DAO 33:101-109 (1998)  -  doi:10.3354/dao033101

Pathology attributed to Mycobacterium chelonae infection among farmed and laboratory-infected Atlantic salmon Salmo salar

D. W. Bruno1,*, J. Griffiths1, C. G. Mitchell1, B. P. Wood1, Z. J. Fletcher1, F. A. Drobniewski2, T. S. Hastings1

1FRS Marine Laboratory, PO Box 101, Victoria Road, Aberdeen AB11 9DB, Scotland, UK
2PHLS Mycobacterium Reference Unit, Dulwich Public Health Laboratory, King's College School of Medicine, Dulwich Hospital, London SE22 8QF, England, UK

This study was promoted following concern over increasing mortality on 2 farms rearing Atlantic salmon Salmo salar in the Shetland Isles, Scotland. A Mycobacterium sp. was isolated from moribund, market-sized Atlantic salmon. Biochemical tests, lipid analysis and PCR (polymerase chain reaction) techniques confirmed the bacterium to be Mycobacterium chelonae. Multiple greyish-white miliary granuloma-like nodules were observed in several tissues. Dense hard-packed nodules contained abundant acid-fast bacteria. Atlantic salmon injected with M. chelonae remained sub-clinically infected, demonstrating the chronic nature of this disease. The source of the pathogen was not identified.


Mycobacteriosis · Mycobacterium chelonae · Atlantic salmon · Pathology · PCR


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