Developments in the control of bacterial kidney disease of salmonid fishes

A study was conducted to evaluate the levels of drugs attained In eggs and alevlns as a result of injecting antibiotics lnto pie-spawning female salmon Oncoihynchus kisutcli and to evaluate i f thls was a n effechve means of controlling vertical transmission of Renlbacterium s a l n~o n~n a r u m (Rs) the causative agent of bactenal kldney disease Flve antibiotics (erythromycin phosphate penicillin G ovytetracychne cephradine and rifampicin) were ~njected into the dorsal slnus of maturing female coho salmon, one antibiotic per fish 2 to 3 wk before spawnlng Eggs from these fish were then infected ~nternally with Rs using a microinjectlon technique The prevalence of the resulting infechons was determned for the eggs at the eyed stage and for alevlns at hatch Concentrations of each antiblotlc were measured in the egg yolk at spawning and in the alemns at hatch All 5 antibiohcs were detected in eggs taken at spawning but only erythromycin and nfampicln were present in measurable amounts ~n t h i n the alevins at hatch The 5 antibiotics all proved to b e effective in significantly reducing the prevalence of Rs infections by the hatch stage The broodstock injection technique therefore appears to be a promising means of reducing the vertical transmission of Rs

Section: Introductionmentioning

confidence: 99%

Control of vertical transmission of Renibacterium salmoninarum by injection of antibiotics into maturing female coho salmon Oncorhynchus kisutch

Brown¹,

Albright²,

Evelyn³

1990

“…Control of both the disease and the dissemination of the agent remains difficult due to the ability of the bacterium to be vertically transmitted from parents to progeny inside the eggs (Bullock et al 1978, Evelyn et al 1984, 1986b, Lee & Evelyn 1989, Pascho et al 1991 and to survive intracellularly within host cells (Young & Chapman 1978, Gutenberger et al 1991, thus reducing bacterial exposure to the host immune defenses and any therapeutants. An effective vaccine is not yet available (Elliott et al 1989) so avoidance of horizontally transmitted Rs (Mitchum & Sherman 1981, Bell et al 1984 and of vertically transmitted Rs is still a primary management strategy. In addition to a water supply free of Rs, avoidance has largely been attempted by using eggs from certified Rs-free fish stocks or by manipulation of Rs-positive broodstocks to reduce vertical transmission to the progeny.…”

Section: Introductionmentioning

confidence: 99%

“…Bacterial kidney disease (BKD) caused by Renibacterium salmoninarum (Rs) continues to be a serious disease concern in salmonid culture worldwide (Fryer & Sanders 1981, Sanders & Barros 1986, Elliott et al 1989. Control of both the disease and the dissemination of the agent remains difficult due to the ability of the bacterium to be vertically transmitted from parents to progeny inside the eggs (Bullock et al 1978, Evelyn et al 1984, 1986b, Lee & Evelyn 1989, Pascho et al 1991 and to survive intracellularly within host cells (Young & Chapman 1978, Gutenberger et al 1991, thus reducing bacterial exposure to the host immune defenses and any therapeutants.…”

Section: Introductionmentioning

confidence: 99%

“…The identification of Rs-positive parents requires rapid and sensitive detection methods that can be applied on a large scale. Several methods have been compared for the detection of the causative agent in carrier broodstocks , Elliott et al 1989, Sakai et al 1989). Due to the ease of application, the most common method has been examination of kidney smears by the fluorescent antibody test (FAT) which replaced the less sensitive Gram stain (Bullock & Stuckey 1975, Bullock et al 1980).…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the enzyme-linked immunosorbent assay (ELISA) and the fluorescent antibody test (FAT) for measuring the prevalences and levels of Renibacterium salmoninarum in wild and hatchery stocks of salmonid fishes in Alaska. USA

Meyers¹,

Short²,

Farrington³

et al. 1993

ABSTRACT. The enzyme-linked immunosorbent assay (ELISA) and the fluorescent antibody test (FAT) were compared for their sensitivity in detection of Renibacterjum salmoninarum (Rs) in kidney tissues of Alaskan salmonids. The ELISA appeared to be more sensitive in detecting Rs infections. The FAT did not detect Rs in 80 % of the ELISA-positive samples but was positive for Rs in 28 'K, of the samples that were ELISA-negative. This contradiction may have been due to low-level washover of Rs cells from smears containing large numbers of Rs cells when slldes containing nlultiple samples were rinsed in d common vessel during the FAT procedures. The FAT routinely did not detect infections in Rs-positive fish the tissues of which produced a mean ELISA optical density value 50.173, and inconsistently detected infections in fish with ELISA values > 0.173 but < 0.978. The 0.978 optical density was the mean ELISA value at which the FAT routinely detected Rs-positive fish. Based on the ELlSA results, Rs occurred in only 9 % of the Alaskan Pacific salmon tested in both wild (85 "/U) and hatchery (81 %) stocks. The very high stock prevalences and levels of Rs antigen detected in wild trout Oncorhynch~~s spp., char Salvelinus spp., and grayling Thymallus arcticus having no clinical signs of bacterial kidney disease suggest these species may be somewhat resistant hosts and important freshwater reservoirs of Rs.

“…Bacterial kidney disease is one of the most difficult bacterial diseases to control in salmonid aquaculture facilities due in part to 2 unusual pathogenic mechanisms of the causative agent, Renibacterium salmoninarum (Elliott et al 1989). First, R. salmoninarum can 'E-mail: wiensg@ohsu.edu "Present address: Department of Veterinary Medicine, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, Taiwan 40227, ROC be vertically transmitted from female fish to offspring via intracellular infection of the egg (Evelyn et al 1984(Evelyn et al , 1986.…”

Section: Introductionmentioning

confidence: 99%

Antigenic and functional characterization of p57 produced by Renibacterium salmoninarum

Wiens

Chien²,

Winton³

et al. 1999

Renibacterium salmoninarum, the causative agent of bacterial kidney disease, produces large quantities of a 57-58 kDa protein (p57) during growth in broth culture and during infection of salmonid fish. Biological activities of secreted p57 include agglutination of salrnonid leucocytes and rabbit erythrocytes. We define the location of epitopes on p57 recognized by agglutination-blocking monoclonal antibodies (MAbs) 4Cl1, 4H8 and 4D3, and demonstrate that the majority of secreted p57 is a nlonomer that retains salrnonid leucocyte agglutinat~ng activity. The 3 MAbs bound a recombinant, amino-terminal fragment of p57 (211 aa) but not a carboxy-terminal fragment (315 aa) demonstrating that the neutralizing epitopes are located within the amino-terminal portion of p57. When combinations of the MAbs were used in an antigen capture ELISA. the epitopes recognized by the 3 MAbs were shown to be sterically separate. However, when the same MAb was used as both the coating and detection MAb, binding of the biotinylated detection MAb was not observed. These data indicate that the epitopes recognized by the 3 agglutination-blocking antibodies are functionally available only once per molecule and that native p57 exists as a monomer Similar ELISA results were obtained when kidney tissues from 3 naturally infected chinook salmon were assayed. Finally, a p57 monomer was purified using anion exchange and size exclusion chromatography that retained in vitro agglutinating activity. A model in which p57 is released from R. salmoninarum as a biologically active monomer during infection of salmonid fish is proposed.