bluuebunny/crossref_metadata_2025 huggingface dataset:
A visceral mycosis in ayu fry, Plecoglossus altivelis Temminck & Schlegel, caused by a species of Phoma
Authors: HATAI K. , FUJIMAKI Y. , EGUSA S. , JO Y.
Published: April 2006

Abstract. Epizootics and histopathology of a new visceral mycosis due to fungi impefecti which occurred in farmed ayu, Plecoglossus altivelis Temminck & Schlegel, in Tokushima Prefecture, Japan are described. Histopathological examination suggested that fungal infection occurred primarily in the airbladder. A fungus with characteristics of the genus Phoma isolated from diseased fish is described and its taxonomic position discussed.
Induction of clinical aspergillomycosis by feeding contaminated diet to tilapia, Oreochromis niloticus (L.)
Authors: OLUFEMI B. E. , ROBERTS R. J.
Published: April 2006

Abstract. Oreochromis niloticus maintained at 17°C and 26°C were fed a pelleted diet contaminated with cultures of Aspergitlus flavus fungus. Affected fish stopped feeding within one week, and became inactive, dark and oedematous. Exophthalmia, often accompanied by corneal or humoral changes, was common and mortalities commenced after 4 weeks. Surviving fish were sacrificed after 5 weeks and the fungus was isolated from all organs, including—irregularly—the eye. The histopathology was predominantly that of a necrotizing septicaemia, with fungal hyphae present in liver, peritoneum, kidney, intestinal wall and, distinctively, in the orbit and eye of affected fish.
Fine structure of hepatocytes and hepatocellular carcinoma of the Atlantic tomcod, Microgadus tomcod (Walbaum)
Authors: CORMIER SUSAN M.
Published: April 2006

Abstract. The fine structure of livers from Atlantic tomcod, Microgadus tomcod (Walbaum), differed between samples from the Hudson and the Pawcatuck Rivers. The hepatocytes of fish from the Pawcatuck River were characterized by cords two cells wide separated by distinct blood sinuses. The hepatocytes contained moderate amounts of glycogen and lipid, rough endoplasmic reticulum, mitochondria and a central nucleus. Hepatocytes of samples from the Hudson River had ceroid plaques, extensive arrays of rough endoptasmic reticulum that were often distended, heavy deposits of lipid that deformed other organelles and no glycogen. The nucleus and cytoplasmic portion of hepatocellular carcinoma cells from the Hudson River were much larger than other hepatocytes and contained fewer fatty deposits, but still had lots of rough endoplasmic reticulum in varying degrees of distension. The pathological manifestations of the hepatocytes are consistent with damage due to exposure to toxic compounds and suggest that the high prevalence of hepatocellular carcinoma from the Hudson River tomcod is due to exposure to environmental carcinogens.
Changes in serum parameters of rainbow trout, Salmo gairdneri Richardson, and Atlantic salmon, Salmo salar L., infected with Renibacterium salmoninarum
Authors: BRUNO D. W.
Published: April 2006

Abstract. Bacterial kidney disease was induced experimentally in rainbow trout, Salmo gairdneri Richardson, and Atlantic salmon, S. salar L., and selected serum parameters measured over a 35‐day period. In those fish which became infected a significant increase in the erythrocyte sedimentation rate and in the serum levels of bilirubin, blood urea nitrogen and potassium were recorded. A significant decrease in total serum protein, cholesterol and sodium also occurred in these fish. Electrophore‐tic analysis of serum proteins showed the fast migrating fraction was reduced before the slower migrating material in infected fish.
Sensitivity of juvenile lobsters, Homarus americanus L., to different concentrations of malachite green during various states of the intermoult cycle
Authors: BOGHEN A. D.
Published: April 2006

Abstract. Survival of the early stages (egg, larva and juvenile) of the American lobster, Homarus americanus L., reared under controlled conditions has often been threatened by a variety of fungi and microbial epibionts. A preliminary study was conducted for the purpose of defining toxicity levels of malachite green for 5th stage juveniles during each of the following intermoult (or fused intermoult) states: A‐B, C4, D0 and D2‐D3 Irrespective of exposure time or concentration, all the lobsters treated during intermoult state A‐B died. This contrasts with seemingly good survival of lobsters in intermoult states C4, D0 and D2‐ D3 treated at concentrations of 900 mg/1 malachite green for exposure periods of 10 min. The findings suggest that an effective treatment combination for lobsters immersed in malachite green may be one which is employed during intermoult state C4, for about 6min and at concentrations of about 700–800 mg/l.
The importance of Lernaea cruciata (Le Sueur) in the initiation of skin lesions in largemouth bass, Micropterus salmoides (Lacepede), in the Chowan River, North Carolina, USA
Authors: NOGA E. J.
Published: April 2006

Abstract. Largemouth bass, Micropterus salmoides (Lacepede), were collected from May to October from the Chowan River, North Carolina and examined for the presence of skin lesions. Over 55% of all largemouth bass greater than 100 mm in length had skin lesions. The largest fish (≥400 mm) had the greatest number of lesions (X̄= 3.4 lesions per fish). When examined by wet mounts, small early lesions frequently (31% of all lesions) had the microscopic recently metamorphosed adult female stage of Lernaea cruciata. Older macroscopically visible adult females were only rarely seen (2% of all lesions). Examinations of wet mounts revealed no identifiable pathogen in 60% of all early lesions but histologically almost all lesions had a similar inflammatory response. Lesions were most common along the ventral surface of the body where 85% of all lesions were present. This was also the most common site of copepod infection, with 95% of all copepods present at this site. Bacterial numbers in early lesions were occasionally high and tended to increase in concentration in advanced lesions. No single organism was consistently identified as predominant in the majority of lesions. The possible relationship of these lesions to red‐sore disease is discussed.
Eimeria spp. from cyprinid fish of the Duero basin (north‐west Spain)
Authors: ALVAREZ‐PELLITERO MARIA‐PILAR , GONZALEZ‐LANZA MARIA‐CAMINO
Published: April 2006

Abstract. We describe three Eimeria spp. from extraintestinal sites of cyprinid fish of the Esla River; Eimeria leucisci from Barbus barbus bocagei, E. rutili from Leuciscus cephalus cabeda and Chondrostoma polylepis polyiepis and E. baueri sp. nov. from Carassius carassius. Data on the prevalence and intensity are given. Histopathological changes of the barbel kidney affected by E. leucisci are described. In the analysis of the population dynamics, a clear pattern of seasonality cannot be deduced. Influence of host age was clear only for E. leucisci in which the prevalence decreased significantly with the age of the barbel. We did not observe a clear influence of host sex on the infections.
The kidney of rainbow trout, Salmo gairdneri Richardson, in the acute phase of viral haemorrhagic septicaemia: in vivo experiments on the renal excretion of fluid, electrolytes and protein
Authors: ELGER B. , NEUKIRCH M. , HENTSCHEL H.
Published: April 2006

Abstract. Kidney function was studied in unanaesthetized rainbow trout, Salmo gairdneri Richardson, with acute infection by VHS virus strain F‐l causing viral haemorrhagic septicaemia. The experiments were performed in diseased and control fish with catheters chronically implanted in the dorsal aorta and the urinary bladder. Glomerular clearance of polyfructosan, tubular handling of fluid and electrolytes and urinary excretion of protein were studied. In diseased fish, plasma concentrations of inorganic solutes were reduced, but plasma osmolarity and systemic blood pressure remained unchanged. Glomerular filtration rate and urine flow, both linearly correlated, were reduced from 5.20±0.40 to 3.08±0.66 ml/h/kg and from 2.51±0.15 to 1.63±0.28 ml/h/kg, respectively (x̄±SEM). The urine osmolarity was augmented due to increased Na and Mg concentrations in the urine. Net tubular secretion of Mg was observed in diseased fish whereas net reabsorption of Mg prevailed in the controls. Decreased renal protein excretion rate prevented a renal loss of protein and, therefore, diminished plasma protein concentrations in VHS‐infected fish may be attributed to extrarenal pathophysiological mechanisms.
Host susceptibility to Lernaea cyprinacea L. and its treatment in a large aquarium system
Authors: SHARIFF M. , KABATA Z. , SOMMERVILLE CHRISTINA
Published: April 2006

Abstract. Host susceptibility to Lernaea cyprinacea was studied during an outbreak of the infection in an aquarium containing 58 species or stocks of fish belonging to 20 families and eight orders. L. cyprinacea was accidentally introduced on two occasions and spread through the recycling of the aquarium exposing all fish to infection. During the first outbreak only 39.7% of the fish species became infected. Approximately 17% carried a mean of less than 10 parasites and 22% carried a mean of more than 10 parasites. During the second outbreak, 6 months after the first, there was a decrease in both the prevalence and intensity of infection; only five species were infected and mean levels of infection were less than 10 per fish except for newly introduced fish. This suggests the possible development of immunity in the previously infected hosts. On both occasions the infection was successfully eradicated by using Unden (2‐isopropoxy‐phenyl‐N‐methylcarbamate) at 0.16 ppm, weekly for 4 weeks and Dipterex (0,0‐dimethyl, 2,2,2‐trichloro‐l‐hydroxyethylphosphate) at 0.16 ppm for the fifth dose, when the larval stages of the parasite revealed resistance to Unden.
Observations on the host‐parasite relations of the Pacific whiting, Merluccius productus (Ayres), and two myxosporean parasites, Kudoa thyrsitis (Gilchrist, 1924) and K. paniformis Kabata & Whitaker, 1981
Authors: MORADO J. F. , SPARKS A.
Published: April 2006

Abstract. Muscle samples from 178 Merluccius productus were examined for two myxosporean parasites, Kudoa thyrsitis and K, paniformis. Kudoa paniformis was found in 51% of the samples, while K. thyrsitis and mixed infections were observed in 7% and 17% of the samples respectively. An inflammatory response that resulted in an encapsulation around a completely replaced muscle fibre was observed in infections with either parasite. Presporogenic and sporogenic stages were common while stages that may represent early forms of the parasites were only rarely observed.
Chemiluminescent responses of striped bass, Morone saxatilis (Walbaum), phagocytes to strains of Yersinia ruckeri
Authors: STAVE J. W. , COOK T. M. , ROBERSON B. S.
Published: April 2006

Abstract. Seventeen strains of Yersinia ruckeri were examined for plasmid DNA by means of agarose gel electrophoresis of partially cleared lysates. All 10 serotype I strains examined contained a 70 Megadalton (Mdal) plasmid, whereas only one of the 7 serotype II strains examined contained a plasmid of about 2–3 Mdal. Yersinia ruckeri exhibited distinctive colonial morphology and serological reactivities which suggested a possible correlation with plasmid content. The luminol‐enhanced Chemiluminescent (CL) responses of striped bass, Morone saxatilis (Walbaum), phagocytes to different strains of Y. ruckeri were also studied. Some variability was observed; however, the greatest phagocyte CL responses were elicited by serotype II strains without the plasmid while serotype I strains harbouring the plasmid consistently elicited weak CL responses from phagocytes.
Lymphocystis infection in snakeskin gourami, Trichogaster pectoralis (Regan), (Anabantidae)
Authors: PAPERNA I. , VENTURA T. M. , de MATOS A. P.
Published: April 2006

Abstract. A lymphocystis infection is described from aquarium‐held snakeskin gourami, Trichogaster pectoralis (Regan). The cytoplasm of the hypertrophic cells revealed virus particles of extended hexagonal profiles with thin two‐layered capsids. Subsequent examination of the fish 4 months later revealed hypertrophic cells showing varying degrees of collapse and degradation. The virus particles loading such cells were of regular hexagonal profiles with thick three‐layered capsids.
Transmission of infectious pancreatic necrosis virus in striped bass, Morone saxatilis (Walbaum)
Authors: WECHSLER S. J. , WOODS L. C. , KRAEUTER J. N. , HETRICK F. M. , MCALLISTER P. E.
Published: April 2006

Abstract. Infectious pancreatic necrosis virus (IPNV) did not cause increased mortality in experimentally challenged striped bass, Morone saxatilis (Walbaum). Fry became transiently infected after waterborne challenge but fingerlings were resistant to that route. However, striped bass fingerlings readily became chronic virus carriers following ingestion of IPNV‐contaminated food. Vertical transmission was not demonstrated using either IPNV‐carrier striped bass adults or IPNV‐exposed sex products.
Cryptobia salmositica: cortisol increases the susceptibility of Salmo gairdneri Richardson to experimental cryptobiosis
Authors: WOO P. T. K. , LEATHERLAND J. F. , LEE M. S.
Published: April 2006

Abstract. Intraperitoneal implants of cortisol (cortisol suspended in hydrogenated coconut oil) were used to induce a graded hypercortisolism in rainbow trout, Salmo gairdneri Richardson. There was no obvious reduction in circulating lymphocytes in cortisol‐implanted rainbow trout (70, 140 or 210μg/g body weight). Cortisol‐implanted fish infected with Cryptobia salmositica had significantly higher parasitaemia and lower antibody litres compared with controls infected with haemonagellate but given coconut oil implants. These confirm the immunodepressive effects of the steroid. The parasite was also more readily detected at the early stage of the infection (shorter prepatent period, more infected fish and higher parasitaemia) in cortisol‐implanted fish (140 and 210 μg/g body weight) than in controls. The mortality of the infected cortisol‐implanted fish was higher than that of the infected fish implanted with only coconut oil, or the cortisol‐implanted but non‐infected fish. This in vivo study suggests that protective immunity against C. salmositica is, in part, due to a humoral response.
A successful vaccination of Atlantic salmon, Salmo salar L., against ‘Hitra disease’ or coldwater vibriosis
Authors: HOLM K. O. , JØRGENSEN T.
Published: April 2006

Abstract. A Vibrio sp. causing the so‐called ‘Hitra disease’ or coldwater vibriosis affecting brood stock Atlantic salmon, Salmo salar L., in Norway, is described by serotyping. Bacteria collected from moribund Atlantic salmon affected by ‘Hitra disease’ in various parts of Norway, were shown to represent a homogeneous group of marine vibrio. A formalized bacterin was made from one isolate. Vaccination of Atlantic salmon parr was carried out by direct immersion in a formalized bacterin prepared from a Vibrio sp. associated with ‘Hitra‐disease.’ After 6 weeks the fish were revaccinated and transferred to net pens in the sea. Compared with unvaccinated controls, vaccinated fish demonstrated excellent protection when challenged 6 months later during a natural outbreak of coldwater vibriosis.
Pathological changes in the midgut epithelium of grayling, Thymallus thymallus L., larvae reared on different kinds of food, and their relation to mortality and growth
Authors: ECKMANN R.
Published: April 2006

Abstract. The histological differentiation of the digestive tract in grayling, Thymallus thymallus L., larvae was studied during the first 20 days after hatching. The normal development was assessed in larvae fed with nauplii of two Anemia strains. These results were compared with a starved control. Grayling larvae reared on lake zoo‐plankton suffered mortality which was ten times higher than that in the Artemia‐fed groups. The histopathology of the zooplankton‐fed larvae was characterized by excessive fat accumulation in the apices of columnar absorptive cells, complete absence of fat transport into the villus lamina propria, and disintegration of enterocyte cell membranes. This pathology is compared with the clinical findings in human abetalipoproteinaemia. It is concluded that the histopathological manifestations and the resulting elevated mortality in larval grayling were provoked by a disturbance of the fat absorption process in the enterocytes. This disturbance is likely to be due to the inability to synthesize chylomicrons. It is further hypothesized that lake plankton either contains a toxic agent which interferes with the build‐up of chylomicrons or is deficient in some lipoprotein moiety which is essential for chylomicron synthesis.
Transmission of protease genes into a protease‐deficient mutant of Aeromonas salmonicida in river sediments
Authors: SAKAI D. K.
Published: April 2006

Abstract. The transformation of Aeromonas salmonicida with DNA fragments from bacterial cell‐free sonicates was investigated with intraspecific, interspecific band intergeneric fish pathogenic bacteria including Aeromonas salmonicida, Aeromonas hydrophila, Pseiidomonas fluorescens and Vibrio anguillarum strains as donor bacteria. A phenotypic marker for transformation was extracellular protease production since a protease‐deficient mutant NTG‐1 induced from pathogenic A. salmonicida strain A‐7301 by mutagenesis was used as a recipient. This mutant was non‐pathogenic to rainbow trout. The mutant was incubated with each sonicate at 20°C for 20 days with a nutrient‐poor medium containing a trace (5 μg/ml each) of both humic acid and tryptone in the presence of clean river sand (100 g/100 ml medium) corresponding with an environment of rivers. During the incubation, the survival of mutant NTG‐1 cells was observed and protease positive NTG‐1 cells were isolated from each culture. The protease production of the isolates was due to the transmission of protease genes of the donor strains. The activity of proteases produced by the transformants extra‐cellularly was determined. These transformants induced with the sonicates of the parent strain, intraspecific strain and with the sonicates of the interspecific A. hydrophila strain were pathogenic to rainbow trout, whereas the transformants derived with the sonicates of the intergeneric strains P. fluorescens and V. anguiUarum showed non‐pathogenicity, although all the donor strains, with the exception of the P. fluorescens strain, were pathogenic. These findings are interesting since they demonstrate that trausformation in A. salmonicida occurs with considerable ease even intergenencally and interspecifically, as well as intraspecifically in river environments, and that there is a large difference in the lethal toxicity of extracellular protease produced by these bacteria.
A study of bacteria present within unfertilized salmon eggs at the time of spawning and their possible relation to early lifestage disease
Authors: SAUTER R. W. , WILLIAMS C. , MEYER E. A. , CELNIK B. , BANKS J. L. , LEITH D. A.
Published: April 2006

Abstract. The eggs of 30 female chinook salmon, Oncorhynchus tshawvtscha (Walbaum), were collected at spawning. Some eggs from each fish were collected for bacteriologic study. Two salmon produced eggs judged to be of poor quality which were not used. The remaining 28 of the 30 groups of eggs were fertilized from a single sperm pool and the eggs incubated in separate groups. Mortality data on the developing salmon were recorded regularly through the twelfth week on feed. Unfertilized eggs from each group were surface‐disinfected with an iodine solution, then crushed and subjected to a culture procedure designed to permit growth of as many bacterial types as possible. Bacteria were cultured and identified, and a comparison made of the types of organisms present in eggs from groups which later incurred high or low mortalities. Bacteria were recovered from both groups of salmon eggs. Although no single organism could be identified as a cause of increased mortality, the more frequent occurrence in the eggs of the ‘high mortality’ group of species of Vibrio, Listeria, Corynebacterium and Staphylococcus suggests that these bacteria may play a role. It is suggested that the cause of so‐called early lifestage disease of salmon is multifactorial.
Serological detection of Edwardsiella ictaluri Hawke lipopolysaccharide antibody in serum of channel catfish, Ictalurus punctatus Rafinesque
Authors: SAEED M. O. , PLUMB J. A.
Published: April 2006

Abstract. Bacterial agglutination, passive haemagglutination, complement‐dependent passive haemolysis, indirect immunofluorescence, agar gel immunodiffusion and agglutination with fractions of immunized fish serum were compared for detecting humoral antibody to the lipopolysacchande (LPS) of Edwardsiella icialuri Hawke in channel catfish. Bacterial agglutination titres averaged 1: 672; passive haemagglutination titres averaged 1: 1152; and complement‐dependent haemolysis titres averaged 1: 2360. Serum from non‐vaccinated fish ranged from 0 to 1:32. Indirect fluorescence and immunodiffusion demonstrated positive reactions to the LPS antibody. Fractionation of immune sera produced three fractions, one of which strongly haemagglutinated E. ictaluri but the other two did not. All six serological techniques were sensitive to E. ictaluri LPS antibody.
Purification of a proteinase produced by the bivalve pathogen Vibrio alginolyticus NCMB 1339
Authors: NOTTAGE A. S. , BIRKBECK T. H.
Published: April 2006

Abstract. A proteinase produced by the bivalve pathogen Vibrio alginolyticus NCMB 1339 was purified by preparative isoelectric focusing and gel filtration. Proteinase activity was associated with two components of molecular weights 43000 and 41000 and was toxic to larval Ostrea edulis. Production of this enzyme was maximal during the late exponential phase of growth and it remained stable throughout the stationary phase of growth. At 37°C, activity against azocasein was optimal at pH 7–5. The enzyme was inhibited by mercuric chloride, dithiothreitol and ethylene diamine tetra‐acetic acid, but not by pepstatin‐A, phenylmethylsulphonyl‐fluoride or tosyl‐L‐lysine chloromethylketone.
Ultrastructure of Thelohania duorara Iversen & Manning, 1959 (Microspora, Thelohaniidae) in the Pink Shrimp, Penaeus duroarum Burkenroad
Authors: IVERSEN E. S. , KELLY J. F. , ALZAMORA D.
Published: April 2006

Abstract. The structure of Thelohania duorara Iversen & Manning, 1959, a micro‐sporidian parasite of pink shrimp. Penaeus duorarum Burkenroad, was examined with electron microscopy. Earliest developmental stages observed were limited to diplokaryotic cells. Both microtubules associated with exospore formation, and hair‐like filaments, projecting from the outer surface of the exospore, were observed during sporogony. The continuity of the cisternae of the polaroplast, the perinuclear cisterna, the outer membrane of the polar filament and membranes surrounding masses of secretion granules were noted. Mature spores had a granular endospore and hair‐like filamentous projections on the exospore surface. The polar filament made 13–14 turns, the most distal being slightly constricted. Information presented here indicates that T. duorarum should be retained within the genus Thelohania as it is now defined.
Clinical, microbiological and epidemiological findings in recent outbreaks of goldfish ulcer disease due to atypical Aeromonas salmonicida in south‐eastern Australia
Authors: WHITTINGTON R. J. , GUDKOVS N. , CARRIGAN M. J. , ASHBURNER L. D. , THURSTAN S. J.
Published: April 2006

Abstract. The spread of goldfish ulcer disease (GUD) from Victoria to New South Wales, Australia, and the first isolation of Aeromonas salmonicida from wild goldfish are reported. Cultural, biochemical and protein SDS‐PAGE characteristics of these recent isolates are compared with those of existing Australian isolates, with strains recovered from goldfish in Italy and the USA (atypical strains) and with strain ATCC 14174 (typical strain). The Australian isolates were identical and closely resembled the exotic atypical strains. Although there were several biochemical differences between the atypical isolates and the typical ATCC 14174 strain, the results of SDS‐PAGE confirmed that these strains were closely related. The homology of the Australian and overseas strains recovered from goldfish supports the common view that A. salmonicida was introduced first into Australia with diseased goldfish in 1974. The three widely separated outbreaks of GUD reported here confirm that an atypical strain of A. salmonicida is now endemic in Australia.
Cranial chondrosarcoma in a paddlefish, Polyodon spathula (Walbaum)
Authors: BEAN‐KNUDSEN D. E. , UHAZY L. S. , WAGNER J. E.
Published: April 2006

Abstract. A large, focally extensive tumour was observed on the posterior aspect of the head of a 14 year‐old paddlefish, Polyodon spathula (Walbaum), taken from Lake of the Ozarks, Missouri, USA. A morphologic diagnosis of chondrosarcoma was made based on the biology, radiographic examination and cellular anaplasia of the mass. The lack of attachment of the tumour of the axial skeleton suggests origin in the dermal bones characteristic of this species. This constitutes the first record of a tumour with these characteristics from cartilaginous non‐elasmobranch or elasmobranch fishes.
Inhibition of infectious pancreatic necrosis virus infectivity by extracts of rainbow trout, Salmo gairdneri Richardson, tissue
Authors: DIXON P.P.
Published: April 2006

Abstract. Extracts of healthy rainbow trout liver, kidney, spleen and whole fry inhibited plaque production of infectious pancreatic necrosis virus (IPNV) in cell cultures. The mode of inhibition is not known, although it appears not to be manifest at the cellular level, as pre‐treatment of the cell cultures with tissue extracts did not inhibit plaque production. Any effect on the virus itself was not permanent as the inhibition could be mitigated by treatment of virus/extract mixtures with 1,1,2‐trichloro‐1,1,2‐trifluoroethane. The inhibition may be caused by prevention or reduction of virus attachment to the cell surface or, alternatively, the tissue extract may cause aggregation of the virus and thereby reduce the number of available infectious units. The inhibitory effect is also lost by dilution of the extract, reinforcing the claim that adequate dilutions of fish extracts prior to attempted virus isolation are necessary, especially for the detection of carrier fish.
Parasite‐associated pathology of the dolphin fish, Coryphaena hippurus L., from Florida waters
Authors: RAPTOPOULOU F. A. , LAMBERTSEN R. H.
Published: April 2006

Abstract. Eleven wild‐caught dolphin fish (Coryphaena hippurus L.) from Florida waters and 16 of the same species from an experimental mariculture facility were examined for evidence of parasitic disease. Thirteen (48–1%) were found to be infected with parasites of the digestive tract. Adults of the digenean trematode Dinurus rornatus were present in the stomach and intestine. Invasive metacercarial stages of the same species were found encysted in the somatic musculature, pericardium and stomach wall. Metacercaria were associated with mild inflammatory cell infiltration of the musculature and gastric submucosa and, in one case, focal degeneration of the muscle fibres. In addition, invasive plerocercoidsof an unidentified cestode species occurred in the stomach and intestine of a moribund juvenile fish; the associated lesions included degeneration and ulceration of the gastric and intestinal mucosa, with haemorrhage and granuloma formation in submucosal tissues. These findings indicate that parasitic infection of the digestive tract can be a significant cause of disease in dolphin fish in Florida waters.
The immune response of rainbow trout, Salmo gairdneri Richardson, to the haemoflagellate, Cryptobia salmositica Katz, 1951
Authors: JONES S. R. M. , WOO P. T. K.
Published: April 2006

Abstract. Rainbow trout that recovered from experimental Cryptobia salmositica infection 6 and 10 weeks earlier were protected against multiple intraperitoneal challenges of 50 000 and 10 000 parasites isolated from infected fish. The immunity was non‐sterile; low parasitaemias were detected following a larger challenge (112 000 parasites). The indirect haemagglutination test was used to detect C. salmositica‐specific agglutimns. Antibody titers increased during the first 18 weeks of infection. The infectivity of cultured C. salmositica was neutralized by incubation in heat‐inactivated immune plasma. Infectivity of C, salmositica from infected fish was not neutralized by similar treatment. Complement fixing antibody was detected using the in vitro immune lysis test. Immune lysis occurred when cultured C. salmositica were used. Adoptive transfer of both leucocytes and plasma from immune fish conferred partial protection against the parasite in naive recipients. Complement fixing antibody may be important during early acute infection while phagocytosis may be important during the later chronic phase.
Spinal curvatures and an encephalotropic myxosporean, Triangula percae sp. nov. (Myxozoa: Ortholineidae), enzootic in redfin perch, Perca fluviatilis L., in Australia
Authors: LANGDON J. S.
Published: April 2006

Abstract. A new myxosporean, Triangula percae sp. nov., (Myxozoa: Ortholineidae) from the brain of redfin perch, Perca fluviatilis L., is described. Spinal curvatures are prevalent in many perch populations in Victoria, Australia, Triangula percae infection was detected in all perch displaying spinal curvatures and in 67% of normal perch from Lake Nillahcootie in north east Victoria. Perch populations exhibiting spinal curvatures in several other waterways were also infected with Triangula percae but the infection was absent in one population which was apparently normal. Triangula percae infection is, thus, considered to be the cause of a proportion of the spinal curvatures. Certain fish surviving outbreaks of epizootic haematopoietic necrosis virus (EHNV) also developed spinal curvatures, which may have been due to viral infection of the central nervous system.
Further consideration of the haematology of proliferative kidney disease (PKD) in rainbow trout, Salmo gairdneri Richardson
Authors: CLIFTON‐HADLEY R. S. , RICHARDS R. H. , BUCKE D.
Published: April 2006

Abstract. A study of selected haematological parameters in rainbow trout, Salmo gairdneri Richardson, exposed to proliferative kidney disease (PKD) under field conditions is described. Changes in the blood picture are related to kidney pathology at different stages of the disease. As extensive renal vascular pathology, haemoglobin crystallization and inflammatory lesions developed, there were progressive decreases in haemoglobin and packed cell volume values, erythrocyte numbers declined to less than 50% of those in control fish, and numbers of misshapen erythrocytes increased. Leucopenia, neutrophilia and thrombocytopenia developed, especially in oedematous fish. With recovery, most values were similar to those of control fish. In recovered, re‐challenged fish, erythrocyte counts, packed cell volume and haemoglobin values decreased in infected fish compared with uninfected fish. The results of the study are compared with those of other authors and the type of anaemia in PKD is discussed.
A bath challenge model for furunculosis in rainbow trout, Salmo gairdneri Richardson, and Atlantic salmon, Salmo salar L.
Authors: ADAMS ALEXANDRA , LESCHEN W. , WILSON ANNE , HORNE M. T.
Published: April 2006

Abstract. A natural bath challenge method has been developed for furunculosis using Atlantic salmon, Salmo salar L., and rainbow trout, Salmo gairdneri Richardson. Fish were placed in an enclosed, continuously circulating tank system, supplemented with additional oxygen, the temperature raised gradually (overnight) to 15–16°C, a low dose of Aeromonas salmonicida (strain 184/186) introduced into the tank and the challenge maintained for 14 days. The challenge strain was characterized with respect to possible virulence factors and possessed an A‐layer, ability to auto‐agglutinate, haemagglutinate, adhere to Atlantic salmon cells and resist destruction by serum. No caseinase activity was detected. LD50 for salmon using this method was 1.8×103 cells per millilitre while trout had an LD50 of 9.5×104 cells per millilitre. Onset of the disease appeared to depend on fish size with larger trout (50 g) taking up to 10 days to show signs of the disease while mortalities in smaller trout (8.5g) commenced on day 1 post‐challenge.
An ultrastructural study of morphological changes in Atlantic salmon, Salmo salar L., during the development of cold water vibriosis
Authors: TOTLAND G. K. , NYLUND A. , HOLM K. O.
Published: April 2006

Abstract. The structural changes which occur in the heart, the lateral muscle and the large intestine during the development of cold water vibriosis in Atlantic salmon, Salmo salar L., have been studied by light and electron microscopy. The results strongly suggest a causative relationship between the presence of the fish pathogen, Vibrio salmonicida, and the observed pathological changes. Cell damage was invariably accompanied by the presence of the bacterium. A close relationship was found between the number of bacteria detected in the tissues and the degree of morphological damage. The most severe cell damage was found in areas with a rich blood supply. The earliest sign of damage was detected in the cell coat and cell membrane on the luminal side of the endothelial cells of the capillaries. Later in the development, the bacteria were also found intracellularly in endothelial cells. In moribund fish, the cells in the vicinity of the capillaries were also severely damaged. Bacteria appeared intracellularly in leucocytes even in early stages of the disease. This caused more severe damage to leucocytes compared to erythrocytes, which seldom contained bacteria.
A new haplosporean infecting the hepatopancreas in the penaeid shrimp, Penaeus vannamei
Authors: DYKOVÁ I. , LOM J. , FAJER E.
Published: April 2006

Abstract. A hitherto unrecorded haplosporean was found in the hepatopancreas of Penaeus vannamei. Multinucleate plasmodia developing within the hepatocytes fragment into unimicleate stages. Eventually the host cells are destroyed and the uninuclear stages are released into the lumen of the secretory tubules. The haplosporosomes are oval, have a thick cortex and contain a small spherical medulla at the broader end. No spores were found and thus the parasite, which is highly pathogenic, could not be assigned any precise taxonomic position.
Ultrastructural pathology of cutaneous tumours of northern pike, Esox lucius L.
Authors: THOMPSON J. S. , MIETTINEN M.
Published: April 2006

Abstract. An epidemic of cutaneous tumours occurs in northern pike, Esox lucius L., from the Åland Islands of Finland. Previous studies have shown that the neoplasm is of mesenchymal origin and that it is not of B‐lymphocytic lineage; however, a T‐lympho‐cytic origin could not be totally excluded. Here the authors provide morphologic evidence that the tumour could, in fact, be monocyte derived. The close apposition of the tumour cells with a lack of cell‐cell junctions is in keeping with the view that it is not of epithelial origin. A striking morphologic characteristic of the tumour cells is the presence of groups of lysosomes and large numbers of cytoplasmic lipid droplets. Therefore, the authors suggest that the tumour cells have features of histiomonocytic cells and that the neoplasm might be a piscine analogue of true histiocytic lymphoma in humans. These studies represent the first description of this type of neoplasm in fish.
Pathological changes in the tiger prawn, Penaeus monodon Fabricius, associated with culture in brackishwater ponds developed from potentially acid sulphate soils
Authors: NASH G. , ANDERSON I. G. , SHARIFF M.
Published: April 2006

Abstract. Abnormal brown discoloration of the gills, soft shells and decreased survival were identified among problems affecting Penaeus monodon Fabricius adults cultured in growout ponds developed from potentially acid sulphate mangrove soils in Johor, Malaysia. A histological and ultrastructural study showed that lamellar ferric hydroxide accumulation and associated gill changes, which led to hypoxic damage in other tissues, were probably responsible for many of the clinical abnormalities observed in the prawns.
Studies on the carrier state of infectious pancreatic necrosis virus infections in rainbow trout, Salmo gairdneri Richardson
Authors: MANGUNWIRYO H. , AGIUS C.
Published: April 2006

Abstract. A rainbow trout population of infectious pancreatic necrosis virus carriers was studied over a one‐year period using both homogenization and co‐cultivation for virus isolation. The percentage of virus‐yielding fish was high between March and June, but declined during the latter part of the year. This was diametrically opposite to the trend in the serum antibody levels indicating that the marked humoral immune response resulted in a very significant reduction in the virus titres. The highest isolation rate was obtained from the kidneys after co‐cultivation underlining the very high sensitivity of this method for virus detection. Virus was occasionally isolated from the faeces indicating that this may well be a possible avenue for horizontal transmission of the virus. No virus was ever detected in gonadal tissue; the mechanism of vertical transmission of the virus is still very poorly understood.
New coccidians from freshwater fishes of Australia
Authors: MOLNAR K. , RHODE K.
Published: April 2006

Abstract. During a survey for coccidian infections of 135 Australian freshwater fish belonging to 14 species, two new Eimeria species, E. philypnodoni sp. nov. from Philypnodon grandiceps and E. ashburneri sp. nov. from Macquaria ambigua, and three new Goussia species, G. langdoni sp. nov, from Macquaria ambigua, G. callinani sp, nov. from Hypseteotris compressa and G. lomi sp. nov. from Maccullochella peeli, were found. Epieimeria anguillae and a Goussia sp. from Anguilla australis and A. reinhardti were recorded. These are the first records of coccidia from Australian fishes.
Cell‐mediated protection in carp, Cyprinus carpio L., against Aeromonas hydrophila
Authors: BABA T. , IMAMURA J. , IZAWA K. , IKED K.
Published: April 2006

Abstract. The mechanism of protection against Aeromonas hydrophila infection in carp was studied. Recipient fish, into which pronephric cells from carp previously immunized by dipping in bacterial crude lipopolysaccharide (LPS) at 25°C for 2h were transferred, demonstrated almost the same level of protective ability as an immunized control group. The protective ability was transmitted by non‐adherent (to nylon fibre) immune pronephric cells. These non‐adherent cells were damaged by anti‐carp thymocyte serum and were, thus, considered to be T‐like cells. The protective ability was depressed in immunized carp treated with anti‐carp thymocyte serum in vivo and was also remarkably reduced in immunized carp whose macrophage function was impaired by Dextran sulphate‐500 treatment. These results indicate that the protection shown by carp immunized by dipping in crude LPS is dependent on cellular immunity regulated by a T‐like cell‐macrophage system.
Isolation and characterization of a surface layer antigen from Vibrio salmonicida
Authors: HJELMELAND K. , STENSVÅG K. , JØRGENSEN T. , ESPELID S.
Published: April 2006

Abstract. A cell surface product (VS‐P1) of Vibrio salmonicida has been purified from culture supernatant by a combination of extensive dialysis, filtration and centrifugation, as well as by salt precipitation and hydrophobic chromatography. SDS‐PAGE analysis showed that the monomeric form of the antigen is a single polypeptide with an apparent molecular weight of 40000. Size exclusion HPLC of purified VS‐P1 as well as VS‐Pl‐containing fish serum revealed, however, oligomeric forms in the range from 300000 to more than 700000 daltons. The antigen contained 6% carbohydrate and several isolectric forms were distinguishable when analysed on an analytical isoelectric focusing electrophoresis system. A ‘sandwich’ ELISA, utilizing polyclonal antibodies, was developed for screening sera from both healthy and moribund Atlantic salmon for the presence of the VS‐P1 antigen.
Monoclonal antibodies against Vibrio salmonicida: the causative agent of coldwater vibriosis (‘Hitra disease’) in Atlantic salmon, Salmo salar L.
Authors: ESPELID S. , HOLM K. O. , HJELMELAND K. , JØRGENSEN T.
Published: April 2006

Abstract. Monoclonal antibodies (Mab) directed against Vibrio salmonicida were produced and partially characterized. The bacterium is the causative agent of ‘Hitra disease’ or cotdwater vibriosis (CV) and differs from all other Vibrio bacteria tested so far with respect to a unique surface antigen (VS‐P1). Thirteen hybridoma clones produced antibodies which exclusively reacted with this antigen in ELISA. The remaining four clones reacted against undefined determinants and were partly cross‐reactive to V. anguiilarum, V. ordalii and V. fischeri. Fifteen Mab were of IgG1/kappa and two of the IgG3/kappa isotypes. Eleven of the IgG1 plus the two IgG3 Mab reacted with the VS‐P1 molecule.
Gastrointestinal histopathology of paddlefish, Polyodon spathula (Walbaum), infected with larval Hysterothylacium dollfusi Schmidt, Leiby & Kritsky, 1974
Authors: MIYAZAKI T. , ROGERS W. A. , SEMMENS K. J.
Published: April 2006

Abstract. Gastrointestinal histopathology of the paddlefish, Polyodon spathula (Walbaum), infected with larval nematodes, Hysterothylacium dollfusi Schmidt, Leiby & Kritsky 1974, was studied. Larval H. dollfusi invaded the gastric mucosa and caused ulcers with accompanying infiltration of eosinophilic granulocytes. The deeper penetration into the stomach and intestine caused the formation of capsular granulation tissues around the worms. Larval worms were also histologicahy studied. The intestinal epithelium of larvae contained glycogen, haemosiderin and ceroid, indicating their blood‐feeding capability.
Ultrastructural observations of the life cycle stages of Ameson atlanticum sp. nov., a microsporidan parasitizing Cancer pagurus L.
Authors: VIVARÈS C. P. , AZEVEDO C.
Published: April 2006

Abstract. Cancer pagurus (Cancridae) from the Atlantic coast of France is parasitized by a new species of microsporida Ameson atlanticum sp. nov. The main stages of the life cycle of the parasite are a monokaryotic and then diplokaryotic meront, tetranucleate (at least) sporont fsporogonial sporont), uninucleate sporoblast and spore. The spore (1.9 × 1.5 μm) possesses 11–12 coils of the polar filament and a lamellar polaroplast. Hairlike appendages are present on the surface of the sporoblastic plasmodium, sporoblast and spore. All stages take place in direct contact with the muscular tissue of the crab. Infection provokes the destruction of 80% of host muscle myofibrils.
Scanning electron microscopy study of the causes of mortality in Oreochromis mossambicus (Peters) eggs under artificial incubation
Authors: SUBASINGHE R. P. , SOMMERVILLE C.
Published: April 2006

Abstract. The practice of artificial incubation of eggs of the mouth brooding cichlid genus Oreochromis has considerable advantages over maternal incubation. However, problems arise in providing the eggs with conditions which simulate the buccal environment during incubation. Investigations into the causes of mortality of O. mossambicus (Peters) eggs under artificial incubation were carried out using scanning electron microscopy. Mechanical injury to the chorionic membrane, potentially pathogenic bacterial action and secondary fungal attack form a series of consequent events occurring on the O. mossambicus eggs under artificial incubation. These events appear to make a considerable contribution towards the mortality of developing eggs. The findings of the study are relevant to the types of treatments used to improve egg survival in hatchery systems.
Haematological and biochemical analyses of Atlantic salmon, Salmo solar L., suffering from coldwater vibriosis (‘Hitra disease’)
Authors: WAAGBØ R. , SANDNES K. , ESPELID S. , LIE Ø.
Published: April 2006

Abstract. Juvenile Atlantic salmon, Salmo salar L. were sampled from a commercial Norwegian fish farm during an outbreak of ‘Hitra‐disease’. One group of fish subjectively judged as healthy and another as diseased were defined on the basis of the classical apathetic behaviour seen in‘Hitra‐disease ? salmon. Haematological and biochemical analyses were carried out from blood and organs in 10 fish from each group. The diseased fish were severely anaemic. The blood indices MVC, MCH and MCHC indicated active erythropoiesis to compensate for the loss. Alkaline phosphatase (AP) activity, total protein, albumin, creatinine, triglycerides and total cholesterol were significantly reduced in the serum of diseased fish, while the activities of aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) showed normal and significantly increased values respectively. Liver and spleen weight relative to the body weight and the content of water and lipid in the liver were significantly elevated in diseased fish. Furthermore, the iron content of the spleen was increased, whereas the zinc content showed no changes. The branched‐chain amino acids valine, leucine and isoleucine were significantly higher and serine significantly lower in muscle extracts of diseased fish.
Ultrastructural observations on the causative agent of epitheliocystis in the brown bullhead, Ictalurus nebulosus Lesueur, from Ontario and a comparison with the chlamydiae of higher vertebrates
Authors: DESSER S. , PATERSON W. , STEINHAGEN D.
Published: April 2006

Abstract. Stages of development of chlamydial organisms were found in intracellular ‘cysts’ in the epithelium of the gill lamellae of brown bullheads. Early, irregularly shaped stages with granular cytoplasm occurred in membrane‐bound vacuotes in host cells of undetermined origin. The organisms enlarged and divided within the grossly hypertrophied host cell. Dense nucleoids were first seen in single, closely packed organisms, which became enlarged and irregular in shape. Small, spherical organisms were formed from larger ones by fission and budding. Mature cysts contained many small, dense, spherical forms, each of which contained a dense central nucleoid. Fine filaments arranged perpendicular to the plasma membrane traversed the space between the inner and outer membranes of the dense spherical forms, which appeared to be the terminal stage of development. The ultrastructural features of the chlamydial agent of epitheliocystis are compared with those in other fish and with chlamydiae in higher vertebrates.
An assessment of the antigenic homogeneity of Edwardsiella ictaluri using monoclonal antibody
Authors: PLUMB J. A. , KLESIUS P.
Published: April 2006

Abstract. Monoclonal antibodies were made against the reference strain of Edwardsiella ictaluri (ATCC 3320). Antibody produced by one of seven anti‐E. ictaluri hybridomas reacted positively by the immunofluorescent antibody technique against 17 other E. ictaluri isolates. All hybridoma antibodies failed to react with six other bacterial species pathogenic to fish including E. tarda. Ouchterlony tests indicated that four anti‐E. ictaluri clones produced only one kind of immunoglobulin. Electrophoresis of 14 different E. ictaluri isolates indicated identical protein bands at 36 and 60 kilodaltons (KD) in all isolates except an isolate from Thailand. Using the immunoblot method, channel catfish anti‐E. ictaluri serum reacted with protein bands at 34 and 60 KD, which indicates that this molecular weight protein in the bacterium may be the dominant immunoprotein.