bluuebunny/crossref_metadata_2025 huggingface dataset:
An in vitro method for testing synergistic action of parasiticides using malachite green and formalin as a model system
Authors: GILBERT J. P. , GRATZEK J. B. , BROWN J.
Published: April 2006

Abstract. An in vitro technique was developed to screen drugs for toxicity to laboratory cultured protozoans. Drugs were diluted using standard microtitration equipment. An easily cultured protozoan, Tetrahymena pyriformis, was added to the dilutions of drugs and viability was checked daily for 10 days. Drugs used as a model system to test the technique were formalin and malachite green. Effective concentrations of formalin determined by this in vitro technique were close to recommended therapeutic treatment levels for Ichthyophthirius. Malachite green was effective at concentrations in excess of recommended therapeutic treatment levels for Ichthyophthirius. The synergistic effect of formalin and malachite green was demonstrated. This technique can he of use in determining effectiveness of new drugs as parasiticides.
Lymphocystis disease in Wisconsin fishes
Authors: AMIN O. M.
Published: April 2006

Abstract. Lymphocystis disease is reported from seven fish species in 48 of Wisconsin's 72 counties (67%). It was previously known from only two fish species in five counties. The record from northern pike, Esox Indus L. is new. Five other host records are new for Wisconsin. A relationship between the disease distribution in new waters and walleye, Stizostedion vitreum (Mitchill), stocking sources is noted. Histologlcal observations from black crappie, Pomoxis nigromaculatus (Lesueur) and walleye are similar to previously published accounts. Events in hyaline capsule degeneration are described for the first time. In Wisconsin, the disease was most commonly observed in the spring, particularly in walleye, but was consistently evident throughout the rest of the year.
Bilateral asymmetry of Diplostomum infections in the eyes of lake whitefish Coregonm clupeaformis (Mitchill) and a computer simulation of the observed metacercarial distribution
Authors: RAU M. E. , GORDON D. M. , CURTIS M. A.
Published: April 2006

Abstract. Fifty‐four per cent of the specimens in a sample of 147 lake whitefish (Coregonus clupeaformis) from northern Quebec exhibited a pronounced lack of bilateral symmetry in the distribution of metacercariae of the genus Diplostomum. This asymmetry was shown not to be a product of chance. A comparable degree of asymmetry was generated by a computer simulation incorporating a positive feedback mechanism. The simulation and the biological significance of such asymmetry are discussed.
Teratoid lesions and other developmental anomalies in the sea lamprey, Petromyzon marinus L.
Authors: PIAVIS G. W. , BECKERMAN T. , HOWELL J. H.
Published: April 2006

Abstract. Sea lampreys handled for other research projects were examined for the presence of tumours. Nine tumours were found including: an ectopic notochordal mass, an epidermoid cyst, an ectopic paranotochordal haematopoietic myeloid mass, and six teratomas. The composition of these sea lamprey tumours did not differ significantly from that of similar lesions in higher vertebrates and thus they were similarly classified. The prevalence of tumours in our specimens was relatively high (1:19).
Studies on a host range variant from different isolates of infectious pancreatic necrosis virus (IPNV)
Authors: NICHOLSON B. L. , THORNE G. W. , JANICKI CARYLE , HANSON ANNE
Published: April 2006

Abstract. Eight isolates of infectious pancreatic necrosis virus (IPNV) propagated solely in RTG‐2 cells (RTG‐IPNV) were examined for ability to replicate in FHM cells. Seven isolates replicated in FHM cells; however, the plaque titres were 10‐ to greater than 100 000‐fold less than titres in RTG‐2 cells. The ability of IPNV to replicate in FHM cells was shown to result from the presence of a host range variant (FHM‐IPNV) that produced plaques in both cell types. Variant‐free preparations of two isolates differed in ability to generate FHM‐IPNV during a single replication cycle in RTG‐2 cells. One isolate did not generate the variant and failed to replicate in FHM cells even upon blind passage.

IPNV propagated in AS cells (AS‐IPNV) was similar to RTG‐IPNV, producing equal numbers of plaques in RTG‐2 and AS cells but failing to form plaques in FHM cells. However, IPNV propagated in BF‐2 cells (BF‐IPNV) was similar to FHM‐IPNV in producing equal numbers of plaques in all three cell lines.

RTG‐IPNV and FHM‐IPNV were identical in size, morphology and density in CsCl but differed in plaque size distribution and neutralization by specific antiserum.

Restriction of the replication of RTG‐IPNV in FHM cells was partially explained by a reduction of 75% in adsorption to FHM cells. However, the synthesis of RTG‐IPNV antigens was reduced 90 to >99% in FHM cells.
Histopathology of superficial fish ‘tumours’ found during a cancer survey of demersal species in Port Philip Bay, Victoria, Australia
Authors: HARD G. C. , WILLIAMS R. , LEE J.
Published: April 2006

Abstract. During an extended survey aimed at investigating the occurrence of neoplasms in the common demersal fish species inhabiting zones of Port Phillip Bay, Victoria, Australia, exposed to domestic and industrial contamination, superficial lesions resembling malignant growths were found in high prevalence (20% and 28% respectively) in two species of leatherjacket (Family Balistidae), Navodon multi‐radiatus and Scobinichthys granulatus, and infrequently (0.3%) in Atopomycterus nichthemerus (Diodontidae). The leatherjacket lesions took three forms, all being histologically consistent with long‐standing granulomatous tissue associated with varying degrees of mononuclear cell infiltration. The A. nichthemerus lesions were histologically similar but located beneath an intact epidermis. In some of the lesions, profiles of parasitic worms (either solitary or several) were found after examination of multiple sections suggesting that the ‘tumours’ may have represented chronic inflammatory tissue reactions to superficial parasite infection (xenomas).

The resemblance to fish neoplasia of both the macroscopic appearance of these lesions, particularly those affecting leatherjacket species, and of certain features of their microscopic structure is discussed. The necessity for critical evaluation of the range of proliferative tissue reactions in fish is emphasized, in order to permit accurate distinction between non‐neoplastic conditions and true neoplasia in epidemiological surveys using fish species as indicators of environmental contamination with specific biological hazards.
Studies on the pathogenesis of streptococcal infection in cultured yellowtails Seriola spp.: effect of the cell free culture on experimental streptococcal infection
Authors: KIMURA H. , KUSUDA R.
Published: April 2006

Abstract. A previous paper has revealed that experimental streptococcal infection was associated with a rapid growth of the intestinal bacteria, suggesting association of the condition with an exotoxin. The present study was undertaken to see the effect of the exotoxin on the streptococcal infection by administering cell free culture before the bacterial challenge. Cell free culture of Streptococcus sp. strain YT‐3 was inoculated intramuscularly at a dosage of 0–5 ml per 100 g body weight 1 h prior to bacterial challenge. Three fish were killed at intervals after challenge for viable counting of bacteria in the viscera and blood. Intramuscular inoculation with either low virulent or virulent bacteria alone at dosages of 106 to 107 cells did not produce the disease in the fish, with almost complete clearance of the bacteria from the viscera and blood within 120 h. When the exotoxin was inoculated intramuscularly prior to the bacterial challenge, however, either low virulent or virulent bacteria at 106 to 107 cells could produce fatal infection with prominent streptococcal clinical signs.
Ultrastructural aspects of a serious disease of hatchery reared larval oysters, Crassostrea gigas Thtinberg
Authors: ELSTON R.
Published: April 2006

Abstract. Ultrastructural observations on a possible aetiological agent and tissue changes in a previously described disease of hatchery reared larval oysters Crassostrea gigas Thünberg are reported. Spherical bodies, implicated in gastro‐intestinal impaction, show a strong resemblance to the marine fungus, Hyalochlorella marina. Similarities include a thick outer wall structure, plate‐like mitochondria and dense cytoplasm with small vacuoles.

The dense fascicular masses, previously observed histologically at epithelial surfaces, consist of accumulations of irregular electron opaque bodies. Large accumulations of these bodies appear to exacerbate tissue damage and prevent normal velar function. In comparison with the reported virus‐like particles in this disease, these dense inclusions and associated lesions are more frequently observed and thus seem to be more important in the disease process.

Notes on normal epithelial surfaces of larval Crassostrea spp. are included.
Renal sphaerosporosis in the common carp Cypnnus carpio L.
Authors: MOLNÁR K.
Published: April 2006

Abstract. Sphaerospora angulata Fujita, 1912, has been identified as a frequent renal parasite of cultured carp populations in Hungary. Its prevalence ranged from 10 to 50% in the pond farms surveyed. The youngest carp infected were 21/2–3 months old. Infections were not common in one‐summer fish and tended to become less frequent with increasing age of the host.

The developing stages of S. angulata are found in the contorted tubules of the trunk‐kidney but never invade the parenchymal tissue of the trunk or head‐kidneys. The pansporoblasts developing in the wide proximal segment of the renal tubules, and the spores arising from the pansporoblasts are typically coelozoic parasites, for they apparently do not damage the tubular lining epithelium, nor its brush border. The main adverse effect of S. angulata is probably depression of resistance owing partly to deprivation of the host of nutrients secreted by the glomeruli and partly to mechanical obstruction of the distal tubular segments.
Observations on the pathogenicity of Haemogregarina sachai Kirmse, 1978, in farmed turbot Scophthalmus maximus (L.)
Authors: KIRMSE P.
Published: April 2006

Abstract. Cultured turbot Scophthalmus maximus (L.) from three farms at Hunterston, Scotland were found to be infected with Haemogregarina sachai. Up to 6% of some populations were affected with gross tumorous lesions of the musculature and viscera. The lesions consisted of necrotic tissue with a caseous centre. Histologically, there was an accumulation of parasitized reticulo‐endothelial cells, cell debris and pyknotic nuclei. Parasitaemias of up to 36% of all blood cell types were observed. The majority of infected cells were neutrophils and monocytes. Infected leucocytes were hypertrophied. There was an erythrocytopenia of infected fish with increases in erythroblasts, monocytes and neutrophils but a decrease in thrombocytes and lymphocytes. Transmission experiments between fish were unsuccessful.
On cell kinetics in skin tumours of the Pacific English sole Parophrys vetulus Girard
Authors: KRANZ HEIDEMARIE , PETERS N. , BRESCHING GISELA , STICH H. F.
Published: April 2006

Abstract. An autoradiographic study of the various types of neoplastic lesions in the skin of Pacific English sole Parophrys vetulus Girard was performed using peritoneally injected tritiated thymidine. The epidermis offish is mitotically active at all cell levels, the most important being the supra‐basal layer. In the hyperplastically growing epidermis of the English sole covering connective tissue nodules and in the papillating epidermis prior to formation of enlarged ovoid cells (X‐cells), the supra‐basal layer also shows the greatest degree of labelling. Parallel to the appearance of these X‐cells, which are characteristic of the skin tumours in Pacific flatfish, the distribution of DNA‐synthesizing cells is altered. In the tumour areas which are more or less filled with X‐cells the ‘envelope cells’ are labelled throughout with a uniform frequency. On the other hand, the directly adjacent X‐cell free areas are labelled with a greater than average frequency.
Post‐spawning mortalities in brown trout Salmo trutta L.
Authors: FERGUSON H. W. , RICE D. A.
Published: April 2006

Abstract. An ‘oedema syndrome’ caused mortality of 55·5% in brood brown trout approximately 2 months after spawning. The pathology and clinical biochemistry of the condition are described. It is suggested that the severe hypoproteinaemia and anaemia were due mainly to the traditional reduction in feed levels prior to spawning at a time when the water temperatures were abnormally high. It is also suggested, however, that the syndrome would not have occurred if the fish had not developed an aeromonad infection prior to stripping. Concurrent fungal infection and subsequent extremely low water temperatures are also thought to have played a role.
Genus Pleistophora (Phylum Microspora): redescription of the type species, Pleistophora typicalis Gurley, 1893 and ultrastructural characterization of the genus
Authors: CANNING ELIZABETH U. , NICHOLAS J. P.
Published: April 2006

Abstract. Pleistophora typicalis Gurley, 1893, a parasite of the striated muscle of Myoxocephalus scorpius has been re‐examined at light‐ and electron‐microscope levels. Foci of infection were almost exclusively found in the ventral body wall where a mixture of schizonts, sporonts and masses of pansporoblasts lay in direct contact with unaltered host myofibrils and mitochondria.

All stages were surrounded by a thick (0‐5 μm) amorphous coat, external to the plasmalemma. In schizonts this was traversed by channels passing from the plasma‐lemma to a layer of vesicles in contact with the muscle. This coat became modified as a pansporoblast envelope surrounding the mature spores: at first a layer of fine granules was laid down about mid‐way across the previously amorphous coat, while the channels disappeared. At the time when the sporogonial plasmodium retracted away from the coat to produce the pansporoblast cavity, the layer of the coat within the granules disintegrated into spherical vesicles. The pansporoblast envelope around the mature spores was composed of two or three layers of different electron density, including one which was strongly electron dense. The pansporoblast envelope as defined here corresponds in function, but not necessarily in origin, to the sporophorous vesicle that encloses the spores in other pansporoblastic microsporidia.

Schizonts had an extensive system of smooth endoplasmic reticulum, composed of expanded vesicles and divided by plasmotomy into smaller multinucleate segments. The endoplasmic reticulum of sporogonial stages was comprised of a network of fine channels, parallel arrays of flat cysternae and close‐packed stacks of membranes. The sporogonial plasmodium divided stepwise through smaller multinucleate segments into uninucleate sporoblasts. Nuclei were isolated throughout development.

Two types of sporonts were recognized: large sporonts gave rise to pansporoblasts containing up to 200 microspores. Macrospore pansporoblasts always contained eight macrospores. Microspores measured 4–4 × 2·3 μm (fresh) and were probably uninucleate. Macrospores measured 7·5 × 3·0 μm (fresh) and were probably binucleate.

Another microsporidium, found in the muscles of Blennius pholis, which had been attributed to the same species by Thélohan (1895), was distinguished on the basis of spore size (microspores 3·9 × 2·3 μm and macrospores 7·7 × 3·8 μm fresh) and by the fact that electron dense components were laid down in the pansporoblast wall early in sporogony. The species was named Pleistophora littoralis n.sp.
Stress‐induced transmission of Yersinia ruckeri infection from carriers to recipient steelhead trout Salmo gairdneri Richardson
Authors: HUNTER VALERIE A. , KNITTEL M. D. , FRYER J. L.
Published: April 2006

Abstract. The transmission of Yersinia ruckeri has been investigated in steelhead trout using asymptomatic carriers of the causative bacterium of enteric redmouth disease. It was found that unstressed carrier fish did not transmit the bacterium to recipient fish to cause either an epizootic or produce new carrier fish. However, when the carriers were stressed with heat, the bacterium was transmitted from the carrier to recipient fish producing a lower intestinal carrier state but no deaths. Examination of experimentally infected fish to determine the number of carriers among the survivors indicated that the frequency varied as a function of time following infection. When immunized fish, were challenged with Y. ruckeri they became temporary carriers of the bacterium for up to 3 days; but were not able to transmit the infection to healthy recipient fish.
Inhibition of epidermal migration in the skin of rainbow trout Salmo gairdneri Richardson in the presence of achromogenic Aeromonas salmonicida
Authors: BULLOCK A. M. , ROBERTS R. J.
Published: April 2006

Abstract. Experimental infection of artificially‐induced skin ulcers in rainbow trout Salmo gairdneri Richardson with an achromogenic strain of Aeromonas salmonicida induced a syndrome similar to that observed in cyprinid fishes. Sequential histological observations showed that the presence of the bacteria completely inhibited any migration of peripheral epidermal cells and subsequent under‐running of the ulcer resulted in its expansion, as peripheral epidermis sloughed.
Aetiology of an ulcerative disease in goldfish, Carassius auratus (L.): characterization of the causative agent
Authors: SHOTTS E. B. , TALKINGTON P. D. , ELLIOTT DIANE G. , MCCARTHY D. H.
Published: April 2006

Abstract. A bacterium resembling Aeromonas salmonicida and determined to be the aetiologic agent of a cutaneous ulcerative disease in goldfish Carassius auratus (L.) was further characterized in this study.

Forty‐five isolates of the bacterium (43 from the United States and one each position (moles % guanine plus cytosine) and DNA homology. The bacteriological atypical A. salmonicida previously described. Several important biochemical characteristics distinguished the goldfish isolates from typical A. salmanicida, but the DNA binding experiments indicated a high degree of relatedness between the goldfish isolates and typical A. salmonicida strains.
Susceptibility of steelhead trout Salmo gairdneri Richardson to redmouth infection Yersinia ruckeri following exposure to copper
Authors: KNITTEL M. D.
Published: April 2006

Abstract. Steelhead trout were exposed to sublethal concentrations of copper and inoculated with Yersinia ruckeri. Copper exposure at 7 and 10 μg/1 for 96 h caused more fish to die of infection than control fish (no copper). Infection susceptibility increased with time of exposure to a single dosage of copper (10 μg/1), reaching a maximum at 48 h. Lowering the copper concentration to 5 μg/1 caused the infection susceptibility to occur at 24 h. The infectious dose of Y. ruckeri was lower in fish exposed to 10 μg/1 copper for 48 h than control fish.
Isolation of infectious pancreatic necrosis (IPN) virus from non‐salmonid fish
Authors: ADAIR B. M. , FERGUSON H. W.
Published: April 2006

Abstract. The isolation and characterization of infectious pancreatic necrosis (IPN) virus from a goldfish, discus fish and bream is described. The fish from which the isolates were recovered showed no pathological signs of IPN. All three virus isolates were neutralized by antiserum to IPN, strain Ab, but not by antiserum to the Sp or VR‐299 strains. They were morphologically identical to IPN virus in negative stain electron microscopy, grew in the cytoplasm of BF‐2 cells, as shown by immuno‐fluorescence and, like IPNV, were stable to heating, lipid solvents and acid pH.
A new viral epizootic of Anguilla japonica Temminck and Schlegel
Authors: SANO T. , OKAMOTO N. , NISHIMURA T.
Published: April 2006

Abstract. In 1969, a new kind of epizootic occurred among eels in Japan and virological investigation was initiated. A new virus designated eel virus european (EVE) was isolated and biological, cytological, serological tests and infectivity trials were carried out. In its CPE on RTG‐2 cells and additionally in its biological properties and particle size, EVE was found to be similar to infectious pancreatic necrosis virus (IPNV). Serologically, EVE was similar to the ? Honnincthun, France, strain of IPNV. However, infectivity trials showed that EVE and IPNV differed; EVE killed Japanese eels Anguilla japonica but not rainbow trout fry Salmo gairdneri, while IPN virus killed rainbow trout fry but not eels. We consider EVE to be the primary agent causing the new epizootic and propose the name viral kidney disease for the resulting clinical condition.
Identification of pathogenic bacteria associated with the occurrence of ‘red spot’ in sea mullet, Mugil cephalus L., in south‐eastern Queensland
Authors: BURKE J. , RODGERS L.
Published: April 2006

Abstract. An investigation was undertaken to determine the bacterial species associated with the fish disease known as ‘red spot’ which affected wild fish stocks in south‐eastern Queensland. Outbreaks of the disease in the Noosa River were examined with particular reference to the sea mullet, Mugil cephalus. The bacterial flora of the skin of healthy fish as well as those exhibiting early and advanced lesions was determined. In the lower Noosa River estuary, Vibrio anguillarum was the sole organism associated with very early lesions. It was later shown that V. alginolyticus was also associated with V. anguillarum in early lesions, but was considered to be a secondary invader. Aeromonas hydrophila was isolated from advanced lesions on fish taken in freshwater reaches of the river. This organism was also regarded as a secondary invader.
Changes in drug resistance of Vibrio anguillarum in cultured ayu, Plecoglossus altivelis Temminck and Schlegel, in Japan
Authors: AOKI T. , KITAO T. , KAWANO K.
Published: April 2006

Abstract. Two‐hundred‐and‐fifty‐nine strains of Vibrio anguillarum isolated from diseased cultured ayu, Plecoglossus altivelis in various districts of Japan from 1974 to 1977 were studied for their sensitivity to 12 different chemotherapeutic agents: chloramphenicol (CM), tetracycline (TC), streptomycin (SM), kanamycin (KM), aminobenzyl penicillin (ABP), colistin (CL), nalidixic acid (NA), oxolinic acid (OA), piromidic acid (PA), furazolidone (NF), sulpharaonomethoxine (SA) and trimethoprim (TMP). One‐hundred‐and‐thirty‐four of the strains were additionally tested for sensitivity to O/129(2,4‐diamino‐6,7‐diisopropyl pteridine) and ormethoprim (OMP). All strains were susceptible to SM, KM and ABP and also highly sensitive to CL. A correlation of resistance was found among the chemically‐related drugs NA, OA and PA, and TMP, OMP and O/129, Nine strains were sensitive to all the drugs tested. The remaining 250 strains were resistant to various combinations of six drugs (CM, TC, NA, NF, SA and TMP). In particular, strains resistant to NA and NF (20.1%), to CM, TC, SA, NA and NF (29.7%) and to all six drugs (28.2%) were frequently detected. NA‐ or NF‐resistant strains have increased since 1974 and TMP‐resistant strains have increased since 1976. Transferable R plasmids were detected in 165 out of 250 resistant strains. The most common type of R plasmid determined resistance to CM, TC and SA. These multiple drug‐resistant strains with transferable R plasmids were isolated from many different districts.
Ultrastructural effects of the coccidium, Eimeria funduli Duszynski, Solangi and Over street, 1979 on the liver of killifishes
Authors: HAWKINS W. E. , SOLANGI M. A. , OVERSTREET R. M.
Published: April 2006

Abstract. Ultrastructural studies were made on the inflammatory response in livers of two killifishes, Fundulus grandis and F. similis, experimentally infected with the coccidium Eimeria funduli. Coinciding with the formation and development of gamonts of E. funduli, changes took place in the liver and leucocytes appeared in that organ. Near areas of developing macrogamonts, many hepatocytes degenerated whereas others contained residual bodies which indicated sublethal damage. The damage was probably associated with merozoite formation and release. Filament‐rich perisinusoidal cells hypertrophied during the development of E. funduli and contributed to walling off aggregates of oocysts from uninfected liver tissue. Leucocytes involved in the host response included lymphocytes, monocytes, heterophils, eosinophils and an unidentified third type of granulocyte. The heterophil was the first granulocyte to respond to the parasite and sometimes appeared to penetrate the parasitophorous vacuole of degenerating macrogamonts. Degranulating eosinophils were often observed near damaged tissues. Both the monocyte and eosinophil were phagocytically active. The monocyte was more phagocytically active and contained both host cells and parasite debris, whereas the eosinophil contained only debris from degenerating macrogamonts. The presence of immature granulocytes in the liver suggests that at least some granulocyte formation occurred in the liver.
A microsporidian infection in a natural population of mosquitofish, Gambusia affinis (Baird and Girard)
Authors: CRANDALL T. A. , BOWSER P. R.
Published: April 2006

Abstract. A microsporidian parasite was found in a natural population of mosquitofish, Gambusia affinis, from southern California. The parasite, a Glugea sp, induced the formation of xenoma complexes in the mesenteries of infected fish. In cases of severe infection, the xenomas occupied the majority of the abdominal cavity and appeared to prevent efficient swimming. This report is an initial documentation of this infection and a description of some of the clinical signs observed.
A light and electron microscopic study of the agent of carp mucophilosis
Authors: MOLNÁR K. , BOROS G.
Published: April 2006

Abstract. The authors failed to detect algae or fungi in the gills of carp showing the typical clinical signs of mucophilosis. Electron microscopic examination showed the presence of rickettsia‐ or chlamydia‐like organisms, inside the characteristic mucophilus cysts. These organisms are believed to be the causative agents of mucophilosis. The organisms develop intracellularly in the gill epithelium and after several divisions give rise to mucophilus cysts 70–80 μm in diameter. The morphological and ultrastructural changes observed in the course of mucophilosis bear a striking resemblance to the cysts and cyst‐inducing causative agents responsible for epitheliocystis disease.
Microsporidian parasites in the gills of salmonid fishes*
Authors: MORRISON CAROL M. , SPRAGUE V.
Published: April 2006

Abstract. A microsporidian parasite was found in the gills of the brook trout, Salvelinus fontinalis (Mitchill), which was similar to Loma morhua Morrison and Sprague, a microsporidian parasite in the gills of cod. It was described and designated as Loma sp. Plistophora (=Pleistophora) salmonae Putz, Hoffman and Dunbar in gills of rainbow and steelhead trout, Salmo gairdneri Richardson, was also observed and was transferred to the genus Loma. All microsporidia known in gills of Gadidae and Salmonidae were judged to belong to the genus Loma but the data were not sufficient to provide a basis for a definitive separation of species. Provisionally, Loma morhua, L. branchialis, L. salmonae and Loma sp. were recognized.
Histopathological changes in two estuarine fishes, Menidia beryllina (Cope) and Trinectes maculatus (Bloch and Schneider), exposed to crude oil and its water‐soluble fractions
Authors: SOLANGI M. A. , OVERSTREET R. M.
Published: April 2006

Abstract. The tidewater silverside, Menidia beryllina, and the hogchoker, Trinectes maculatus, were exposed to south Louisiana whole crude oil (WCO) and its water‐soluble fractions (WSF) to assess histopathological effects on their gills, olfactory organ, and liver. Both fishes were exposed to 5 mg WCO/1, 100 mg WCO/1, 5% WSF, and 50% WSF. Additionally, M. beryllina was exposed to 100 mg WCO/1 with 20 ppm Terramycin® to study possible complications caused by bacteria. Exposure of M. beryllina lasted 21‐30 days, whereas experiments using T. maculatus continued for 38‐60 days. Pathological changes in M. beryllina appeared by day 7 and became severe as experiments progressed to day 30. Histological alterations in the silverside included epithelial hyperplasia and fusion of gill lamellae, separation of respiratory epithelium from underlying tissue, hyperplasia of sustentacular cells of olfactory lamellae, necrosis of both neurosensory and sustentacular epithelium, extensive lipid vacuolation in hepatocytes, and atrophy and necrosis of intrahepatic exocrine pancreatic nodules. Of the tissues examined, the pancreas served as the most specific pathological indicator of oil pollution. In T. maculatus, hepatocytes of exposed individuals did not become vacuolated, and, except for gills exposed to 100 mg WCO/1, response by gills in the other three tests remained limited to slight hyperplasia. Olfactory mucosa of the hogchoker exhibited severe necrosis of both neurosensory and sustentacular cells in the high concentrations of oil, but no damage in low concentrations. The intrahepatic pancreas of fish exposed to all test‐concentrations atrophied and became necrotic by the end of experiments. Limited studies using both Terramycin and a combination of Terramycin and WCO indicated lack of bacterial involvement in tissue damage in oil‐exposed silverside, but the size of hepatic nuclei increased in the Terramycin‐control fish, and the shape of lipid vacuoles appeared unusual subsequent to exposure to the combination. Menidia beryllina became hyperactive and refrained from feeding for up to 6 h after the initial administration of oil, whereas T. maculatus apparently never fed, and it exhibited hyperactivity after all exchanges of sea water and fresh oil. Deaths appeared to correspond both to degree of pathological damage and to exposure‐concentrations. Partial to complete recovery was observed in gills, olfactory organ, and pancreas of M. beryllina exposed to WCO or WSF for 20 days and then maintained in oil‐free sea water for 17 days.
In vitro effect of fungicides on hyphal growth and sporogenesis of Lagenidium spp. isolated from Penaeus monodon larvae and Scylla serrata eggs*
Authors: LIO‐PO G. D. , SANVICTORES M. E. G. , BATICADOS M. C. L. , LAVILLA C. R.
Published: April 2006

Abstract. The sensitivity of Lagenidium spp. isolated from Penaeus monodon and Scylla serrata to 34 antimycotic compounds was determined. Mycostatic effects were evaluated from observations of chemicals on the development of vesicles, zoospores and mycelial growth and on these bases three classes of mycostatic effect were recognized. Zoospores were inhibited by < 1 mg/1 of clotrimazole, crystal violet, econazole nitrate, malachite green, treflan and trifluralin; 1‐5 mg/1 of benzalkonium chloride, daconil, domestic detergent, basic fuchsin and furanace; and 10‐50 mg/1 benlate, formalin, griseofulvin, phenol and potassium permanganate. Variable mycostatic levels, however, were exhibited with copper sulphate, 2,4‐D, hydrogen peroxide, methylene blue, pimaricin, resiguard and tolnaftate while amphotericin, iodine, nystatin, triacetin, boric acid, fungitox and PVP‐iodine proved to be poor antifungal agents.
In vitro testing of fisheries chemotherapeutants
Authors: ALDERMAN D. J.
Published: April 2006

Abstract. The development of in vitro test techniques for use with fish parasitic fungi is described. Reasons for the selection of criteria to be met by these test methods are discussed using selected results from a wide‐scale test programme on fisheries fungicides. The need for test techniques to relate to the eventual environment in which chemotherapeutants will be used is stressed.
Vibriosis in rainbow trout, Salmo gairdneri Richardson, in fresh water in north‐eastern Italy
Authors: GIORGETTI G. , CESCHIA G.
Published: April 2006

Abstract. Vibriosis is a significant problem in rainbow trout, Salmo gairdneri Richardson, culture in fresh water in north‐eastern Italy. Furunculosis is the main cause of disease in brown trout, Salmo trutta L., and brook trout, Salvelinus fontinalis (Mitchill). Spontaneous outbreaks over the period 1975–1978 are described together with relevant husbandry and environmental parameters associated with them. Biological, chemical and physiological characteristics of 40 bacterial strains isolated from outbreaks are described.
Effect of increased liver glycogen and liver weight on liver function in rainbow trout, Salmo gairdneri Richardson: recovery from anaesthesia and plasma 35S‐sulphobromophthalein clearance
Authors: HILTON J. W. , DIXON D. G.
Published: April 2006

Abstract. Juvenile rainbow trout (initial mean body weight 17 g) reared on practical trout diets containing different levels of available carbohydrate for 8–24 weeks were assayed for liver function based on the time required to recover from the anaesthetics tricaine methanesulphonate (MS222), 2‐phenoxyethanol (2PE) and tertiary‐amyl alcohol (TAA), as well as plasma clearance of 35S‐sulphobromo‐phthalein (BSP), Liver/body weight ratios (LBW) and percentage liver glycogen content (LG) increased in a linear manner with increased available carbohydrate. The mean recovery time (MRT) of trout anaesthetized with 2PE and TAA increased linearly with increased LBW and LG. No difference was observed in the MRT of trout anaesthetized with MS222 which is not metabolized in the trout liver. There was a significant linear regression of the biological half‐life of plasma BSP on LBW (MR2= 95.7) and LG (MR2= 99.6). The results indicate that increased liver glycogen and liver weight due to higher levels of available carbohydrate affect the liver function of rainbow trout. These liver function tests may be applicable in determining acceptable levels of available carbohydrate in practical trout diets.
Duration of immunity in salmonids vaccinated by direct immersion with Yersinia ruckeri and Vibrio anguillarum bacterins
Authors: JOHNSON K. A. , FLYNN J. K. , AMEND D. F.
Published: April 2006

Abstract. The level of protective immunity was determined for several salmonid species following vaccination by the direct immersion method with commercial Vibrio anguillarum (two serotypes) and Yersinia ruckeri (Hagerman strain) bacterins. The duration of protective immunity varied with the bacterin concentration, size and species of fish, but the duration between the two bacterins was comparable. In fish under 1 g duration of protective immunity was longest when the most concentrated bacterin was used. Generally, immunity lasted in 1‐g fish for about 120 days, in 2‐g fish for about 180 days, but in 4‐g fish and larger immunity lasted for a year or longer. Coho salmon (Oncorhynchus kisutch) and sockeye salmon (O. nerka) retained immunity for a longer time and pink salmon (O. gorbuscha) the shortest time. Chinook salmon (O. tshawytscha) and rainbow trout (Salmo gairdneri) were intermediate. Field data generally followed the laboratory tests, but the duration appeared somewhat shortened. In one test 20‐g rainbow trout were vaccinated by the shower method and no loss of immunity occurred after 311 days.
Dermocystidium from cultured eels, Anguilla anguilla L., in Scotland
Authors: WOOTTEN R. , McVICAR A. H.
Published: April 2006

Abstract. An outbreak of Dermocystidium infection in cultured eels, Anguilla anguilla L., from Scotland is described. The disease appeared in the winter months but did not cause significant mortalities or adversely affect the growth of the eels. Infected eels had large, elongate white cysts on the gills. The cysts consisted of a homogeneous layer of parasite origin surrounded by a fibrous capsule and hyper‐plastic epithelium. Within the cysts were small spherical parasite cells with a densely staining central area and peripheral granular, vacuolated cytoplasm. The cell wall appeared to be broken down in many cases and the cells appeared degenerate. The cysts eventually collapsed and the cavity was filled with epidermal tissue.
Comparative stability of two salmonid viruses and poliovirus in fresh, estuarine and marine waters
Authors: TORANZO ALICIA E. , METRICIC F. M.
Published: April 2006

Abstract. The inactivation rates in the aquatic environment of two fish pathogens, infectious pancieatic necrosis virus (IPNV) and infectious haematopoietic necrosis virus (IHNV), were compared with that of poliovirus type 1 as a representative of the human enterovirus group. The survival studies were performed using untreated fresh, estuarine and sea water samples held at 15 and 20°C. The results indicated that the salmonid viruses survived longer than poliovirus in the saline waters, whereas in fresh water poliovirus was the most stable of the three viruses. IPN virus proved to be most stable in estuarine water at 15°C, whereas the survival of IHN virus was favoured in fresh water. We also observed that at 20°C the inactivation rate for each virus was independent of salt concentration in estuarine and sea water. Although temperature exhibited a marked effect on virus stability in fresh water, the salmonid viruses presented similar survival patterns at both temperatures in sea water. In general the period of greatest viral inactivation correlated with higher bacterial numbers in the waters.
Conchiolin infection and surface coating Vibrio: shell fragility, growth depression and mortalities in cultured oysters and clams, Crassostrea virginica, Ostrea edulis and Mercenaria mercenaria
Authors: ELSTON R. , ELLIOT ELISA L. , COLWELL R. R.
Published: April 2006

Abstract. A disease of cultured juvenile European oyster, Ostrea edulis, and American oysters, Crassostrea virginica, was characterized by infection of conchiolinous ligament and periostracum by surface‐coating Vibrio spp. bacteria. A similar bacterium was isolated from diseased cultured hard clams, Mercenaria mercenaria, held in a facility about 300 km distance from the oyster hatcheries. The oysters demonstrated fragile, undercalcified peripheral shell and apparently excessive chalky deposits. Histological and scanning electron microscopical examination revealed that the oysters' eroded ligaments and perforated peripheral periostracum were infected with uniform rod‐shaped bacteria. The infection appeared to interfere with normal proteinaceous and calcareous shell deposition and possibly with normal ligament function. Histological examination of the digestive system organs suggested that normal digestive processes were also interrupted. Two predominant bacteria were isolated from oyster samples and one predominant bacterium was isolated from clam samples. One of the isolates from oyster culture facilities was found almost exclusively associated with oyster shell surfaces and culture tank surfaces, this isolate was similar to the one taken from clam shell surfaces. The other predominant bacterium was found in water column samples in oyster culture facilities at levels from about 105 to 107 per ml. This isolate had a DNA base ratio (moles % G + C) of 43.6; the two surface‐associated isolates had base ratios of 43.6 and 44.5%. These Gram‐negative, oxidase positive, fermentive rods have been identified as a Vibrio spp. group. Specific antibody was produced which differentiated these bacteria from each other and from other similar isolates. Practical procedures for controlling the bacteria in shellfish culture systems are described.
A more sensitive technique for isolating infectious pancreatic necrosis virus from asymptomatic carrier rainbow trout, Salmo gairdneri Richardson
Authors: AGIUS C. , MANGUNWIRYO H. , JOHNSON R. H. , SMAIL D. A.
Published: April 2006

Abstract. An improved technique for isolating infectious pancreatic necrosis virus (IPNV) is described. It involves trypsinization of the suspect tissue, separation of the trypsinized cells and their co‐cultivation with indicator RTG‐2 cells. This co‐cultivation method is compared with homogenization, followed by membrane filtration, a procedure routinely employed by most disease diagnostic laboratories. From the two IPN‐infected farms studied, IPNV could be isolated by homogenization from only 50 and 66%, respectively, of the fish from which virus was detected by co‐cultivation. This difference in sensitivity can be explained in two ways, viz: (a) some of the virus is being retained by the membrane filter during filtration to remove contaminants following homogenization; (b) the presence of neutralizing factors in the tissue homogenate are neutralizing the virus and thus no cytopathic effect ensues. No correlation between serum neutralizing antibody levels and the differences in sensitivity of the two methods was found. The co‐cultivation method is as practical as, and certainly no more time‐consuming than, the homogenization technique.
The histopathology of larval anisakid nematode infections in the liver of whiting, Merlangius merlangus (L.), with some observations on blood leucocytes of the fish
Authors: ELARIFI A. E.
Published: April 2006

Abstract. The cellular response of whiting, Merlangius merlangus (L.), to Contracaecum and Anisakis larvae parasitic in the liver was characterized by the presence of neutrophils, macrophages and proliferating fibroblasts. A capsule formed around the larvae after the removal of all necrotic debris by phagocytic cells. Melanin granules were deposited around the capsule. Four types of blood leucocytes were identified; thrombocytes, lymphocytes, monocytes and neutrophils. Phagocytic activity of the neutrophils and macrophages was suggested by the presence of dark stained bodies within them.
An ultrastructural study of Myxobolus exlguus Thelohan, 1895 (Myxosporea) from grey mullet, Crenimugil labrosus (Risso)
Authors: PULSFORD ANN , MATTHEWS R. A.
Published: April 2006

Abstract. An ultrastructural study of Myxobolus exiguus Thelohan, 1895 using interlamellar and subdermal plasmodia from thick‐lipped grey mullet, Crenimugil labrosus, revealed differences in the structure of the plasmodia and host tissue reaction. Both plasmodia showed structural evidence of pinocytotic activity, but the surface area of subdermal plasmodia was considerably increased by digitiform extensions of the ectoplasm. A filamentous glycocalyx was a feature of the surface membrane of plasmodia, being more distinct on the interlamellar form. Sporo‐genesis involved two morphologically distinct types of generative cells, producing a disporous pansporoblast. Mature spores were oval, measuring 9‐0 μm×7.5 μm. Sporogenesis and capsulogenesis were essentially similar to other myxosporea. In the juvenile fish examined the host tissue reaction was slight, involving hyperplasia of epithelial cells associated with interlamellar plasmodia and some collagen deposition and localized melanization associated with subdermal plasmodia.
Serological comparison of selected isolates of Aeromonas salmonicida ssp. salmonicida
Authors: HAHNEL G. B. , GOULD R. W. , BOATMAN E. S.
Published: April 2006

Abstract. Eight isolates of Acronionus salmonicida ssp. salmonicida were collected during furunculosis epizootics in North American Pacific coast states and provinces. Both virulent and avirulent forms of each isolate, confirmed by challenge and electron microscopy, were examined. Serological comparisons by cross‐absorption agglutination tests revealed no serological differences between isolates. Using the double diffusion precipitin test, a single band was observed when antigen from a sonicated virulent strain was reacted with antiserum against a sonicated, virulent strain absorbed with homologous, avirulent strain. The presence of the single band was eliminated by excess sonication.
Ultrastructure of the macrogamont of Eimeria funduli, a coccidium parasitizing killifishes
Authors: HAWKINS W. E. , SOLANGI M. A. , OVERSTREET R. M.
Published: April 2006

Abstract. The ultrastructurc of the macrogamont of Eimeria funduli was studied in hepatocytcs of the killifish Funldulus grandis and F. similis. The macrogamont developed in a parasitophorous vacuole (PV) that was bounded by two unit membranes probably derived from an envelope of modified host rough cndoplasmic reticulum (RER). The membrane adjacent to the host‐cell cytoplasm was lined with ribosomes. whereas the membrane facing the PV was smooth and blebbed into the PV. Intravacuolar tubules were not observed in the PV. The macrogamonts had a single limiting membrane with lew micropores. Developing macrogamonts had abundant RER. few Golgi bodies, and a few small polysaccharide granules. Nuclei of developing macrogamonts had dispersed chromatin and compact nucleoli. Polysaccharide granules in developing and mature macrogamonts were identified with the periodic acid‐thiocarbohydrazide‐silver proteinate technique. In mature macrogamonts, polysaccharide granules as large as 1 –2 μm in diameter nearly filled the cytoplasm. The cytoplasm contained three kinds of inclusions that were associated with either the RER or Golgi apparatus. Inclusions identified as type I wall‐forming (WF) bodies were small, dense, membrane‐bound granules that developed from the Golgi apparatus. Inclusions identified as type II WF bodies were usually dense, irregularly shaped bodies that occupied RER cisternae. Some type II WF bodies had a heterogeneous content but most were homogeneous. A third type of inclusion was related to the cytoplasmic aspect of RER cisternae and consisted of tubules and vacuoles enclosed in a membrane.
Pathogenesis of vibriosis in cultured juvenile red abalone, Haliotis rufescens Swainson
Authors: ELSTON R. , WOOD G. S. LOCK
Published: April 2006

Abstract. Morbidity of intensively cultured red abalone, Haliotis rufescens, as well as experimentally stressed (elevated temperature and hyper‐oxygenation) abalone, was studied using clinical, histological, immunofluorescent and bacteriological techniques. Histological study showed a typical pattern of bacterial infection from all groups studied, characterized by epithelial exfoliation or rupture and systemic growth of the bacteria along vascular sinuses and along neural sheaths. Peripheral neurons degenerated rapidly and a responsive host cellular infiltrate did not appear to effectively retard the advancement of the infection. Nine bacterial isolates from the culture system water or sick animals were characterized biochemically. All were Gram‐negative, facultatively anaerobic, non‐aerogenic, oxidase‐positive rods with single polar flagella and thus appeared related to the Vibrio group. Further characterization showed that most isolates did not correspond to specifically characterized vibrios, Antiserum prepared to the isolates contained antibody both to common group antigens (from all nine strains) and to strain‐specific antigens. Selection of antiserum and subsequent absorption permitted the use of the antiserum for specific recognition of each isolate. Immunofluorescent studies clearly demonstrated that antiserum to an isolate corresponding to Vibrio alginolyticus was the predominant antiserum producing positive staining of infecting bacteria in the typical lesions in abalone tissues. The pattern of positive staining corresponded to histopathological observations of the disease. The disease can be managed in husbandry systems by both limiting the number of potentially pathogenic bacteria and by limiting the exposure of the animals to physico‐chemical stresses.