELISA. Virus was isolated in external and GI tract mucus from both waterborne and injection challenged fish, and showed significantly higher titers in fish challenged by the injection route. Histological examination of fish exposed to IHNV showed a moderate inflammatory response in the mucosal epithelial layer of the skin with minor focal areas of cellular necrosis in severely infected fish. When the study was repeated, in addition to cutaneous mucus and GI tract washings, serum was monitored for antibody production in juvenile rainbow trout (mean weight 2.4 g) out to 28 days post-exposure (dpe). Antiviral activity was confirmed in the GI mucus, and virus neutralizing antibodies were detected in the serum at 21 and 28 dpe in IHNV challenged fish. Antibodies in skin and GI mucus were not detected by ELISA. Virus antigen was visualized by immunohistochemistry in the kidney, spleen, liver, heart, pancreatic tissue, and smooth muscle of the stomach wall. Results from these experiments reveal innate mechanisms of viral resistance which may be important as a first line of defense against IHNV. Cardenas,-W.; Dankert,-J.R, Use of fluorescein isothiocyanate-lipopolysaccharide for the detection of lipopolysaccharide-binding proteins in crustacea, Journal-of-Shellfish-Research 1998 vol. 17, no. 1, p. 321 Current knowledge of crustacean immunology has failed to prove the presence of immunoglobulin molecules in the host defense system of these animals. However, these organisms must possess an innate defense system that can protect them against the invasion of potential pathogens in the environment. The pro-PO system has been shown to be a potential candidate of the innate defense mechanism of these animals. This enzymatic cascade is located within granules of the hemocytes and can be activated by molecules of microbial origin, such as zymosan and lipopolysaccharides (LPS). The active compound in zymosan (carbohydrates of yeast cell walls) is beta -1,3-glucan. The activation of the pro-PO system by this polymer seems to be mediated by a beta -1,3-glucan-binding protein found in the plasma of crayfish and shrimps. We have been able to detect a putative LPS-binding (LBP) protein from the plasma of the white river crayfish Procambarus zonangulus by using an indirect immunoblot technique. This protein was obtained from a weak cation exchange column, electrophoresed in a BioRad Mini Transblot, and electro-transferred to nitrocellulose paper. The putative LBP was detected by hybridizing the blotted proteins with FITC-LPS. Bound LPS was probed with a primary monoclonal anti-FITC antibody from mouse. Primary antibody was detected with Goat anti-mouse IgG (Fc specific) alkaline phosphatase conjugate. This technique depicted some unspecific binding when compared to a control (No FITC-LPS addition), but a single band of an apparent molecular mass of 128.6 kDa seems to bind specifically to FITC-LPS. This LBP has a similar molecular mass to the 100 kDa beta -1,3-glucan binding protein isolated from crayfish. Competitive binding experiments will be able to helps us determine which region of the LPS molecule (O-antigen polysaccharide or Lipid A) is recognized by the LBP. Castro,-R.; Couso,-N.; Obach,-A.; Lamas,-J. Effect of different beta -glucans on the respiratory burst of turbot (Psetta maxima) and gilthead seabream (Sparus aurata) phagocytes, Fish-and-Shellfish-Immunology [Fish-Shellfish-Immunol] 1999 vol. 9, no. 7, pp. 529-541 The in vitro effect of several beta -glucans on the respiratory burst of turbot and gilthead seabream phagocytes was examined. Three particulated beta -glucans from yeast, Saccharomyces cerevisiae and a particulate glucan from the fungus Schizophyllum commune were used. In some experiments, cells were incubated for 1 or 2 h with a mixture of glucan (0-500 mu g ml super(-1)) and nitroblue tetrazolium (NBT). In others, cells were preincubated with glucans for 1, 3 and 6 h and then incubated for 1 h with NBT with or without PMA. Cells from gilthead seabream and turbot responded similarly to glucans, and differences in activity depended mainly on the concentration of glucans, the length of incubation period of cells and glucan, and on the glucan used. Incubation of cells with glucans for 1 h directly induced a respiratory burst which increased with the concentration of glucan. However, after 2 h incubation a decrease in NBT reduction occurred at the highest glucan concentrations. An enhancement of the respiratory burst, which increased with the concentration of glucan, was also seen when cells were preincubated with glucans and then incubated with NBT without PMA. However, when PMA was added to the NBT solution, the highest NBT reduction was found at low glucan concentrations whereas with higher concentrations of glucan the NBT reduction decreased significantly. Thus high concentrations of glucan directly induced respiratory burst and led to exhaustion. Low concentrations of glucan primed the phagocytes to be capable of enhanced production of reactive oxygen species on subsequent activation of the respiratory burst. The former may increase disease susceptibility, the latter increase resistance. Chilmonczyk,-S.; Monge,-D. Flow cytometry as a tool for assessment of the fish cellular immune response to pathogens, Fish-and-Shellfish-Immunology [Fish-Shellfish-Immunol] 1999 vol. 9, no. 4, pp. 319-333 Flow cytometry provides rapid and reproducible methods for analysing fish leucocyte subpopulations and cellular immune functions. Assays devoted to the study of non-specific cellular defence mechanisms of rainbow trout were developed. In addition to the assessment of these defence mechanisms (phagocytic activity, oxidative burst and natural cytotoxicity assays), the modulations of cell responses under pathological conditions were analysed. Flow cytometric profiles of cell populations are representative of the organ from which the leucocytes originated. Diseases induce modifications of cell number and cell morphology. Study of cytograms provides helpful information on the fish reaction to pathogens. Thus the kidney inflammatory response characterizing proliferative kidney disease is mostly due to the proliferation of the kidney lymphocytes. Flow cytometric study of the cell cycle has allowed the demonstration of the in situ proliferation of the pronephros lymphocytes. Impairment of phagocytic activity occurred very early after VHSV experimental infection. Despite wide inter-fish variability, a reduced phagocytic activity was demonstrated in PKX-infected trout. The oxidative burst was not affected by either of these pathogens. Non-specific cytotoxic activity was observed in blood, pronephros, spleen and thymus. The levels of cytotoxicity varied considerably between individual fish. Even though the large inter-fish variability hampered the interpretation of the data, flow cytometry provides useful techniques for the study of immunological and clinical aspects of fish pathology. Espenes,-A.; Press,-C.M.; Reitan,-L.J.; Landsverk,-T. The trapping of intravenously injected extracellular products from Aeromonas salmonicida in head kidney and spleen of vaccinated and nonvaccinated Atlantic salmon, Salmo salar L., FISH-SHELLFISH-IMMUNOL. 1996 vol. 6, no. 6, pp. 413-426 Trapping of intravenously injected crude extracellular products from Aeromonas salmonicida was studied in Atlantic salmon, Salmo salar L. Frozen tissue from head kidney and spleen was collected 1 h and 8 h after the injection and localisation of A. salmonicida antigens, complement factor 3 and immunoglobulin was investigated in vaccinated and nonvaccinated fish using a double immunofluorescence staining technique. In the head kidney of vaccinated fish, A. salmonicida antigens was colocalised with complement factor 3 and immunoglobulin in sinusoidal cells. A weaker reactivity to A. salmonicida antigens was detected in colocalisation with complement factor 3 alone in nonvaccinated fish. In the spleen, ellipsoidal sheaths showed reactivity to A. salmonicida antigens in fish from both groups. In addition, the ellipsoids that trapped A. salmonicida antigens were stained for complement factor 3 and immunoglobulin in the vaccinated fish but stained for complement factor 3 alone in nonvaccinated fish. Computer-assisted morphometric analysis was further used to provide semi-quantitative estimates of A. salmonicida antigens and complement factor 3 in the head kidney. The estimated stained areas were significantly larger for the two antigens in vaccinated fish compared with nonvaccinated fish. Estepa,-A.; Coll,-J.M. An in vitro method to obtain T-lymphocyte-like
cells from the trou
We describe a methodology to obtain from the trout T-lymphocyte-like cell cultures showing in vitro antigen-dependent cell (ADC) proliferation. ADC cultures were developed from each of 3 outbred rainbow trout that survived two consecutive viral haemorrhagic septicaemia virus (VHSV) infections (an important salmonid fish disease in Europe). As stimulating antigen, we used a yeast recombinant form of the glycoprotein G (G4) of VHSV. No similar ADC cultures could be obtained from non-infected control trout kidney cells incubated in the presence of G4, confirming previously published observations. For long-term culture, and to overcome the absence of inbred trout populations, autologous haematopoietic adherent (Ad) cells were obtained and maintained from each individual trout kidney and periodically used as viral antigen-presenting cells (called G4-pulsed Ad cells) to autologous ADC cultures. The methodology to obtain trout ADC lines constitutes a new tool that would facilitate further studies on the comparative and developmental immunology of lower vertebrates. It could also be applied to research on fish vaccination and viral antigen-presentation mechanisms. Eya,-J.C.; Lovell,-R.T. Effects of dietary phosphorus on resistance of channel catfish to Edwardsiella ictaluri challenge, J.-Aquat.-Anim.-Health 1998 vol. 10, no. 1, pp. 28-34 Young-of-year channel catfish Ictalurus punctatus were fed an egg-white-based purified diet supplemented with serial concentrations of phosphorus from monosodium phosphate for 10 weeks; they were subsequently challenged by a 24-h immersion in a cell suspension of Edwardsiella ictaluri (10 super(5.4) cells/mL) at 25 plus or minus 1 degree C. Fish responses, which included weight gain, serum phosphorus concentration, serum alkaline phosphatase activity, mortality of challenged fish, and antibody production, were compared with dietary phosphorus concentration by regression analysis. Significant (P < 0.05) quadratic responses occurred in weight gain, serum alkaline phosphatase activity, mortality of challenged fish, and antibody production. Serum phosphorus concentration showed a significant linear response. The break points in the quadratic response curves showed that 0.38, 0.40, and 0.42% dietary phosphorus amounts were required for maximum alkaline phosphatase activity, survival from E. ictaluri challenge, and weight gain, respectively. This study showed that dietary phosphorus concentration influences the resistance of channel catfish to E. ictaluri challenge and that the dietary requirement for maximum weight gain is sufficient for maximum resistance against E. ictaluri challenge in young fish. Findlay,-V.L.; Munday,-B.L. Further studies on acquired resistance to amoebic gill disease (AGED) in Atlantic salmon, Salmo salar, Journal-of-Fish-Diseases [J-Fish-Dis] 1998 vol. 21, no. 2, pp. 121-125 Trials were designed to test the efficacy of freshwater treatments for amoebic gill disease (AGD) of Atlantic salmon, Salmo salar L., and the effect they had on the acquisition of resistance to reinfection with AGD. The first trial involved fish being given an industry-simulated freshwater bath of 2-3 h duration which simulated treatments given on farms. These fish did not display appreciable resistance to reinfection. The second trial involved four groups of fish which had been infected with and treated for AGD in a number of different ways. Once again the fish that had been infected for the first time and given a single 2-3 h freshwater bath and then re-exposed did not exhibit appreciable resistance to reinfection. In contrast, those fish that had been given a second 2-3 h freshwater bath and those that had been maintained in freshwater for 4 weeks displayed high levels of resistance. There is preliminary evidence to suggest that this resistance could be related to stimulation of the non-specific immune system. Ford,-L.A.; Barbash,-P.A.; Cipriano,-R.C. Control of furunculosis and enteric redmouth disease in sea-run Atlantic salmon broodstock in the Connecticut and Merrimack Rivers, Prog.-Fish-Cult. 1998 vol. 60, no. 2, pp. 88-94 The infectious bacterial disease furunculosis (causative agent, Aeromonas salmonicida), causes losses among sea-run Atlantic salmon Salmo salar that are captured from the Merrimack and Connecticut rivers and held for spawning. Enteric redmouth disease (ERM), caused by Yersinia ruckeri, has been a bacterial pathogen of lesser concern to managers of sea-run broodstock holding facilities throughout New England. Adult sea-run Atlantic salmon Salmo salar captured and transported to Richard Cronin National Salmon Station (Sunderland, Massachusetts), Nashua National Fish Hatchery (Nashua, New Hampshire), and Whittemore State Fish Hatchery (Waterford, Connecticut) during 1986-1992 were treated with oxolinic acid and a bacterin. The bacterin was developed against furunculosis and enteric redmouth disease. Among the 2,552 fish that were treated since 1986, 362 died and 65 (18%) of those fish had furunculosis. Among 206 untreated fish that were maintained as controls, 109 died and 63 (57.8%) had furunculosis. The reduction in mortality could not be attributed to either vaccine or antibiotic alone without further study. A 3-year study was designed to investigate if adult Atlantic salmon, undergoing the stress of migration, handling, and spawning, could mount a protective humoral immune response. Although the salmon were able to produce an agglutinin response, evidence was not found for production of a protective humoral response by these vaccinated Atlantic salmon. Fredriksen,-A.; Endresen,-C.; Wergeland,-H.I. Immunosuppressive effect of a low molecular weight surface protein from Renibacterium salmoninarum on lymphocytes from Atlantic salmon (Salmo salar L.), FISH-SHELLFISH-IMMUNOL. 1997 vol. 7, no. 4, pp. 273-282 The immunosuppressive effect of Renibacterium salmoninarum surface proteins, p22 and p57, on lymphocytes was studied. It has been shown earlier that the p57 protein suppresses the antibody production by salmonid B cells. In this study, the suppressive effect of a surface protein with a molecular weight of 22 kDa was compared with that of p57. The p22 and p57 proteins were isolated by gel filtration. The purity of the proteins was assessed by SDS-PAGE and Western blotting using a monoclonal antibody to p57 and a mouse antiserum to p22. Both p22 and p57 were found to suppress the specific antibody production by salmonid B cells in vitro, as measured by ELISPOT. The proteins also agglutinated salmon leucocytes. Gannam,-A.L.; Schrock,-R.M. Immunostimulants in Fish Diets,Journal-of-Applied-Aquaculture [J-Appl-Aquacult] 1999 vol. 9, no. 4, pp. 53-70 Various immunostimulants and their methods of application in fish culture
are examined in this review. Important variables such as life stage and
innate disease resistance of the fish; immunostimulant used, its structure
and mode of action; and the fish's environment are discussed. Conflicting
results have been published about the efficacy of immunostimulants in fish
diets. Some researchers have had positive responses demonstrated as increased
fish survival, others have not. Generally, immunostimulants enhance individual
components of the non-specific immune response but that does not always
translate into increased fish survival. In addition, immunostimulants fed
at too high a dose or for too long can be immunosuppressive.
Gray,-W.L.; Williams,-R.J.; Griffin,-B.R., Detection of channel catfish virus DNA in acutely infected channel catfish, Ictalurus punctatus (Rafinesque), using the polymerase chain reaction, Journal-of-Fish-Diseases [J-Fish-Dis] 1999 vol. 22, no. 2, pp. 111-116 Channel catfish virus (CCV) causes an acute haemorrhagic disease in channel catfish, Ictalurus punctatus (Rafinesque), fry and fingerlings. The present study describes a polymerase chain reaction (PCR)-based assay for detection of CCV DNA in the tissues of acutely infected juvenile catfish. The assay is rapid, sensitive and specifically detects CCV DNA derived from epidemiologically distinct viral isolates. The use of two independent PCR primers sets, each specific for particular CCV genes (open reading frames 8 and 59), provides a means to confirm the results and minimize false-positive results. The method identifies CCV DNA in several tissues of acutely infected fish, including the brain, blood, intestine, kidney and liver. The CCV PCR assay is useful for the diagnosis of acute CCV disease and for studies to investigate the molecular basis of CCV pathogenesis. Gudding,-R.; Lillehaug,-A.; Evensen, Recent developments in fish vaccinology, Veterinary-Immunology-and-Immunopathology [Vet-Immunol-Immunopathol] 1999 vol. 72, no. 1-2, pp. 203-212 During the last 10 to 20 years vaccination has become established as an important method for prevention of infectious diseases in farmed fish, mainly salmonid species. So far, most commercial vaccines have been inactivated vaccines administered by injection or immersion. Bacterial infections caused by Gram-negative bacteria such as Vibrio sp., Aeromonas sp., and Yersinia sp. have been effectively controlled by vaccination. With furunculosis, the success is attributed to the use of injectable vaccines containing adjuvants. Vaccines against virus infections, including infectious pancreatic necrosis, have also been used in commercial fish farming. Vaccines against several other bacterial and viral infections have been studied and found to be technically feasible. Pasteurellosis, streptococcosis (lactococcosis) and infections with iridoviruses are candidate diseases for control by immunoprophylaxis in the near future.The overall positive effect of vaccination in farmed fish is reduced mortality. However, for the future of the fish farming industry it is also important that vaccination contributes to a sustainable biological production with negligible consumption of antibiotics. A potential side-effect associated with injectable vaccines is local reactions in the peritoneal cavity.The paper presents recent developments in immunoprophylaxis of fish and some problems that should be addressed by the research community in the years to come. Hadge,-D.; Lachmann,-I.; Wagner,-U.; Drossler,-K. Characterization of core-oligosaccharide- and O-polysaccharide-specific monoclonal antibodies against Aeromonas salmonicida LPS binding to typical and atypical Aeromonas salmonicida isolates, AQUACULTURE 1997 vol. 157, no. 1-2, pp. 155-169 Monoclonal antibodies (mAbs) directed against Aeromonas salmonicida ssp. salmonicida (A+/F 216.1/83) lipopolysaccharide (LPS) were produced and characterized. The mAbs 4E8 and 10F4 recognized periodate-resistant epitope(s) on the O-polysaccharide (O-PS) chains, while mAbs 3G3, 2G11, and 7C4 reacted with periodate-sensitive epitopes(s) on the core-oligosaccharide (core-OS) region of LPS detected by ELISA and immunoblotting. The mAb 7F5 bound to O-PS epitope(s), too, but the recognized epitope(s) are partly periodate-resistant and partly periodate-sensitive. The three core-OS- and the three O-PS-specific mAbs recognized epitopes of LPS from all tested ten typical and five atypical A. salmonicida isolates when assayed by ELISA or immunoblotting, whereas only the three O-PS-specific mAbs reacted in a dot blot assay. All the O-PS- and the core-OS-specific mAbs bound to the high-molecular sugar component H2 detected in the LPS fractions of all the A. salmonicida isolates used (SDS-PAGE and immunoblotting). Consequently, these H2-components contain core-OS- and O-PS-epitopes. Using the O-PS-specific mAbs, no reaction was obtained with LPS from bacterial culture supernatants or whole cell lysates of two A. hydrophila isolates (ELISA, immunoblotting, dot blotting). However, the core-OS-specific mAbs reacted with A. hydrophila LPS (ELISA, immunoblotting), while dot blot studies did not result in binding of those mAbs to the bacterial cells. The described A. salmonicida LPS-specific mAbs with O-PS- and core-OS-specificity represent valuable tools for using in serodiagnosis or research. Hedrick,-R.P.; El-Matbouli,-M.; Adkison,-M.A.; MacConnell,-E. Whirling disease: re-emergence among wild trout, Immunological-Reviews [Immunol-Rev] 1998 vol. 166, pp. 365-376 Whirling disease of rainbow trout is caused by Myxobolus cerebralis, a myxozoan parasite possessing a life cycle well adapted to the natural environments where salmonid fish are found. Whirling disease was first described in Europe in 1898 among farmed rainbow trout but recent occurrences have been devastating to wild trout in North America. The disease is considered a major threat to survival of wild rainbow trout in the intermountain west of the United States. Difficulties in containing the spread and potentially eliminating the pathogen are tied to features of a complex life cycle involving two hosts, the salmonid fish and an aquatic oligochaete. Details of the morphologic development of the parasite have been described in each host but only now are we beginning to appreciate the breadth of interactions between these developmental forms and the sequential responses of the host. Fundamental mechanisms of the recognition and attachment of the parasite to the hosts, how host immunity is evaded and the unknown influences of environmental factors all contribute to a rather poor understanding of the biology of the parasite. Although the biology and ecology of the salmonid host are better known than for the oligochaete host, our knowledge is inadequate to interpret their complex interactions with the parasite. This uncertainty precludes the development of effective management activities designed to enhance the viability and productivity of wild trout populations in M. cerebralis-positive river systems. Improving our understanding of the hosts, the parasite and the environmental factors determining their interaction should provide for more focused and effective control methods for containing the spread and devastating effects whirling disease is causing to our wild trout populations. Hogan,-R. Antiviral Cytotoxic Cells in the Channel Catfish, Dissertation-Abstracts-International-Part-B:-Science-and-Engineering [Diss-Abst-Int-Pt-B-Sci-and-Eng] 1999 vol. 60, no. 4, p. 1425 The goals of this research were: (1) to determine if virus-infected cells were lysed by catfish peripheral blood leukocyte (PBL) effectors, (2) to examine the mechanism(s) used to lyse lymphoid target cells, and (3) to establish a model system with which to study viral antigen-specific, MHC-restricted CTLs. Initial experiments showed that PBLs possessed the ability to distinguish "self" (autologous) from "non-self" (allogeneic). Thus autologous cells were spared lysis whereas allogeneic cells were readily lysed. However, after infection with channel catfish virus (CCV), both allogeneic and autologous target cells were susceptible to PBL-mediated lysis. Subsequent depletion experiments showed that removal of alloreactive effectors (ARE) from PBLs resulted in decreased killing of uninfected allogeneic targets. In contrast, the remaining PBLs retained the ability to lyse CCV-infected allogeneic targets indicating the presence of a population of effector cells which recognized and lysed virus-infected cells. Furthermore, infection with UV-inactivated CCV and treatment of CCV-infected target cells with acycloguanosine (ACG) indicated that the production of early viral gene products was sufficient for enhanced PBL-mediated lysis. These data suggest that the peripheral blood of the channel catfish contains two populations of cytotoxic cells: one which recognizes and kills allogeneic cells, and another which recognizes and kills virus-infected cells. Recovery from disruption of natural killer-like activity of leucocytes due to Zn or Mn deficiency in rainbow trout, Oncorhynchus mykiss (Walbaum), by the oral administration of these elements Inoue,-M.; Satoh,-S.; Maita,-M.; Kiron,-V.; Okamoto,-N., Journal-of-Fish-Diseases [J-Fish-Dis] 1998 vol. 21, no. 3, pp. 233-236 Nutrition is linked to immune functions in fish as in other animals. Several studies have revealed the dietary dependence of immunosurveillance. Natural killer (NK)-like activity of leucocytes has been reported in some species of fish active against protozoans, virus-infected cells, and certain cultured tumour cells. Recently, Kiron, Gunji, Okamoto, Satoh, Ikeda & Watanabe (1993) reported that the feeding of zinc-deficient diets to rainbow trout caused lower NK activities. In this study, the recovery from derangement of NK-like activity of leucocytes due to a deficiency of zinc (Zn) or manganese (Mn) in rainbow trout was studied by oral administration of these elements. Compositions of the experimental diets and the macro and trace element mixtures used are shown in Tables 1 & 2. White fish meal was used as a protein source. The essential element mixture used was the Ogino salt mixture, which satisfies the trace element requirements of rainbow trout at a dose of 5% of the diet (w/w). The Zn- and Mn-deficient diets were prepared by deleting the respective elements from the trace element-sufficient diet. Rainbow trout, Oncorhynchus mykiss (Walbaum), of both sexes were used for tests of recovery of NK-like activity. Fish were kept in 581 tanks with running water at a temperature of 15 plus or minus 1 degree C in our laboratory for 3 months and fed a commercial diet to satiation twice a day. To prepare trace element-deficient fish, prereared fish (2.1 g mean body weight) were fed Zn- or Mn-deficient diets for one year (groups Z and M, respectively). The diets were then changed to a trace element-sufficient diet. Control fish were fed a trace element-sufficient diet during the experiment (group C). At the time the diets were changed, the mean body weight was 228 g in group Z, 300 g in group M, and 326 g in group C. NK-like activity was measured just before the change in the diets and 4, 8 and 16 weeks after changing the diets. Jenkins,-J.A.; Klesius,-P.H. Elicitation of macrophages from the peritoneal cavity of channel catfish, J.-Aquat.-Anim.-Health 1998 vol. 10, no. 1, pp. 69-74 Four chemicals were evaluated for elicitation of macrophages in peritoneal cavities of 250-300-g healthy channel catfish Ictalurus punctatus. Cellular exudates were collected at 3, 5, 7, 10, 14, and 20 d following intraperitoneal injections with squalene, Freund's incomplete adjuvant (FIA), goat serum, thioglycollate, or as a control, phosphate-buffered saline. Injection with either squalene or FIA induced significantly greater (P less than or equal to 0.0001) macrophage recruitment than the other chemicals. The effectiveness of squalene and FIA was compared further by macrophage collection daily for 7 d. Squalene and FIA elicited similarly high macrophage responses (P less than or equal to 0.0450), the highest being 3.43 x 10 super(6) macrophages/mL (SE, 2.4 x 10 super(6)) at 99% purity at day 2 and 2.1 x 10 super(6) macrophages/mL (SE, 0.7 x 10 super(6)) at day 14 at 80% purity, respectively. In both experiments, the time after injection was not statistically significant, nor was there an interaction between time and chemicals. The occurrence of cells other than macrophages decreased with time to yield macrophage recoveries of 47-99% for squalene and 30-80% for FIA. Two subsets of macrophages were observed by means of flow cytometry. As demonstrated by chemiluminescence, the squalene-elicited cells produced high-energy oxygen compounds important to the phagocytic process. Jia,-X.; Patrzykat,-A.; Devlin,-R.H.; Ackerman,-P.A.; Iwama,-G.K.; Hancock,-R.E.W. Antimicrobial peptides protect coho salmon from Vibrio anguillarum infections,m Applied-and-Environmental-Microbiology [Appl-Environ-Microbiol] 2000 vol. 66, no. 5, pp. 1928-1932 Fish losses from infectious diseases are a significant problem in aquaculture worldwide. Therefore, we investigated the ability of cationic antimicrobial peptides to protect against infection caused by the fish pathogen Vibrio anguillarum. To identify effective peptides for fish, the MICs of certain antimicrobial peptides against fish pathogens were determined in vitro. Two of the most effective antimicrobial peptides, CEME, a cecropin-melittin hybrid peptide, and pleurocidin amide, a C-terminally amidated form of the natural flounder peptide, were selected for in vivo studies. A single intraperitoneal injection of CEME did not affect mortality rates in juvenile coho salmon infected with V. anguillarum, the causative agent of vibriosis. Therefore, the peptides were delivered continuously using miniosmotic pumps placed in the peritoneal cavity. Twelve days after pump implantation, the fish received intraperitoneal injections of V. anguillarum at a dose that would kill 50 to 90% of the population. Fish receiving 200 mu g of CEME per day survived longer and had significantly lower accumulated mortalities (13%) than the control groups (50 to 58%). Fish receiving pleurocidin amide at 250 mu g per day also survived longer and had significantly lower accumulated mortalities (5%) than the control groups (67 to 75%). This clearly shows the potential for antimicrobial peptides to protect fish against infections and indicates that the strategy of overexpressing the peptides in transgenic fish may provide a method of decreasing bacterial disease problems. Kent,-M.L.; Dawe,-S.C.; Speare,-D.J. .Resistance to reinfection in chinook salmon Oncorhynchus tshawytscha to Loma salmonae (Microsporidia), Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1999 vol. 37, no. 3, pp. 205-208 Chinook salmon Oncorhynchus tshawytscha were experimentally infected per os with Loma salmonae and held in flow-through seawater tanks at 12 to 14 degree C. The fish exhibited 100% infection when first examined at 7 wk post initial exposure (p.e.), and by 20 wk p.e. they had completely recovered from gill infections. The recovered fish were then reexposed the following week. All of these fish showed strong protection to new L. salmonae infections, while naive fish exposed to the same inoculum developed the infection. Most of the re-exposed fish exhibited a few free spores or spores within phagocytes in the kidney interstitium at 20 to 29 wk p.e., but xenomas were not detected in either the gills or visceral organs. The kidney is the primary site of reticulo-endothelial activity, and thus these spores were likely deposited in the kidney by entrapment by fixed macrophages. It is possible that these spores provide immunologic stimuli to reinforce the resistance to new L. salmonae infections. Khangarot,-B.S.; Rathore,-R.S.; Tripathi,-D.M. Effects of Chromium on Humoral and Cell-Mediated Immune Responses and Host Resistance to Disease in a Freshwater Catfish, Saccobranchus fossilis (Bloch), Ecotoxicology-and-Environmental-Safety [Ecotoxicol-Environ-Saf] 1999 vol. 43, no. 1, pp. 11-20 The effects of subtoxic levels of Cr on humoral and cell-mediated immune responses, blood parameters, susceptibility to bacterial (Aeromonas hydrophila) infection, and macrophage activity in the freshwater air-breathing Asian catfish, Saccobranchus fossilis, during a 28-day exposure were examined by a static bioassay test procedure. At 0.1, 1.0, and 3.2 mg / liter Cr, dose-dependent Cr accumulation in kidney, liver, and spleen was observed at the end of the experiment. Chromium exposure caused a significant change in spleen to body weight ratio. Fish exposed to Cr concentrations had lower antibody titer values, reduced numbers of splenic and kidney plaque-forming cells, and higher counts of splenic lymphocytes but reduced counts of kidney cells when compared with the control group. At 0.1, 1.0, and 3.2 mg /liter Cr, dose-dependent decreases in red blood cell counts, hemoglobin content, and packed cell volume were observed. Differential leukocyte counts revealed that Cr exposure caused a significant decrease in large and small lymphocytes, whereas neutrophils and thrombocytes increased. Effects of Cr exposure to mitogen (Con A) on proliferation of splenic and pronephric lymphocytes suggests a decrease in mitogenic response. The eye-allograft rejection time, as a parameter of cell-mediated immunity, was statistically increased at 1.0 and 3.2 mg/liter Cr. Fish exposed to Cr for 28 days exhibited higher susceptibility to A. hydrophila infection than control fish. The results suggest that Cr exposure reduced the resistance of catfish to bacterial infections. The phagocytic activity of splenic and pronephros macrophages was examined in vitro and found to be significantly decreased. Klesius,-P.H.; Sealey,-W.M. Chemotactic and chemokinetic responses of channel catfish macrophages to exoantigen from Edwardsiella ictaluri, J.-AQUAT.-ANIM.-HEALTH 1996 vol. 8, no. 4, pp. 314-318 The ability of Edwardsiella ictaluri to attract macrophages of channel catfish Ictalurus punctatus was investigated. Exoantigen from E. ictaluri was tested for macrophage chemotactic activities both in vitro and in vivo. The exoantigen was chemotactic and chemokinetic for macrophages in vitro. Peritoneal injection of 750 mu g of exoantigen protein into normal (E. ictaluri-free) channel catfish induced a marked increase in macrophage accumulations at 24 and 48 h. Neutrophil accumulation did not occur at the injection sites. Edwardsiella ictaluri exoantigen attracts macrophages, and this attraction may play an important role in macrophage responses during E. ictaluri infections. TypeLaPierre,-L.A.; Holzschu,-D.L.; Bowser,-P.R.; Casey,-J.W. Sequence and Transcriptional Analyses of the Fish Retroviruses Walleye Epidermal Hyperplasia Virus, Journal-of-Virology [J-Virol] 1999 vol. 73, no. 11, pp. 9393-9403 Walleye epidermal hyperplasia virus types 1 and 2 (WEHV1 and WEHV2 respectively) are associated with a hyperproliferative skin lesion on walleyes that appears and regresses seasonally. We have determined the complete nucleotide sequences and transcriptional profiles of these viruses. WEHV1 and WEHV2 are large, complex retroviruses of 12,999 and 13,125 kb in length, respectively, that are closely related to one another and to walleye dermal sarcoma virus (WDSV). These walleye retroviruses contain three open reading frames, orfA orfB, and orfC, in addition to gag, pol, and env. orfA and orfB are adjacent to one another and located downstream of env. The OrfA proteins were previously identified as cyclin D homologs that may contribute to the induction of cell proliferation leading to epidermal hyperplasia and dermal sarcoma. The sequence analysis of WEHV1 and WEHV2 revealed that the OrfB proteins are distantly related to the OrfA proteins, suggesting that orfB arose by gene duplication. Presuming that the precursor of orfA and orfB was derived from a cellular cyclin, these genes are the first accessory genes of complex retroviruses that can be traced to a cellular origin. WEHV1, WEHV2, and WDSV are the only retroviruses that have an open reading frame orfC, of considerable size (ca. 130 amino acids) in the leader region preceding gag. While we were unable to predict a function for the OrfC proteins, they are more conserved than OrfA and OrfB, suggesting that they may be biologically important to the viruses. The transcriptional profiles of WEHV1 and WEHV2 were also similar to that of WDSV; Northern blot analyses detected only low levels of the orfA transcripts in developing lesions whereas abundant levels of genomic, env, orfA and orfB transcripts were detected in regressing lesions. The splice donors and acceptors of individual transcripts were identified by reverse transcriptase PCR. The similarities of WEHV1, WEHV2, and WDSV suggest that these viruses use similar strategies of viral replication and induce cell proliferation by a similar mechanism. Lindenstrom,-T.; Buchmann,-K. Dexamethasone treatment increases susceptibility of rainbow trout, Oncorhynchus mykiss (Walbaum), to infections with Gyrodactylus derjavini Mikailov, Journal-of-Fish-Diseases [J-Fish-Dis] 1998 vol. 21, no. 1, pp. 29-38 The parasite population dynamics of a Danish isolate of Gyrodactylus derjavini Mikailov, 1975 on immunosuppressed fry of rainbow trout, Oncorhynchus mykiss (Walbaum), were investigated and compared with immunocompetent fry. Immunosuppression was induced 14 days prior to infection by intraperitoneal injections of dexamethasone (fluoro-methyl-prednisolone). Treated and untreated fish were infected by cohabitation with Gyrodactylus-infected donorfish, carrying 4-week-old infections. Initial infections did not differ between the two groups. However, parasite populations increased significantly faster and reached significantly higher levels in the dexamethasone-treated group from day 13 post-exposure and during the following 3 weeks when compared with the untreated group. Microhabitat distribution of parasites on the two host groups differed from day 20 post-exposure, which could indicate a different host response to infection. Changes in the density of superficial mucous cells in the caudal fins were investigated during the course of infection. No differences in mucous cell density between untreated and dexamethasone-treated groups were found. Recombinant vaccines: experimental and applied aspects Lorenzen,-N.; Lapatra,-S.E. Immunity to rhabdoviruses in rainbow trout: the antibody response, Fish-and-Shellfish-Immunology [Fish-Shellfish-Immunol] 1999 vol. 9, no. 4, pp. 345-360 Interactions between host and pathogen, as in the case of fish pathogenic viruses, represent interesting models for analyses of the relationships between structure and function of the teleost immune system. Two salmonid rhabdoviruses, IHNV and VHSV, have received special attention due to their occasional detrimental effect on rainbow trout farming. Research efforts have been focused on understanding the mechanisms involved in protective immunity. Several specific and nonspecific cellular and humoral parameters are believed to be involved, but only the antibody response has been characterised in detail so far. Analysis of the specificity of anti-virus trout antibodies has been complicated by a generally insufficient ability of the antibodies to bind the viral proteins in assays such as immunoblotting. However, other assays, specifically designed for detection of fish anti IHNV/VHSV antibodies, have demonstrated that rainbow trout can produce specific and highly functional antibodies that are able to neutralise virus pathogenicity in vitro as well as in vivo . The apparently more restricted antibody response to IHNV and VHSV antigens in fish compared to mammals could possibly be explained by different kinds of epitopes being differently immunogenic in fish and in mammals. Also, it may be assumed that the requirements for the assay-antigens in terms of antigenicity, may differ for mammals and fish. The present text includes an initial presentation of the pathogens, followed by basic and applied aspects of antibody response and antibody reactivity with IHNV and VHSV antigens. Lygren,-B.; Sveier,-H.; Hjeltnes,-B.; Waagbo,-R. Examination of the immunomodulatory properties and the effect on disease resistance of dietary bovine lactoferrin and vitamin C fed to Atlantic salmon (Salmo salar) for a short-term period, Fish-and-Shellfish-Immunology [Fish-Shellfish-Immunol] 1999 vol. 9, no. 2, pp. 95-107 Atlantic salmon were fed commercial diets with or without supplementation of 140 mg bovine lactoferrin (Lf) kg super(-1) feed, and with 150 or 1000 mg vitamin C (ascrobic acid, AA) equivalents/kg feed using AA polyphosphate, in a 2 super(2)-factorial design for 19 days. Following the dietary treatment the experimental fish were challenged with Aeromonas salmonicida ssp. salmonicida or infectious salmon anaemia (ISA) virus. The specific growth rates were unaffected by the dietary treatments. Liver AA concentration was increased in all dietary groups demonstrating that the fish had been eating. Liver iron and head kidney catalase did not differ significantly between the groups. Lysozyme activity in serum and head kidney, spontaneous and antibody specific serum complement-mediated haemolysis as well as phagocytic chemiluminescent responses were all unaffected by the differences in dietary composition. In the furunculosis and ISA challenge experiments there were no significant differences in cumulative mortality between the groups. In conclusion, under the experimental conditions used in this study we were not able to detect any effects on non-specific immunity or disease resistance after feeding Atlantic salmon Lf and/or AA supplemented diets for a short period, but masking of potential effects due to low water temperature (8.4 degree C) and limited feed intake cannot be excluded. Lunden,-T.; Miettinen,-S.; Lonnstrom,-L.G.; Lilius,-E.M.; Bylund,-G. Effect of florfenicol on the immune response of rainbow trout (Oncorhynchus mykiss), Veterinary-Immunology-and-Immunopathology [Vet-Immunol-Immunopathol] 1999 vol. 67, no. 4, pp. 317-325 Florfenicol, a drug effective against several bacterial diseases of fish, was tested for possible immunomodulatory effects. The aim of the study was to follow the kinetics of the immune response after vaccination with simultaneous oral antibiotic treatment. The fish were immunised with a commercial oil-based divalent (furunculosis /vibriosis) vaccine and were simultaneously given oral antibiotic treatment. The specific immune response was monitored by analysing the levels of specific antibodies with ELISA. As an indicator of the non-specific immune response the phagocytic activity of circulating leucocytes was measured by a chemiluminescence assay. Total circulating leucocyte counts and differentials were also monitored. The disease resistance was evaluated by challenge tests at the end of the experiment. The results showed that florfenicol did not have any significant effect on antibody production and circulating leucocyte levels but caused a suppression in chemiluminescence response/phagocytic cell 5-6 weeks after vaccination. The survival after challenge was slightly suppressed by the florfenicol treatment. The RPS-value for the vaccinated group was 98% and for the florfenicol-treated group was 88%. Marsden,-M.J.; Collins,-E.; Secombes,-C.J. .Factors influencing the clearance of a genetically attenuated ( Delta aroA) strain of Aeromonas salmonicida from rainbow trout Oncorhynchus mykiss, DIS.-AQUAT.-ORG. 1996 vol. 27, no. 2, pp. 89-94 Clearance of an aroA deletion mutant of Aeromonas salmonicida from tissues of rainbow trout Oncorhynchus mykiss was studied under a number of conditions. Following intraperitoneal injection into trout, the bacteria were rapidly found in all tissues/body fluids examined (kidney, spleen, liver, heart, muscle, blood and peritoneal fluid), with highest recoveries in the spleen and peritoneal fluid. Whilst in some tissues numbers increased over the first few days post-injection, in general clearance had been effected within 7 to 9 d at 16 degree C regardless of the inoculum dose. However, with the highest dose (2 x 10 super(9) bacteria per fish) used some fish mortalities occurred. Temperature was shown to influence clearance, with low water temperatures significantly delaying clearance. Whole body homogenates confirmed that some increase in bacterial numbers occurred in vivo, after an initial and immediate dramatic drop in bacterial viability. Finally, a 2 h crowding stress which significantly elevated blood glucose levels had no effect upon clearance. These results are discussed with respect to the possible use of this deletion mutant as a live vaccine in aquaculture. Tort,-M.J.; Kuhl,-A.J.; Wooster,-G.A.; Bowser,-P.R. Modification of walleyes Stizostedion vitreum tolerance to hydrogen peroxide bath treatment, Journal-of-the-World-Aquaculture-Society [J-World-Aquacult-Soc] 1998 vol. 29, no. 4, pp. pp.499-504 Hydrogen peroxide is being evaluated for its potential as a therapeutic compound for a variety of external disease organisms of fish. The value of hydrogen peroxide as a therapeutic compound for use in walleye Stizostedion vitreum culture has been questioned due to the high sensitivity (i.e., high mortality) of walleyes to this compound. We conducted bioassays and histopathological studies to determine if exposure of walleye to hydrogen peroxide bath treatments would result in increased tolerance to subsequent exposure. Test fish exhibited increased tolerance to hydrogen peroxide after initial exposures. This phenomenon of increased tolerance of walleyes to hydrogen peroxide may be of value in the development of management strategies for the successful treatment of fish diseases. Trobridge,-G.D.; Chiou,-P.P.; Leong,-J.-A.C Cloning of the rainbow trout (Oncorhynchus mykiss) Mx2 and Mx3 cDNAs and characterization of trout Mx protein expression in salmon cells, J.-VIROL. 1997 vol. 71, no. 7, pp. 5304-5311 Two rainbow trout (Oncorhynchus mykiss) Mx cDNAs were cloned by using RACE (rapid amplification of cDNA ends) PCR and were designated RBTMx2 and RBTMx3. The deduced RBTMx2 and RBTMx3 proteins were 636 and 623 amino acids in length with molecular masses of 72 and 70.8 kDa, respectively. These proteins, along with the previously described RBTMx1 protein (G. D. Trobridge and J. A. Leong, J. Interferon Cytokine Res. 15:691-702, 1995), have between 88.7 and 96.6% identity at the amino acid level. All three proteins contain the tripartite GTP binding domain and leucine zipper motif common to Mx proteins. A monospecific polyclonal antiserum to an Escherichia coli-expressed fragment of RBTMx3 was generated, and that reagent was found to react with all three rainbow trout Mx proteins. Subsequently, endogenous Mx production in RTG-2 cells induced with poly(IC) double-stranded RNA was detected by immunoblot analysis. The cellular localization of the rainbow trout proteins was determined by transient expression of the RBTMx cDNAs in CHSE-214 (chinook salmon embryo) cells. A single-cell transient-transfection assay was used to examine the ability of each Mx cDNA clone to inhibit replication of the fish rhabdovirus infectious hematopoietic necrosis virus (IHNV). No significant inhibition in the accumulation of the IHNV nucleoprotein was observed in cells expressing either trout Mx1, Mx2, or Mx3 in transiently transfected cells. Van-Muiswinkel,-W.B.; Wiegertjes,-G.F.; Stet,-R.J.M The influence of environmental and genetic factors on the disease resistance of fish, Aquaculture 1999 vol. 172, no. 1-2, pp. 103-110 Despite impressive progress in fish farming during the last years, the impact of fish diseases is still an important problem in aquaculture. Current methods to control diseases consist, among others, of medication or eradication of diseased animals in combination with disinfection of facilities. Another alternative approach is to prevent diseases by improving the immune capacity of fish by vaccination or genetic selection. It is known from studies in mammals, that a limited number of major genes, including the major histocompatibility complex (MHC), is involved in the regulation of the immune response. The existence of a classic MHC in fish is still a matter of debate. Recently, the dogma of the MHC being a single chromosomal region was challenged by investigations into the segregation of MHC genes in fish and other vertebrates. The observed absence of linkage between class I and class II major histocompatibility genes in fish would allow for an independent segregation of immunological traits associated with cytotoxic responses to virus infection (class I) or humoral responses to bacteria (class II). This could be an explanation why in challenge experiments the resistance to one disease is not necessarily correlated with resistance to another disease. Weiland,-L.K.; Mesa,-M.G.; Maule,-A.G. Influence of Infection with Renibacterium salmoninarum on Susceptibility of Juvenile Spring Chinook Salmon to Gas Bubble Trauma, Journal-of-Aquatic-Animal-Health [J-Aquat-Anim-Health] 1999 vol. 11, no. 2, pp. 123-129 During experiments in our laboratory to assess the progression and severity of gas bubble trauma (GBT) in juvenile spring chinook salmon Oncorhynchus tshawytscha, we had the opportunity to assess the influence of Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease, on the susceptibility of salmon to GBT. We exposed fish with an established infection of Rs to 120% total dissolved gas (TDG) for 96 h and monitored severity of GBT signs in the fins and gills, Rs infection level in kidneys by using an enzyme-linked immunosorbent assay (ELISA), and mortality. Mortality occurred rapidly after exposure to 120% TDG, with a LT20 (time necessary to kill 20% of the population) of about 37 h, which is at a minimum about 16% earlier than other bioassays we have conducted using fish that had no apparent signs of disease. Fish that died early (from 31 to 36 h and from 49 to 52 h) had significantly higher infection levels (mean plus or minus SE ELISA absorbance = 1.532 plus or minus 0.108) than fish that survived for 96 h (mean plus or minus SE ELISA absorbance = 0.828 plus or minus 0.137). Fish that died early also had a significantly greater number of gill filaments occluded with bubbles than those that survived 96 h. Conversely, fish that survived for 96 h had a significantly higher median fin severity ranking than those that died early. Our results indicate that fish with moderate to high levels of Rs infection are more vulnerable to the effects of dissolved gas supersaturation (DGS) and die sooner than fish with lower levels of Rs infection. However, there is a substantial amount of individual variation in susceptibility to the apparent cumulative effects of DGS and Rs infection. Collectively, our findings have important implications to programs designed to monitor the prevalence and severity of GBT in juvenile salmonids in areas like the Columbia River basin, and perhaps elsewhere. Yin,-Z.; Lam,-T.J.; Sin,-Y.M. Cytokine-mediated antimicrobial immune response of catfish, Clarias gariepinus, as a defence against Aeromonas hydrophila, FISH-SHELLFISH-IMMUNOL. 1997 vol. 7, no. 2, pp. 93-104 The proliferative response of head kidney (HK) leucocytes from catfish
(Clarias gariepinus) immunised against Aeromonas hydrophila strain PPD
134/91 was significantly increased compared with that of naive HK leucocytes
using whole bacterial cells as the in vitro stimulant. A correlation between
the proliferation of immune HK leucocytes and the production of macrophage-activating
factor (MAF) was also observed. The production of reactive oxygen and nitrogen
intermediates from the resident phagocytes of control fish was enhanced
after incubating with the MAF-containing supernatants for 48 h. Both cytokine-containing
supernatants and the incubated phagocytes of the immune fish also exhibited
a significant increase of bactericidal activity. The study also showed
that nitric oxide (NO) production and microbicidal activity of the antigen-activated
phagocytes were partially blocked with N super(G)-monomethyl-L-arginine
(N super(G)-MMLA), suggesting that NO might be an important antimicrobial
effector in fish phagocytes as in mammals.
Ajuzie,-C.C. Aspects of behavior in European sea bass juveniles, Aquacult.-Mag. 1998 vol. 24, no. 2, pp. 37-44 There has been, in recent times, an enormous progress in fish propagation techniques. This has contributed immensely to the successful farming of commercially important species. However, heavy larval mortality and slow growth rates during the initial culture period are still problems militating against profitable fish culture. The behavior of juvenile fish may be a significantly influencing factor that help to compound this problem. Hence, fish behavioral studies are indeed necessary for the aquaculturist; for fish behavior can be used as an indicator which can give the fish farmer an early warning on changes in environmental or health conditions. The European sea-bass Dicentrarchus labrax, hereafter referred to as sea-bass, is a commercially important species that is extensively raised on the European and Mediterranean coasts. There is a great deal of information on the reproductive biology, growth and nutrition of this animal. But information on its behavior is scanty. Genetically modified fish in aquaculture: technical, environmental and management considerations, Biotecnologia-Aplicada [Biotecnol-Apl] 1999 vol. 16, no. 2, pp. 127-130 Genetically modified (GM) fish offer new possibilities for the improvement of production in aquaculture. It allows the introduction of novel traits or the improvement of old ones, in such a way that is out of reach for classical selection breeding. Examples of genes with commercial potential are among those which control growth, disease resistance, freeze tolerance, sexual maturation, food quality and food preservation parameters. Consumption of GM fish does not represent a health risk in principle. The safety of GM food is dependent on the character of the transgene, the transgene product and the new phenotype. Ethics and animal protection concerns demand the development of healthy fish only. Environmental safety calls for efficient biological containment in order to minimize possible effects caused by released farm animals. Improvements of disease control will support both production economy and the environment, in case of escapes. Since aquaculture includes both marine and fresh water species, it can be developed as new food production strategies in most countries all over the world. To avoid large-scale technology transfer failures, it is important to adapt to the regional and local needs. This calls for international research collaboration aiming at regional and local competence development sufficient for the technology implementation. Bailey,-J. Genetic issues concerning the use of foreigh strains in salmon aquaculture in Eastern North America, Northeast Aquaculture Conf. & Expo., Rockport, Maine (USA), 18-19 Nov 1998, Abstracts-of-the-First-Annual-Northeast-Aquaculture-Conference-and-Exposition Barber,-B.-(ed.) 1998 p. 73 The viability of salmon aquaculture depends upon the operators' ability to remain globally competitive by carefully managing production costs. Worldwide, rapid advances are being made with respect to husbandry, nutrition, health management, and the development of selected, domestic strains. In New Brunswick, the salmon aquaculture industry is limited to the Saint John River strain, a restriction industry perceives as a hindrance to their ability to remain competitive. The regulation was enacted to minimize the risks posed to local wild salmon stocks by interactions with escaped, farmed salmon. The perceived risks include the possibility of: 1) introducing and spreading exotic diseases and/or parasites (fish health interactions); 2) altering genetic adaptivity in wild stocks (genetic interactions); 3) displacing wild stocks with escaped, domestic salmon (environmental interactions). In many cases, there is insufficient quantitative data to determine such risk. As a result, the regulatory approach has been conservative and restrictive. This paper will demystify and concentrate on genetic interactions. It will identify conclusions that have been drawn from sound scientific evidence and separate them from those that arose through passion and/or more forceful opinion. Barlow,-S. Fish oil: Technology, nutrition and marketing - A postscript, Fish-Oil:-Technology,-Nutrition-and-Marketing Hamilton,-R.J.;Rice,-R.D.-eds. PJ-Barnes-and-Associates 1995 138 pp I thought I would try to list what I believe are the critical issues. In our consideration of omega-3 polyunsaturated fatty acids (PUFA), we must not forget that this whole industry, if you like, was started by people like Sinclair, Bang and Dyerberg and others being challenged by the role of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in certain western diseases. All this came together in a very nice way with extensive research being done in the USA, Europe and Japan. Epidemiological data and lots of supporting animal data were produced to give the biochemical basis for the EPA/DHA story both in heart disease and anti-inflammatory diseases, (e.g. rheumatoid arthritis and so on). (DBO) Battaglene,-S.; Fielder,-S. The status of marine fish larval-rearing technology in Australia, Hydrobiologia 1997 vol. 358, no. 1-3, pp. 1-5 Over 20 marine fish species have been studied for farming or stock enhancement in Australia. However, commercial production has been dominated by the cage culture of Salmo salar in Tasmania, Thunnus maccoyii in South Australia, and to a lesser extent Lates calcarifer in Queensland. A major impediment to the commercial production of new species has been the large-scale production of juvenile fish. The development of marine fish larval rearing technology in Australia has had four main influences over the last decade: culture system technology from France, live food culture and nutritional enhancement from Belgium, artificial diets from Japan and extensive pond culture from the USA. Microalgae and live food culture is based on traditional aquaculture species and methods. Recent Australian research has focused on induced spawning, the role of stress in inhibiting ovulation, factors influencing initial swim bladder inflation in larvae, larval nutrition, extensive culture and diagnosis of disease. Over the next 5 years, Australian aquaculturists should be able to produce industrial quantities of a range of native marine fish, either in intensive fish hatcheries, or in combination with extensive pond culture. Bengtson,-D.A. Aquaculture of summer flounder (Paralichthys dentatus): status of knowledge, current research and future research priorities, Aquaculture 1999 vol. 176, no. 1-2, pp. 39-49 Commercial aquaculture of summer flounder began in 1996. Both the research leading to commercialization and the production itself have been heavily oriented toward the hatchery phase. Producers of summer flounder larvae experience many of the same problems that producers of turbot and Japanese flounder larvae have faced and, in some cases, overcome. The extended period of metamorphosis and settling of summer flounder leads to problems with cannibalism and weaning to formulated diets that appear more severe than those in turbot. Producers are experimenting with both recirculation systems and net pens to identify the equipment that optimizes grow-out production. The major research problems that industry and academia should jointly address are (1) establishment of broodstock selection programs, (2) identification of broodstock nutritional requirements, (3) development of methods for volitional spawning by broodstock, (4) management of the microbial ecology in larval rearing tanks, (5) synchronization of metamorphosis to reduce cannibalism and enhance weaning, (6) optimization of production systems and diets for grow-out, and (7) reduction of disease through good husbandry and vaccination. Birnbaum,-N.G. Licensing and regulation of veterinary biologics for fish in the United States, Nutrition-and-Technical-Development-of-Aquaculture Howell,-W.H.; Keller,-B.J.; Park,-P.K.; McVey,-J.P.; Takayanagi,-K.; Uekita,-Y.-(eds.) New-Hampshire-Univ,-Durham-USA-Sea-Grant-Program 1998 pp. 33-38 The U.S. Department of Agriculture (USDA) regulates biologics for fish, including vaccines, bacterins, and diagnostic test kits, produced in, imported into, or exported from the United States. The regulatory process is designed to ensure that biologics under USDA jurisdiction are not contaminated, worthless, dangerous, or harmful. The Animal and Plant Health Inspection Service (APHIS), an agency within the USDA, licenses and inspects biologics production facilities, and licenses and tests veterinary biological products. Veterinary biological products should be pure, safe, potent, and efficacious. A biologics-producing firm located in the United States may sell its products provided the firm possesses a valid U.S. Veterinary Biological Product License for each product produced for sale, as well as a valid U.S. Veterinary Biologics Establishment License. A permittee (i.e., the legal representative in the United States of a biologics-producing firm located outside the United States) may import biologics into the United States provided the permittee possesses a valid U.S. Veterinary Biological Product Permit. Biologics available in the United States for fish are manufactured by Alpharma NW Inc., Aqua Health Ltd., and DiagXotics. Monovalent and multi-faction bacterins (i.e., antigenic suspensions of inactivated bacterial organisms) are available for the vaccination of fish to aid in the prevention of furunculosis caused by Aeromonas salmonicida, enteric septicemia of catfish caused by Edwardsiella ictaluri, columnaris disease caused by Flavobacterium columnare, vibriosis caused by Vibrio anguillarum and V. ordalii, cold water vibriosis caused by V. salmoninarum, and enteric redmouth diseases caused by Yersinia ruckerii. Qualitative and quantitative test kits to diagnose the presence of the bacterial kidney disease antigen Renibacterium salmoninarum in fish are also available in the United States. A bacterin recommended as an aid in the prevention of winter ulcers caused by V. viscosus is produced in the United States for export only. Blogoslawski,-W. Overview, 16th Milford Aquaculture seminar, J.-SHELLFISH-RES. 1996 vol. 15, no. 2, p. 451 The 16th Annual Milford Aquaculture Seminar attracted 37 eminently qualified speakers, whose topics ranged from shellfish and finfish disease and propagation through sponsorship of specific programs designed to assist displaced fisherman in the development of aquaculture ventures. The 160 attendees from the United States, Canada, the United Kingdom and the People's Republic of China met in formal and informal sessions to discuss the latest developments in technology and government extension activities. It was noted with interest by attendees that many of the concerns of the industry, such as overharvesting in the late 19th century, were the same as those influencing shellfish farmers today. Speakers from 12 states, Canada, and the United Kingdom discussed sea and bay scallop propagation and the control of shellfish diseases as well as aquaculture training and culture of finfish. Twenty-six marine laboratories and hatcheries and twenty universities, were represented during this exchange. Genetics, nutrition, and disease, as related to the culture and survival of shellfish, were prominent topics of discussion. Bosworth,-B.G.; Wolters,-W.R.; Wise,-D.J.; Li,-M.H. Growth, feed conversion, fillet proximate composition and resistance to Edwardsiella ictaluri of channel catfish, Ictalurus punctatus (Rafinesque), blue catfish, Ictalurus furcatus (Lesueur), and their reciprocal F1 hybrids fed 25% and 45% protein diets, Aquacult.-Res. 1998 vol. 29, no. 4, pp. 251-257 Juvenile channel catfish, Ictalurus punctatus (Rafinesque), blue catfish, I. furcatus (Lesueur), and their reciprocal F1 hybrids were fed practical diets containing 25% and 45% protein during a 10-week trial to determine the effects of genotype, dietary protein level and genotype x diet interactions on growth, feed conversion ratio (FCR), fillet proximate composition and resistance to the bacterium Edwardsiella ictaluri. Rankings of genotypes (best to worst) for absolute weight gain, percentage weight gain and FCR were: channel, channel female x blue male, blue, and blue female x channel male for the 25% protein diet; and channel, channel x blue, blue x channel, and blue for the 45% diet. Diet did not affect growth or FCR of channel catfish, but growth and FCR were better for blue catfish and both hybrids fed the 25% diet compared to those fed the 45% diet. Channel catfish additive genetic and maternal effects were favourable, and heterosis was negative for growth and FCR. After adjusting for effects of fish size, genotype had no effect on fillet composition. Fillet protein was higher for all genotypes, and fillet lipid was lower for blue catfish and hybrids fed the 45% diet than for fish fed the 25% diet. Genotype x diet interactions observed for growth, FCR and fillet lipid appeared to be a result of poor palatability of the 45% diet to blue catfish and hybrids. Survival (76-93%) and antibody levels (0.10-0.24 OD) after exposure to E. ictaluri at the end of the feeding trial were not affected by genotype or diet. Hybridization of blue catfish and channel catfish would not be an effective method for improving the traits measured for the fish strains and diets used in this study. Bengtson,-D.A. Aquaculture of summer flounder (Paralichthys dentatus): status of knowledge, current research and future research priorities, Aquaculture 1999 vol. 176, no. 1-2, pp. 39-49 Commercial aquaculture of summer flounder began in 1996. Both the research leading to commercialization and the production itself have been heavily oriented toward the hatchery phase. Producers of summer flounder larvae experience many of the same problems that producers of turbot and Japanese flounder larvae have faced and, in some cases, overcome. The extended period of metamorphosis and settling of summer flounder leads to problems with cannibalism and weaning to formulated diets that appear more severe than those in turbot. Producers are experimenting with both recirculation systems and net pens to identify the equipment that optimizes grow-out production. The major research problems that industry and academia should jointly address are (1) establishment of broodstock selection programs, (2) identification of broodstock nutritional requirements, (3) development of methods for volitional spawning by broodstock, (4) management of the microbial ecology in larval rearing tanks, (5) synchronization of metamorphosis to reduce cannibalism and enhance weaning, (6) optimization of production systems and diets for grow-out, and (7) reduction of disease through good husbandry and vaccination. Birnbaum,-N.G. Licensing and regulation of veterinary biologics for fish in the United States, Nutrition-and-Technical-Development-of-Aquaculture Howell,-W.H.; Keller,-B.J.; Park,-P.K.; McVey,-J.P.; Takayanagi,-K.; Uekita,-Y.-(eds.) New-Hampshire-Univ,-Durham-USA-Sea-Grant-Program 1998 pp. 33-38 The U.S. Department of Agriculture (USDA) regulates biologics for fish, including vaccines, bacterins, and diagnostic test kits, produced in, imported into, or exported from the United States. The regulatory process is designed to ensure that biologics under USDA jurisdiction are not contaminated, worthless, dangerous, or harmful. The Animal and Plant Health Inspection Service (APHIS), an agency within the USDA, licenses and inspects biologics production facilities, and licenses and tests veterinary biological products. Veterinary biological products should be pure, safe, potent, and efficacious. A biologics-producing firm located in the United States may sell its products provided the firm possesses a valid U.S. Veterinary Biological Product License for each product produced for sale, as well as a valid U.S. Veterinary Biologics Establishment License. A permittee (i.e., the legal representative in the United States of a biologics-producing firm located outside the United States) may import biologics into the United States provided the permittee possesses a valid U.S. Veterinary Biological Product Permit. Biologics available in the United States for fish are manufactured by Alpharma NW Inc., Aqua Health Ltd., and DiagXotics. Monovalent and multi-faction bacterins (i.e., antigenic suspensions of inactivated bacterial organisms) are available for the vaccination of fish to aid in the prevention of furunculosis caused by Aeromonas salmonicida, enteric septicemia of catfish caused by Edwardsiella ictaluri, columnaris disease caused by Flavobacterium columnare, vibriosis caused by Vibrio anguillarum and V. ordalii, cold water vibriosis caused by V. salmoninarum, and enteric redmouth diseases caused by Yersinia ruckerii. Qualitative and quantitative test kits to diagnose the presence of the bacterial kidney disease antigen Renibacterium salmoninarum in fish are also available in the United States. A bacterin recommended as an aid in the prevention of winter ulcers caused by V. viscosus is produced in the United States for export only. Blogoslawski,-W. Overview, 16th Milford Aquaculture seminar, J.-SHELLFISH-RES. 1996 vol. 15, no. 2, p. 451 The 16th Annual Milford Aquaculture Seminar attracted 37 eminently qualified speakers, whose topics ranged from shellfish and finfish disease and propagation through sponsorship of specific programs designed to assist displaced fisherman in the development of aquaculture ventures. The 160 attendees from the United States, Canada, the United Kingdom and the People's Republic of China met in formal and informal sessions to discuss the latest developments in technology and government extension activities. It was noted with interest by attendees that many of the concerns of the industry, such as overharvesting in the late 19th century, were the same as those influencing shellfish farmers today. Speakers from 12 states, Canada, and the United Kingdom discussed sea and bay scallop propagation and the control of shellfish diseases as well as aquaculture training and culture of finfish. Twenty-six marine laboratories and hatcheries and twenty universities, were represented during this exchange. Genetics, nutrition, and disease, as related to the culture and survival of shellfish, were prominent topics of discussion. Bosworth,-B.G.; Wolters,-W.R.; Wise,-D.J.; Li,-M.H. Growth, feed conversion, fillet proximate composition and resistance to Edwardsiella ictaluri of channel catfish, Ictalurus punctatus (Rafinesque), blue catfish, Ictalurus furcatus (Lesueur), and their reciprocal F1 hybrids fed 25% and 45% protein diets, Aquacult.-Res. 1998 vol. 29, no. 4, pp. 251-257 Juvenile channel catfish, Ictalurus punctatus (Rafinesque), blue catfish, I. furcatus (Lesueur), and their reciprocal F1 hybrids were fed practical diets containing 25% and 45% protein during a 10-week trial to determine the effects of genotype, dietary protein level and genotype x diet interactions on growth, feed conversion ratio (FCR), fillet proximate composition and resistance to the bacterium Edwardsiella ictaluri. Rankings of genotypes (best to worst) for absolute weight gain, percentage weight gain and FCR were: channel, channel female x blue male, blue, and blue female x channel male for the 25% protein diet; and channel, channel x blue, blue x channel, and blue for the 45% diet. Diet did not affect growth or FCR of channel catfish, but growth and FCR were better for blue catfish and both hybrids fed the 25% diet compared to those fed the 45% diet. Channel catfish additive genetic and maternal effects were favourable, and heterosis was negative for growth and FCR. After adjusting for effects of fish size, genotype had no effect on fillet composition. Fillet protein was higher for all genotypes, and fillet lipid was lower for blue catfish and hybrids fed the 45% diet than for fish fed the 25% diet. Genotype x diet interactions observed for growth, FCR and fillet lipid appeared to be a result of poor palatability of the 45% diet to blue catfish and hybrids. Survival (76-93%) and antibody levels (0.10-0.24 OD) after exposure to E. ictaluri at the end of the feeding trial were not affected by genotype or diet. Hybridization of blue catfish and channel catfish would not be an effective method for improving the traits measured for the fish strains and diets used in this study. Hedrick,-R.P. Relationships of the host, pathogen, and environment: Implications for diseases of cultured and wild fish populations, Journal-of-Aquatic-Animal-Health 1998 vol. 10, no. 2, pp. 107-111 Many effects of diseases on cultured fish are known; they are less clear in wild fish populations. Cultured fish represent captive populations that can be subjected to intense scrutiny with an increasing range of diverse and powerful tools. Disease represents a spectrum from acute mortality to rather benign or inconsequential syndromes, all sharing the common feature of a deviation from the normal structure or function of the host. Understanding these deviations among cultured and wild fish populations and balancing their implications against ecological, economic, and political concerns are challenges for both fish health scientists and fisheries managers. The severity of a given disease is dependent on the interaction of numerous variables of the host, the parasite, and the environment. To understand diseases and their impacts on fish populations, we must know which variables are important, how we measure them, and finally how we assess the results of our measurements. We have perhaps been most successful with variables associated with the pathogen. We often can more easily isolate and scrutinize the pathogen than either the host or the environment. The host variables of importance (for which we lack considerable knowledge) include actions of the immune system in general and specifically the influence of genetics and nutrition on host resistance-susceptibility to disease. Lastly, the contribution of the environment, a nebulous term encompassing everything other than the host and pathogen, is only partly appreciated. While we can measure certain physical and chemical parameters of the environment, we have a poor understanding of the biological-ecological variables that influence host-pathogen interactions. Ultimately, diseases of wild fish must be considered in the context of these complex interactions including numerous physical, chemical, biological, and ecological parameters, which may yet be discovered as integral parts of the aquatic habitat. Hunt,-S.L.; Mulligan,-T.J.; Komori,-K. Oceanic feeding habits of chinook salmon, Oncorhynchus tshawytscha, off northern California, Fishery-Bulletin [Fish-Bull] 1999 vol. 97, no. 3, pp. 717-721 The chinook salmon, Oncorhynchus tshawytscha, is an important commercial and recreational species inhabiting rivers and nearshore coastal waters from San Diego, California, to the Bering Sea and Japan (Miller and Lea, 1972). Many West Coast populations are in a serious decline (Pearcy, 1992). Nehlsen et al. (1991) reported an overall decrease in salmonid numbers in the coastal waters of the Pacific Northwest and suggested that northern California chinook salmon runs may be at high risk of extinction owing to 1) habitat damage and mainstream passage problems; 2) overharvesting; and 3) hybridization, predation, competition, disease, and poor ocean survival conditions. Surprisingly, little research has been done off the northern California coast regarding the diet of salmonids during oceanic migrations. Iwama,-G.K.; Pickering,-A.D.; Sumpter,-J.P.; Schreck,-C.B.-(eds.) Fish stress and health in aquaculture, SOC.-EXP.-BIOL.-SEM.-SER. CAMBRIDGE,-UK CAMBRIDGE-UNIVERSITY-PRESS 1997 no. 62, 287 pp Stressors in intensive aquaculture are unavoidable. While severe stress can result in massive mortalities, sublethal stress can compromise various physiological and behavioural functions, leading to suppressed disease resistance and growth rate, both contributing to suboptimal production. The recognition of stressed states, as well as the management of fish health are therefore critical to the success of an aquaculture operation. The objective of this book is to review current knowledge about stress and health in fish in the context of aquaculture. There is a need to update the knowledge in this field, as it has been more than a decade since a similar volume on fish stress was published. This book also represents some of the papers that were presented as a well-attended Symposium with this theme at the annual meeting of the Society for Experimental Biology in Canterbury. Thus, the book opens with chapters on the physiology of the stress response in fish, and about stress in aquaculture. The genetic basis for the stress response and the effect of nutrition on fish health are reviewed in two chapters. The effects of stress on fish behaviour, immune function and on ionic and osmotic regulation are also presented in respective chapters. Finally, there is a review of current techniques on the detection of stressed states in fish in the field because it is here that the application of knowledge occurs. While the initial focus of this volume was stress in fish husbandry, the chapters are holistic and we believe that others interested in fish biology and management will also find the book of value. We wish to thank the authors of the individual chapters for their contribution. We believe that their excellent reviews contribute to our understanding of the nature of stress in fish, and to the importance of this knowledge in growing and managing fish through aquaculture as well as other endeavours. We also thank reviewers for their helpful comments on drafts on each chapter. Finally, we wish to thank Paige Ackerman and Grace Cho, who were both critical to this project. Ji,-Y. Thiamine Nutrition in Relation To Lake Trout (Salvelinus namaycush) Reproduction in the Great Lakes, Dissertation-Abstracts-International-Part-B:-Science-and-Engineering [Diss-Abst-Int-Pt-B-Sci-and-Eng] 1998 vol. 58, no. 8, p. 3980 The lack of successful restoration of naturally reproducing populations of lake trout (Salvelinus namaycush) in the Great Lakes may be due to a thiamine destroying enzyme, thiaminase in their prey species, smelt (Osmerus mordax) and alewife (Alosa pseudoharengus). Smelt and alewives from Lakes Huron, Michigan and Superior were confirmed to have high thiaminase activities. The average whole body thiaminase activity was 362 pmol super(.) g [-1] super(.) min [-1] for smelt and 357 for alewives. Large differences were found in thiaminase activities between smelt and alewives from different locations in the Great Lakes region and at different sampling times. Adult lake trout from Lake Michigan, where lake trout natural reproduction is absent, had significantly lower blood thiamine pyrophosphate (TPP) levels than those from Lake Superior, where natural reproduction is evident. Adult female lake trout fed thiaminase containing alewives under laboratory conditions had significantly reduced blood TPP levels compared to those fed a commercial trout diet. These reduced levels were comparable to those found in Lake Michigan lake trout. Semi-purified thiamine deficient diets failed to produce thiamine deficiency as indicated by blood or liver TPP levels. Neither the thiamine deficient diet nor thiaminase containing alewives affected ovulation rate or gonado-somatic index of adult female lake trout under laboratory conditions. Radioactive thiamine was used to determine thiamine synthesis in the gastro-intestinal tract of lake trout and retention time of thiamine by lake trout. Reasons for lack of overt symptoms of thiamine deficiency in lake trout under laboratory conditions were attributed to thiamine synthesis, presumably by bacteria, and the long retention of thiamine by lake trout. Up to 81% of total thiamine in the content of posterior intestine was of non-dietary origin. Adult female lake trout fed the thiamine deficient diet retained up to 34% of thiamine for 27 weeks in the liver. Continuous consumption of a thiaminase containing diet may cause impairment of natural reproduction in lake trout through Early Mortality Syndrome (EMS). The lower thiamine nutritional status exhibited in Lake Michigan lake trout may be the cause of EMS, a disease common in Lake Michigan, but not Lake Superior fish. Jones,-S.H.; Summer-Brason,-B.; Nardi,-G. Microbiology of early larval stages of summer flounder Paralichthys dentatus growth in a recirculating water system, Nutrition-and-Technical-Development-of-Aquaculture Howell,-W.H.; Keller,-B.J.; Park,-P.K.; McVey,-J.P.; Takayanagi,-K.; Uekita,-Y.-(eds.) New-Hampshire-Univ,-Durham-USA-Sea-Grant-Program 1998 pp. 45-52 Finfish in early larval stages of growth can suffer high mortality in aquacultural facilities because of diseases and nutritional problems. Recent studies suggest that bacteria associated with the live feed and hatchery environments that colonize finfish can have beneficial or detrimental effects on fish health. A local commercial facility that grows summer flounder in a recirculating water system has been the subject of microbiological studies for their first four production runs. The culture of summer flounder is in its infancy and the microbiology of these fish is not well characterized. Samples of fish, tank water, and feed collected at times of change in feeding regime, metamorphosis and episodic high mortality and disease events were analyzed for different bacteria. Growth media targeting total heterotrophs, total vibrios and Vibrio anguillarum were used to enumerate and isolate bacteria. Isolates were identified to species and/or genus. Differences and similarities in microbial community diversity and abundance at different life stages and feeding regimes were noted. The results provide an initial database for determining the role of bacteria in the onset of disease and the health of early stages of summer flounder growth (Paralichthys dentatus) Langdon,-C.J.; Buchal,-M.A. Comparison of lipid-walled microcapsules and lipid spray beads for the delivery of water-soluble, low-molecular-weight materials to aquatic animals, Aquaculture-Nutrition [Aquacult-Nutr] 1998 vol. 4, no. 4, pp. 275-284 Microparticles (< 40 mu m diameter) composed of 600 mg g super(-1) tripalmitin/400 mg g super(-1) fish oil were used to encapsulate the low-molecular-weight (mol. wt 460) antibiotic oxytetracycline in the form of either oxytetracycline hydrochloride (OTC.HCl) or oxytetracycline hemicalcium salt (OTC.HEM). Dry, finely ground particles of core material were encapsulated in spray beads. Dissolved core material was encapsulated in lipid-walled microcapsules. Oxytetracycline (OTC) was most efficiently delivered ( approximately 46.5 mg g super(-1) lipid after 24 h suspension in seawater) as a hemicalcium salt in spray beads. Lipid-walled microcapsules were most efficient for delivering OTC ( approximately 8.7 mg g super(-1) lipid) as OTC.HCl dissolved in 0.2 M HCl at a concentration of 300 mg mL super(-1). Spray beads containing OTC.HEM were very stable over 1 month in storage. Lipid-walled microcapsules containing aqueous OTC.HCl lost approximately 30% of their core material during storage. Freeze-drying of both microparticle types did not improve storage of spray beads, but showed promise for reducing leakage from lipid-walled microcapsules during storage and delivery to suspension feeders. Li,-M.H.; Robinson,-E.H. Dietary Ascorbic Acid Requirement for Growth and Health in Fish, Journal-of-Applied-Aquaculture [J-Appl-Aquacult] 1999 vol. 9, no. 2, pp. 53-78 Most fish lack the ability to biosynthesize ascorbic acid (AA) or, if
they have the capability to synthesize the vitamin, the quantity produced
is insufficient to meet metabolic needs. Thus AA must be provided in the
diet. Since it is an essential dietary component that functions in numerous
metabolic processes, considerable research has been conducted concerning
the role of AA in the nutrition of fish. Literature pertaining to AA in
fish nutrition and its relationship with fish health are examined herein.
Topics addressed include deficiency signs, dietary requirement, effect
on reproduction, immune response and disease resistance, stress response,
tissue storage, assessment of status, stability during feed manufacture
and storage, bioavailability, and supplementation.
Lim,-C. Future considerations in fish nutrition
Considerable progress has been made in the field of fish nutrition during the past two decades. Nutritional data for some species such as trout, salmon, channel catfish, and common carp are well established and efficient feeds have been developed. However, nutrition of fish species commercially important in the Southeast Asian region is still in its infancy and much of the existing information needs further verification. Basic requirements for some of the 5 major nutrient classes and energy have been determined. However, knowledge of larval and broodstock nutrition is limited. The role of nutrition in immune function and disease resistance should be investigated. Nutritional value and nutrient bioavailability of local feedstuffs as well as methods for improving the nutritional quality of inferior feedstuffs should be given priority. The potential benefits of additives, and harmful effects of toxicants and anti-nutritional factors need to be assessed. The effects of the diet on product quality are becoming increasingly important, but work on feed processing technology in relation to the physical and nutritional quality of feeds is lacking. Emphasis must also be given to the improvement of feed performance and feeding strategies for various life stages under different production systems and management practices in order to reduce production costs and minimize the negative impact of feeds on the environment. Lutz,-C.G. Red drum: A re-emerging aquaculture species, Aquaculture-Magazine [Aquacult-Mag] 1999 vol. 25, no. 4, pp. 38-45 Once lauded, later shunned, the red drum has taken a long and bumpy road to reach its present status as a re-emerging species in aquaculture. Over the past 15 years, extensive efforts by researchers and industry in several countries have resulted in a wealth of baseline information critical to understanding reproduction, larval culture, nutrition, disease control, and other aspects of red drum culture. Although many researchers and entrepreneurs in the US have long since moved on to other, more en vogue species, a wealth of published information is available to anyone wishing to pursue red drum culture anywhere in the world. Culturists in several parts of the world are doing just that, with considerable success. Moriarty,-D.J.W. The role of microorganisms in aquaculture ponds, AQUACULTURE 1997 vol. 151, no. 1-4, pp. 333-349 Microorganisms have major roles in pond culture, particularly with respect to productivity, nutrient cycling, the nutrition of the cultured animals, water quality, disease control and environmental impact of the effluent. Management of the activities of microorganisms in food webs and nutrient cycling in ponds is necessary for optimising production, but the objectives will differ with the type of aquaculture, the species cultivated and the economics. Unlike the pastoralists who fertilise and seed pastures with selected species, fish farmers only fertilise ponds and hope that useful species of algae, bacteria and other microorganisms will develop. Factors controlling the composition and development of blooms of both desired and undesirable species of algae and bacteria need to be investigated. Analysis of the complex food webs in ponds, combined with measurements of primary productivity, C cycling through bacteria, zooplankton and meiofaunal biomass changes and nitrogen cycling will provide the basic data for generating a model to describe and predict fish productivity in ponds. Algae and bacteria have often been regarded as single groups of organisms by aquatic biologists, but there is a great diversity of species of each, with different roles and interactions in their ecosystems. This fact, together with the many environmental variables, makes it difficult to develop a single comprehensive, predictive model as a tool for managing food webs and water quality in ponds, but small models specific to given pond systems or stages of grow-out are likely to be successful. Mustafa,-A.; MacKinnon,-B.M. Atlantic salmon, Salmo salar L., and Arctic char, Salvelinus alpinus (L.): comparative correlation between iodine-iodide supplementation, thyroid hormone levels, plasma cortisol levels, and infection intensity with the sea louse Caligus elongatus, Canadian-Journal-of-Zoology; Revue-Canadien-de-Zoologie [Can-J-Zool; Rev-Can-Zool] 1999 vol. 77, no. 7, pp. 1092-1101 The interrelationship between plasma cortisol levels, iodine-iodide nutritional supplementation, plasma thyroid hormone levels (tri- and tetra-iodothyronine, T sub(3) and T sub(4) respectively), and infection intensity with the sea louse Caligus elongatus were investigated in Atlantic salmon, Salmo salar L., and Arctic char, Salvelinus alpinus (L.). Cortisol-implanted Atlantic salmon had significantly higher mean intensities of sea lice than salmon not implanted with cortisol. Untreated Arctic char had significantly higher plasma cortisol levels and sea lice infections than untreated salmon. Cortisol-implanted salmon had lower plasma levels of T sub(3) and T sub(4). Salmon and char treated with iodized feed and iodinated water had higher plasma T sub(3) and T sub(4) levels, higher plasma T sub(3)/T sub(4) ratios, and lower plasma cortisol levels than controls. Sea lice infections were significantly reduced on salmon treated with either iodized feed (P < 0.05) or iodinated water (P < 0.05). Char treated with iodized feed also had significantly reduced infections (P < 0.05). In general, iodized feed had a greater effect than iodinated water in reducing sea lice numbers. This study indicates that elevated plasma cortisol levels in salmon and char result in lower plasma levels of thyroid hormone and an increased susceptibility to sea lice infections. It is concluded that providing the fish with sufficient iodine-iodide increases thyroid hormone levels, reduces plasma cortisol levels, and reduces susceptibility to sea lice infections. Omar,-E.; Al-Sagheer,-F.M.; Nour,-A.M.; Abou-Akkada,-A.R. Effect of protein level and stocking density on growth performance, feed utilization and resistance of Nile tilapia (Oreochromis niloticus) to infection against aeromonas septicemia (Aeromonas hydrophila), Feeding-tomorrow'-s-fish.-Proceedings-of-the-Workshop-of-the-CIHEAM-Network-on-Technology-of-Aquaculture-in-the-Mediterranean-TECAM,-jointly-organized-by-CIHEAM,-FAO-and-IEO,-Mazarron-Spain,-24-26-June-1996. Tacon,-A.;Basurco,-B.-eds. Zaragoza-Spain CIHEAM 1997 vol. 22 pp. 67-77 A 14-week laboratory feeding trial was conducted to ascertain the effect of 2 dietary crude protein levels (30 and 40 CP%) and stocking densities (10, 30 and 40 fish/105 l) on growth performance, feed and nutrient utilization, and the resistance of Nile tilapia (Oreochromis niloticus) to infection with Aeromonas hydrophila. Fish were reared within indoor glass aquaria containing dechlorinated water supplemented with aeration and temperature controlled at 28 degree C for the duration of the experiment. The results showed that growth performance of tilapia fingerlings was significantly reduced at the higher dietary protein level and stocking densities. Feed and nutrient efficiency was also significantly reduced at the higher dietary protein and stocking densities tested. Moreover, at the end of the 14-week experiment, the immune response of tilapia after immunization within formalin-killed A. hydrophila bacteria was studied; the results of antibody titer of the immunized fish after 28 days differing significantly between individual treatments. The highest titer was obtained with fish stocked at the lowest stocking density and fed the lowest protein diet. By contrast, the lowest antibody titer was found in fish reared at the highest stocking density and fed the lowest level of dietary protein. Percentage survival rate after bacterial challenge was also highest for fish reared at the lowest stocking density and fed the lowest dietary protein level. The results clearly showed that fish growth was best at the lowest stocking density and low dietary protein level tested, and that these parameters significantly affected the capability of fish to resist infection against Aeromonas septicemia. Page,-G.I.; Hayworth,-K.M.; Wade,-R.R.; Harris,-A.M.; Bureau,-D.P. Non-specific immunity parameters and the formation of advanced glycosylation end-products (AGE) in rainbow trout, Oncorhynchus mykiss (Walbaum), fed high levels of dietary carbohydrates, Aquaculture-Research [Aquacult-Res] 1999 vol. 30, no. 4, pp. 287-297 The effects of long-term hyperglycaemia (5 months), through feeding high levels of dietary carbohydrates, on the non-specific immunity parameters of rainbow trout, Oncorhynchus mykiss (Walbaum), was assessed. Fish were fed one of three diets composed of a basal diet containing approximately 14% digestible carbohydrate which was progressively diluted with gelatinized potato starch in the following ratios of basal diet to supplemental carbohydrate (gelatinized potato starch): 65:00, 65:20, 65:35. The three diets were pair-fed based on the feed intake of the fish fed the diet containing the highest level of starch (65:35) and representing 100% intake. The other diets were then fed at different levels in a manner that allowed all the groups of fish in the same block to receive the same amount of the basal diet [e.g. the basal diet (undiluted, 65:00) was fed at 65% of the dietary intake of the 65:35 diet]. Blood glucose concentrations and relative liver-to-body size increased with increased dietary carbohydrate intake. Feeding supplemental carbohydrates resulted in a small increase in weight gain of the fish at both supplemental levels. Pronephros tissue lysozyme activity and pronephros macrophage superoxide production were not affected by the dietary treatments. The results suggest the presence of advanced glycosylation end-products in muscle tissue collagen, but were not significantly different between treatments. No substantial effect of long-term feeding of a high carbohydrate diet on the non-specific immunity of rainbow trout was observed. However, the results suggest that dietary carbohydrates may have a slight stimulatory effect on phagocytosis at low-moderate levels. Prickett,-R.A. European sea bass and sea bream industry: Dvelopment, present status and prospects for the future, Proceedings-of-the-Special-Session-on-Marine-Fish-Culture-Aquaculture-Canada-'-97 Brown,-J.-(ed.) 1998 no. 98-1, pp. 21-29 Sea bass (Dicentrarchus labrax) and gilt-head bream (Sparus aurata) are highly rated species in southern Europe. Although they have been produced in limited quantities for several decades using extensive pond systems, most of the production today comes from cage farms in Greece, Italy, Spain, Turkey, and France, with an increasing tonnage from North Africa. Production in 1996 totalled over 40,000 metric tons with an average selling price of about 6.2 ECU/kg (Can$9.70/kg) for sea bass and 5.9 ECU/kg (Can$9.26/kg) for sea bream. Average market size is about 350 g and most of the production is sold fresh, ungutted, and in the round. Most of the research and development phase occurred in the 1970s and early 1980s in France and Italy, and focused primarily on problems related to large scale fry production. Once fry production problems had been solved, particularly the problem of swimbladder inflation, the industry rapidly expanded using salmonid net-pen technology and financing from generous EU grants. As the industry reaches maturity, sales prices have fallen by 50% since 1990 and the emphasis has shifted to reducing production costs and expanding markets, especially in the supermarket sector. New technical developments such as brood stock selection, disease control, improved nutrition, and the production of related species are only beginning and are still several years behind the salmon industry. Rigos,-G.; Christophilogiannis,-P.; Giahnishi,-M.; Andriopoulou,-A.; Koutsodimoy,-M.; Nengas,-I.; Alexis,-M. Amyloodinium occelatum infestation on sharpsnout sea bream, Puntazzo puntazzo Cetti, Bull-Eur-Assoc-Fish-Pathol 1998 vol. 18, no. 6, pp. 198-200 The devastating effect of Amyloodinium occelatum on sharpsnout sea bream, Puntazzo puntazzo Cetti is described in this note. Massive and rapid mortalities (100% in 48 h) of cultured juvenile (12 g) sharpsnout sea bream were attributed to an epizootic infection with the dinoflagellate A. occelatum parasitising the gills. A clinical infection was also apparent in gilthead sea bream, Sparus aurata L (10 g) kept in adjacent cages but 25% of the infected population survived the infection. On the contrary, sea bass, Dicentrarchus labrax L. (20 gr) that were maintained near to the infected Sparids remained unaffected. This epizootic was attributed to the location of the cages site and the optimum for the parasite water temperature. The incidence confirms the lethal identity of the particular pathogen on cultured fish. Rigos,-G.; Grigorakis,-K.; Nengas,-I.; Christophilogiannis,-P.; Yiagnisi,-M.; Koutsodimou,-M.; Andriopoulou,-A.; Alexis,-M. Stress-related pathology seems a significant obstacle for the intensive farming of common dentex, Dentex dentex (Linnaeus 1758), Bull.-Eur.-Assoc.-Fish-Pathol. 1998 vol. 18, no. 1, pp. 15-18 High mortalities of pathological origin were evident when juvenile common dentex (Dentex dentex) L. were exposed to stress situations and increased handling. The pathological examination of an outbreak revealed the presence of two parasites, two bacterial pathogens and a chlamydia-like organism. These pathological findings that were accompanied with a moderate agonistic behaviour of the fish and cannibalism signs seem to be associated with the relatively high susceptibility of common dentex to stress conditions. The stressed individuals found to succumb easily to disease problems leading to progressive mortalities. Similar findings were appeared in the investigation of a new disease incidence due to bacterial infections. Neither pathological signs nor agonistic behaviour or cannibalism bites were evident when the fish were exposed to minimum stress situations and not extensively handled. Ringoe,-E. Does Carnobacterium divergens isolated from Atlantic salmon, Salmo salar L., colonize the gut of early developing turbot, Scophthalmus maximus L., larvae?, Aquaculture-Research [Aquacult-Res] 1999 vol. 30, no. 3, pp. 229-232 It is well established from endothermic animals that the adhesion of lactic acid bacteria involves host specificity (Fuller 1986). In juvenile fish, Joeborn, Olsson, Westerdahl, Conway & Kjellberg (1997) reported by in vitro tests that a Carnobacterium sp. isolated from Atlantic salmon, Salmo salar L., colonized the gastrointestinal tract of rainbow trout, Onchorynchus mykiss (Walbaum). However, no information from fish larvae is available on whether the adhesion of lactic acid bacteria involves host specificity. This is relevant in the context of whether or not it is possible to colonize the gastrointestinal tract of larvae at early stages with probiotics, notably Gram-positive bacteria, such as lactic acid bacteria, or by a resident microflora, which may contribute to nutrition. The purpose of the current study, was to evaluate whether a C. divergens, orginally isolated from Atlantic salmon, was able to colonize the gut of turbot larvae by adding this bacterial species to the rearing water and to compare these results with those for larvae exposed to V. pelagius, by using the ELISA method. Scheibling,-R.E.; Hennigar,-A.W.; Balch,-T. Destructive grazing, epiphytism, and disease: the dynamics of sea urchin-kelp interactions in Nova Scotia, Can-J-Fish-Aquat-Sci; J-Can-Sci-Halieut-Aquat 1999 vol. 56, no. 12, pp. 2300-2314 The rate of advance of urchin (Stronylocentrotus droebachiensis) feeding aggregations (fronts) as they destructively grazed kelp beds (Laminaria longicruris) at both a wave-exposed site and a sheltered site in Nova Scotia over 3.5 years was measured. The grazing fronts were composed of high densities of large adults (up to 98 and 70 per 0.25 m super(2) at the exposed and sheltered sites, respectively). Urchins in the recently formed barrens, or in adjacent kelp beds, occurred at much lower densities and consisted mainly of juveniles. The fronts moved onshore into shallower water at each site, but their rate of advance varied markedly between sites and over time at each site, ranging from 0 to 4 m times month super(-1). The rate of advance of a front was related to the biomass of urchins, fronts did not advance below a threshold biomass of similar to 2 kg times m super(-2). Infestations of kelp by an epiphytic bryzoan (Membranipora membranacea) caused marked reductions in kelp canopy cover and biomass during winter, but the canopy regenerated through recruitment of juvenile sporophytes in spring. A localized outbreak of disease decimated S. droebachiensis at the exposed site in 1993, which enabled kelp to recolonize the barrens. Surviving urchins gradually reaggregated and resumed destructive grazing after similar to 1.5 years. A recurrence of disease in 1995 eliminated urchins at both sites and terminated the transition from kelp beds to barrens on a coastal scale. These findings have important implications for the management of the urchin fishery, which targets grazing fronts for harvesting. Sealey,-W.M.; Gatlin,-D.M.,III Overview of Nutritional Strategies Affecting Health of Marine Fish, Journal-of-Applied-Aquaculture [J-Appl-Aquacult] 1999 vol. 9, no. 2, pp. 11-26 Proper nutrition plays a critical role in maintaining normal growth and health of cultured fish. A variety of nutritional strategies may influence fish health, including adjustment of specific nutrient levels in the diet, manipulation of nutritional condition through feeding regimens, and administration of non-nutrient immunostimulants in the diet. Research with several fishes, including some marine and diadromous species such as salmonids, has established that immunocompetence and disease resistance can be compromised by deficiencies of various nutrients, especially certain vitamins and minerals. Thus, adequate levels of these micronutrients must be supplied in prepared diets to support optimal growth and production efficiency of fish in aquaculture. In addition, dietary supplementation of some of these micronutrients in excess of minimum requirement levels has been shown to significantly enhance immune responses and disease resistance of various animals. Overfortification of such nutrients as vitamin C, vitamin E, and selenium have shown positive influences on immunity and disease resistance in some studies but no effects in other studies. Management practices that affect the nutritional condition of fish also may influence their health and ability to resist disease. Recent research with freshwater fish indicates certain feeding regimens, including moderate feed deprivation, alter a fish's resistance to disease. Such feeding regimens potentially may be applied to reduce losses of marine fish in aquaculture. Dietary supplementation of non-nutrient immunostimulatory compounds also has attracted considerable interest due to positive responses of several fish species in terms of non-specific immunity and disease resistance. Compounds such as beta -1,3-glucans which are derived from yeasts and fungi have been shown to change the activation level of different parts of the non-specific immune system, resulting in significantly reduced mortality after challenge with various pathogens. Some of these compounds have become commercially available in recent years, but their efficacy has been variable when administered in the diet. Specific examples concerning application of these various nutritional strategies in aquaculture are presented. Further advancements in these areas may allow nutritional modulation of the immune response to be used as an effective and relatively inexpensive alternative to chemical therapy in combating diseases of fish in aquaculture. Swain,-S.K.; Das,-B.K. Effects of micronutrients in immune response and disease resistance of fish, Fish.-Chimes 1996 vol. 16, no. 7, pp. 21-23 Fishes are protected from infections, transformed cells and other foreign invaders by several interdependent immunological mechanisms. The nutritional status of fish may influence the resistance to diseases. Trace elements are required as co-enzymes for irreplaceable metalloenzymes, vital for maintenance of cellular functions in the immune systems. Vitamin C acts as a immunostimulator in fish. Vitamin E and B complex also influence the immune system of fish. Tachibana,-K.; Yagi,-M.; Hara,-K.; Mishima,-T.; Tsuchimoto,-M. Effects of feeding of beta -carotene-supplemented rotifers on survival and lymphocyte proliferation reaction of fish larvae (Japanese parrotfish (Oplegnathus fasciatus) and Spotted parrotfish (Oplegnathus punctatus)): preliminary trials, Hydrobiologia 1997 vol. 358, no. 1-3, pp. 313-316 Japanese parrotfish (Oplegnathus fasciatus) and Spotted parrotfish (Oplegnathus punctatus) larvae were fed with beta -carotene supplemented rotifers or unsupplemented control rotifers for 24 days after hatchout. Results show that survival rates of beta -carotene supplemented groups of both Japanese parrotfish and Spotted parrotfish larvae were higher than that of control groups. beta -carotene supplemented and unsupplemented control groups exhibited similar growth in both species during this experiment. Proliferation of spleen lymphocytes with 100 mu g ml super(-1) of ConA, 10 or 50 mu g ml super(-1) of Poke weed mitogen from beta -carotene supplemented group was higher than that of a control group of Japanese parrotfish. In Spotted parrotfish treated with 100 mu g ml super(-1) of ConA from the beta -carotene supplemented groups lymphocytes proliferated to a higher degree than in the control. Results suggest that the supplementation of beta -carotene to rotifers, might be of benefit in production of healthy, resistive larvae against infectious disease. Tonguthai,-K. Control of freshwater fish parasites: A southeast asian perspective, International-Journal-for-Parasitology 1997 vol. 27, no. 10, pp. 1185-1191 Parasites commonly found in freshwater fishes and other aquatic animals primarily belong to Protozoa, Platyhelminthes, Acanthocephala, Nematoda, Hirudinea and Crustacea. Most of these parasites are external parasites of the skin, fins or gills, while few are internal parasites living in the epidermal intralamellar gills, intestine or intramuscular tissues. Possible control measures involving manual removal, cleaning by topical cleaners, management practices, nutritional improvement, vaccination, chemoprophylaxis, chemotherapy, and quarantine and certification, etc., are discussed. Xi -S. Effects of Fish Oil On Cytokines and Antioxidant Defenses in Mice With Murine Aids, Diss.-Abst.-Int.-Pt.-B-Sci.-and-Eng. 1997 vol. 58, no. 6, p. 2968 The effects of fish oil on cytokines and antioxidant defenses in murine AIDS were studied. Female C57BL/6 mice (n = 32/group) were fed either corn oil or fish oil diet which was modified from AIN76A basal diet. After 4 week's feeding, half of the mice (16) from each group were infected with LP-BM5 virus (murine leukemia virus) by i.p. injection. The other half served as the control group. At 4 weeks and 10 weeks post-infection, half of the mice from each group were killed and the tissues including blood, the liver, lung, kidney, heart and spleen were exercised for various assays. Splenocytes were isolated and cultured immediately. Supernatant was collected for the assays of cytokines (TNF alpha , IL-1 beta , IL-6, IL-2 and IFN gamma ) and leukotriene B sub(4) (LTB 4) by ELISA method. Tissues and the remaining spleens were frozen immediately under nitrogen for later assays. The assays included glutathione (in tissue homogenate) and antioxidative enzymes (catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase in tissue supernatant) by spectrophotometric method; fatty acids (in the liver) by gas chromatography; virus mRNA (in both the liver and spleen) by RT-PCR and a nuclear transcription factor (NFkB) by gel shift (both the liver and spleen). Adams,-C.A.; Austin,-B.; Meaden,-P.G.; McIntosh,-D. Molecular characterization of plasmid-mediated oxytetracycline resistance in Aeromonas salmonicida, Applied-and-Environmental-Microbiology [Appl-Environ-Microbiol] 1998 vol. 64, no. 11, pp. 4194-4201 Using broth conjugation, we found that 19 of 29 (66%) oxytetracycline (OT)-resistant isolates of Aeromonas salmonicida transferred the OT resistance phenotype to Escherichia coli. The OT resistance phenotype was encoded by high-molecular-weight R-plasmids that were capable of transferring OT resistance to both environmental and clinical isolates of Aeromonas spp. The molecular basis for antibiotic resistance in OT-resistant isolates of A. salmonicida was determined. The OT resistance determinant from one plasmid (pASOT) of A. salmonicida was cloned and used in Southern blotting and hybridization experiments as a probe. The determinant was identified on a 5.4-kb EcoRI fragment on R-plasmids from the 19 OT-resistant isolates of A. salmonicida. Hybridization with plasmids encoding the five classes (classes A to E) of OT resistance determinants demonstrated that the OT resistance plasmids of the 19 A. salmonicida isolates carried the class A resistance determinant. Analysis of data generated from restriction enzyme digests showed that the OT resistance plasmids were not identical; three profiles were characterized, two of which showed a high degree of homology. Ahne,-W.; Kurath,-G.; Winton,-J.R. A ribonuclease protection assay can distinguish spring viremia of carp virus from pike fry rhabdoviru, Bull-Eur-Assoc-Fish-Pathol 1998 vol. 18, no. 6, pp. 220-224 Thirteen rhabdovirus isolates from 10 teleost fish species as well as reference strains of spring viraemia of carp virus (SVCV) and pike fry rhabdovirus (PFRV) cross-reacted in an indirect immunofluorescence assay and were thus indistinguishable by this method. A ribonuclease protection assay (RPA) using a super(32)P-labeled RNA probe made from a cloned copy of the full length SVCV glycoprotein (G) gene was able to discriminate clearly between the type strains of SVCV and PFRV and among the 13 rhabdovirus isolates. Results for the RPA were generally in agreement with standard serum neutralisation assays; however, the RPA was also able to detect genomic differences between isolates of SVCV. These results have implications for fish disease control programs for SVCV. Alfred-Ockiya,-J.F.; Akeodi,-J. Comparative study of fungal infestation of three traditionally smoked-dried freshwater fishes in Rivers State, J-Aquat-Sci 1998 vol. 13, pp. 41-43 Samples of 3 species of traditionally smoked-dried freshwater fishes (grey catfish Chrysichthys nigrodigitatus, mud catfish Clarias gariepinus and snake-head Parachanna obscura) were obtained from Port Harcourt fish market in Nigeria and examined for fungal infestation. All fish species showed signs of fungal infestation after incubation for three days on Potatoes Dextrose Agar (PDA) medium. Fungi isolated and identified included Aspergillus sp., Rhizopus sp., Fusarium sp. and Mucor sp. Five fungal species were identified on C.nigrodigitatus, 4 and 2 fungal species were identified on P.obscura and on C.gariepinus, respectively. Ali,-M.A. Henneguya ghaffari sp. n. (Myxozoa: Myxosporea), infecting the Nile perch Lates niloticus (Teleostei: Centropomidae), Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] Inter-Research 1999 vol. 38, no. 3, pp. 225-230 Light microscopical description is presented for a new
myxozoan species, Henneguya ghaffari, which infects the Nile perch Lates
niloticus (Linnaeus, 1758) in Lake Wadi El-Raiyan in Egypt. The spore is
characterized by a triangular thickening at the base of the caudal processes.
The relatively long caudal processes run adherent to each other for two-thirds
of their length, then bifurcate to very fine processes. Prevalence of infection
was 34.6% and peaked during winter and early spring. The infection was
concentrated along the intestinal tract, and in severe cases gills and
gill rakers were also infected. Histology revealed that, in contrast to
findings of previously published works on related species, intralamellar
plasmodia did not develop inside the blood capillaries of the gills. Intestinal
plasmodia were very pathogenic due to their large number and size. These
plasmodia caused atrophy of the muscularis layer, and replaced and distended
the submucosal and mucosal layers. The validity of some Henneguya species
in Africa is discussed.
Almeida,-M.; Berthe,-F.; Thebault,-A.; Dinis,-M.T. Whole clam culture as a quantitative diagnostic procedure of Perkinsus atlanticus (Apicomplexa, Perkinsea) in clams Ruditapes decussatus, Aquaculture 1999 vol. 177, no. 1-4, pp. 325-332 The protozoan parasite Perkinsus atlanticus (Azevedo,
1989) causes severe losses among cultured clams, Ruditapes decussatus.
This parasite is routinely diagnosed by means of histology or incubation
of gills in fluid thioglycollate medium. However, in order to develop models
of experimental reproduction of the disease, a procedure for infection
intensity evaluation was required. Thus, a diagnostic method has been developed,
based on the culture of all clam tissues in fluid thioglycollate medium,
followed by sodium hydroxide lysis, and iodine staining of the parasites
on cellulose filters. This method was compared with histology. Results
suggest that histology is not sensitive enough to detect low levels of
infection. The whole-clam culture technique allows detection of low levels
or early infection of clams by P. atlanticus. Moreover, this method provides
a quantification of infection intensity as number of parasites per gramme
wet weight tissue.
Amaro,-C.; Hor,-L.-I.; Marco-Noales,-E.; Bosque,-T.; Fouz,-B.; Alcaide,-E. Isolation of Vibrio vulnificus serovar E from aquatic habitats in Taiwan, Applied-and-Environmental-Microbiology [Appl-Environ-Microbiol] 1999 vol. 65, no. 3, pp. 1352-1355 The existence of strains of Vibrio vulnificus serovar E that are avirulent for eels is reported in this work. These isolates were recovered from water and oysters and differed from eel virulent strains in (i) fermentation and utilization of mannitol, (ii) ribotyping after HindIII digestion, and (iii) susceptibility to eel serum. Lipopolysaccharide of these strains lacked the highest molecular weight immunoreactive bands, which are probably involved in serum resistance. Amcoff,-P.; Boerjeson,-H.; Landergren,-P.; Vallin,-L.; Norrgren,-L. Thiamine (vitamin B sub(1)) concentrations in salmon (Salmo salar), brown trout (Salmo trutta) and cod (Gadus morhua) from the Baltic Sea, Ambio 1999 vol. 28, no. 1, pp. 48-54 The sea-run Baltic salmon populations are affected by the M74 syndrome, an early life-stage mortality associated with low thiamine (vitamin B sub(1)) concentrations in the offspring. In order to study whether sea-run brown trout with symptoms and mortalities similar to M74 also suffer from low thiamine concentrations, analyses of thiamine were performed. Also, tissues of Baltic cod were analyzed for their content of thiamine. This study confirms that Baltic salmon that are affected by M74 suffer from low thiamine levels and that the temporal onset of the development of M74 may be correlated to the thiamine concentration in the eyed egg. Also, thiamine concentrations of muscle and ovaries from females that produced offspring with M74 were significantly lower than those of females that produced healthy progeny, which indicates that M74 may be a maternally transmitted thiamine deficiency. Preliminary data from searun Baltic brown trout showed that yolk-sac fry with symptoms that resembled those of M74-lethargy, darkening of skin and 100% mortality-had low mean thiamine concentrations (0.14 nmol g super(-1) in 1994 and 0.34 in 1998) compared with those of healthy progeny (4.4 nmol g super(-1) in 1994 and 3.9 in 1998. This indicates that some family groups of Baltic brown trout may be affected by a reproduction disorder related to thiamine deficiency. In spawning Baltic cod, hepatic and ovarian thiamine concentrations showed great variance, with values ranging from 0.56 to 4.7, and 3.8 to 30 nmol g super(-1), respectively. Whether Baltic cod also suffer from mortality associated with a thiamine deficiency is not known. Amcoff,-P.; Lundstroem,-J.; Teimert,-L.; Boerjeson,-H.; Norrgren,-L. Physiological and morphological effects of microinjections of oxythiamine and PCBs in embryos of Baltic salmon (Salmo salar): a comparison with the M74 syndrome, Ambio 1999 vol. 28, no. 1, pp. 55-66 Since 1974, sea-run Baltic salmon (Salmo salar) populations have been afflicted by an early life-stage mortality known as the M74 syndrome. The syndrome has been shown to be associated with a thiamine (vitamin B,) deficiency that causes neurological disturbances associated with necrotic brain cells. Treatment with thiamine may counteract development of M74. In this study, eyed eggs of sea-run Baltic salmon were given the thiamine antagonist oxythiamine and the commercial PCB-blend Clophen A50 by means of microinjection into the yolk sac. The aim was to study the effects of an experimentally induced thiamine deficiency and how it affected the biotransformation system CYP1A using the 7-ethoxyresorufin-O-deethylase (EROD) assay. After hatching, we attempted to reverse the deficiency in half of each exposure group by immersion in a thiamine solution and investigated its effect on survival and ERODactivity. Yolk-sac fry from groups of eggs that were injected with oxythiamine, either with or without Clophen A50, demonstrated a loss of co-ordination, lethargy, exophthalmia, and whitened liver followed by complete mortality (100%). Based on this and the time to death, between 124-193 posthatch degree-days (d degree C), the effects of oxythiamine were comparable to those of M74-development, however, dissimilarities were also noted. Thiamine treatment of oxythiamine injected groups delayed mortalities that were reduced to between 64.8 and 91.8%. A dose and time-dependent induction of EROD-activity recorded for Clophen A50 groups was strongly suppressed in oxythiamine groups. Histopathological examination of oxythiamine groups at 103 and 182 d degree C revealed reduced levels of hepatic glycogen, degenerating hepatocytes and a higher prevalence of necrotic brain cells, all of which are pathological features found in salmon yolksac fry affected by M74. Groups injected with Clophen A50 demonstrated no histopathological changes. Beaman,-H.J.; Speare,-D.J.; Brimacombe,-M. Regulatory Effects of Water Temperature on Loma salmonae (Microspora) Development in Rainbow Trout, Journal-of-Aquatic-Animal-Health [J-Aquat-Anim-Health] 1999 vol. 11, no. 3, pp. 237-245 Water temperature, a pivotal factor influencing interactions between teleosts and pathogens, was examined to determine its effects on the kinetics of xenoma formation and dissolution subsequent to experimental exposure of rainbow trout Oncorhynchus mykiss to the microsporidian gill pathogen Loma salmonae. The permissive water temperature range in which xenomas developed was between 9 degree and 20 degree C. Parasite development was arrested at temperatures outside this range, as indicated by the absence of visible xenomas among exposed fish. In addition, when these trout were subsequently moved to temperatures within the permissive range, xenomas failed to develop. Water temperature, within the permissive range, had no significant effect on either the number of xenomas that formed or the proportion of fish that developed xenomas following gastric intubation with a standard dose of spores. The relationship between water temperature and xenoma onset-time was best described (R super(2) = 88.3%) by polynomial regression analysis: onset = 320 - 33.4T + 0.9547T super(2), where T is temperature ( degree C). Xenoma onset rate was also described through a modified degree-days model, yielding a predictive equation appropriate for use under conditions of fluctuating temperature. The thermal units, expressed as days X ( degree C above 7 degree C) necessary for xenoma onset were 298.6 on average. Xenoma dissolution rates, from the time of onset, also appeared to have a trend; more rapid dissolution occurred as temperatures increased. However. this trend correlated minimally with regression models. Begg,-G.S.; Bruno,-D.W. The common dab as definitive host for the Pennellid copepods Lernaeocera branchialis and Haemobaphes cyclopterina, Journal-of-Fish Biology [J-Fish-Biol] 1999 vol. 55, no. 3, pp. 655-657 Seven (0.039%) and five (0.028%) of 18 163 common dab from the east coast of Scotland were definitive hosts to Lernaeocera branchialis and to Haemobaphes cyclopterina, respectively. Both represent new host records. Muscle necrosis and localized haemorrhage were associated with H. cyclopterina infestation and as described from other definitive hosts. Belas,-R.; Faloon,-P.; Hannaford,-A. Potential applications of molecular biology to the study of fish mycobacteriosis, ANNU.-REV.-FISH-DIS. 1995 vol. 5, pp. 133-173 Fish mycobacteriosis is a chronic bacterial disease that has the potential for infecting most fish species from both freshwater and saltwater habitats. The causative agents of fish mycobacteriosis are three species of Mycobacterium: M. chelonae, M. fortuitum, and M. marinum. Infections of fish by these bacteria result in a slow, degenerative disease with symptoms that include wasting, fading of color, exophthalmia, and frequently, granulomas and other types of skin ulcers. The disease is transmissible from fish to fish and also from fish to man, where the bacteria produce a potentially serious medical condition. Little is known about the molecular biological aspects of the disease or the host-pathogen interactions. Using the knowledge gained from recent advances in the study of M. tuberculosis and other human mycobacterial pathogens, we suggest a set of strategies to begin a molecular biological study of fish mycobacteriosis. Although no conclusions may be drawn at this early stage in understanding this disease, the prospects are very good that the techniques of molecular biology will shed light on this longstanding and misunderstood disease. Ferraz,-E.; Sommerville,-C. Pathology of Piscinoodinium sp. (Protozoa: Dinoflagellida), parasites of the ornamental freshwater catfishes Corydoras spp. and Brochis splendens (Pisces: Callichthyidae), Diseases-of-Aquatic-Organisms [Dis-Aquat-Org] 1998 vol. 33, no. 1, pp. 43-49 Piscinoodinium sp. (Protozoa, Dinoflagellida) was commonly found on routine smears of samples of Brochis splendens and Corydoras spp. imported into Britain from South America, and on samples of the same group of fish examined at the exporters' holding facilities in Brazil. Infected fish had trophonts of different sizes on the gills and skin. In histological sections of the skin, the trophonts were found to be attached within depressions of different depths or enclosed by hyperplastic epithelial cells. Such enclosed trophonts have not previously been reported. Since some of the enclosed trophonts were dead, it was thought that enclosure was a result of the deep penetration of the trophont and the host defence mechanism. On the gills the Piscinoodinium infection was commonly associated with epithelial hypertrophy, focal and diffuse hyperplasia, oedema of the respiratory epithelium and lamellar fusion. The presence of this protozoan on different species of fish from the same shipment suggests that the infection was acquired before export. The source of infection and the stages of the export process which expose the fish to the highest risk of infection are discussed. Fischer,-K. Avoiding diseases in hatchery systems,m FISH-FARM.-INT. 1997 vol. 24, no. 1, vp In the farming of salmon and trout, diseases are notorious hazards in the hatchery. Initials such as PKD, IPN, IHN roll off like codes, but it is no secret that they can bring heavy losses to hatchery operators through most of Europe. Infectious pancreatic necrosis (IPN) has for many years caused high mortalities among first feeders, often up to 90 per cent in Danish rainbow trout hatcheries. Since the mid-1980s, the so-called young fry disease has also brought heavy economic losses. Fishelson,-L.; Becker,-K. Rodlet Cells in the Head and Trunk Kidney of the Domestic Carp (Cyprinus carpio): Enigmatic Gland Cells or Coccidian Parasites?, Naturwissenschaften 1999 vol. 86, no. 8, pp. 400-403 Rodlet cells have been found in the head and trunk kidneys
of the common carp (Cyprinus carpio L.). From an experimental sample of
50 carps of various ages, we detected these cells in only seven fishes,
contradicting the hypothesis that they constitute a normal component of
the fish epithelia. The rodlet cells have a typical structure: 12-16 mu
m in diameter, with a basal nucleus various in form, and an encasing layer
of fibrillar structure. The cells contain rodlets, composed of elongated,
opaque sacs featuring dark rods in the center, which strongly elongate
in ripening cells. Remarkable pseudopodia-like extensions from the apical
parts of the rodlet cells penetrate into the delicate blood vessels and
sinusoids of the organs. The encasing layer at the cell apex then opens
to release the rodlets into the bloodstream. No junctions were found between
the rodlet cells and neighboring cells. It is suggested that these cells
comprise some kind of "symbiosis" between leukocyte, possible granulocyte
cells, and the parasitic rodlets. The cells serve the rodlets as an incubation
chamber, as well as a means of transportation into the bloodstream after
ripening.
Comparative susceptibilities of salmonid species in Alaska to infectious hematopoietic necrosis virus (IHNV) and North American viral hemorrhagic septicemia virus (VHSV)Follett,-J.E.; Meyers,-T.R.; Burton,-T.O.; Geesin,-J.L.,J.-AQUAT.-ANIM.-HEALTH 1997 vol. 9, no. 1, pp. 34-40 Juveniles of eight Alaskan salmonid species were exposed to waterborne challenges of infectious hematopoietic necrosis virus (IHNV) and North American viral hemorrhagic septicemia virus (VHSV) to determine individual host susceptibilities for potential disease management purposes. Challenges with each of the viruses were conducted at doses of 10 super(3) and 10 super(5) plaque-forming units (pfu) per milliliter for 1 h. Duplicate tanks were exposed at each dose level; one tank was monitored for fish mortality and the other for virus replication at 5-d intervals. Arctic char Salvelinus alpinus, Arctic grayling Thymallus arcticus, and pink salmon Oncorhynchus gorbuscha were refractory to experimental infection with IHNV, whereas lake trout S. namaycush supported limited replication of the virus with associated clinical disease. Mortality of lake trout ranged 5-15% higher than mortality of fish not exposed to IHNV. Similarly exposed sockeye salmon O. nerka used as positive controls for susceptibility to IHNV sustained dose-dependent losses of 48% (low dose) and 85% (high dose) with typical signs of IHNV disease. Coho salmon O. kisutch, chinook salmon O. tshawytscha, and pink and sockeye salmon were refractory to VHSV after waterborne virus exposure. However, rainbow trout O. mykiss exhibited clinical signs of disease and a virus-specific mortality of 12% after VHSV exposure of 10 super(5) pfu/mL. Khan,-M.H.; Marshall,-L.; Thompson,-K.D.; Lilley,-J.H. Susceptibility of five fish species (Nile tilapia, rosy barb, rainbow trout, stickleback and roach) to intramuscular injection with the oomycete fish pathogen, Aphanomyces invadans, Bull-Eur-Assoc-Fish-Pathol 1998 vol. 18, no. 6, pp. 192-197 Tilapia (Oreochromis niloticus), rosy barb (Puntius schwanenfeldi), rainbow trout (Oncorhynchus mykiss), roach (Rutilus rutilus) and stickleback (Gasterosteus aculeatus) were challenged with Aphanomyces invadans, the Oomycete fungus considered to be the causative agent of epizootic ulcerative syndrome (EUS). At least 16 fish of each species were injected intramuscularly with 1-15 x 10 super(3) zoospores of A. invadans, kept at 11-24 degree C depending on species, and periodically sampled for histology and immunohistochemistry using anti-A. invadans polyclonal antiserum. Most tilapia remained healthy throughout the experiment with no significant histopathological changes, except for two tilapia, which died on day 20 and 21 post-injection (p.i.) showing invasive fungal growth and typical EUS-type lesions. All rosy barbs rapidly developed clinical signs of EUS. Fungus was seen in histological sections by day 7 p.i. In addition, all fish died by day 22 p.i. Rainbow trout also demonstrated signs of fungal growth and the progressive development of lesions, but these occurred at a slower rate than in the rosy barbs. The sticklebacks remained clinically and histologically normal, except for two fish, which died on day 13 p.i. with fungal infection of the integument and peritioneal cavity. However, this is believed to have been a secondary non-invasive fungus. Most roach displayed some scale loss and mild histological changes, but two roach sampled on days 25 and 35 p.i., showed typical EUS histopathology with fungal hyphae associated with muscle necrosis and a granulomatous inflammatory response. Khan,-R.A.; Payne,-J.F. A multidisciplinary approach using several biomarkers, including a parasite, as indicators of pollution: a case history from a paper mill in Newfoundland,Parassitologia 1997 vol. 39, no. 3, pp. 183-188 Several biomarkers are currently used to determine chronic exposure of fish to environmental contaminants. In studies to assess the effects of pulp mill effluent on winter flounder (Pleuronectes americanus), body and hepatosomatic indices (HSIs), histopathology, levels of hepatic detoxifying enzymes, mixed function oxygenases (MFO), muscle acetylcholinesterase (Ache) and selected parasite abundance were compared in samples taken near a paper mill (sulphite-bleaching) and a number of reference sites. Our studies revealed a number of significant (P<0.05) differences between samples taken near the paper mill and reference sites. Flounder captured at two locations near the mill were greater in length and weight, had elevated HSIs and more lesions in the liver and spleen while an acanthocephalan, Echinorhynchus gadi, located in the digestive tract, was lower than at more distant sites. Activity of MFO and Ache were similar at most sites and might be a reflection of the fish's foraging behaviour and consequently intermingling of populations from different locations during summer. These results support the view that several biomarkers should be utilised when assessing the health of fish living in habitats degraded by pollutants. Kim,-K.H.; Choi,-E.S. Treatment of Microcotyle sebastis (Monogenea) on the gills of cultured rockfish (Sebastes schelegeli) with oral administration of mebendazole and bithionol, AQUACULTURE 1998 vol. 167, no. 1-2, pp. 115-121 Oral administration of mebendazole or bithionol for the control of Microcotyle sebastis were evaluated by applying a single high dosage using a intubation tube or multiple low dosages in the diet. A single dose of 50 mg mebendazole/kg B.W., 100 mg bithionol/kg B.W. or 200 mg bithionol/kg B.W. significantly reduced the number of parasites on the gills of infected fish. The monogeneans in two groups intubated bithionol were completely eliminated. The number of M. sebastis in groups fed experimental diets supplemented with mebendazole or bithionol was significantly lower than that from the control group. Lapierre,-L.A., Molecular Characterization of Two Retroviruses Associated with Walleye Discrete Epidermal Hyperplasia, Dissertation-Abstracts-International-Part-B:-Science-and-Engineering [Diss-Abst-Int-Pt-B-Sci-and-Eng] 1998 vol. 59, no. 4, [np] Walleye discrete epidermal hyperplasia (WEH) is a hyperproliferative
skin disease of walleye fish that appears and regresses on a seasonal basis.
Presented herein is work that describes the cloning and molecular characterization
of two new piscine retroviruses, walleye epidermal hyperplasia viruses,
type 1 and type 2 (WEHV1 and WEHV2) that are associated with WEH. WEHV1
and/or WEHV2 were found to be associated with WEH by PCR, Southern and
Northern blot analysis. The viruses were cloned and sequenced showing they
are related to one another and to walleye dermal sarcoma, a large complex
retrovirus that is etiologically associated with dermal sarcoma. WEHV1,
WEHV2, and WDSV have a similar genomic organization; each has three open
reading frames in addition to gag, pol, and env. The orfA and orfB genes
are located downstream of env, and orfC is located upstream of gag. Comparative
sequence analysis of WEHV1, WEHV2, and WDSV showed that their OrfA genes
encode cyclin D homologs (rv-cyclins). Since D-type cyclins regulate cell-cycle
progression at the G1/S boundary, and overexpression of human cyclin D1
occurs in many types of human tumors, we hypothesize that the rv-cyclins
induce cell proliferation leading to epidermal hyperplasia or dermal sarcoma.
Analysis of the OrfB proteins showed that they are distantly related to
the OrfA proteins, suggesting that these genes arose by duplication. WEHV1
and WEHV2 gene expression was investigated using Northern blot analysis
and RT- PCR. Analogous to WDSV, WEHV1 and WEHV2 exhibit a complex RNA expression
pattern displaying major transcripts of about 13, 7.0, 2.6 and 1.8 kb.
Furthermore, there is temporal and differential regulation of viral gene
expression; fall lesions contain low levels of subgenomic transcripts (orfA
and orfB) and spring lesions contain abundant levels of all viral transcripts.
These results suggest that the OrfA and OrfB proteins play a central role
in viral replication. The presence of rv-cyclin transcripts (orfA) in developing
tumors (fall) is consistent with the hypothesis that the rv-cyclin proteins
contribute to disease.
Alikin,-Y.S.; Shchelkunov,-I.S.; Shchelkunova,-T.I.; Kupinskaya,-O.A.; Masycheva,-V.I.; Klimenko,-V.P.; Fadina,-V.A., Prophylactic treatment of viral diseases in fish using native RNA linked to soluble and corpuscular carriers, J.-FISH-BIOL. 1996 vol. 49, no. 2, pp. 195-205 The potential of double- (ds) and single-stranded (ss) yeast RNA preparations for protection of carp Cyprinus carpio against experimental infection with Rhabdovirus carpio, the infectious agent of spring viraemia of carp, was studied. Prophylactic intraperitoneal injection of fish with dsRNA proved efficient while ssRNA had a much smaller effect. The protective effect of yeast dsRNA in 1-year-old carp lasted for at least 3 weeks. The efficacy of the preparations decreased considerably if they were administered by the bath method. Both insoluble and soluble carriers for dsRNA were studied to increase the preparation efficacy. Screening of the preparations revealed the importance of DEAE-groups on the carriers. Their biological efficiency is confirmed by the method of phagocytosis of the mouse peritoneal macrophages. Bonami,-J.-R., Crustacean viral diseases: Recent developments, Bull.-Eur.-Assoc.-Fish-Pathol. 1997 vol. 17, no. 6, pp. 188-190 Amongst the known diseases of Crustacea, and particularly in species of economic importance, viral diseases appear now as one of the most important factors in terms of culture limitation. In farmed prawns, the Penaeids are the most extensively cultivated throughout the world and this paper focuses on them. Tools of molecular biology are now available and are very helpful in checking the health status of a shrimp population. Castric,-J., Viral diseases in fish mariculture, Bull.-Eur.-Assoc.-Fish-Pathol. 1997 vol. 17, no. 6, pp. 220-228 Viral diseases in maricultured fish species constitute a limiting factor to the development of this promising industry, mainly because of the high losses they cause in larvae and juveniles. The viruses associated with those diseases can be tentatively grouped in ten families. All countries practising fish farming and all cultivated species in seawater are concerned. If some viral diseases have direct economical consequences on the fish production, some others, due to agents of lower virulence, can decrease the resistance of fish to secondary infections or lead to clinical signs during stress or under bad environmental conditions. In numerous cases, the viruses can be transmitted by the spawners or by cultivated infected fish, but the presence of wild latently infected carriers must be considered in the open sea where sanitary measures are hardly applied. Flegel,-T.W., Major viral diseases of the black tiger prawn (Penaeus monodon) in Thailand, WORLD-J.-MICROBIOL.-BIOTECHNOL. 1997 vol. 13, no. 4, pp. 433-442 There are five different viruses which are currently being studied for their impact on commercial farming of the black tiger prawn (Penaeus monodon) in Thailand. Some of these viruses cause disease in other penaeid shrimp species and even other crustacean species. Some occur not only in cultivated shrimp in other Asian countries, but also in those from Australia and the western hemisphere. In descending order from greatest to least economic impact on the Thai shrimp industry, the five viruses are: white-spot baculovirus, yellow-head virus, hepatopancreatic parvo-like virus, infectious hypodermal and hematopoeitic necrosis virus and monodon baculovirus. The purpose of this review is to summarize recent work on these viruses and to suggest future directions of research that may be useful in the effort to develop a sustainable shrimp industry. Nakajima,-K., Viral diseases in marine aquaculture in Japan, INTERACTIONS-BETWEEN-CULTURED-SPECIES-AND-NATURALLY-OCCURRING-SPECIES-IN-THE-ENVIRONMENT. Keller,-B.J.;Park,-P.K.;McVey,-J.P.;Takayanagi,-Kazufumi;Hosoya,-Kazumi-eds. 1997 no. 24 pp. 139-144 In Japan, marine aquaculture often has mass mortalities of cultured animals due to infectious diseases. This paper reviews diseases caused by viruses. These include viral diseases of marine cultured fish, viral diseases of shrimp and possible viral diseases of cultured abalone. Olesen,-N.J.; Korsholm,-H., Control measures for viral diseases in aquaculture: Eradication of VHS and IHN, Bull.-Eur.-Assoc.-Fish-Pathol. 1997 vol. 17, no. 6, pp. 229-233 Viral haemorrhagic septicaemia (VHS) and infectious hematopoietic necrosis (IHN) are both notifiable diseases. Within the European Union it has been agreed that the economic impact of the diseases may justify an eradication policy and it has been proposed by the Scientific Veterinary Committee, subgroup Aquaculture, to include the diseases on the list of Veterinary fund in context of Council Decision 90/4240EEC. In order to ensure that member States proceeding to the eradication of VHS and IHN can act on the basis of common criteria, a report has been prepared. The present paper presents the content of this report. The report is divided into three chapters: 1) Basic, general criteria for the approval of an eradication programme for VHS and IHN, 2) Eradication strategies and, 3) Requirements on sanitation programmes presented for the Commission. Annex 1 gives recommendations for stamping-out procedures in aquaculture. It is proposed that sanitation programmes are divided in to 3 phases: Preparation, initial stamping-out programme, and total, simultaneous eradication measures. Panchayuthapani,-D.; Corpron,-K.E., Rapid diagnostic methods for viral diseases of shrimp, Fish-Chimes 1997 vol. 17, no. 2, p. 31 Pointing out the limitations of the conventional diagnostic methods in the diagnosis of viral diseases of shrimp, the paper tells about the nucleic acid based test methods with DNA probes or gene probes now available for rapid detection of most known shrimp viruses. Dot blot hybridisation, in situ hybridisation and polymerase chain reaction are the three formats available now. Shankar,-K.M.; Mohan,-C.V., Epidemiological aspects of shrimp viral diseases in India- a review, J.-Aquacult.-Trop. 1998 vol. 13, no. 1, pp. 43-49 Since July 1994, two distinct epizootics causing mass mortaliites of cultured shrimp in India have been noticed. Here, we present epidemiological, clinical and pathological evidences to suggest that the two diseases namely, Yellow-Head Disease (YHD) and White Spot Disease (WSD) are caused by two different viruses. Spann,-K.M.; Lester,-R.J.G, Viral diseases of penaeid shrimp with particular reference to four viruses recently found in shrimp from Queensland, WORLD-J.-MICROBIOL.-BIOTECHNOL. 1997 vol. 13, no. 4, pp. 419-426 The culture of penaeid shrimp world-wide is primarily dependent on wild-caught broodstock which has an enormous potential to introduce new pathogens, particularly viruses, into culture systems. Of the 13 viruses described for cultured penaeid shrimp, seven have been described within the past 5 years; the most devastating viral epidemics on record for cultured penaeid shrimp have also occurred within the past 5 years. During examination of local wild and cultured shrimp, four new viruses were found. Bennettae baculovirus was discovered in the digestive gland of wild Metapenaeus bennettae. It closely resembles monodon baculovirus (MBV) but has a more slender virion, does not cross-react with a DNA probe for MBV and is not infectious to Penaeus monodon. Two morphologically indistinguishable viruses, one pathogenic (gill-associated virus, GAV) and the other benign (lymphoid organ virus, LOV), were found in cultured P. monodon, LOV and GAV closely resemble yellow head virus (YHV) of Thailand. A parvo-like virus was found recently in dying post-larvae of P. japonicus. As the intensity of shrimp culture world-wide increases, researchers can expect to discover more penaeid viruses. The need to close the life cycle of P. monodon and other cultured species and develop rapid diagnostic methods for viral infections has become imperative. Wang,-Min; Dai,-Jixun, Viral diseases of Penaeid shrimp, Mar-Sci-Bull; Haiyang-Tongbao 1999 vol. 18, no. 5, pp. 76-85 Viral diseases of penaeid shrimp may cause high mortalities of and severe
damage to shrimp cultures. Many scientists have focused their attention
on the viral diseases of penaeid shrimp. In this paper, the authors describe
the recent progress in pathogens, transmission, diagnosis and prevention
of viral diseases of penaeid shrimp.
Internet Sites on Fish Disease The following are some Internet sites related to fish and aquamarine
life diseases. These sites contain a wealth of information in a variety
of forms, such as glossary of tems, guidelines for treatment and diagnosis,
articles, book reviews, frequently asked questions, and many
more.
Aquaculture and fish health: From DFRA
Argent Laboratories: Aquatic health care products and services.
Common Freshwater Diseases: A Glossary
Diagnosis Of Fish Diseases
Diagnostic Manual forAquatic Animal Diseases-2000-
FINS: The Fish Information Service
Fish Diseases Index: Guide picks. From Saltwater Aquariums
Fish Health Info : from the Department of Fisheries
Fishdoc : The home of fish health and fish disease diagnosis and treatment.
OIE Collaborating Centre: For Information On Aquatic Animal Diseases
The Aquaculture Health Page
The Great Lakes Fish Health Committee
The World Wide Web Vertual Library: Fish/Shellfish Diseases
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