bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on the development of Bunodera luciopercae (Müller, 1776) (Trematoda: Allocreadiidae) under field and laboratory conditions
Authors: ANDREWS C. , CHUBB J. C.
Published: April 2006

Abstract. The intramolluscan development of Bunodera luciopercae was studied in laboratory infected pisidia maintained at three thermal regimes and compared with the seasonal development within a population of naturally infected first intermediate hosts at Llyn Tegid, Wales. At 4–8°C B. luciopercae did not develop beyond the sporocyst stage, although the development at 16–21°C We s similar to that reported by previous workers. The early stages of the intramolluscan development of B. luciopercae at Llyn Tegid were similar to the observed development at 16–21°C. However, the results suggest that falling autumn‐winter temperatures may initiate the production of immature cercariae within first generation rediae. Cercariae matured and were shed at Llyn Tegid during a short period between March and May. Live, juvenile B. luciopercae were artificially transferred from recently killed perch Perca fluviatilis, gill netted from Llyn Tegid, into live uninfected, laboratory maintained perch. The effect of temperature on the development of B. luciopercae in its definitive host was investigated at four thermal regimes. At 16–20°C development did not proceed normally and the infection had disappeared after 130 days. At 4–8°C and at natural environmental temperatures, gravid flukes were produced after 158–168 days. An increase in temperature on infected fish maintained at 4–8°C for 43 days did not stimulate parasite maturation. It is suggested that B. luciopercae may require an extended period of vernalization to elicit maturation in its definitive host and that temperature has a major influence on the life history of this parasite.
A comparative study of the tissue response to invasion and encystment by Stephanochasmus baccatus (Nicoll, 1907) (Digenea: Acanthocolpidae) in four species of flatfish
Authors: SOMMERVILLE CHRISTINA
Published: April 2006

Abstract. Four species of flatfish [plaice, Pleuronectes platessa L.; turbot, Scophthalmus maximus (L.); Dover sole, Solea solea (L.) and the common dab, Limanda limanda (L.)] were experimentally infected with cercariae of Stephanochasmus baccatus under similar conditions and examined at intervals up to 7 weeks post‐infection‐ The tissue response was found to be qualitatively the same in all four hosts and was consistent with a chronic granulomatous inflammatory reaction induced by resistant particulate foreign bodies. The intensity and rate of the response varied between host species but the capsule formation was essentially similar in all. The mature capsule consisted of an inner layer composed of leucocytes which underwent epithelioid transformation. The cellular structure of this tissue gradually degenerated from the oldest layer to form a dense eosinophilic ground substance in which was embedded nuclear debris. The outer layer of the capsule consisted of fibroblasts and reticulin collagen fibres. Muscle and fin cysts differed, with muscle cysts tending to be less discrete and more fibrous. The rate and intensity of the response to the parasite varied between different host species. Plaice and turbot showed the most intensive response and in turbot the reaction was considerably accelerated. Mortality of encysted metacercariae was only seen in turbot. The overall effect on larger 1‐group fish was minimal, but the smaller 0‐group plaice were more severely affected by the relatively large cvsts that interfered with organ function.
The effects of exposure to water‐soluble fractions of crude oil on selected histochemical parameters of the liver of Atlantic croaker, Micropogon undulatus L.
Authors: EURELL JO ANN , HAENSLY W. E.
Published: April 2006

Abstract. Micropogon undulatus L. were sampled from Galveston Bay, Texas, and transported to the research laboratory. Groups of five fish were exposed to 5 and 10% dilutions of the water soluble fraction (WSF) of southern Louisiana crude oil for 1, 3, 7, 14 and 21 days. Selected histochemical parameters of liver sections from control and WSF‐exposed fish were evaluated. Glycogen was reduced in amount while glucose‐6‐phosphate dehydrogenase, lipid and cholesterol were increased in liver sections of WSF‐exposed fish. These observations support a hypothesis that exposure to petroleum hydrocarbons increases mixed‐function oxidase activity. The alterations were more obvious in sections from fish exposed to the higher level of the WSF. The histochemical parameters appeared most altered in hepatocytes near afferent hepatic blood vessels. These hepatocytes were the first cells of the liver to contact the pollutants.
Effect of polybrene on the infectivity of infectious haemopoietic necrosis virus in tissue culture
Authors: LEONG J. C. , FENDRICK J. L. , YOUNGMAN S. , LEE A.
Published: April 2006

Abstract. enhancement of plaque formation by IHN virus on CHSE‐214 cells was obtained with 2–5 /(μ/ml polybrene. The enhancement is due to increased infectivity of small plaque variants in the IHN virus stock.
The effect of Eimeria sp. infection on the condition of blue whiting, Micromesistius poutassou (Risso)
Authors: MACKENZIE K.
Published: April 2006

Abstract. Eimeria sp. infection of blue whiting, Micromesistius poutassou (Risso), taken to the north and west of Scotland, was investigated with particular reference to the effect on host condition. Eimeria sp. is a parasite of the liver parenchyma and causes extensive lesions. Juvenile blue whiting were not found to be infected before the late 1‐group stage, but all 308 adult (3‐ to 17‐group) fish examined were infected. Condition factor (k= 100w/l3) showed a statistically significant decrease with increasing intensity of infection. Average value of liver weight, expressed as a percentage of total body weight, also decreased with increasing intensity of infection. It is concluded that Eimeria sp. infection is a major factor contributing to loss of condition in blue whiting from the study area. The loss of weight in fish with moderate‐to‐heavy infections was estimated at from 6 to 10%; this figure does not take account of mortalities resulting from Eimeria infection nor does it take account of the most heavily infected fish which could not be included in the analysis because sufficiently accurate estimates of the large numbers of oocysts present were not made.
Egtved virus: temperature‐dependent immune response of trout to infection with low‐virulence virus
Authors: JØRGENSEN P. E. VESTERGÅRD
Published: April 2006

Abstract. The present report deals with experiments concerning the theoretical basis for development of a live, attenuated vaccine against viral haemorrhagic septicaemia (VHS) of rainbow trout, Salmo gairdneri Richardson, on the basis of a virus strain derived from the Egtved virus reference strain F, the pathogenicity of which has been strongly reduced by in vitro passage. It is shown that the low pathogenicity of the virus (designated the Reva strain) is a genetically stable feature and that the protection against VHS induced by infection with the virus is due to an immune response. Following immunological priming at 10°C partial protection developed at 5° 10° and 15° but not at 20°C, whereas neutralizing antibody was produced at all four temperatures by some of the fish. The duration of virus persistence in trout was found to be inversely proportional to the water temperature.
Comparative sensitivity of five fish cell lines to wild type infectious haematopoietic necrosis virus from two Oregon sources
Authors: FENDRICK J. L. , GROBERG W. J. , LEONG J. C.
Published: April 2006

Abstract. Five fish cell lines (CHSE‐214, STE‐137, RTG‐2, EPC and FHM) were compared for sensitivity to infectious haematopoietic necrosis virus (IHNV) from samples obtained from naturally‐infected fish. Infectious ovarian fluids were obtained from steelhead trout, Salmo gairdneri Richardson, at the Round Butte Hatchery in central Oregon and tissue homogenates were prepared from chinook salmon, Oncorhynchus tshawytscha (Walbaum), alevins during an IHN virus epizootic at the Elk River Hatchery in coastal Oregon. The only lines to show characteristic viral cytopathology by plaque or end‐point dilution assay for the steelhead trout virus isolate were the EPC and FHM cell lines. The chinook salmon isolates produced CPE in CHSE‐214, STE‐137, FHM and EPC cells. The titre of the salmon virus isolate was 10‐50‐fold higher on FHM and EPC cells by both assay methods. Neither by end‐point nor plaque assay did the Round Butte or Elk River isolates produce CPE on RTG‐2 cells. With both virus isolants both cell lines showed that greater sensitivity was obtained with plaque assay than with end‐point titration. Pre‐treatment of the cells with the polycation, polybrene, did not increase the virus titre in either assay. However, a transient enhancement in virus titre was observed in polybrene‐treated STE‐137 and CHSE‐214 cells.
The life history of Haplorchis pumilio (Looss, 1896) from cultured tilapias
Authors: SOMMERVILLE CHRISTINA
Published: April 2006

Abstract. The metacercaria of Haplorchis pumilio (Looss, 1896) (Digenea: Hetero‐phyidae) was found to occur commonly in intensively reared tilapias (Tilapia, Sarotherodon) in an East African fish farm. The life cycle on the farm was found to involve the gastropod Melanoides tuberculata (Müller) as the first intermediate host. The infection was experimentally transmitted to fish in fresh water from naturally infected molluscs. The salinity of the water on the farm varied with season from 0 to 3%0, but cercariae were shown to remain infective up to 10%0 although longevity was reduced at 7.5%0. Piscivorous predators, Ardea cinerea L., Phalocrocorax sp. and Varanus sp., which were resident or regular visitors to the farm were heavily infected with the parasite. Mice, hamsters and pigeons were found to be convenient laboratory hosts. H. pumilio shows a lack of specificity at the second intermediate and final host level as well as a wide geographic range and has been reported to infect man. Its potential as a possible cause of zoonoses, and control methods are discussed.
Some marine fish coccidia of the genera Eimeria Schneider, Epieimeria Dyková & Lom and Goussia Labbé
Authors: LOM J. , DYKOVÁ I.
Published: April 2006

Abstract. Descriptions of six coccidian species infecting marine fishes are presented. Goussia cascosa sp.nov. is described from the visceral organs of the roughhead grenadier, Macrourus berglax Lacépède, from Newfoundland waters; it is a species closely related to G. gadi. Goussia luciae sp.nov. is described from the intestine of sea mullet, Mullus barbatus L., collected, as were the hosts of all the following species, from the French Mediterranean coast at Banyuls‐sur‐Mer. Goussia lucida (Labbé, 1893) is redescribed from the intestine of a new host, the lesser spotted dogfish, Scyliorhinus canicula (L.). Epieimeria isabellae sp.nov. is described from the intestine of conger eel, Conger conger L. Two species were provisionally allotted to the genus Eimeria: E. banyulemis sp.nov. from the intestine of axillary wrasse, Crenilabrus mediterraneus L., and Eimeria insignis sp.nov. from the intestine of scorpion fish, Scorpaena notata Rafinesque. Taxonomic affinities and the pathogenicity of these coccidian species are discussed.
A serotypic survey and cross‐protection test of North American field isolates of Yersinia ruckeri
Authors: McCARTHY D. H. , JOHNSON K. A.
Published: April 2006

Abstract. A serological study of 23 North American strains of Yersinia ruckeri showed that they were comprised essentially of one serotype–the classical ‘Hager‐man’ serotype. Cross‐protection tests showed that rainbow trout could be protected from challenge with various strains. Continuous surveillance of enteric redmouth disease and further work including DNA binding studies is necessary to determine the precise significance of the other related serotypes.
The pathology of Saprolegnia infections of Anguilla anguilla L. elvers
Authors: COPLAND J. W. , WILLOUGHBY L. G.
Published: April 2006

Abstract. The clinical signs and histopathology of Saprolegnia sp. [related to S. diclina Humphrey (syn. S. parasitica Coker)] are described in cultured Anguilla anguilla L. elvers under an intensive production system. The main lesions observed were loss of epithelium leading to ulceration, oedema and myofibrillar degenerative changes of the muscle mass. The oedema resulted in swelling of the inter‐myotomal connective tissue, loss of nuclei and minor host reaction. Traumatic lesions with subsequent bacterial infections had a mononuclear inflammatory response. It is suggested that the rapid extension of the lesion is due to the loss of integrity of the integument and the widespread oedema, which altered the viability of tissues and assisted the Saprolegnia infection. The condition was fatal for infected elvers.
Pathogenesis of infectious pancreatic necrosis virus infection in brook trout, Salvelinus fontinalis (Mitchill), following intraperitoneal injection
Authors: SWANSON R. N. , CARLISLE J. C. , GILLESPIE J. H.
Published: April 2006

Abstract. The pathogenesis of IPNV infection was examined in young brook trout following intraperitoneal inoculation. Fish were sampled sequentially and the distribution of virus determined by virus isolation, histopathology and immunofluorescence. Following intraperitoneal inoculation, virus entered the peritoneal cavity and by 2 days post‐inoculation virus had interacted with the pancreatic exocrine cells. Replication in these cells resulted in the production of IPNV‐specific antigen, necrosis of infected cells, and spread of infectious virus to adjacent tissue. Areas of viral replication were at first multifocal but tended to merge as they grew. Eventually, most of the acinar tissue became involved and only small pockets of normal acinar cells remained. Twelve‐week old brook trout survived with only a small amount of functional exocrine pancreas and limited virus replication continued in this tissue for weeks. Extensive virus replication appeared to take place only in the pancreas although viral antigen and slight pathological changes were found in the renal interstitium and livers of some fish.
Nodular coccidiosis in the gut of the tench, Tinca tinca L.
Authors: MOLNÄR K.
Published: April 2006

Abstract. In the intestinal epithelium of 3–5‐summer old tench, Tinca tinca L., an unknown Eimeria sp. developing white, pinhead‐sized nodules was found. Oocysts were shed in a non‐sporulated state, but at 20°C in tap water they completed sporulation and resembled Eimeria subepithelialis, a parasite of common carp. During the period of examination, in April and May, only young oocysts and gamogonic stages developing in the epithelium of the mucosa were detected. Despite the morphological similarities and nodular occurrence there are significant differences between the nodular coccidiosis of the tench and common carp.
Studies on the pathogenesis of streptococcal infection in cultured yellowtails, Seriola spp.: effect of crude exotoxin fractions from cell‐free culture on experimental streptococcal infection
Authors: KIMURA H. , KUSUDA R.
Published: April 2006

Abstract. Exotoxins prepared from streptococcal bacteria of Seriola spp. origin were grown in fluid culture and fractionates of the supernatant used in toxicity studies in Seriola by oral and percutaneous exposure. Toxic fractions were then applied simultaneously with oral challenge with Streptococcus spp. bacteria. Two fractions E and G were shown to have a significant effect on the pathogenesis of infection.
Stumpbody Sarotherodon aureus (Steindachner) (=Tilapia aurea) and tail‐less S. niloticus (L.) (=T. niloticd): two vertebral anomalies and their effects on body length
Authors: TAVE D. , BARTELS J. E. , SMITHERMAN R. O.
Published: April 2006

Abstract. Two gross phenotypic anomalies in tilapia are described: Stumpbody Sarotherodon aureus (=Tilapia aurea) and tail‐less S. niloticus (= T, nilotica). Vertebral anomalies associated with each disorder are described. A body length: vertebra length ratio is developed to assess the effects that vertebral anomalies have on body lengths. The Stumpbody phenotype is a non‐heritable, congenital defect.
An investigation into the bacterial aetiology of ‘black patch necrosis’ in Dover sole, Solea solea L.
Authors: CAMPBELL A. C. , BUSWELL J.A.
Published: April 2006

Abstract. A recurring disease known as ‘black patch necrosis’ (BPN) has been the cause of severe mortalities in 0‐group and 1‐group Dover sole during the period 1974‐1978 at the Sea Fish Industry Authority's Marine Cultivation Unit at Hunter‐ston, Ayrshire, Scotland. Samples of diseased and healthy Dover sole tissue were examined microbiologically and a long thin filamentous Gram‐negative organism, strongly resembling Flexibacter columnar's, was repeatedly isolated from diseased tissue but was not found in healthy tissue. This organism was pathogenic to Dover sole, producing 100% mortality in 96 h at 17.5°C (±2°C) and the organism was reisolated from all the infected fish. The pathogenic isolate and reisolate were examined and compared with reference strain NCMB 1038 of Flexibacter columnarts, formerly known as Chondrococcus columnaris or Cytophaga columnaris. The isolate, reisolate and type culture were identical with respect to cell morphology, oxidase test, catalase production, production of H2S, casein hydrolysis, gelatin liquefaction, hydrolysis of Tween 20, degradation of tyrosine and starch hydrolysis. All bacterial types showed similar patterns of sensitivity to a range of antibiotics. It is proposed that a Flexibacter columnari's‐like organism is associated with the condition in farmed Dover sole known as ‘black patch necrosis’.
Antigenic relationships of selected strains of infectious pancreatic necrosis virus and European eel virus
Authors: OKAMOTO N. , SANO T. , HEDRICK R. P. , FRYER J. L.
Published: April 2006

Abstract. An antigenic comparison of ten strains of infectious pancreatic necrosis virus (IPNV) and a single strain of European eel virus (EEV) revealed the presence of three distinct groups separable by cross‐neutralization. The 1/r value calculated from the formula r=√r1× r2 (Archetti & Horsfall 1950) was used to divide the virus strains into: group I, which included all six U.S.A. strains: Buhl, Idaho; Reno, Nevada; ATCC VR 299; Powder Mill, New Hampshire; West Buxton, Maine; and Cascade Locks, Oregon: group II, the European strains: ?Honnincthun, France; Sp Denmark; and Bonnamy, France: group III, Ab Denmark and EEV. The group II European strains of IPNV were more closely related to the group I U.S.A. strains than to those viruses in group III. European eel virus (EEV) was antigenically most closely related to the Ab strain of IPNV.
Melanotic visceral fibrosis associated with larval infections of Posthodiplostomum minimum and Proteocephalus sp. in bluegill, Lepomis macrochirus Rafinesque, in central Iowa, U.S.A.
Authors: MITCHELL L. G. , GINAL J. , BAILEY W. C.
Published: April 2006

Abstract. Severe melanotic liver and visceral fibroses in bluegill associated with infections of plerocercoids of Proteocephalus sp. and metacercariae of the digenean Posthodiplostomum minimum, were studied by light and transmission electron microscopy. Fibrosis was most evident in bluegill carrying heavy worm burdens. Tubular and multilocular melanotic and non‐melanotic cysts were formed of concentric layers of non‐cellular eosinophilic connective tissue surrounding central spaces containing basophilic material. Moribund and deteriorating plerocercoids and metacercariae were surrounded by, and sometimes invested with, fibrous tissue. Living plerocercoids in the liver were surrounded by necrotic and compressed hepatocyte zones. Fibro‐blasts, epithelioid cells and eosinophilic granulocytes were common in compressed cell zones. Intrahepatic fibrotic cysts were surrounded by granulomatous zones. Parenchyma in fibrotic livers showed increased numbers of macrophages, melano‐macrophage centres and engorged blood vessels with thickened walls. Histochemical tests for lipofuscin and haemosiderin were strongly positive in melanotic liver tissue. Ultrastructural changes in hepatocytes adjacent to fibrotic cysts and epithelioid zones included intranuclear lipid and glycogen inclusions, chromatin alterations and mitochrondrial degeneration. Bile canaliculi, sinusoids and perisinusoidal spaces showed reduced micro villarsurfacesand a decrease in luminar diameter. Degenerating hepatocytes contained phagolysosomes and myelin bodies.
Susceptibility of five species of fish to Edwardsiella ictaluri
Authors: PLUMB J. A. , SANCHEZ D. J.
Published: April 2006

Abstract. Five species of fingerling fish, channel catfish, Ictalurus punctatus, tilapia, Sarotherodon aureus, golden shiner, Notemigonus crysoleucas, largemouth bass, Micropterus salmoides and bighead carp, Aristichthys nobilis, were tested to determine their susceptibility to the bacterium, Edwardsiella ictaluri, at 26°C, Channel catfish demonstrated high susceptibility to E. ictaluri as 100% of those fish injected with 1.5 × 103 cells died within 10 days. Tilapia demonstrated slight susceptibility to the pathogen while golden shiner, bighead carp and largemouth bass were not susceptible. E. ictaluri was isolated from a higher percentage of peritoneal cavities, livers and kidneys of channel catfish than of other species. Sequential growth of E. ictaluri in the liver of channel catfish is described.
Loma salmonae (Putz, Hoffman and Dunbar, 1965) in the rainbow trout, Salmo gairdneri Richardson, and L. fontinalis sp. nov. (Microsporida) in the brook trout, Salvelinus fontinalis (Mitchill)
Authors: MORRISON CAROL M. , SPRAGUE V.
Published: April 2006

Abstract. Loma salmonae (Putz, Hoffman and Dunbar, 1965), Morrison & Sprague, 1981, in the rainbow trout, Salmo gairdneri Richardson, was studied with the electron microscope. It is morphologically very similar to L. morhua Morrison and Sprague, 1981, in the Atlantic cod, Gadus morhua L., having only minor differences. Loma sp. Morrison and Sprague, 1981, in the brook trout, Salvelinus fontinalis (Mitchill), is more like L. salmonae than the other species of Loma, but was deemed to be distinct. It was named L. fontinalis sp. nov.
The effects of dissolved gas supersaturation on larval striped bass, Morone saxatilis (Walbaum)
Authors: CORNACCHIA J. W. , COLT J. E.
Published: April 2006

Abstract. Gas bubble disease in larval striped bass, Morone saxatilis (Walbaum), was characterized by overinflation of the swimbladder and the formation of intestinal bubbles. This accumulation of gas hindered normal swimming of the fish and in extreme cases resulted in floating fish. As gas accumulated in the gut, the inner mucosal lining was compressed down into a cuboidal epithelium and in more advanced cases nearly the entire digestive tract was reduced to a squamous inner epithelium surrounded by a thin serosa. A significant increase in swimbladder volume was observed at total gas pressures as low as 102.9% and mortality was increased at 105.6‐106.0%. The older larvae (30‐day‐old) were less sensitive to gas supersaturation than 10‐ to 19‐day‐old larvae.
Immunization of rainbow trout, Salmo gairdneri Richardson, against bacterial kidney disease: preliminary efficacy evaluation
Authors: MCCARTHY D. H. , CROY T. R. , AMEND D. F.
Published: April 2006

Abstract. A bacterin for immunization against bacterial kidney disease of salmonid fishes caused by Renibacterium salmoninarum is described. Cultures were grown in Evelyn's KDM2 medium containing 10% calf serum in a fermenter under the following conditions: pH 7.2, 15°C, 800ml/min air, 200 rev/min agitation and 5–15 days of incubation. Possible substitutes for calf serum were 10% horse serum 0.15% starch and leptospira medium. The bacterins were inactivated with 0.3% formalin and no adjuvants were used. Other tests evaluated pH‐lysed bacterin, 50% concentrated bacterin and 50% concentrated pH‐lysed bacterin. Juvenile rainbow trout, salmo gairdneri Richardson, were vaccinated either by intraperiotoneal (i.p.) injection, 2 min immersion or 2‐step hyperosmotic infiltration. Fish were held from four to six weeks at 11°C, then challenged by i.p. injection with the homologous virulent bacterium. Fish died from days 19 to 40 after challenge. The best preparation was pH‐lysed bacterin given by a single i.p. injection; hyperosmotic and immersion vaccination were not effective. Typically when 80% or more of unvaccinated controls were infected as detected by Gram stain, 10% or less of the vaccinated fish were infected.
The pathology of chronic ammonia toxicity in rainbow trout, Salmo gairdneri Richardson
Authors: DAOUST P.‐Y. , FERGUSON H. W.
Published: April 2006

Abstract. Two groups of rainbow trout fingerlings were exposed for 90 days to 0.2 and 0.4 mg/1 of un‐ionized ammonia, respectively. Several fish exposed to the higher concentration soon developed clinical signs suggestive of a neurological dysfunction but subsequently recovered. No lesion attributable to ammonia was seen in the gills of any of the fish. This raises questions about the precise role of ammonia in the production of gill diseases in intensively cultured trout.
Occurrence and characterization of Aerococcus viridans from lobsters, Homarus gammarus L., dying in captivity
Authors: GJERDE J.
Published: April 2006

Abstract Dead lobsters from five lobster parks have been examined over a period of 5 months for the occurrence of Aerococcus viridans. Isolated strains of the bacterium were characterized biochemically and by means of intracellular protein patterns using thin layer isoelectric focusing in polyacrylamide gel. In a lobster park where a high mortality occurred, A. viridans was isolated from 29 of 33 dead lobsters. The bacterium was also isolated from 7 of 10 dead lobsters in a lobster park with low mortality. Probably, infection with A. viridans occurs more frequently in Norwegian lobster parks than hitherto suspected. Gram‐positive cocci sharing many characteristics with A. viridans were isolated from some dead lobsters. These bacteria did not form tetrads, they were catalase positive and had different protein patterns from A. viridans.
An evaluation of residual contamination by Clostridium botulinum in a trout farm following an outbreak of botulism in the fish stock
Authors: CANN D. C. , TAYLOR LESLEY Y.
Published: April 2006

Abstract Following an outbreak of botulism in the fish stock of a British trout farm in 1980, a survey of the residual contamination of the farm was carried out. Commencing in November 1980, the farm was examined monthly for one year after the disease had been eliminated. A nearby unaffected farm was examined as a control. Examination of pond muds showed that the affected farm remained contaminated throughout the year, counts of Clostridium botulinum type E ranging from 1‐800/g compared with counts at the control farm of 0.1‐0.7/g. Both C. botulinum types B and E were found in the control farm, either singly or together in individual samples of pond mud. Fish taken from the affected farm in May and August of 1981 showed a 77.1 % (s.e. ±7.7) contamination by type E. Examination of the environs of the affected farm yielded C. botulinum in 36 of 60 samples of mud and soil using enrichment culture techniques. Clostridium botulinum type E predominated in muds, occurring in 26 of 28 samples taken from the waters supplying and by‐passing the farm. In contrast, of the 32 soil samples tested from around the farm, eight yielded type B whereas only three contained type E.
Zschokkella russelli Tripathi (Myxozoa: Myxosporea) from the five‐bearded rockling, Ciliata mustela L., (Teleostei: Gadidae) in Wales
Authors: DAVIES ANGELA J.
Published: April 2006

Abstract. Up to 88‐9% of five‐bearded rocklings, Ciliata mustela L., from three localities in Wales harboured the coelozoic myxozoan parasite Zschokkella russelli Tripathi. Previously recorded only from the gall‐bladder of British rocklings, Z. russelli was also found to produce proliferation, enlargement and thickening of hepatic ducts, lowering of the duct epithelium and pericholangitis. Histological, scanning and transmission electron microscopy techniques were used to examine the parasite, and comparisons were drawn between Z. russelli from Welsh fish and infections recorded elsewhere, particularly from Plymouth, Devon.
Dynamics of challenge infections of Gyrodactylus bullatarudis Turnbull (Monogenea) on guppies, Poecilia reticulata (Peters)
Authors: SCOTT MARILYN E.
Published: April 2006

Abstract. Comparison of the population dynamics of Gyrodactylus bullatarudis o fish that were reinfected at 0, 1, 2, 4, or 6 weeks post‐recovery from an initial, infection were based on the following parameters: percentage establishment, recovery and death, mean peak parasite burden, mean time to peak burden, mea duration of infection, mean time to death. Of fish that recover from an initial, infection, some are immediately susceptible to a challenge infection. Other fish are able to harbour a challenge infection hut parasite numbers increase less and the infection is of shorter duration than the initial. These fish regain their fu susceptibility within 4‐6 weeks post‐recovery. A third group of fish become totally refractory to reinfection and only slowly regain their ability to support an infection Thus even at 6 weeks post‐recovery they are only partially susceptible t reinfection. It is probable that the three groups in fact represent a continuum increasing susceptibility to challenge infection.
Control of bacterial kidney disease in Atlantic salmon, Salmo salar L., by dietary modification
Authors: LALL S. P. , PATERSON W. D. , HINES J. A. , ADAMS N. J.
Published: April 2006

Abstract. The effects of dietary treatments were investigated as a prophylactic measure to minimize the occurrence and severity of bacterial kidney disease (BKD) infections in Atlantic salmon, Salmo salar L., at Margaree Fish Culture Station, Nova Scotia, Canada. Six diets containing various levels of calcium, magnesium, zinc, iron, copper, manganese, cobalt and iodine in addition to one commercial diet were fed to post–yearling Atlantic salmon in two consecutive experiments. Natural infection was utilized to examine the effects of each diet on the prevalence of BKD. Diet containing high levels of iodine (4.5 mg/kg feed) and fluorine (4.5 mg/kg) reduced BKD prevalence rate to 3% and 5% respectively compared to 95% and 38% with commercial feed. Some other experimental diets also reduced prevalence of BKD, but to a lesser degree than the diet with additional iodine and fluorine.
Identification of lymphocytes in the epidermis of the rainbow trout, Salmo gairdneri Richardson
Authors: PELETEIRO MARIA C. , RICHARDS R. H.
Published: April 2006

Abstract The presence of lymphocytes in the epidermis of the rainbow trout, Salmo gairdneri Richardson, was confirmed by light and electron microscopical observation and by the use of an indirect immunocytochemical technique utilizing peroxidase‐labelled antibody. These results are compared with those of other workers and the source and function of these cells in the epidermis of teleosts is discussed.
Detection of channel catfish virus in channel catfish, Ictalurus punctatus (Rafinesque): use of a nucleic acid probe*
Authors: WISE JANET A. , BOYLE J. A.
Published: April 2006

A nucleic acid probe for channel catfish virus (CCV) was constructed using recombinant DNA techniques. This probe consisted of a specific viral DNA fragment generated by digestion of CCV DNA with the restriction enzyme EcoRI. The probe was used to examine DNA isolated from tissues of fish that had been injected with CCV. Viral DNA was detected in some tissues of various injected fish. The sensitivity limit of detection was determined to be one viral DNA per cell.
Serum chemistry of diseased English sole, Parophrys vetulus Girard, from polluted areas of Puget Sound, Washington
Authors: CASILLAS E. , MYERS M. S. , RHODES LINDA D. , McCAIN B. B.
Published: April 2006

Relationships between selected serum components and microscopically detected idiopathic liver and kidney lesions were evaluated for English sole, Parophrys vetulus, sampled from urban and non‐urban areas of Puget Sound, Washington. The normal range for each serum chemistry parameter was based on English sole with no lesions, or sole with minor parasitic conditions or with lesions in tissues other than liver and kidney which did not significantly affect serum chemistry values. Generally, sole with idiopathic liver lesions had significantly different haematocrit values and levels of serum albumin, calcium, and bilirubin when compared to sole which were free of idiopathic liver and/or kidney lesions. Serum aspartate aminotransferase and alanine aminotransferase activity and serum levels of glucose, total protein, phosphates and magnesium were also abnormal, but appeared to be associated only with certain types of liver lesions. No association between kidney lesions and abnormal serum chemistry values was identified. In addition, English sole sampled from some urban areas of Puget Sound had particular serum chemistry values and liver lesion prevalences which were significantly different from those of sole sampled from non‐urban areas. These findings support the hypothesis that sole near highly urbanized environments may display other signs of impaired health in addition to high prevalences of tissue lesions. Thus, measurements of serum chemistry parameters, in conjunction with histopathological examination, appear to be useful techniques for evaluating the health of English sole.
Oomycete fungi associated with ulcerative mycosis in menhaden, Brevoortia tyrannus (Latrobe)
Authors: NOGA E. J. , DYKSTRA M. J.
Published: April 2006

Abstract. Deep necrotic ulcers in Atlantic menhaden, Brevoortia tyrannus (Latrobe), were consistently associated with the presence of oomycete fungi. These organisms were found in over 95% of all lesions both early and late. More than one species of fungus appears to be involved, indicating that these organisms are secondary to some other stressor. However, all characteristically elicit an atypical intense granulomatous inflammatory response and do not behave pathologically as typical oomycetes. Our observation that these fungi appear to be the only organisms consistently present in the earliest stages of the disease indicates that some non‐infectious stressor may be responsible for initiating the lesions and subsequently allowing the fungi to induce this atypical response.
Haematological assessment of rainbow trout, Salmo gairdneri Richardson, and Atlantic salmon, Salmo salar L., infected with Renibacterium salmoninarum
Authors: BRUNO D.W. , MUNRO A.L.S.
Published: April 2006

Abstract. Groups of rainbow trout, Salmo gairdneri Richardson, and Atlantic salmon, S. salar L., were infected with Renibacterium salmoninarum, injected with killed bacteria or starved. Selected red and white cell parameters were measured over a 35–day period. As a result of successful infection a typical granulomatous disease developed during which haematocrit, red cell count, haemoglobin, red cell diameter and the ratio of mature to immature erythrocytes all decreased. Red cell depletion was shown to be caused by their retention in the spleen and to be the cause of the observed splenomegaly. Increases in monocytes, thrombocytes and neutrophils were recorded in both infected groups.
Potential for recovery in nodular gill disease of rainbow trout, Salmo gairdneri Richardson
Authors: DAOUST P.‐Y. , FERGUSON H. W.
Published: April 2006

Abstract. Nodular gill disease characterized by severe multifocal epithelial hyperplasia was diagnosed in a group of rainbow trout, Salmo gairdneri Richardson, fingerlings. Gills of a large proportion of fish transferred from the affected tank to smaller aquaria showed a marked decrease in severity of the lesions after 2 months. Repair of hyperplastic lesions may occur in various forms of proliferative gill disease, provided that the basement membrane lining the primary and secondary disease, provided that the basement membrane lining the filaments and lamellae remains intact.
A study of the pathological effect of isolated Aeromonas salmonidda extracellular protease on Atlantic salmon, Salmo salar L.
Authors: FYFE LORN A , FINLEY A. , COLEMAN G. , MUNRO A. L. S.
Published: April 2006

Abstract. A comparison was made between the effects of Aeromonas salmonidda extracellular protease and total extracellular products (ECP) following intramuscular injection into juvenile Atlantic salmon, Salmo salar L. Thus, 20, 10, 5, 2.5 and 1.5 units of salt‐free protease in 0.2 ml water were compared with ECP preparations with the same levels of proteolytic activity. The highest concentration of ECP produced a gross pathology with a large furuncular lesion 36 h after injection. The corresponding protease preparation had a lesser effect, although a furuncle was formed and tissue liquefaction was produced. These effects were less marked with reduced concentrations. At the lowest level studied, no significant effect was observed with protease alone but ECP (0.8 μg of protein) produced a small, characteristic lesion similar to that achieved with 5 units of isolated protease.
First report of viral erythrocytic necrosis in Alaska, USA, associated with epizootic mortality in Pacific herring, Clupea harengus pallasi (Valenciennes)
Authors: MEYERS T. R. , HAUCK A. K. , BLANKENBECKLER W. D. , MINICUCCI T.
Published: April 2006

Abstract. Viral erythrocytic necrosis (VEN) has been associated with large epizootics and high mortality in Pacific herring, Clupea harengus pallasi (Valenciennes), from two different locations in south‐eastern Alaska, USA. Clinical signs of disease included whirling, pale gills, watery colourless blood, discoloured livers, pathog‐nomonic magenta erythrocytic inclusion bodies and histopathological changes consistent with other infectious haemolytic anaemias in higher animals. Transmission electron microscopy confirmed the presence of iridovirus‐type particles associated with the cytoplasmic erythrocytic inclusion bodies. Other apparently healthy herring of various age classes from four additional areas in south‐east Alaska also had clinical signs of VEN suggesting a wide distribution of the virus in Alaskan Pacific herring populations. Evidence regarding the two herring epizootics indicated that osmoregulatory stress may have precipitated mortalities in fish having severe anaemia caused by the VEN virus. This is the first reported occurrence of VEN in Alaska and the first natural epizootic known to be associated with the disease.
The effects of malachite green upon proliferative kidney disease
Authors: CLIFTON‐HADLEY R. S. , ALDERMAN D. J.
Published: April 2006

Abstract. When rainbow trout infected with proliferative kidney disease (PKD) held in the laboratory were treated with malachite green and formalin to cure ichthyophthiriasis it was observed that subsequent development of PKD was delayed. Experiments are reported which indicate that this was due to the malachite green treatment. The possible use of malachite green in the treatment of PKD, tissue levels of malachite green achieved during treatments and the toxicity risks from multiple dose therapy with malachite green are discussed.
A study of the sequential clinical and pathological changes during proliferative kidney disease in rainbow trout, Salmo gairdneri Richardson
Authors: CLIFTON‐HADLEY R. S. , BUCKE D. , RICHARDS R. H.
Published: April 2006

Abstract. A histological study of 0+ rainbow trout, exposed to proliferative kidney disease (PKD) on an infected farm, showed evidence of infection from the beginning of June, gross pathological changes from the beginning of July, and clinical signs from mid‐July. Evidence of healing was present in some samples from the second week of August. Kidney samples were divided into five grades (0–4) representing increasing severity of pathology. A sixth grade (H) was applied to kidneys showing signs of healing. The most frequent clinical signs were abdominal distension and exophthalmos. Melanosis, corneal cloudiness and ecchymoses were observed occasionally. Apart from renal enlargement, other internal gross pathological changes included ascites, gill and liver pallor, oedema, petechiation, and splenic enlargement. The majority of clinical signs and internal changes were only seen in fish with advanced renal swelling (grades 3 and 4). Histopathology was most marked in the kidney and was of three types: haemopoietic hyperplasia, vascular pathology and diffuse inflammatory change. Vascular changes, including occlusion of blood vessels in several organs and apparent haemoglobin crystallization, and destruction of renal excretory structures within areas of chronic diffuse inflammation were marked features of the histopathology in fish with clinical signs. The pathogenesis of PKD is discussed with reference to the histopathological changes.
Regression and development of epidermal papillomas affecting white suckers, Catostomus commersoni (Lacépède), from Lake Ontario, Canada
Authors: SMITH I. R. , ZAJDLIK B. A.
Published: April 2006

Abstract. Epidermal papillomas affect white suckers, Catostomus commersoni (Lacepede), from various areas of the Great Lakes of North America, particularly regions receiving industrial pollution. Three morphologically distinct but histologically similar papillomas were found on a group of fish from a polluted site. The diameter of focal soft‐skin plaques, focal hard‐skin papillomas and focal lip tumours was monitored on individual fish before and after a 12–week observation period in our laboratory. Many papillomas disappeared completely, while others persisted. Individually lip tumours had a lesser frequency of regression (22%), compared to skin plaques (79%) or papillomas (64%). Papillomas which persisted had only slightly smaller diameters after 12 weeks. New tumours developed on 23 and 60% of the survivors in two separate groups. The development of tumours in the laboratory suggests a cause unrelated to the environmental pollution which is correlated with papilloma incidences in wild white suckers. The behaviour of white sucker papillomas under laboratory conditions contrasts with the persistence and often enlargement of similar papillomas reported for other poikilothermic species.
Histological effects of the inert suspended clay kaolin on the gills of juvenile rainbow trout, Salmo gairdneri Richardson
Authors: GOLDES S. A. , FERGUSON H. W. , MOCCIA R.D. , DAOUST P.‐Y.
Published: April 2006

Abstract. Juvenile rainbow trout were exposed to 36, 171, 1017 and 4887 mg/1 of suspended kaolin clay for 64 days. Gills were analysed qualitatively and quantitatively using histology. Branchial pathology was absent at all sample times in fish exposed to 36, 171 and 1017 mg/1 kaolin, although intracellular kaolin was visible within filament and lamellar epithelium in gills exposed to 171, 1017 and 4887 mg/1 kaolin at 4, 8, 16, 32 and 64 days. Lesions were found in gills exposed to 4887 mg/1 kaolin at 16 and 32 days but the marked lamellar proliferation was associated with moderate to large numbers of protozoa identified as Ichthyobodo necator. Gills regained normal architecture by 64 days despite continued exposure to kaolin. It is suggested that while the gill lesions were probably a direct result of protozoan infection, kaolin was indirectly responsible for creating a favourable environment for protozoan colonization. The recovery of normal architecture and reduction of protozoan numbers between 32 and 64 days was probably a function of increased mucus secretion, immune response and turnover of branchial epithelium. The authors conclude that exposure to prevailing levels of this inert clay particle, even for periods as long as 64 days, probably has little direct effect on gill structure at the light microscope level. The action of non‐inert and organic particles remains to be investigated.
Rhabdomyosarcoma in the Japanese medaka, Oryzia latipes (Temminck & Schlegel) and guppy, Poecilia reticulata Peters
Authors: HAWKINS W. E. , FOURNIE J. W. , OVERSTREET R. M. , WALKER W. W.
Published: April 2006

Abstract. Three cases of skeletal muscle neoplasms occurring in two small fish species used in carcinogen tests are reported. The cases illustrated a wide range of histologic patterns, and consisted of a well‐differentiated juvenile type, a well‐differentiated pleomorphic type and a poorly differentiated pleomorphic type. A rhabdomyosarcoma with juvenile type features developed in the Japanese medaka, Oryzias latipes, exposed to 0·5 ml/1 of the solvent dimethylformamide. A pleomorphic type rhabdomyosarcoma occurred in one medaka and in one guppy, Poecilia reticulata, exposed to the carcinogen methylazoxymethanol acetate. These cases indicate the potential for skeletal muscle cells in medaka and guppy to become neoplastic but, because the tumours occurred at a low frequency, there may not necessarily be a chemical aetiology.
Ichthyophthirius multifiliis: standardization of the infection‐response model in Ameca splendens (Miller & Fitzsimons)
Authors: CLAYTON G. M. , PRICE D. J.
Published: April 2006

Abstract. The goodeid fish Ameca splendens (Miller & Fitzsimons) was exposed to the parasite Ichthyophthirius multifiliis. Exposure levels were 2000,3000,6000 and 12000 theronts per fish. After 3 days, infection levels were determined and the body area of the fish was measured. A rise in the number of trophozoites per fish was observed, up to a level of 6000 theronts per fish. Standardization of infection and response by area, to theronts per square centimetre and trophozoites per square centimetre respectively, produced a significant linear relationship, up to an exposure of 2800 theronts per square centimetre, and also removed the between‐tank within‐dose variation. The measures of controlling exposure to 1. multifiliis and evaluating response in previous research are reviewed. Adoption of the technique described here will facilitate the collation of research on ichthyophthiriasis by permitting comparisons of different studies utilizing different sizes and species of fish.
Cryptobia salmositica: an in vitro and in vivo study on the mechanism of anaemia in infected rainbow trout, Salmo gairdneri Richardson
Authors: THOMAS P. T. , WOO P. T. K.
Published: April 2006

Abstract. There are two basic antigenic components in Cryptobia that are responsible for the anaemia in infected rainbow trout. A ‘lytic component’, which is dosage‐dependent, causes lysis of red blood cells independent of antibody or complement. The second, an ‘immune‐complex‐forming component’, attaches to red blood cells, forms immune complexes with specific antibody and activates complement resulting in haemolysis. These two antigenic components, from both live and lysed Cryptobia, were present in the serum of infected fish. When sonicated antigen or heat‐inactivated antiserum (from infected fish) was incubated with red cells from uninfected fish, a portion of the red cells was lysed and a positive Coombs’ reaction was observed with the remaining intact red cells. The positive Coombs’ reaction was due to immune complexes adsorbed onto the red cells and these lysed when incubated with complement. Antibody by itself did not adsorb onto the red cells. From the fourth week post‐infection, a positive Coombs’ reaction was observed in all infected fish and haemolysis occurred with complement. The authors suggest that, in infected fish, one or more components of the complement cascade is depleted continually during infection and that the anaemia is due to the lytic action of the antigen and immune complex formation on red cells. These lead to intra‐vascular haemolysis as well as erythrophagocytosis. In general, the mechanism of anaemia in cryptobiosis appears similar to that in African trypanosomiasis.