Pathology associated with meningoencephalitis during bacterial kidney disease of salmonids

Ostland, V. E.; Ferguson, H. W.

doi:10.1016/0034-5288(93)90006-2

Cited by 10 publications

(3 citation statements)

References 19 publications

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“…Hyperemia and hemorrhaging at the bases of fins are common clinical signs of BKD (Smith 1964, Kimura 1978, Warren 1991, and careful examination of the affected tissues may reveal septic thrombosis associated with R. salmoninarum infections (Ferguson 1989). The involvement in BKD of major blood vessels and organs such as the heart (Bruno 1986), and the sensitive detection of R. salmoninarum nucleic acids in blood by some PCRs (Rhodes et al 1998, Bruno et al 2007 suggest that hematogenous distribution of bacteria is common during R. salmoninarum infections (Speare et al 1993, Speare 1997. The significant positive correlation between kidney and fin R. salmoninarum levels observed in our study may have been indicative of developing bacteremia in these fish.…”

Section: Discussionmentioning

confidence: 50%

Testing of candidate non-lethal sampling methods for detection of Renibacterium salmoninarum in juvenile Chinook salmon Oncorhynchus tshawytscha

Elliott¹,

McKibben²,

Conway³

et al. 2015

Dis. Aquat. Org.

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Non-lethal pathogen testing can be a useful tool for fish disease research and management. Our research objectives were to determine if (1) fin clips, gill snips, surface mucus scrapings, blood draws, or kidney biopsies could be obtained non-lethally from 3 to 15 g Chinook salmon Oncorhynchus tshawytscha, (2) non-lethal samples could accurately discriminate between fish exposed to the bacterial kidney disease agent Renibacterium salmoninarum and non-exposed fish, and (3) non-lethal samples could serve as proxies for lethal kidney samples to assess infection intensity. Blood draws and kidney biopsies caused ≥5% post-sampling mortality (Objective 1) and may be appropriate only for larger fish, but the other sample types were non-lethal. Sampling was performed over 21 wk following R. salmoninarum immersion challenge of fish from 2 stocks (Objectives 2 and 3), and nested PCR (nPCR) and real-time quantitative PCR (qPCR) results from candidate non-lethal samples were compared with kidney tissue analysis by nPCR, qPCR, bacteriological culture, enzyme-linked immunosorbent assay (ELISA), fluorescent antibody test (FAT) and histopathology/immunohistochemistry. R. salmoninarum was detected by PCR in >50% of fin, gill, and mucus samples from challenged fish. Mucus qPCR was the only non-lethal assay exhibiting both diagnostic sensitivity and specificity estimates>90% for distinguishing between R. salmoninarum-exposed and non-exposed fish and was the best candidate for use as an alternative to lethal kidney sample testing. Mucus qPCR R. salmoninarum quantity estimates reflected changes in kidney bacterial load estimates, as evidenced by significant positive correlations with kidney R. salmoninarum infection intensity scores at all sample times and in both fish stocks, and were not significantly impacted by environmental R. salmoninarum concentrations.

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Section: Discussionmentioning

confidence: 50%

Testing of candidate non-lethal sampling methods for detection of Renibacterium salmoninarum in juvenile Chinook salmon Oncorhynchus tshawytscha

Elliott¹,

McKibben²,

Conway³

et al. 2015

Dis. Aquat. Org.

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“…A recently (1992) 1991-1995 described retrovirus-like virus that infects the brain causes abnormal spinning motion in various salmonid species in Japan (Oh et al 1995). Bacterial infections of the meninges or brain by Flexibacter psychrophilus (= Cytophaga psychrophila) In coho salmon (Kent et al 1989, Entrala et al 1996 or rainbow trout (Bustos et al 19951, and Renibacterium salmoninarum in Atlantic and coho salmon (Bustos et al 1992, Speare et al 1993, also cause spiral swimming behaviour. Furthermore, chronic infections of vertebrae by F psychrophilus also cause spinal deformities that may be suggestive of myxosporean WD (Conrad & DeCew 1967).…”

Section: Discussionmentioning

confidence: 99%

Diseases of salmonids resembling myxosporean whirling disease, and the absence of Myxosoma cerebralis, in South America

Ml¹,

Ml²,

Bustos³

1996

Dis. Aquat. Org.

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Previously publ~shed reports of whirling disease (WD) of salmonids (rainbow trout Oncorhynchus rnykiss, chinook salmon 0. tshawytscha and coho salmon 0. kisutch) in 4 South Arnerican countries (Venezuela, Colombia, Ecuador, Chile) are reviewed. The disease(s) were shown not to be associated with infections with the myxosporean Myxobolus cerebralis, the cause of myxosporean WD. Our recent observations in Ecuador and Chile of salmonid diseases with clinical signs resembling those of myxosporean WD further demonstrated that the diseases in South America were not caused by M. cerebralis. In Chile, the diseases in coho salmon and rainbow trout were attributed to bacterial infections, whereas no infectious agent was associated with afflicted rainbow trout in Ecuador We conclude that myxosporean WD of salmonids does not occur in South America. The causes of several other diseases of salmonids with clinical signs similar to those of myxosporean WD (e g whirling behaviour. skeletal deformities, blackened tails) include bacter~al or microsporidial infections of the meninges or brain, myxobacterial infections of the vertebrae, and dietary deficiencies. A diagnosis of myxosporean MID, therefore, cannot be made on clinical signs alone. Laboratory confirmation of the diagnosis through demonstration of the presence of M. cerebralis is necessary.

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“…From the seven fish described above, kidney tissue was aseptically collected and cultured on blood agar and trypticase soy agar with and without 2% NaCl. Impression smears were also collected from each sample and examined using Gram staining and indirect fluorescent antibody testing (IFAT) for bacterial kidney disease (BKD) using methods previously described for detecting Renibacterium salmoninarum in salmonid tissues (Speare, Ostland & Ferguson 1993). Biochemical tests of the predominant isolate (Table 1) were performed at the Atlantic Veterinary College (Charlottetown, PEI) and also at the Laboratory Centre for Disease Control (Health Canada, Ottawa, Ontario) using standard methods.…”

Section: Bacterial Isolation and Characterizationmentioning

confidence: 99%

Experimental transmission of a salmonid Rhodococcus sp. isolate to juvenile Atlantic salmon, Salmo salar L.

Brocklebank

MacNair

Bernard

1995

Journal of Fish Diseases

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. This paper provides further characterization of a ‘Rhodocoecus’‐like pathogen of Atlantic salmon, Salmo salar L., and describes its experimental transmission. An isolate from naturally infected fish was determined to be ‘Rhodococcus’ ‐like based on its biochemical profile and from gas liquid chromatography assessment of its cellular fatty acid methyl esterase profile in comparison to a data base. This isolate was used in an infectivity trial in which Atlantic salmon juveniles received an intraperitoneal injection of known concentrations of the bacteria. Fish receiving 0.5 ml of a 109bacteria ml−1 solution developed severe peritoneal granulomatous reactions, and bacteria were recovered from the peritoneum and the kidney. In contrast to the natural disease, in which pathological changes are often most dramatic in the renal interstitium, in our study, the lesions were restricted to the injection site—the peritoneal cavity. However, in this location, the large colonies of bacteria and the nature of the host response were both characteristic of the changes noted in the renal interstitium of naturally infected fish. Lesser concentrations of injected bacteria resulted in either no or minimal pathological change, and subsequent recovery of bacteria from injected fish was poor. Horizontal transmission to non‐injected co‐habitants was not achieved.

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Pathology associated with meningoencephalitis during bacterial kidney disease of salmonids

Cited by 10 publications

References 19 publications

Testing of candidate non-lethal sampling methods for detection of Renibacterium salmoninarum in juvenile Chinook salmon Oncorhynchus tshawytscha

Testing of candidate non-lethal sampling methods for detection of Renibacterium salmoninarum in juvenile Chinook salmon Oncorhynchus tshawytscha

Diseases of salmonids resembling myxosporean whirling disease, and the absence of Myxosoma cerebralis, in South America

Experimental transmission of a salmonid Rhodococcus sp. isolate to juvenile Atlantic salmon, Salmo salar L.

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