bluuebunny/crossref_metadata_2025 huggingface dataset:
Histopathology of atypical Aeromonas salmonicida infection in Atlantic cod, Gadus morhua L.
Authors: MORRISON C.M. , CORNICK J.W. , SHUM G. , ZWICKER E.
Published: April 2006

Abstract. The histopathology of an atypical Aeromonas salmonicida found in Atlantic cod, Gadus morhua L., is described. Unlike members of the Salmonidae, the cod showed a well‐developed host reaction to A. salmonicida involving encystment of the bacteria. When Atlantic salmon, Salmo salar L., were given an intramuscular injection with suspensions of cultures of this strain of A. salmonicida no cellular host reaction was observed. When cod were given a similar injection the bacteria showed degenerative changes, leucocytes accumulated, and cyst formation was seen in the spleen and kidney. Since cod can be infected by this organism the possibility exists that they could act as carriers, a source of infection for salmonids in saltwater cage culture or in the wild.
Proliferative kidney disease of salmonid fish: a review
Authors: CLIFTON‐HADLEY R. S. , BUCKE D. , RICHARDS R. H.
Published: April 2006

Abstract A detailed review of proliferative kidney disease (PKD) in salmonids is presented. The introduction places the disease in a historical context. The various aspects of the disease are described from the existing literature, together with latest findings from current research. Particular emphasis is given to epidemiology, aetiology and pathology.
The reaction of the immune system of fish to vaccination: development of immunological memory in carp, Cyprinus carpio L., following direct immersion in Aeromonas hydrophila bacterin
Authors: LAMERS C. H. J. , de HAAS M. J. H. , van MUISWINKEL W. B.
Published: April 2006

Abstract. The development of immunological memory was investigated in carp following direct immersion in Aeromonas hydrophila bacterin. A single bath did not induce an increase in serum antibody (Ab) levels. A second bath at 1, 3 or 8 months resulted in clear secondary Ab responses. The highest Ab levels were reached in the group boosted after 3 months. However, at 12 months a second bath gave no further significant response. When a booster was given at the same intervals by intramuscular injection, instead of immersion, the induced memory was not expressed as a clear secondary response. It is concluded that direct immersion in a bacterial antigen did induce immunological memory. The duration of this slowly developing memory is limited in time (less than 12 months) and was only demonstrated following a second immersion. This last feature suggests the existence of a local or mucosal activity during the immune response after bath vaccination.
The impact of solar ultraviolet radiation upon the skin of rainbow trout, Salmo gairdneri Richardson, farmed at high altitude in Bolivia
Authors: BULLOCK A. M. , COUTTS R. R.
Published: April 2006

Abstract. The damaging effect of solar ultraviolet (UV) light upon the skin of hroodstock rainbow trout held on a high altitude fish farm in Bolivia is described. Both clinical observations and histoputhological findings confirm the lesions to be of a UV aetiology. An irradiation trial, on the same site, using juvenile rainbow trout was conducted over a 3‐month period and the sequential pathogencsis of the UV‐induced dorsal fin lesions paralleled those found in the broodstock fish. These findings are discussed in relation to the importance of recognizing sunlight as an environmental stress factor.
Sphaerospora tincae Plehn, 1925 in tench, Tinca tinca L., fry
Authors: HERMANNS W. , KÖRTING W.
Published: April 2006

Abstract. The occurrence of Sphaerospora tincae Plehn, 1925 from tench in pond farms from northern and southern Germany is reported. The parasites form large masses in the anterior part of the body displacing the head kidney. They seem to be host specific for tench and are not found in the excretory part of the kidney. Mortalities caused by rupture of the abdomen may reach 100%, but usually appear to be low.
Malachite green: a review
Authors: ALDERMAN D. J.
Published: April 2006

Abstract. A detailed review of malachite green and its chemical and physical properties as they relate to fisheries interests. Many of the confusions and misconceptions about malachite green are discussed. Its mode of action, toxicity and fate are considered.
In vitro effects of fungicides on Haliphthoros philippinensis*
Authors: LIO‐PO G. D. , BATICADOS M. C. L. , LAVILLA C. R. , SANVICTORES M. E. G.
Published: April 2006

Abstract. Pure cultures of the fungus Haliphthoros philippinensis isolated from infected Penaeus monodon larvae were exposed for 24 h to varying concentrations of the antifungal agents Benlate, calcium hypochlorite, clotrimazole, copper sulphate, Daconil, formalin, Fungitox, Furanace, griseofulvin, hydrogen peroxide, malachite green, Mysteclin C, phenol, potassium permanganate, Resiguard, Tide, tolnaftate and Treflan. The efficiency of each compound in inhibiting sporulation and mycelial growth of the fungus was measured. The results establish mycostatic and mycocidal levels for each fungicide.
Muscular and myocardial degeneration in cultured Atlantic salmon, Salmo salar L., suffering from ‘Hitra disease’
Authors: FJØLSTAD M. , HEYERAAS A. L.
Published: April 2006

Abstract. In this investigation of the condition known currently as ‘Hitra disease’, anaemia was usually seen and transudates to the peritoneal cavity and pericardial sac were often found. Muscular and myocardial degeneration were constant features and deposits of ceroid were sometimes found in the livers. Compared to similar conditions in fish and in higher animals it is reasonable to suggest that the main cause of the disease may be related to vitamin E/selenium deficiency and diets high in polyunsaturated fatty acids. The levels of unsaturated fatty acids in particular would appear of great importance in the formulation of diets for cultured salmon.
Detection of channel catfish virus in asymptomatic adult channel catfish, Ictalurus punctatus (Rafinesque)*
Authors: WISE JANET A. , BOWSER P. R. , BOYLE J. A.
Published: April 2006

Abstract. Two populations of channel catfish were examined for the presence of channel catfish virus (CCV) by use of a nucleic acid probe. In one population of 22 fish with no history of CCV, viral DNA was found in every liver. These fish had previously been examined by a technique involving co‐cultivation of their leucocytes with catfish tissue culture cells. The co‐cultivation method had identified virus in 10 of these fish. The second fish population consisted of 14 adults that had survived a CCV outbreak in 1980. Of the 14 fish, 11 showed positive indication of CCV DNA. The tissue distribution of the CCV differed from fish to fish. All fish from the first group and one fish from the second group showed some alterations in the DNA banding patterns expected from pure CCV DNA. This might be indicative of modifications in the genomic structure of the CCV DNA when the virus is latent in a fish.
Nodular gill disease: a unique form of proliferative gill disease in rainbow trout, Salmo gairdneri Richardson
Authors: DAOUST P.‐Y. , FERGUSON H. W.
Published: April 2006

Abstract. An outbreak of proliferative gill disease occurred in a group of rainbow trout fingerlings. kept for experimental purposes. Lesions were multifocal among filaments and uniquely severe in the distal region of affected filaments, forming nodules; this contrasted with the more common forms of proliferative gill disease in Ontario, such as bacterial gill disease, in which lesions are diffuse along and among filaments. The cause of the condition is unknown, although cells with a very distinctive morphology were closely associated with the lesions.
Effects of temperature and salinity on the course of infection with the haemoflagellate Cryptobia salmositica in juvenile Pacific salmon, Oncorhynchus spp.
Authors: BOWER SUSAN M. , MARGOLIS L.
Published: April 2006

Abstract. At 9°C juvenile sockeye salmon, Oncorhynchus nerka, inoculated intraperitoneally with 105Cryptobia (=Trypanoplasma) salmositica began to succumb about day 15, with mortalities exceeding 90% by day 28. Fish inoculated at 8°C and acclimatized to 13°C began to die at about the same time but total mortalities were only about 75%. At 5°C the infection progressed more slowly, with the first mortalities occurring about day 25, but the disease seemed equally as lethal as at 9°C. All fish inoculated at 8°C and acclimatized to 20°C within 11 days survived the infection. Changes in salinity from fresh to sea water (30%o salinity) at 9°C or 13°C had almost no effect on the course of infection either when presmolts were slowly acclimatized to sea water over a period of 6‐8 days or when smolts were transferred to sea water quickly (within 1‐2 days). However, there were differences in susceptibility to disease among three species of salmon of smoking age. The order of decreasing sensitivity was chinook salmon, Oncorhynchus tshawytscha, with 100% mortality, sockeye salmon with 56 to 74% mortality and coho salmon, Oncorhynchus kisutch, with no mortality.
The ontogenetic development of the reticulo‐endothelial system in the rainbow trout, Salmo gairdneri Richardson
Authors: TATNER MARY F. , MANNING MARGARET J.
Published: April 2006

Abstract. The phagocytosis of colloidal carbon in the adults and fry of Salmo gairdneri Richardson was investigated. Adult fish accumulated trapped carbon in the spleen, kidney and heart. Fry, as early as 4 days post‐hatch, had an efficient phagocytic system, the carbon being engulfed by free macrophages which accumulated in the connective tissue, under the skin, in the gut and in the gills. By 18 days post‐hatch the situation was similar to that found in the adult. The trapping of carbon in the gills of young fry is discussed, and it is suggested that it acts as a special mechanism to protect the thymus from undesirable, and possible tolerigizing antigen exposure, before immunocompetence is attained.
Immunogenicity of vaccines from a virulent and an a virulent strain of Aeromonas salmonicida
Authors: OLIVIER G. , EVELYN T. P. T. , LALLIER R.
Published: April 2006

Abstract. Injected vaccines consisting of formalin‐killed cells and extracellular antigens prepared from a virulent and an avirulent strain of Aeromonas salmonicida were tested for their efficacy in protecting juvenile coho salmon. Oncorhychus kisutch (Walbaum). Against experimental furunculosis following active and passive immunization. Sera used in the passive immunization experiments were raised in subadult coho salmon and in rabbits. Results indicated that the avirulent strain was inferior to the virulent strain in its immunogenicity for coho salmon. Thus, even though avirulent cells possessed at least one immunogen–an immunogen that was show in passive immunization experiments to be well recognized by rabbits–the immunogen was only inefficiently protection when vaccinated with avirulent cells. Furher, extracellular antigens of the avirulent strain were not protective for coho salmon even though they elicited the production of anti‐A. salmonicida agglutinins. In contrast, the killed cells and extracellular antigens of the virulent strain were both immunogenic in coho salmon. By passively immunizing coho salmon with rabbit sera raised against the virulent and the virulent strain produced at least two immunogens, only one of which was shared in common with the avirulent strain. The extra immunogen possessed by the virulent strain is presumably responsible for its superior immunogenicity in coho salmon; the immunogen had the properties of a protein and is believed to be the A‐protein.
Experimental infection of lemon sharks, Negaprion brevirostris (Poey), with Vibrio species
Authors: GRIMES D. J. , GRUBER S. H. , MAY E. B.
Published: April 2006

Abstract Healthy lemon sharks, Negaprion brevirostris (Poey), were inoculated with Vibrio carchariae and V. damsela, two vibrios known to cause disease in other shark species. Vibrio damsela was not recovered from the inoculated sharks; V. carchariae infected the healthy lemon sharks, but did not produce clinically observable disease. However, histological evaluation revealed active splenic and hepatic disease with Gram‐negative bacteria found in association with mononuclear cells. When the experiment was repeated with a physiologically compromised lemon shark, V. carchariae was lethal for the test animal, but V. damsela was again cleared. Vibrio carchariae was also isolated from skin lesions of a lemon shark infested with monogeneans (Dermophthirius nigrellii). Histological evidence indicated that this shark died of protozoan infection. Thus, lemon sharks are susceptible to infection with V. carchariae which can cause subclinical disease in otherwise healthy specimens. We suggest that D. nigrellii may act as a vector of V. carchariae and that stress plays a role in the clinical manifestation of this disease.
The ontogenetic development of the reticulo‐endothelial system in the rainbow trout, Salmo gairdneri Richardson
Authors: TATNER MARY F. , MANNING MARGARET J.
Published: April 2006

Abstract The phagocytosis of colloidal carbon in the adults and fry of Salmo gairdneri Richardson was investigated. Adult fish accumulated trapped carbon in the spleen, kidney and heart. Fry, as early as 4 days post‐hatch, had an efficient phagocytic system, the carbon being engulfed by free macrophages which accumulated in the connective tissue, under the skin, in the gut and in the gills. By 18 days post‐hatch, the situation was similar to that found in the adult. The trapping of carbon in the gills of young fry is discussed, and it is suggested that it acts as a special mechanism to protect the thymus from undesirable, and possible tolerigizing antigen exposure before immunocompetence is attained.
Proliferative kidney disease in brown trout, Salmo trutta L., and Atlantic salmon, Salmo salar L., parr: histopathological and epidemiological observations
Authors: ELLIS A. E. , McVICAR A. H. , MUNRO A. L. S.
Published: April 2006

Abstract Proliferative kidney disease (PKD) has been described in cultivated rainbow trout but major outbreaks have not been recognized in other fish species. This paper describes light and electron microscope studies and presents epidemiological data of a disease condition in first summer Salmo salar parr and S. trutta, which is associated with an organism apparently identical to the aetiological agent of PKD. The pathology was found to be similar to that described for PKD in rainbow trout. The epidemiology in the brown trout suggests that exposure after May does not result in infection. The data from the outbreaks in two salmon hatcheries appear complex and suggest different susceptibilities to PKD among salmon originating from different sources.
Evaluation of antimicrobial compounds for the control of bacterial kidney disease in rainbow trout, Salmo gairdneri Richardson
Authors: AUSTIN B.
Published: April 2006

Abstract From a comparison of over 70 antimicrobial compounds by in vitro and in vivo methods, it was found that clindamycin, erythromycin, kitasamycin, penicillin G and spiramycin could be used successfully for combating early clinical cases of bacterial kidney disease (BKD) in rainbow trout, Salmo gairdneri Richardson. In addition, cephradine, lincomycin and rifampicn were effective for chemoprophylaxis of BKD, although they were of no use for therapeutic purposes.
Notes on kidney‐infecting species of the genus Sphaerospora Thélohan (Myxosporea), including a new species S. gobionis sp.nov., and on myxosporean life cycle stages in the blood of some freshwater fish
Authors: LOM JIŘÍ , PAVLÁSKOVÁ MILENA , DYKOVÁ IVA
Published: April 2006

Abstract Freshwater fish in Czechoslovakia were examined for species of the genus Sphaerospora Thélohan, 1892 and for myxosporean life cycle stages in the blood. In addition to perch infected with S. pectinacea Bocharova & Donets, 1974, renal tubules of seven host species harboured thus far unidentified Sphaerospora species. A new species, S. gobionis sp.nov. is described from renal tubules of Gobio gobio. In populations of Gobio gobio, Tinea tinea and Rutilus rutilus harbouring infections with different Sphaerospora species, organisms identified as mobile myxosporean life cycle stages were detected in the blood, where they undergo a proliferative cycle. These organisms were reminiscent of stages in the blood of common carp fingerlings, supposedly identical with Sphaerospora renicola Dyková & Lorn. It is possible that the blood stages found in the three cyprinid hosts represent stages of the life cycle of their respective Sphaerospora species. If this is correct, further studies may show if the presence of proliferative stages in the bloodstream is a character distinctive of the genus Sphaerospora.
Niacin requirement for optimum growth, feed conversion and protection of rainbow trout, Salmo gairdneri Richardson, from ultraviolet‐B irradiation
Authors: POSTON H. A. , WOLFE MARILYN J.
Published: April 2006

Triplicate groups of 75 rainbow trout, Salmo gairdneri Richardson, (mean weight 0–76 g) were fed a semipurified diet containing added niacinamide in amounts of 0.0, 1.25, 2.5. 5, 10, 20, 40, 80 or 160 mg/kg diet (ppm), for 16 weeks to determine the amount of niacinamide needed for optimum growth, feed conversion, and prevention of dermatopathy induced by UV light. At the end of the study, fish were exposed to a 275‐W sun lamp limiting in the UV‐B spectrum (280–360 UV) for 20h. Trout fed no supplemental niacinamide grew significantly slower than all other fish. Growth increased with each niacinamide increment through 10ppm. but not at higher increments. Feed conversion paralleled growth response to niacinamide. Exposure to UV light induced dermal lesions in trout fed less than 10ppm niacinamide. Initially, focal white spots appeared anterior to the dorsal fin, and caudal and pectoral fins became depigmented and translucent. Later, extensive erosion in caudal and pectoral fins was accompanied by desquamation of the epidermis and underlying tissues of the caudal peduncle, head and snout. Results indicated that rainbow trout need at least 10ppm niacinamide for optimum growth, feed conversion and protection against 'sunburn’caused by UV light.
Acid water and aluminium exposure: gill lesions and aluminium accumulation in farmed brown trout, Salmo trutta L.
Authors: KARLSSON‐NORRGREN L. , DICKSON W. , LJUNGBERG O. , RUNN P.
Published: April 2006

Abstract. Brown trout, Salmo trittta L., from two fish farms, situated within acid‐susceptible areas in Sweden, were studied with respect to aluminium accumulation and gill pathology. The total aluminium concentrations, after liming of the water in both farms, were between 200 and 300μg/1 at sampling. Brown trout from a third farm in a non‐acidified area (total aluminium concentration of water 35μg/1 were included as a control. The aluminium concentrations in gills from farmed brown trout in acidified areas were approximately 20μg/g and 90μg/g wet weight respectively compared with approximately 2μg/g wet weight in control brown trout gills. Light‐ and electron microscopic examination disclosed two major types of gill lesions characterized by chloride cell hyperplasia in the secondary lamellar epithelium and enlargement of the intercellular spaces in the secondary lamellar epithelium. The difference in the aluminium speciation and accumulation may explain the difference in the gill pathology of farmed fish from acidified areas. The chloride cell hyperplasia together with a relatively low aluminium accumulation is considered to reflect a long‐term exposure effect.
Acid water and aluminium exposure: experimentally induced gill lesions in brown trout, Salmo trutta L.
Authors: KARLSSON‐NORRGREN L. , BJÖRKLUND I. , LJUNGBERG O. , RUNN P.
Published: April 2006

Abstract. Brown trout gills were examined after exposure to different aluminium concentrations (50, 200,500μg/1) at pH 5.5 and 7.0 for up to 6 weeks. The influence of humus (Pt 0, Pt 20) and water temperature (2.5°C, 15°C) was recorded. The gill structure was studied by light, scanning and transmission microscopy, together with a complementary morphometric analysis of centrally located secondary lamellae. Low water temperature (2.5°C) resulted in advanced gill lesions after exposure to aluminium at pH 5.5. The lesions were characterized by enlargement of the secondary lamellae due to an increased number of chloride cells in the epithelia. Furthermore, the chloride cells contained cytoplasmic aluminium precipitates. Addition of humus (Pt20) or increased pH (7.0) reduced or inhibited the effects of aluminium on the gills. A high water temperature (15°C) reduced the early gill lesions observed after exposure to water at 2.5°C. Prolonged exposure to a temperature of 15°C resulted in alterations in the gill structure in all groups, including the control group.
Protection against enteric redmouth disease in rainbow trout, Salmo gairdneri Richardson, after vaccination with Yersinia ruckeri bacterin
Authors: COSSARINI‐DUNIER MURIEL
Published: April 2006

Abstract. Rainbow trout, Salmo gairdneri Richardson, (average weight 100g) were vaccinated intraperitoneally (i.p.) with Yersinia ruckeri bacterin in saline or in oily adjuvant. Agglutinating antibody kinetics were followed during 445 days before challenge (1.2×107 bacteria i.p.). Fourteen days after challenge 88.5% of the control fish had died while few mortalities were observed with vaccinated fish regardless of their agglutinating titre. Protection against Y. ruckeri does not seem to be due to antibodies.
Aeromonas hydrophila B‐haemolysin: purification and examination of its role in virulence in 0‐group channel catfish, Ictalurus punctatus (Rafinesque)
Authors: THUNE R. L. , JOHNSON MAUREEN C. , GRAHAM T. E. , AMBORSKI R. L.
Published: April 2006

Abstract. A single step procedure for purification of B‐haemolysin from Aeromonas hydrophila is described which recovered 94% of the haemolytic activity with a sixfold increase in specific activity. Toxicity of haemolysin in 0‐group channel catfish was 0–6 mg of purified protein per gram offish. Of six strains of A. hydrophila evaluated for differential toxin production and virulence in 0‐group channel catfish, three B‐haemolysin‐deficient strains were virulent while three B‐haemolysin‐producing strains were avirulent.
Light and electron microscopic studies on Epieimeria anguillae (Léger & Hollande, 1922), a coccidium parasitizing the European eel, Anguilla anguilla L.
Authors: MOLNÁR K. , BASKA F.
Published: April 2006

Abstract. The foregut of eels naturally infected by Epieimeria anguillae (Léger & Hollande, 1922) was studied by light and electron microscopy. It has been established that this parasite, which develops in a characteristic location on the surface of epithelial cells, and was classified on this basis by Dyková & Lom (1981) as a member of the genus Epieimeria, undergoes intracellular merogony and gamogony similarly to other eimerians; however, its sporogony takes place outside the fish or intercellularly. The trophozoites and merogonic and gamogonic stages each develop in a para‐sitophorous vacuole which is half embedded in the epithelial cell and protrudes into the intestinal lumen. The parasitophorous vacuote is surrounded by a single membrane; however, towards the intestinal lumen it is covered also by the cell membrane. In its location, Epieimeria anguillae resembles cryptosporidia, but differs from the latter significantly in its relationship with the host cell.
Mycoplasma contamination in fish cell lines: an evaluation of detection by differential incorporation of 3H‐uridine and 14C‐uracil
Authors: SCHULTZ C. L. , LIDGERDING B. C. , McALLISTER P. E. , HETRICK F. M.
Published: April 2006

Abstract. Differential incorporation of uridine and uracil was used to assay for mycoplasma contamination in five fish cell lines: bluegill fry (BF‐2), chinook salmon embryo (CHSE‐214), epithelioma papillosum cyprini (EPC), fathead minnow (FHM) and rainbow trout gonad (RTG‐2). The method was not suitable for monitoring BF‐2, CHSE‐214, FHM, and RTG‐2 cell lines because they incorporated uracil. Differential incorporation of uridine and uracil may be applicable for screening EPC cells because only this cell line could distinguish cultures experimentally infected with Mycoplasma orale from cultures known to be free from microbial contaminants.
Histopathology of leech, Austrobdella bilobata Ingram, infestation on the yellowfin bream, Acanthopagrus australis (Günther), in northern New South Wales
Authors: ROUBAL F. R.
Published: April 2006

Abstract. The histopathology of leech, Austrobdella bilobata, infestation on the upper palate and pelvic fin of the yellowfin bream, Acanthopagrus australis (Günther), is described. The feeding site was often haemorrhagic and swelling surrounded the attachment site. Histological examination revealed massive cellular infiltration (predominantly lymphocyte and macrophage) in the submucosa beneath the feeding and attachment sites. The latter also had a complete erosion of the integument beneath the parasite. Localized proliferation of connective tissue fibres and zones of necrosis and oedema were present in some cases.
Hepatic microsporidiosis of juvenile grey mullet, Chelon labrosus (Risso), due to Microgemma hepaticus gen.nov. sp.nov.
Authors: RALPHS J. R. , MATTHEWS R. A.
Published: April 2006

Abstract. Microgemma hepaticus gen.nov. sp.nov. is described from the liver of juvenile grey mullet, Chelon labrosus (Risso). Development occurs within xenomas (diameter 500μm) which have microvillar surfaces, encircling bands of mitochondria and a reticulate hypertrophic nucleus. Vegetative developmental stages, meronts, are plasmodial and divided by plasmotomy. These stages are enclosed by host membranes. Sporogonic stages are free in the cytoplasm and divide by multiple exogenous budding. Uninucleate spores (2·4μm × 4·2μm) possess 7–9 coils of the polar filament and a lamellar polaroplast. Xenomas are associated with liver connective tissue, and cause necrosis of adjacent liver cells in certain circumstances. Host response to infection involves leucocyte infiltration and granuloma formation, with spores being destroyed by repeated macrophage phagocytosis and necrosis and resulting in gradual resolution of the lesion. Although juveniles apparently tolerate large parasite burdens there is some evidence of a contribution by the parasite to stress‐related mortality. The transmission of the disease and its potentially high pathogenicity to larval fishes is discussed.
Toxicity to marine bivalves of culture supernatant fluids of the bivalve‐pathogenic Vibrio strain NCMB 1338 and other marine vibrios
Authors: NOTTAGE A. S. , BIRKBECK T. H.
Published: April 2006

Abstract. Culture supernatant fluids from twelve Vibrio strains were toxic to spat of the European and Pacific oysters, Ostrea edulis L., and Crassostrea gigas L. At least three factors were present in culture supernates of one of the most virulent strains (NCMB 1338). The first was a heat‐labile protein of molecular weight approximately 39000 which was lethal to oyster spat. This toxin was released during the stationary phase of culture and 72‐h culture supernates contained 23·0LC50ml when assayed against 2–3 mm Crassostrea gigas spat for 24 h at 20°C. Under the same assay conditions, 7‐mm C. gigas spat were six times less sensitive to the toxin. The second factor was a relatively heat‐stable ciliostatic toxin of molecular weight < 5000 and the third a proteinase of molecular weight 30000 which degraded gill segments of Mytilus edulis L. In addition, a haemolysin of molecular weight 20000 was produced. All these factors could be involved in the pathogenesis of ‘vibriosis’ in oyster larvae.
Therapeutic aminoglycoside antibiotic levels in brown shark, Car char hinus plumb eus (Nardo)
Authors: STOSKOPF M. K. , KENNEDY‐STOSKOPF SUZANNE , ARNOLD JILL , ANDREWS J. , PERLSTEIN MARIE T.
Published: April 2006

Abstract. The kinetics of gentamicin and tobramycin in juvenile brown sharks, Carcharhinus plumbeus (Nardo), were studied using a commercially available radioimmune assay (Clinical Assays, Cambridge, Massachusetts). Preliminary recovery studies in vitro demonstrated 95% recovery of antibiotic spiking with no detection of interfacing substances. There were no differences between serum and plasma data using this assay. Both drugs demonstrated distinct two‐compartment characteristics. The mean half‐life of the alpha component was 5.4±1.0 h for gentamicin and 3.2±0.5 h for tobramycin. The half‐lives of the beta components were markedly longer, 54±4.9 h for gentamicin and 48±2 h for tobramycin. The experimental designs could not exclude third compartments. A therapeutic dosage schedule for gentamicin of 2 mg/kg intramuscularly followed by 1 mg/kg at 8 and 72 h was tested. This schedule avoided plasma levels greater than 12μg/ml and troughs greater than 2 μg/ml but more frequent administration may be required to treat infections with bacteria which are less sensitive to aminoglycoside antibiotics. A therapeutic tobramycin schedule of 2.5 mg/kg intramuscularly followed by 1.0 mg/kg, 4 h later and daily thereafter, achieved plasma levels within the human therapeutic range (5.8μg/ml) on the second day of therapy. Levels considered toxic to humans were not reached for 5 days.
Aphanomyces astaci: isolation and culture
Authors: ALDERMAN D. J. , POLGLASE JANE L.
Published: April 2006

Abstract. Methods for the isolation and culture of Aphanomyces astaci, the causative organism of crayfish plague, are presented. The sensitivity of the pathogen to various antimicrobial agents was investigated, and a combination of penicillin G and oxolinic acid was chosen to provide a selective medium for isolation. A full description of the pathogen as isolated from a recent British outbreak of crayfish plague is presented, giving new descriptive details lacking in the classical descriptions of the organism.
Eimeria scardinii Pellérdy and Molnár, 1968 in the kidneys of Rutilus rutilus (L,) and Scardinius erythrophthalmus (L.) from northern Greece
Authors: ATHANASSOPOULOU‐RAPTOPOULOU F. , VLEMMAS J.
Published: April 2006

Abstract. The occurrence of Eimeria scardinii in roach, Rutilus rutilus (L.), and rudd, Scardinius erythrophthalmus (L.), from a lake in northern Greece is reported. The coccidium was found in the renal haemopoiettc tissue, mainly in the form of mature sporulated oocysts. The morphology and dimensions of the parasite, as well as the host reaction, were very similar in both species of fish examined. The overall prevalence of infection in roach and rudd was 6·67% and 6·3%, respectively. The prevalence of infection of roach was higher during summer (22·22%) but less than 5% in other seasons.
Granulomatous nodules in fish: an experimental assessment in rainbow trout, Salmo gairdneri Richardson, and turbot, Scophthalmus maximus (L.)
Authors: BALOUET G. , LAURENCIN F. BAUDIN
Published: April 2006

Abstract. In an attempt to obtain information on the aetiology and histogenesis of granulomatous nodules as described in wild or cultured fishes, rainbow trout, Salmo gairdneri Richardson, and turbot, Scophthalmus maximus (L.), received subcutaneous and intraperitoneal injections of talc and BCG. The development of dermal, perivisceral, peritoneal and gill nodules occurred after 15 days, and the evolution of early solid, then mature necrotic (BCG) or cystic (talc) nodules followed until the ninetieth day. The presence of the injected material was demonstrated within phagocytic epithelioid or giant cells. Turbot responded more intensely to experimental injection than rainbow trout. Histological descriptions allowed a distinction between neoplastic nodules, epithelial liver pseudo‐nodules, histiocytic nodules (melanin‐macrophage centres), and reactional granulomatous nodules. In the last case, the specific structure and development may correspond to different causes, some well known (infection, foreign bodies), others enigmatic and possibly related to immunological reactions.
Sporogenesis of the myxosporean Kudoa paniformis Kabata & Whitaker, 1981 infecting the muscle of the Pacific whiting, Merluccius productus (Ayres)
Authors: STEHR CARLA
Published: April 2006

Abstract. This ultrastructural study examines Sporogenesis of Kudoa paniformis, a monosporous myxosporean that causes a softened muscle texture in cooked Pacific whiting, Merluccius productus. Capsulogenesis and valvogenesis occur in a manner similar to that of other myxosporeans, while some aspects of generative cell interaction and sporoplasm ultrastructure differ from most other myxosporeans that have been examined with electron microscopy. Capsulogenesis of K. paniformis includes the formation of an external tubule which is continuous with the polar capsule, followed by the apparent internalization and modification of the external tubule to form a polar filament winding within the polar capsule. Valvogenesis occurs with the accumulation of electron‐dense material on the cytoplasmic side of the outer membrane of each valvogenic cell to form a valve wall, Sporogenesis of K. paniformis differs from other myxosporeans in two aspects: (1) spore development does not appear to begin as a result of one generative cell engulfing another, and (2) the sporoplasm of developing and mature spores contains two morphologically distinct cells, one of which surrounds the other.
Host‐parasite interaction of the myxosporeans Kudoa paniformis Kabata & Whitaker, 1981 and Kudoa thyrsites (Gilchrist, 1924) in the muscle of Pacific whiting, Merluccius productus (Ayres): an ultrastructural study
Authors: STEHR CARLA , WHITAKER D. J.
Published: April 2006

Abstract. Kudoa paniformis and Kudoa thyrsites infect the muscle of Pacific whiting, Merluccius productus, and K. paniformis is known to cause a softened muscle texture after death of the fish. Ultrastructural studies were conducted on the host‐parasite interaction between Pacific whiting and these myxosporeans at two stages of their infection: (1) unencapsulated plasmodia that contained mature and developing spores, and (2) encapsulated plasmodia that contained deteriorating spores. Unencapsulated plasmodia of both species had a microvillar border that was closely associated with the host muscle. Species‐specific characteristics included the presence of multi‐vesicular bodies in plasmodia of K. paniformis whereas the cytoplasm of K. thyrsites plasmodia contained an array of vesicles, microfilaments and microtubules. Differences in the predominant organelles of the plasmodia may be related to the production of different proteolytic enzymes by each species. A host response became apparent only after a plasmodium had replaced the width of an infected muscle fibre. At that time, the plasmodia of both species became encapsulated by a wall of fibroblast‐like cells that were connected by numerous desmosomes. Occasional phagocytes were located at the edge of these capsules. Ultrastructural evidence suggests that the encapsulated plasmodia were not proteolytically active. Melanin deposition did not occur. However, encapsulated plasmodia with deteriorating spores contained electron‐dense breakdown products.
An enzyme‐linked immunosorbent assay (ELISA) for detecting penaeid baculovirus
Authors: LEWIS D. H.
Published: April 2006

Abstract. A technique for detecting shrimp haculovirus based upon the sandwich indirect enzyme‐linked immunosorbent assay (elisa) was developed. Baculovirus antiserums were developed in rabbits and guinea‐pigs. Wells of microagglutination plates were coated with guinea‐pig antiserum. Various dilutions of the purified virus preparation suspended either in Hanks’ balanced salt solution (BSS) or in 30% hepatopancreas tissue in BSS were placed in wells. After washing, secondary anti‐serum (rabbit antibaculovirus serum) was added. Goat horseradish peroxidase‐labelled anti‐rabbit globulin was used to detect reactions between baculovirus and rabbit antiserum. At least 10 ng viral protein could be detected by the technique.
Transmission of some fish pathogenic viruses by the heron, Ardea cinerea
Authors: PETERS F. , NEUKIRCH M.
Published: April 2006

Abstract. Various possibilities of transmitting fish pathogenic VHS, SVC and IPN viruses by the heron, Ardea cinerea, were investigated. Shedding of IPN virus in the faeces could be demonstrated for a period of 7 days when about 1 g of IPN virus‐infected trout fry was fed to the birds once only, whereas feeding larger quantities of infected fish on 5 consecutive days resulted in virus excretion for a further 5 days only. Infectious IPN virus could not be isolated from samples of blood and virus specific neutralizing antibodies could not be demonstrated in serum samples. A waterborne infection of trout fry was established by adding very small (0·2 g) quantities of faeces from herons fed IPN virus‐contaminated fish to 20 1 water. Infectious SVC and VHS virus was also re‐isolated from samples of food which were regurgitated by the herons at different times up to 120 min after feeding of contaminated fish. It was concluded that herons are able to act as mechanical vectors for IPN, VHS and SVC viruses and therefore, may be a potential source of infection and spread of the diseases.
Experimental studies on the pathogenicity of a Vibrio sp. isolated from Atlantic salmon, Salmo salar L., suffering from Hitra Disease
Authors: HJELTNES B. , ANDERSEN K. , ELLINGSEN H.‐M. , EGIDIUS E.
Published: April 2006

Abstract. A marine Vibrio sp. was isolated from Atlantic salmon suffering from Hitra Disease. This Vibrio sp. could be transmitted to Atlantic salmon through the water and from previously infected fish. The bacteria enter the fish through gills, although wounds appear to enhance the infectivity. Infected Atlantic salmon developed a condition similar to Hitra Disease, from which bacteria could be easily reisolated from dead and moribund fish.
The influence of antibiotics on the immune system: immuno‐pharmokinetic investigations on the primary anti‐SRBC response in carp, Cyprinus carpio L., after oxytetracycline injection
Authors: GRONDEL J. L. , NOUWS J. F. M. , VAN MUISWINKEL W. B.
Published: April 2006

Abstract. The present study was performed to obtain further details on the immuno‐modulating effects of oxytetracycline (OTC) in carp, Cyprinus carpio L. The immuno‐logical study was extended by investigating the pharmacokinetic behaviour of OTC. Oxytetracycline, at a dosage of 60 mg/kg, was administered five times intra‐peritoneally at 3‐day intervals; the first injection was given 1 day before immunization. The kinetics of the primary anti‐sheep red blood cell (SRBC) response, during a short‐term OTC treatment revealed that the kinetics of the plaque‐forming cell (PFC) response was not significantly affected by OTC nor its solvent. In contrast, the number of plaque‐forming cells was significantly decreased. The anti‐SRBC antibody production was delayed by 2–4 days in both experimental groups (OTC and solvent). However, within 12–14 days post‐immunization, the same antibody levels were detected as in the control group. High OTC plasma levels (>50 μg/ml) were detected about 10 h after a single i. p. injection. A mean plasma elimination half‐life (T1/2) of 34·5 h was calculated.
Efficacy of formalin in reducing the levels of peritrichous ciliates on cultured marine shrimp
Authors: BELL T. A. , ARUME C. S. , LIGHTNER D. V.
Published: April 2006

Abstract. Tests were performed to measure the efficacy of formalin in reducing peritrichous ciliates on the surface of cultured marine shrimp. The tests were conducted at concentrations above and below those being used in shrimp culture and were designed to define the concentration providing the most effective rapid reduction of ciliates. Penaeus stylirostris Stimpson,‘preconditioned’ in a single large tank, were divided equally (after diagnosis of significant ciliate epifaunation) into ten 1000 litre fibreglass tanks; each received 235 shrimp of 10–15 g average weight. These tanks were divided into five treatments: 0, 12·5, 25, 50 and 100 ppm; two replicates per treatment. Treatments were conducted under static conditions for 4 h. Ciliate levels were measured on day 0 (pretreatment) and days 1, 2 and 7 post‐treatment. Formalin at 25, 50 and 100 ppm was demonstrated to be effective in reducing ciliates, while 12·5 ppm did not differ from the control (0 ppm). In addition, the higher the level of formalin used (within the effective range), the more pronounced was the initial ciliate reduction and the longer was the protection from further ciliate epifaunation.
Pathology and significance of fatal inflammatory bacteraemia in the Pacific oyster, Crassostrea gigas Thünberg
Authors: ELSTON R. A. , BEATTIE J. H. , FRIEDMAN C. , HEDRICK R. , KENT M. L.
Published: April 2006

Abstract. Inflammatory bacteraemia was found in 27–31% of Pacific oysters in two bays over 2 years in Puget Sound, Washington, USA. Mantle discolouration and raised yellow to green nodules are associated with the disease in 52% and 85% of the observed cases, respectively. The disease is caused by systemically distributed, branching. Gram‐positive, acid‐fast bacteria suggestive of an actinomycete. Clusters of the bacteria elicit a marked inflammatory response. Glycogenic degeneration of host vesicular cells occurs in the advanced infections and results in the formation of the characteristic nodules comprised of lipid filled cells. The disease is, thus, significant to the health of individual oysters and also appears to be an important factor in the historically observed phenomenon of summer mortality in certain areas of Puget Sound.
Studies on the proposed role of Tubifex tubifex (Muller) as an intermediate host in the life cycle of Myxosoma cerebralis (Hofer, 1903)
Authors: HAMILTON A. J. , CANNING E. U.
Published: April 2006

Abstract. In a recently proposed hypothesis for the transmission of Myxosoma cerebralis, the causative agent of salmonid whirling disease, it was suggested that there was a developmental cycle in tubificid worms culminating in actinosporean spores, which were infective to the fish. Results are presented here which do not support the actinosporean involvement in the life cycle. On addition of M. cerebralis spores to Tubifex tubifex colonized in sterilized medium, no significant change in the prevalence of Triactinomyxon dubium (i.e. T. gyrosalmo) was found. Although it is shown that these worms are capable of ingesting M. cerebralis spores, neither hatching of the spores nor further development within the worm has been observed. Field observations on the distribution of actinosporean species show no obvious correlation between the occurrence of T. dubium and M. cerebralis.
Pharmacokinetics and tissue distribution of oxytetracycline in carp, Cyprinus carpio L., following different routes of administration
Authors: GRONDEL J. L. , NOUWS J.F.M. , DE JONG M. , SCHUTTE A. R. , DRIESSENS F.
Published: April 2006

Abstract. The objective of this pharmacokinetic study was to investigate absorption, distribution, elimination and bioavailability of oxytetracycline (OTC) in carp, Cyprinus carpio L., after different routes of administration, OTC was administered intravenously (i.v.), intramuscularly (i.m.) and orally at 60 mg/kg body weight. OTC levels were determined in plasma and several tissues. Analysis of the plasma drug concentration‐time curves following i.v. OTC injection revealed three distinct phases. A three‐compartment open model was used to derive pharmacokinetic parameters. Compared to mammals, a very extended final elimination half‐life was observed (139.8±38.1 h). Following i.m. OTC administration, Cmax was 56.8±10.9μg OTC/ml at 14 h post‐injection. The Vd area was 2.1 ± 0.66 1/kg. Extreme differences were observed with respect to bioavailability following i.m. and oral administration; approximately 80 and 0.6%, respectively. Following i.m. injection tissue OTC determinations revealed that the drug was accumulating in pronephros, bone tissue and scales. After 21 days the OTC concentrations were 2.9±0.8, 5.2±0.3 and 4.7±3.1 μg/ ml, respectively. In tissue samples from the dorsal region (muscle), including the injection site, OTC could not be demonstrated at that time. The pharmacokinetic data are discussed in relation to the susceptibility of the immune system of fish for modulation.
IHHN disease of Penaeus stylirostris: effects of shrimp size on disease expression
Authors: BELL T. A. , LIGHTNER D. V.
Published: April 2006

Abstract. Populations of Penaeus stylirostris, free of infectious hypodermal and haematopoietic necrosis virus (IHHNV), were divided into five size groups (PL2 [2‐day‐oldpostlarvae, approximately 5.0 mg], 3.7 g, 14.5 g, 21.3 g and 36.9 gaverage initial weight), and experimentally exposed to IHHNV per or. Statistical comparisons (histologically‐derived) of infection severity ratings from six weekly sample periods indicated the relative abundance of pathognomonic Cowdry type A intranuclear inclusion bodies (and, hence, the severity of the disease) differed between sizes. The results of comparisons showed a tendency for larger animals to have a significantly lower prevalence of inclusion bodies and associated histopathology than smaller animals. The results also indicated that the smaller (average weight) the group was, the shorter was the period of time from initial exposure to the first histological detection of the disease. Thus, the larger (in average weight) a population of P. stylirostris is upon initial exposure to IHHNV, the less acute will be disease manifestation within a given time and the longer will be the period before the disease is first histologically detectable. A predictive equation that defines the epizootiological relationship of IHHN disease within an intensively cultured population of P. stylirostris is also presented.
Ultrastructural aspects of infestation by Ichthyobodo necator (Henneguy, 1883) on the skin and gills of the salmonids Salmo salar L. and Salmo gairdneri Richardson
Authors: ROUBAL F. R. , BULLOCK A. M. , ROBERTSON D. A. , ROBERTS R. J.
Published: April 2006

Abstract. Ultrastructural changes in the skin and gill epithelia of Salmo salar L. and Salmo gairdneri Richardson caused by Ichthyobodo necator are described. Sloughing of Malphigian cells and epidermal spongiosis result in the characteristic clinical signs of costiasis. Destruction of subsurface cells may facilitate rapid development of spongiosis. Infested surface cells show dramatic degeneration of the cytoplasm but the nucleus usually remains intact. It is concluded that I. necator does not feed specifically on the nucleus.
The parasitic barnacle, Sacculina granifera Boschma, affecting the commercial sand crab, Portunus pelagicus (L.), in populations from two different environments in Queensland
Authors: WENG H. T.
Published: April 2006

Abstract. The parasitic barnacle, Sacculina granifera, changed the abdominal morphology of the host crab, Portunus pelagicus (L.). Three different shapes were recognizable with increase of the host size. Crabs carrying externae could be found throughout the year with higher percentages in the dry season (May‐October) in the Gulf of Carpentaria and in warm months (October‐March) in Moreton Bay. The parasite infested more males than females in the Gulf but both sexes of crabs equally in the Bay. Generally, the parasite matured when the host (always immature) reached the size of mature crabs. The smallest crab carrying an externa was 70 mm carapace width from the Gulf and 90 mm CW from the Bay. Overall, 6.6% of P, pelagicus were found with externae in the Bay, a subtropical area where crabs are heavily exploited by amateur and commercial fishermen. In comparison, only 1.2% of crabs were found with externae in the Gulf, a tropical area where no commercial fishery is targeted at this species.
Solar ultraviolet radiation as a causal factor of ‘summer syndrome’ in cage‐reared Atlantic salmon, Salmo solar L.: a clinical and histopathological study
Authors: McARDLE J. , BULLOCK A. M.
Published: April 2006

Abstract. During the exceptionally good summer of 1984, severe losses occurred at a number of marine salmon farms in the west of Ireland. Clinical signs and associated histopathology of the disease are described together with relevant meteorological data gathered during the course of the mortalities. The clinical, histopathological and meteorological data observed strongly suggest that prolonged exposure to solar ultraviolet radiation played a major role in the losses which occurred. Other contributory factors involved in the mortalities are described and discussed.