bluuebunny/crossref_metadata_2025 huggingface dataset:
Antigen‐trapping in the spleen and kidney of the plaice Pleuronectes platessa L.
Authors: ELLIS A. E.
Published: April 2006

Abstract. The process of the localization of bovine serum albumin (BSA) within the lymphoid tissues of the plaice is described. The spleen is seen to be of particular importance. Antigen is held, probably as an immune complex, in an extracellular position associated with the metalophil reticular fibres present mainly in the ellipsoid walls and scattered throughout the peri‐ellipsoid areas and the melano‐macrophage centres. In the kidney tissue, antigen was present mainly intracellularly within the reticulo‐endothelial system (RES) and free macrophages. The extracellular antigen within the spleen persisted the longest (at least 37 days). Localization of BSA differed markedly from colloidal carbon in that the metalophil fibres of the ellipsoids and to a small extent those of melano‐macrophage centres, are the site of BSA localization and not, as with carbon, macrophages which aggregate within melano‐macrophage centres. The thymus and RES of the atrium of the heart played no part in uptake of BSA. The significance of antigen‐trapping in vertebrates is discussed and the possible analogous function of the ellipsoid system in fish and germinal centres of higher vertebrates is considered.
Cryptobia branchialis Nie from fish gills: ultrastructural evidence of ectocommensal function
Authors: LOM J.
Published: April 2006

Abstract. Flagellates infesting the gills of freshwater fish are reviewed and Cryptobia branchialis Nie is differentiated from them. Gill filaments of two species of fish heavily infested with C. branchialis were examined with the transmission electron microscope. The flagellates are attached to the surface of the gill epithelium by their recurrent flagella. A prominent ridge on the flagellar membrane contacts the host cell membrane, forming a zone of gap junction and leaving a space of about 10 nm between the two membranes. The flagella do not penetrate into the epithelial cells. No other modifications of the cell membrane could be detected and the host cell reveals no signs of damage. Assumptions on the pathogenicity of C. branchialis are discussed in view of ultrastructural findings, which suggest that this flagellate is non‐pathogenic and ectocommensal.
Cell and tissue reactions of turbot Scophthalmus maximus (L.) to Tetramicra brevifilum gen. n., sp. n. (Microspora)
Authors: MATTHEWS R. A. , MATTHEWS B. F.
Published: April 2006

Abstract. Tetramicra brevifilum gen, n. sp, n. is described from the connective tissues throughout the body musculature of turbot Scophthalmus maximus (L.). Uninucleate spores (4.8·2 μm) are characterized by a large posterior vacuole, electron dense inclusion bodies in cytoplasm and nucleus and short filaments with 3–5 coils (50 μm extruded). Sporogony is apansporoblastic and tetrasporoblastic, within a host vacuole. Features of the xenoma (2 mm diameter) include a microvillous surface layer with microtubules and microfilaments and a reticulate nucleus with numerous nucleoli. Adherence between adjacent xenomas results in composite cysts of various sizes and shapes depending on site, being dendritic in the myomeres, arms extending between the fibres. Effects on the host, other than eventual destruction of the host cell, include displacement of muscle fibres in myomeres with loss of attachment to myocommata. Breakdown of the xenoma with release of spores into the connective tissue matrix was associated with a localized necrosis affecting surrounding muscle fibres, with leucocyte infiltration and collagen deposition. Spores phagocytosed by macrophages were destroyed in vacuoles, some with multi‐laminate walls. Experimental infections established by intramuscular injection at marked sites remained localized, which suggested that xenomas afford sufficient scope for spore production without the need of secondary invasion. The swimming efficiency of turbot would be impaired in severe infections leading to lowered growth rates and increased mortality in wild populations due to predation and starvation. Feeding hierarchies exist in turbot and the disease could prove significant in farming conditions.
Experimental pathogenicity of reovirus 13p2 for juvenile American oysters Crassostrea virginica (Gmelin) and bluegill fingerlings Lepomis macrochirus (Rafinesque)
Authors: MEYERS T. R.
Published: April 2006

Abstract. A viral agent (13p2), isolated from clinically normal juvenile American oysters (Crassostrea virginica) and characterized as a new serotype of reovirus, was tested to determine if it could replicate and produce disease in experimental juvenile oysters. Because the virus replicated well in the bluegill fry (BF‐2) fish cell line, fingerling bluegills Lepomis macrochirus were included in the pathogenicity experiments. Exposure of oysters to the 13p2 virus in ambient seawater resulted in no significant mortality and no increased virus titres or histological lesions. Virus particles were not observed in tissues of exposed oysters when examined with transmission electron microscopy (TEM). Intraperitoneal inoculation of the 13p2 virus into bluegills resulted in 44% mortality associated with a focal necrotic hepatitis. Evidence of virus replication, when evaluated histological or by virus titration, was observed in 94% of 32 inoculated fish. Samples of infected livers examined with TEM revealed typical cytoplasmic arrays of 13p2 virus particles in affected hepatocytes. Rising virus titres and hepatic lesions also occurred in bluegills exposed to water containing the 13p2 virus. These results indicated the natural host of the 13p2 virus was not the American oyster, but that it was a significant pathogen for at least one fish species.
Attempts to control Ichthyophthirius multifiliis Fouquet (Ciliophora: Ophryoglenidae) by chemotherapy and electrotherapy
Authors: FARLEY D. G. , HECKMANN R.
Published: April 2006

Abstract. New methods were studied for the control of Ichthyophthirius muttifiliis Fouquet, one of the most serious parasites of fish. Totals of 272 fish, 354 I. Multifiliis trophozoites and 562,500 tomites were used in the screening of amprolium, ronidizole, and silver nitrate for parasite control. In addition, 1,465 trophozoites and 600 tomites were subjected to pulsed DC electrotherapy trials. Silver nitrate at 0·67 ppm was 100% effective in eradicating tomites, while ronidizole at 750 ppm gave 100% and 97% control of trophozoites and tomites, respectively. Amprolium and electrotherapy were both ineffective against trophozoites and tomites. Silver nitrate has promise as a safe and effective alternative to chemicals currently used to control I. multifiliis.
The prevalence and pathology of the cestode Polyonchobothrium clarias (Woodland, 1925) in the teleost, Clarias mossambicm (Peters)
Authors: WABUKE‐BUNOTI M. A. N.
Published: April 2006

Abstract. The prevalence and pathology of the pseudophyllidean cestode, Polyonchobothrium clarias in the gastrointestinal tract of the teleost, Clarias mossambi‐cus have been studied. The cestodes were most abundant in the gall bladder where they caused pronounced nodular outgrowths in the mucosa and exhibited a gradual decrease in number distally towards the rectum. Generally the intensity of the infection due to P. clarias was higher in young fish than in old fish.
Nutritional deficiency disease in an Indian major carp, Cirrhina mrigala Hamilton, due to avitaminosis C during early growth
Authors: AGRAWAL N. K. , MAHAJAN C. L.
Published: April 2006

Abstract. Experiments with a purified vitamin test diet on newly hatched Cirrhina mrigala Hamilton, a major carp of great piscicultural importance, are reported. Experimentally induced vitamin C deficiency for 330 days was followed by recovery treatment for 30 days. Retarded growth and greater mortality accompanied by structural deformities such as lordosis and scoliosis, increasing with prolonged deficiency, were recorded. Haematological and haematopoietic studies revealed hypochromic macrocytic anaemia accompanied by anisocytosis. Correlated studies on erythropoiesis revealed increased reticulocytes and an overall decrease in small lymphoid haemoblasts. Total and differential leucocyte counts revealed leucopenia and thrombopenia accompanied by an increase in neutrophils and eosinophils. Recovery treatment halted and in some cases even compensated these pathophysio‐logical changes to some extent.
Histochemical, fluorescent and electron microscopical appearance of hepatocellular ceroidosis in the Atlantic salmon Salmo salar L.
Authors: ROALD S. O. , ARMSTRONG D. , LANDSVERK T.
Published: April 2006

Abstract. In this work it is established that a close relationship exists between the feeding of rancid feed (containing high amounts of lipid peroxides and α, β‐unsaturated aldehydes) and lipoid liver degeneration (LLD) in fish. The main feature of the disease is a large accumulation of ceroid in hepatocytes, giving positive histochemical staining reactions with a number of selective stains. Tissues also reacted strongly for lipid peroxides and fluoresced a bright yellow‐green at 450 nm. This is the first report on the ultra structure of ceroid in LLD. The accumulations consist of bodies containing cholesterol or cholesterol ester crystals and inclusions with membranous profiles. The latter type of inclusion is considered to be representative of ceroid.
The role of Aeromonas salmonicida extracellular products in the pathology of furunculosis
Authors: ELLIS A. E. , HASTINGS T. S. , MUNRO A. L. S.
Published: April 2006

Abstract. The extracellular products (ECP) of Aeromonas salmonicida, prepared by the cellophane overlay method, are lethal to rainbow trout when administered parenterally. Sublethal doses when injected i.p. or i.m. are shown to reproduce all the lesions that have been described in the literature as being associated with furunculosis. In addition, meningitis may be an important feature of furunculosi s and is reproduced by injection of ECP. A serum factor, probably an α‐globulin, present in normal serum of rainbow trout, is capable of neutralizing the toxic effects of ECP. The pathology is discussed with reference to the proteolytic and leucocidal properties of the ECP and its effects upon the eosinophilic granular cells which are caused to disperse and degranulate with the possible release of histamine.
Pathogenesis and autoradiographic studies of the epidermis of salmonids infested with Ichtyobodo necator (Henneguy, 1883)
Authors: ROBERTSON D. A. , ROBERTS R. J. , BULLOCK A. M.
Published: April 2006

Abstract. The sequential pathology of Ichtyobodo necator infestations of the skin of 0+ and 1+ salmon and rainbow trout was studied. Areas of greatest shelter from water currents were found to be most commonly infested and no parasites were found attached to the epidermis on the head of the fish. The parasite caused hyperplasia of the malphigian cells and exhaustion of the goblet cells below infestations, followed by spongiosis of the underlying epidermis. The epidermal plaque then sloughed off leaving a single layer of cells attached to the basement membrane. Cell kinetic studies showed that I. necator caused the cells immediately below infestations to divide, a markedly different pattern from that of normal teleost epidermal cell proliferation. The possibility that the parasite secretes some form of digestive enzyme is postulated. In areas where sloughing had occurred, the remaining malphigian cells were seen to be in the process of division.
The histopathology of the eye of big head carp, Aristichthys noblis (Richardson), infested with Lernaea piscinae Harding, 1950
Authors: SHARIFF M.
Published: April 2006

Abstract. The histopathological changes in the eye due to the penetration and growth of the parasite, Lernaea piscinae, in the host tissue of big head carp is described. Distinct pathological changes were hyperplasia of the corneal epithelium, severe inflammatory response mainly around the anchor of the parasite, in the anterior chamber, the corneal stroma and the vitreous body and detachment of the vitreous and retinal layers. Rupture of the lens capsule and fibrous tissue response around the process of the anchor structure of the parasite were also observed. The development of an immune response to the parasite within the body of the host is thought to have led to the infection of the cornea, an avascular site.
Microsporidium rhabdophilia n. sp. from rodlet cells of salmonid fishes
Authors: MODIN J. C.
Published: April 2006

Abstract. A microsporidian parasite, Microsporidium rhabdophilia n. sp. is described from rodlet cells of salmonid fishes. Chinook salmon, Oncorhynchus tshawytscha, coho salmon, Oncorhynchus kisutch, steelhead rainbow trout, Salmo gairdnerii gairdnerii, and various strains of domesticated rainbow trout were found infected. In living wet mount phase‐contrast observations of various tissues, 16 mature spores could be seen infecting the nucleus of rodlet cells. The number of spores infecting each nucleus generally numbered 16 and spores were not found in any cell or organelle other than the nucleus of the rodlet cell. All observations were limited to California hatchery‐reared fish.
The influence of fish age and water temperature on mortalities of rainbow trout, Salmo gairdneri Richardson, caused by a European strain of infectious pancreatic necrosis virus
Authors: DORSON M. , TOUCHY C.
Published: April 2006

Abstract. Rainbow trout fry were infected by a pathogenic Sp type of infectious pancreatic necrosis virus isolated in France. Fry held at 10°C and infected at different ages showed a decrease of sensitivity with increasing age and ceased to be susceptible to the disease when 20 weeks old. Mortality was delayed at 6°C and lowered or suppressed at 16°C. When fry were moved from 10 to 16°C before infection mortality was also lowered but not when they were moved from 16 to 10°C. Late infection of siblings kept at different temperatures before infection suggested a relation between the number of degrees x days and the final mortality recorded.
The occurrence and distribution of Myxidium giardi Cépède, 1906 in wild and cultured European eels, Anguilla anguilla L., in England
Authors: COPLAND J. W.
Published: April 2006

Abstract. Myxidium giardi was found in wild and cultured eels. The prevalence rate in elvers was 77% in the River Torridge (Devon), 80% in the River Parrett (Somerset) and 90% in the River Ouse (Yorkshire). Adult eels from the River Ouse had a prevalence rate of 53%, Cultured fingerlings and adults had a prevalence rate of 60% and 1%, respectively. There was an apparent age‐related pattern in the organ location of the histozoic trophozoite: an initially high prevalence of kidney trophozoites which gradually decreased with age; in the gills of elvers there was a low prevalence of histozoic trophozoites which increased in the adult stage. Histozoic trophozoites were also found in the stomach and intestine of elvers and fingerlings. A qualitative estimate of trophozoite numbers in each organ of elvers is given. The coelozoic trophozoite of M. giardi in the gall bladder of elvers and fingerlings is also described for the first time.
The use of chemosterilants to lower the frequency of skin fungal infection amongst precocious male 1+ Atlantic salmon parr, Salmo salar L.
Authors: MURPHY T. M.
Published: April 2006

Abstract. Precocious male 1+ Atlantic salmon parr were treated with methallibure and cyproterone acetate during the later stages of spermatogenesis. These drugs prevented hyperplastic changes in the epidermis and lowered the prevalence of fungal infection. They did not alter the mucohistochemical staining pattern or the superficial mucous cell concentration of the skin.
Action of selected antibiotics on four common bacteria associated with diseases of fish
Authors: NUSBAUM K. E. , SHOTTS E. B.
Published: April 2006

Abstract. Four bacteria commonly associated with diseases of fish (Aeromonas hydrophila complex, Aeromonas salmonicida, Flexibacter columnaris‐like organisms and Pseudomonas fluorescens) were evaluated in a serial dilution system for susceptibility to four antibiotics commonly used in the treatment of bacterial fish diseases (chloramphenicol, erythromycin, furpyrinol and oxytetracycline). Findings were expressed as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Furpyrinol was found to have the lowest MIC and MBC against A. hydrophila complex, A. salmonicida and F. columnaris‐like organisms. MIC and MBC's for oxytetracycline were complicated by the presenceof R‐plasmids, but were less than 4.0 mcg/ml for those without plasmids. Pseudomonas fluorescens was susceptible only to oxytetracycline. MIC for all groups of organisms using chloramphenicol was generally less than 16.0 mcg/ml. Susceptibility to erythromycin by these groups of organisms was greater than 16 mcg/ml.
Thyroid dysfunction in Great Lakes coho salmon, Oncorhynchus kisutch (Walbaum): seasonal and interlake differences in serum T3 uptake and serum total and free T4 and T3 levels
Authors: LEATHERLAND J. F. , SONSTEGARD R. A.
Published: April 2006

Abstract. Sexually mature spawning and prespawning adult and ‘jack’ coho salmon, Oncorhynchus kisutch, were collected during their potamodromous migration from Lakes Ontario, Erie and Michigan in late autumn. In addition, sexually immature spring salmon were collected from Lakes Ontario and Erie. Serum total thyroxine (TT4), serum free thyroxine (FT4), serum total triiodothyronine (TT3) and serum free triiodothyronine (FT3) levels showed marked seasonal variability in salmon from Lakes Ontario and Erie with peak hormone levels evident in the spring fish and lowest levels in the sexually mature adults and ‘jacks’. Seasonal changes in serum triiodothyronine uptake (T3U) values were inverse of those of serum TT4, FT4, TT3 and FT3 levels. When data of the whole collection were combined significant positive correlation coefficients were evident as follows: serum TT3 v. serum TT4, FT4 and TT3; serum TT4 v. serum FT4 and FT3; serum FT4 v. serum FT3, and significant negative correlations as follows: serum T3U v. serum TT3, TT4, FT4 and FT3. When individual groups were examined significant correlations were either absent, or in some instances the reverse of those of whole data. The data provide further evidence of interlake differences in dysfunction of thyroid hormone metabolism in Great Lakes coho salmon; the possible involvement of environmental agents is discussed.
Herpesvirus salmonis: pathological changes in parenterally‐infected rainbow trout, Salmo gairdneri Richardson, fry
Authors: WOLF K. , SMITH C. E.
Published: April 2006

Abstract. After fry of rainbow trout, Salmo gairdneri Richardson, had been infected parenterally with Herpesvirus salmonis, moribund or freshly dead specimens were examined histopathologically. The virus produced a generalized infection, the first signs of which appeared after 2–3 weeks. Visceral and respiratory organs and the heart showed major pathological changes, and pancreatic syncytia were judged to be pathognomonic. Kidneys were prime targets for the virus and showed the highest levels of infectivity; lesser amounts of virus were present in the stomach, liver, and intestine. The virus did not spread by contact to produce clinical disease nor could disease or viral replication be induced by parenteral inoculation of yearling Oncorhynchus nerka (Walbaum).
Fish coccidia: critical notes on life cycles, classification and pathogenicity
Authors: DYKOVÁ IVA , LOM J.
Published: April 2006

Abstract. The present knowledge of oocyst morphology, life cycles, classification and pathogenicity of eimeriid coccidia infecting fishes is reviewed. Compared with typical Eimeria species from higher vertebrates, fish coccidia, currently classified as all belonging to the same genus, differ in having, as a rule, a thin oocyst wall and endogenous sporulation. Some species possess a bivalved sporocyst, a structure and consequently an excystation mechanism, essentially different from that of the genus Eimeria. An analysis of the life cycles of more than 120 recorded species of fish coccidia has shown six different types of developmental patterns. The life cycles offish coccidia are compared with the life cycles of coccidia in general. None of the fish coccidia having a sporocyst with a Stieda body sporulates exogenously and therefore do not display a true eimerian developmental pattern. In view of the importance of sporocyst structure and developmental patterns in taxonomy, the revalidation of Labbé's genera Goussia and Crystallospora is proposed along with the establishment of a new genus, Epieimeria n.g. Most of the species offish coccidia are left within the genus Eimeria until new data make possible their correct classification. Detailed data on histopathological changes are available only in infections by two carp‐infecting species, E. carpelli and E. subepithelialis and E. funduli infections in killifishes. The potential threat of coccidiosis in fishes reared under intensive conditions requires a thorough study of the pathogenicity of further species infecting commercially important hosts.
Pathology of spontaneous tuberculosis and pseudotuberculosis in fish
Authors: MAJEED S. K. , GOPINATH C. , JOLLY D. W.
Published: April 2006

Abstract. The pathology of two infectious granulomatous diseases of aquarium‐maintained fish are described. Two fish showed widespread occurrences of hard and soft tubercles which contained clumps of acid‐fast bacilli, confirming the diagnosis of fish tuberculosis. Four other fish showed predominantly large soft tubercles containing peripheral arrangement of Gram‐negative, non‐acid fast bacilli diagnosed as flavobacterium. The various features are described and discussed with emphasis on differential diagnosis.
Unicauda magna sp.n. (Protozoa: Myxozoa): a new myxozoan from the fin tissues of the fathead minnow, Pimephales promelas Rafinesque
Authors: MINCHEW C. D.
Published: April 2006

Abstract. Unicauda magna sp.n. (Protozoa: Myxozoa) was found in hatchery‐raised fathead minnows, Pimephales promelas (Cyprinidae) from Pennsylvania. A large number of whitish‐coloured cysts were located in the tissues of the pectoral, pelvic and caudal fins of infected fish. Spore dimensions (in μm) based on 30 measurements (10 spores/cyst) included the following: total length, 109.6 (75–170); spore body length, 15.5 (14–17); spore body thickness, 12.1 (10–13); spore body width, 13.2 (12–14.5); tail length, 94.1 (60–154); polar capsule lengths, 8.6 (7.5–9.5); polar capsule width 4.1 (3.0–5.0); sutural ridge width, about 1. The tail and body of the spores differed in colour when stained with each of three dyes. They are, therefore, composed of different material.
An experimental study of the susceptibility of Atlantic salmon fry, Salmo salar L., to viral haemorrhagic septicaemia
Authors: DE KINKELIN P. , GASTRIC J.
Published: April 2006

Abstract. Infection trials using two serotypes of VHS viruses (type 1 and 23/75) demonstrated that Atlantic salmon fry were susceptible to the disease when injected intraperitoneally (i.p.) with 103 pfu of virus/fish but resistant to infection by a bath method when exposed for 3 h in water containing 5 × 104 pfu of virus/ml. In the i.p.‐infected fish, mortality reached 78 and 67% within 13 days with VHSV1 nad 23/75 serotypes, respectively. High virus yields were recovered from infected fish and virus shedding was demonstrated by the onset of VHS in rainbow trout kept in the outflow water from the aquaria containing infected salmon. Neither mortality nor virus shedding occurred in salmon infected by the water route but virus multiplication was demonstrated in 2 of 60 fish with VHSV1 and 3 of 60 fish with virus 23/75. On day 79 post‐infection the sera from surviving salmon of both i.p. and bath infection trials exhibited good neutralizing titres (around 1000) against the homologous viruses.
Ultrastructural studies on the cellular response of roach, Rutilus rutilus L., to the plerocercoid larva of the pseudophyllidean cestode, Ligula intestinalis
Authors: HOOLE D. , ARME C.
Published: April 2006

Abstract. Infections of roach, Rutilus rutilusL., with the plerocercoid larva of Ligula intestinalis result in a pronounced host cellular response which consists of a leucocyte and connective tissue component. Using ultrastructural, histochemical and tracer techniques, three leucocyte cell types (L1, L2 and L3) have been observed. L1 cells, the most numerous cell type, pass through a number of characteristic developmental stages. Phagocytosis occurs in stages 1, 2 and 3. Stages 1 and 2 contain predominantly primary lysosomes and secondary lysosomes respectively, and in cells of stage 3 residual bodies are found which may be released following disruption of the cell at stage 4. The lysosomes and residual bodies do not contain acid phosphatase although arylsulphatase activity is present in all secondary lysosomes and residual bodies and in a few primary lysosomes. L1 cells are thought to be macrophages. L2 and L3 cells are relatively rare. The former contain granules resembling those found in mammalian eosinophils but which themselves are not eosinophilic or acid phosphatase and arylsulphatase positive. L2 cells are phagocytic and are thought to be neutrophils. L3 cells are also phagocytic and may represent macrophage precursors. Despite the presence of a host cellular response parasites survive apparently unharmed as long as the host lives. The significance of this is discussed.
In vitro and in vivo passage of bacteria across restricted areas and isolated tissues of trout, Salmo trutta L. and S. gairdneri Richardson
Authors: BOWERS A. , ALEXANDER J. B.
Published: April 2006

Abstract. Isolated areas of the skin and gills of rainbow and brown trout were subjected to hyperosmotic infiltration with E. coli both in vitro and in vivo and examined for the passage of bacteria. Bacteria were recovered from the isolated gill arches only after treatment with balanced salt solution at x 10 concentration, followed by the bacterial suspension. All the skin flap experiments were negative. Bacteria were recovered from the blood offish when that part of the animal anterior to the pectoral fins was exposed to the infiltrating bacteria. They were only recovered when the animal was exposed to the full hyperosmotic infiltration schedule. The evidence strongly supports the view that the bacteria enter the animal through the gills.
Onset of immunity in salmonid fry vaccinated by direct immersion in Vibrio anguillarum and Yersinia ruckeri bacterins
Authors: JOHNSON K. A. , FLYNN J. K. , AMEND D. F.
Published: April 2006

Abstract. The fry of several salmonid species were vaccinated by direct immersion in either Yersinia ruckeri or Vibrio anguillarum bacterin and the level of protective immunity was determined by the survival of fish after bath challenge with virulent organisms. The immersion time for effective vaccination was obtained within 5 s and protective immunity was demonstrated within 5 days at 18°C and within 10 days at 10°C. The minimum size at which maximum protective immunity occurred was between 1.0 and 2.5 g. Immunity appeared to be a function of size and not age, but differences in response among several species were indicated. In fish under 1.0 g, the level of protective immunity could be increased using a more concentrated bacterin. The results were similar with both bacterins.
The pathology of Haplorchis pumilio (Looss, 1896) infections in cultured tilapias
Authors: SOMMERVILLE CHRISTINA
Published: April 2006

Abstract. Haplorchis pumilio (Looss, 1896) is a common digenean parasite of many species of fish of economic importance and has been found to infect cultured Sarotherodon spp. Fry of S. spilurus (Günther), S. mossambicus (Peters) and S. galilaea (L.) were experimentally infected with cercariae of H. pumilio from natural infections of Melanoides tuberculata (Müller) from an East African fish farm. Large numbers of cercariae were lethal to the fry within a few hours. Histopathological examination showed that the most significant pathological effect was focal haemorrhages in skeletal muscles in heavily infected fish. Migration of cercariae was through connective tissue and the final location of the metacercariae was connective tissue associated with skeletal structures. Clusters of cysts occurred at the bases of fins and in the loose connective tissue of the head, but the reaction to encysted metacercariae was insignificant. The overall effect on growth performance and thus economic importance of H. pumilio infection was assessed. Growth studies showed no significant differences between specific growth rate, food conversion ratios and condition of infected and uninfected fish.
Effects of temperature on biochemical reactions and drug resistance of virulent and a virulent Aeromonas salmonicida
Authors: HAHNEL G. B. , GOULD R. W.
Published: April 2006

Abstract. Incubation temperatures of 11°, 18° and 28° did not substantially affect biochemical reactions of either virulent or avirulent forms of Aeromonas salmonicida subspecies salmonicida. The only change observed, amygdalin fermentation, was positive at 11° and 18° but negative at 28°C. Several isolates utilized sucrose, a characteristic not normally recognized for A. salmonicida subspecies salmonicida. Antimicrobial susceptibility screening indicated resistance to novobiocin increased at the higher incubation temperatures. Standardized drug sensitivity testing procedures and precise zone diameter interpretive standards for bacterial fish pathogens are needed.
Light and electron microscope observations on pathological changes in the gills of the marine fish Lycodes lavalaei Vladykov and Tremblay associated with the proliferation of an unidentified cell
Authors: DESSER S. S. , KHAN R. A.
Published: April 2006

Abstract. Pale and swollen gills were observed in 23 of 240 Laval's eelpouts, Lycodes lavalaei Vladykov and Tremblay (Perciformes), taken from several locations off the coasts of Newfoundland and southern Labrador. Light microscopic study of histological sections revealed clusters of unidentified cells (‘X‐cells’) in the basal region of secondary gill lamellae and extending along the latter, between the epithelium and lamellar capillaries. In the electron microscope two types of X‐cells were enclosed in a network of cytoplasmic processes from dense ‘envelope’ cells. Both types of X‐cells were bound by a densely‐coated limiting membrane and had nuclei with large, dense nucleoli, numerous mitochondria with short vesicular cristae, lipid inclusions, abundant smooth endoplasmic reticulum and small dense inclusions. The Type II X‐cells were larger, contained a much greater concentration of lipid and small dense inclusions, and an additional inclusion with a dense core surrounded by a light halo. The X‐cells are compared with strikingly similar cells described from epidermal and pseudobranch tumours of marine fish. Although transformation of a host cell by virus or possibly pollution has been suggested, neither the nature nor the origin of the X‐cells can be determined.
An outbreak of botulism in rainbow trout, Salmo gairdneri Richardson, farmed in Britain
Authors: CANN D.C. , TAYLOR L.Y.
Published: April 2006

Abstract. An outbreak of disease in a British trout farm was identified as fish botulism. The diagnosis was established by demonstration of toxin in the serum and intestinal contents of fish, and was confirmed by the production of experimental botulism in trout inoculated with toxin from a strain of Clostridium botulinum type E isolated from intestinal contents of a sick fish. The outbreak was controlled and eliminated within 1 month by conservative measures which comprised the emptying, cleaning and heavy liming of affected ponds; intensive examination of all ponds for immediate removal of dead and sick fish and, on public health grounds, the banning of movement of fish outwith the farm. This episode, although of considerable financial consequence to the farmer, was shown to have no public health significance.
Replication of infectious pancreatic necrosis virus in trout leucocytes and detection of the carrier state
Authors: YU K.K‐Y. , MACDONALD R.D. , MOORE ANNE R.
Published: April 2006

Abstract. The exact cellular site of replication of infectious pancreatic necrosis virus (IPNV) in carrier fish is unknown. In order to determine if IPNV replicates in trout leucocytes, we purified leucocytes from normal (non‐carrier) trout and separated the cells into an adherent and a non‐adherent population. IPNV replicated in less than 0‐01 % of the adherent leucocytes with a yield of about 400 p.f.u./cell. IPNV also became associated with less than 0.07% of the non‐adherent leucocytes; either IPNV did not replicate in these cells or the yield was, at best, only a few p.f.u./cell. Trout persistently infected with IPNV (carrier fish) were tested for the presence of IPNV in leucocytes by co‐cultivating with a sensitive fish cell line; this same population of trout was also tested for IPNV by organ sampling using standard methods. Ninety‐eight per cent of the trout were positive for IPNV by organ sampling, but only 75 % yielded IPNV from leucocytes. Thus a blood sample from a living fish can be used to detect the presence of IPNV.
A Lactobacillus sp. from diseased female rainbow trout, Salmo gairdneri Richardson, in Newfoundland, Canada
Authors: CONE D. K.
Published: April 2006

Abstract. Post‐spawning mortalities of 2‐ to 3‐year old female rainbow trout, Salmo gairdneri Richardson, at a Newfoundland hatchery were studied. The fish were found to have a mixed bacterial infection involving primarily a Lactobacillus sp. (a Gram‐positive, chain‐forming coccobacillus) and to a lesser degree Enterobacteriaceae, Aeromonas hydrophila and Pseudomonas fluorescens. The bacteria were isolated from the visceral organs, kidney, and ascitic fluid present in the coelomic cavity. The fish had extensive degeneration and necrosis of the liver, spleen and kidney, and sloughing of intestinal epithelium, but whether these were caused directly by the bacterial infection was not established because the fish appeared to have received substantial stress from the mechanical stripping and from the retention of dead, unshed eggs in the coelomic cavity. Tissue sections suggested that substantial growth of the Lactobacillus sp. was occurring within these unshed eggs. The present study describes this unusual observation and compares the Lactobacillus sp. to two other Lactobacillus isolates from cultured trout.
Eimeria branchiphila sp.nov. sporulating in the gill filaments of roach, Rutilus rutilus L.
Authors: DYKOVÁ IVA , LOM JIŘÍ , GRUPCHEVA GINKA
Published: April 2006

Abstract. Eimeria branchiphila sp. nov. is described from the roach, Rutilus rutilus L., collected in Bulgaria. Sporulated oocysts were found in gill secondary lamellae and less frequently were associated with melano‐macrophage centres in the spleen and in kidney interstitial tissue. In the gills, parasite cells identified as zygotes and sporulation stages were also encountered. This unusual site of sporulation represents a mechanism of sporocyst dispersal previously not recorded in fish coccidia.
Saddleback: a dominant, lethal gene in Sarotherodon aureus (Steindachner) (=Tilapia aurea)
Authors: TAVE D. , BARTELS J. E. , SMITHERMAN R. O.
Published: April 2006

Abstract. S, a dominant, lethal, atitosomal gene, was discovered in Auburn University's population of Surotherodon aureus (=Tilapia auera). When present in the heterozygous state (S+). the S gene produces the saddleback phenotype. Saddlebacks are missing part of or all of the dorsal fin. Some fish thai are missing most of or the entire dorsal fin have additional fin disorders and are missing various combinations of the pectoral, pelvic, and anal fins. Each fin disorder is associated with gross skeletal anomalies. Viability in saddlebacks is reduced by 67% during the first three months of life. Those that survive are less resistant to stress and subsequent infection than normal fish. When challenged by Saprolcegnia sp., saddlebacks were far more susceptible to infection (P<0.01). When present in the homozygous state (SS), the gene causes death in fry prior to swim‐up. Thus, a single S gene reduces viability by 67%, and two S genes reduce viability by 100%. The S gene did not affect early growth or dressing percentage. Because it is a dominant gene, the S gene can be eliminated from any population in one generation by culling all saddlebacks.
Method for in vitro screening of aquatic fungicides
Authors: BAILEY T. A.
Published: April 2006

Abstract. Methods were developed for in vitro screening of candidate aquatic fungicides for efficacy against Achlya flagellata, A. racemosa, Saprolegnia hypogyna and S. megasperma. Agar plugs containing fungal hyphae, removed from the edge of actively growing colonies, were placed in the depressions of spot plates containing 1.0, 10.0 and 100 mg/l of the candidate compounds for 15 or 60 min. After exposure, the plugs were transferred on to filter papers (0.45‐μm pore) in a holder, rinsed, and then placed on cornmeal agar medium in tri‐petri dishes. The plates were checked for mycelial growth after 48, 96 and 168 h of incubation in a lighted (400–800 μm) environmental control chamber at 20±2°C. Criteria for the acceptance or rejection of candidate aquatic fungicides for further study were based on the antifungal spectrum index (ASI) comparisons between respective compounds and malachite green after 48 h and the concentration level producing complete growth inhibition. Candidate compounds whose ASI was Jess than 50% that of malachite green after 48 h or did not inhibit growth at levels less than 100 mg/l were rejected. This method provides a base from, which in vivo and definitive test regimens can be developed. Preliminary in vitro screening of candidate fungicides reduces the need for costly in vivo tests on compounds that have low antifungal activity.
Immunization of rainbow trout, Salmo gairdneri Richardson, against vibriosis: comparison of an extract antigen with whole cell bacterins by oral and intraperitoneal routes
Authors: AGIUS C. , HORNE M. T. , WARD P. D.
Published: April 2006

Abstract. An extract vaccine against Vibrio anguillarum was compared with other vaccine preparations when administered to rainbow trout intraperitoneally or orally on food. Intraperitoneal vaccination resulted in virtually 100% protection within two weeks whereas oral vaccination gave a maximum protection of 50–70% after eight weeks. When administered intraperitoneally the extract performed better than formalin killed cells but when administered orally formalin killed cells were better. The addition of alum as adjuvant enhanced the response to antigen administered by both routes. Serum agglutinin litres after oral vaccination were low and variable but after intraperitoneal injection they reached a consistent peak of 64. As the response to oral vaccination was so low it was not possible to relate agglutinin titre to protection in a quantitative relationship.
Characterization of Herpes virus vitreum isolated from hyperplastic epidermal tissue of walleye, Stizostedion vitreum vitreum (Mitchill)*
Authors: KELLY R. K. , NIELSEN O. , MITCHELL S. C. , YAMAMOTO T.
Published: April 2006

Abstract. A new virus, provisionally named Herpesvirus vitreum, was isolated from hyperplastic epidermal tissue from a walleye, Stizostedion vitreum vitreum (Mitchill), taken in Saskatchewan, Canada. The virus, which was isolated in the walleye ovarian (WO) cell line, was identified as a herpesvirus on the basis of size (190–230 nm), morphology and apparent pattern of replication. The virus, which passes polycarbonate membranes of 200 nm mean pore diameter, was ether‐labile. Virus replicated in WC‐1 cells at 4 and 15°C, but not at 20°C. Although walleye cell lines (WO, WC‐1, We‐2) were susceptible to infection at 15°C, non‐period cell lines were refractory. Syncytial formation and lysis occurred in susceptible cell lines. Virus was quantified by plaque assay at 13 to 15°C for two weeks. Replication was inhibited by 10‐3.0m phosphonoacetate and by 10‐5.0m 5‐bromodeoxyuridine (BUDR), but addition of excess thymidine reversed the inhibition by BUDR. Viral replication in WO cells, but not in WC‐1 cells, was inhibited by the antiherpetic drug acyclovir (10‐5.0m). The relationship of the herpesvirus isolate and epithelial neoplasms was not determined.
Detection of infectious haematopoietic necrosis virus in river water and demonstration of waterborne transmission
Authors: MULCAHY D. , PASCHO R. J. , JENES C. K.
Published: April 2006

Abstract. In a study of the possible role of waterborne infectious haematopoietic necrosis virus in transmission of the disease among spawning sockeye salmon, Oncorhynchus nerka (Walbaum), both infection rates and virus titres were higher in fish held at high density in a side channel than in fish in the adjacent river. Virus was never isolated from river water, but was found in water from the side channel at levels ranging from 32.5 to 1600 plaque‐forming units (p.f.u.)/ml. Uninfected yearling sockeye salmon held in a box in the side channel developed localized gill infections with IHN virus. The disease did not progress to the viscera until a threshold titre of about 105 p.f.u./g was reached in the gill. The effectiveness of the gill as a barrier limiting development of systemic infections means that waterborne IHN virus probably does not greatly increase the infection rate in a sockeye salmon population during spawning.
Opsonization by fish antibody and complement in the immune phagocytosis by peritoneal exudate cells isolated from salmonid fishes
Authors: SAKAI D. K.
Published: April 2006

Abstract. Opsonic activities of fish antibody and complement in the phagocytic responses of fish leucocytes have been investigated using salmonid peritoneal exudate cells (PEC) and viable cells of Aeromonas salmonicida as antigenic particles. PEC were isolated from liquid paraffin‐injected coho salmon, masu salmon and rainbow trout. After incubation at 20°C for 2 h, phagocytosis by PEC was evaluated. Phagocytic activity was attributed to neutrophil‐like and macrophage‐like cells, though in the absence of immune serum activity was low. The addition of fish antibody (heal‐inactivated antiserum) slightly increased the activity. On the addition of normal serum as a complement source phagocytic activity was dramatically accelerated. This acceleration was interpreted as opsonization as a result of the classical pathway activation of fish complement by an antigen‐antibody reaction. The complement of mammals (goat, guinea pig and rabbit) did not possess opsonic activity in the presence of fish antibody.
Comparison of histopathology caused by Vibrio anguillarum and Vibrio ordalii in three species of Pacific salmon*
Authors: RANSOM D. P. , LANNAN C. N. , ROHOVEC J. S. , FRYER J. L.
Published: April 2006

Abstract. The histopathology associated with naturally acquired vibriosis in chum salmon, Oncorhynchus keta (Walbaum), fingerlings caused by Vibrio anguillarum was compared with that caused by infection with Vibrio ordalii. Pathogenesis of the two forms was found to be different. Bacteraemia caused by V. anguillarum occurred in the early stages with pronounced histopathological changes in blood, loose connective tissue, kidney, spleen, gills and posterior gastrointestinal tract. Bacterial cells appeared uniformly dispersed throughout the affected tissues but were most abundant in the blood. With V. ordalii, bacteraemia developed only in late stages of the disease and the concentration of bacterial cells per ml of blood was less than in the V. anguillarum infection by a factor of 102–103. Tissues with most pronounced changes were skeletal and cardiac muscle, anterior and posterior gastrointestinal tract and the gills. Vibrio ordalii observed in the tissues was not evenly dispersed but was present within tissue as colonies or aggregates of cells. The differences in pathology observed in naturally infected chum salmon were produced experimentally with each pathogen by waterborne exposure of chum; coho, Oncorhynchus kisutch (Walbaum); and chinook salmon, Oncorhynchus tshawytscha (Walbaum). Severe decreases in circulating leucocytes accompanied bacteraemia caused by either bacterial species.
The developmental cycle of epitheliocystis in carp, Cyprinus carpio L.
Authors: PAPERNA I. , ALVES DEMATOS A. P.
Published: April 2006

Abstract. Epitheliocystis infections in the gills of carp from Israel and Portugal occurred in lining epithelial cells as well as mucus and chloride cells. Ultrastructural studies of infected cells revealed several morphological forms of epitheliocystis showing the existence of a pleomorphic developmental cycle. The following stages were observed: chlamydia‐like round cells (RC), non‐dividing round cells (NRC) and bullet‐shaped small cells (SC). All these were identical in shape to RC and SC described from epitheliocystis of other fish, The rickettsia‐like cells (PLC and ILC) which occur in epitheliocystis from other fish species and produce the SC were absent in carp epitheliocystis and instead the RC were seen transforming into SC. Transformation to SC, however, occurred at any stage of the developmental process, even before the replication potential of the RC was exhausted, i.e. before reaching the NRC stage.
An idiopathic proliferative disease syndrome of the midgut and ventral nerve in the Kuruma prawn, Penaeus japonicus Bate, cultured in Hawaii
Authors: LIGHTNER D. V. , REDMAN R. M. , BELL T. A. , BROCK J. A.
Published: April 2006

Abstract. Populations of postlarval, juvenile and adult Kuruma prawns, Penaeus japonicus Bate, have been affected by an unusual proliferative condition of the midgut and ventral nerve cord. Animals affected with this gut and nerve syndrome have been observed from various shrimp systems in Hawaii, including high density tanks and raceways, low density ponds, and adult broodstock held in a maturation system. Affected shrimp ranged in age from ∼20‐day‐old postlarvae of ∼0.02g average weight to adult shrimp of ∼ 60 g average weight. The principal lesions observed in affected animals were a hypertrophy of the anterior midgut mucosal epithelium basement membrane (BM) and a hyperplasia of the epineurium that covers the ventral nerve cord and segmental ganglia in the gnathothorax. There seemed to be a positive correlation between increased thickness of the BM and disease, and possibly a relationship between ataxia and lethargy and the degree of hyperplasia of the epineurium.
Serological variation among Yersinia ruckeri strains
Authors: STEVENSON R. M. W. , AIRDRIE D. W.
Published: April 2006

Abstract. Strains of Yersinia ruckeri, the enteric redmouth (ERM) bacterium, show greater serological diversity than previously supposed. A distinct sub–group of the otherwise homogeneous serovar I (Hagerman) strains includes the salmonid blood spot (SBS) bacterium. Two other new serological varieties, serovars IV and V, have been designated.
The taxonomic position of the coccidian genus Crystallospora (Protozoa, Apicomplexa)
Authors: LEVINE N. D.
Published: April 2006

The genus Crystallospora was established by Labbé (1896) for a coccidium that Thélohan (1893) had found in the Atlantic Ocean off France. Dogel’ (1948) later found it in Peter the Great Gulf (Pacific Ocean) off Japan. It was transferred to Eimeria by Doflein (1909) and remained there until Dyková & Lom (1981) revived it because of its unique sporocyst structure. Actually, its structure necessitates its removal from the family Eimeriidae and placement in the family Barrouxiidae (see Levine [1983] for a review of this family). The pertinent taxa and their diagnoses therefore become: