摘要:

Abstract.The myxosporean parasiteKudoa thyrsites(Gilchrist) is well recognised as a cause of flesh liquefaction post‐mortem in several fishes from both hemispheres. The observation of this condition in cultured mahi mahi,Coryphaena hippurusL., in Western Australia led us to search for possible reservoirs of infection amongst the abundant clupeoid fishes of the area. Prevalent and severe infections were found inSardinops sagax neopilchardus(Steindachner), which we consider to be a major reservoir host forK. thyrsitesin south‐west Australian coastal waters. The parasite occurred less frequently inSpratelloides robustusOgilby,Sardinetla lemuruBleeker andEngraulis austratis(Shaw) from the same waters. Infection was not detected inHyperlophus vittatus(Castelnau),Etrumeus teres(De Kay) orNematalosa vlaminghi(Munro), which may reflect differences in range or dietary composition.Engraulis japonicus(Temminck&Sehlegel) imported from Japan were also infected, but a single sample ofE. mordaxGirard from California contained only an equipolarKudoaspecies. These records expand the known host range ofK. thyrsitesto 20 species in 10 families, and several of these host species appear to be major reservoirs of infection in certain locations. Flesh spoilage due to the liquefactive effects of the parasite could occur in any of these hosts, and was seen here inS. sagax neopilchardus, S. robustusandE. japonicusin association with mature spores. Detection of infection with ultra‐violet light was found to be ineffective because a cellular host response was not mounted by the clup

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00678.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.A 587 bp Pvu II restriction fragment from the 70‐kDaAeromonas salmonicidaserine protease gene, containing the‘active serine’ site sequence of the enzyme, has been cloned into the Sma I restriction site of pUEX2 which on expression, inEscherichia coliDH5α, produced a 142‐kDa hybrid protein in high yield. The hybrid consisted of a fusion between an essentially complete β‐galactosidase subunit and approximately one‐third of the serine protease. A further 42‐kDa hybrid was constructed from the same fragment of serine protease fused to a truncated α‐galactosidase subunit. Both fusion proteins were shown to possess recognizable epitopes by dot blotting against rabbit anti‐A. salmonicida70‐kDa se

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00679.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Two different commercial vaccines against furunculosis, caused byAeromonas salmonicidasubsp.salmonicida, were tested in Atlantic salmon on seven fish farms. Both vaccines were based on formalin‐inaclivated bacterins containing aluminium salts as adjuvants. The fish were vaccinated by intraperitoneal injection in the spring approximately one month prior to transfer to sea water, and they were challenged by natural outbreaks of furunculosis. During the first year, six of the farms experienced disease outbreaks. The overall mortality was 7·14% in vaccinated fish and 21·7% in unvaccinated controls, giving a relative percentage survival (RPS) of 67%. In the seventh farm, outbreaks of furunculosis more than one year after vaccination revealed that there was still a trend towards lower mortality in vaccinated fish, though the mean RPS fell to 22%. The use of adjuvants in the vaccines resulted in local lesions in the abdominal cavity of vaccinated fish. However, the severity of the lesions declined gradually, and they did not influence fish quality at the time of slaughtering. Vaccination also had a moderately adverse impact on fish weight gain in most ca

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00680.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The host‐parasite relationship between O‐group carp and the ciliatcIchthyophthirius multifiliisFouquet was investigated, with the specific aim of characterizing the fate of parasites encountering immunized fish. Carp were immunized by repeated controlled infections; immunized fish and control fish naive toI. multifiliiswere then infected in the caudal fin epidermis by a single controlled exposure to theronts, which were applied in a droplet suspension to the tail surface. The number of parasites present within the caudal fin was monitored over a subsequent 5‐day period by means ofin situparasite mapping. Results indicated that, contrary to previous reports, theronts penetrated the skin of immunized fish in numbers comparable to those of fish receiving a primary infection. However, the majority of parasites which penetrated immune skin did not complete normal development; 79% of the parasites which had initially penetrated the immune skin were not relocated within 2h of exposure, and since no parasite material was detected at penetration sites, it was concluded that these parasites had prematurely exited the skin rather than been killedin situ.Subsequently, these sites became populated by leucocytes, predominantly macrophages, and the infiltrations continued for up to 5 days after the initial exposure. In contrast, at sites where mature trophonts had exited the skin of fish following a primary infection, more diffuse leucocytic infiltrations were recorded, and these were predominated by neutrophils. Differences in the response to parasite exit from immunized and previously unexposed control fish skin are discussed, with particular reference to the mode of protection and the fate of parasites encountering immune

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00681.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Haematological variations were studied in a European eel population,Anguilla anguillaL., naturally infested by the sanguivorous nematodeAnguillicola crassus.This occurred off the Swedish Baltic coast in an area receiving heated cooling water from a nuclear power station. The erythrocyte count, haematocrit, leucocrit, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentrations, the various cell types in peripheral blood, serum iron concentration, the amount of total serum protein, and scrum protein fractionsα1, β1,α2,β2andγwere all measured. Each variable was correlated to: (1) the intensity of infestation, i.e. number of parasites per host; and (2) a parasitization index, i.e. the weight of parasites per somatic weight of the host. Most variables showed no or only minor reactions to the infestation. However, a marked increase in theγ‐fraction of scrum proteins, reduced lymphocyte numbers and increased granulocyte numbers are indicative of a humoral and cellular immune r

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00682.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Two monoclonal antibody probes were produced against PK'X’ cells. The parasites were partially purified by filtration and centrifugation of kidney tissue from rainbow trout with proliferative kidney disease and used as antigen for immunization of mice. The resulting monoclonal antibodies reacted with PK'X’ cell antigens in enzyme‐linked immunosorbent assay and immunohistochemistry tests. One antibody (Mab 12) appeared to be specific for PK'X’in kidney tissue, while the other (Mab 18) cross‐reacted with host cell antigens in the kidney tubules. These probes are invaluable tools for the investigation of parasite surface antigens and life cycl

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00683.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Atlantic salmon,Salmo salarL., infected with the pre‐adult and adult stages ofLepeophtheirus salmoniswere obtained from sea loch cage sites on the west coast of Scotland, and infection experiments were carried out in the laboratory. The motile parasites were retained at the point of attachment by prefixation with cooled alcohol. They were studied using light and scanning electron microscopy.Lepeophtheirus salmoniswere found to leave an oval‘imprint’ corresponding to the margin of the parasite cephalothorax on the host skin and/or to wedge under its scales. General pathological changes including oedema, hyperplasia, sloughing of cells and cellular inflammation were observed in the host at and around the point of feeding and attachment. In gross lesions, serious damage occurred to the host epidermis with scale loss and haemorrhage a common feature. The most obvious changes were associated with the louse mouthtube, marginal membrane, second antenna, maxilliped and sternal

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00684.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The typical strains ofAeromonas salmonicidaexamined secreted a PMSF‐sensitive proteolytic activity, and with few exceptions, gave a positive colony hybridization with a 70‐kDa scrinc protease gene probe. By contrast, atypical strains produced a spectrum of responses with various combinations of (1) secreted/did not secrete PMSF‐inhibited protease, (2) colonies hybridized/did not hybridize with the gene probe, and (3) produced protease not inhibited by PMSF. It is suggested that certain strains might be reassigned as typical or atypical on the basis of the presence or absence of the protease

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00685.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00686.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0140-7775    

DOI:10.1111/j.1365-2761.1992.tb00687.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY