Marc M. Terrazas, Montana Fish, Wildlife & Parks, 4801 Giant Springs Road, Great Falls, MT 59405
Leo R. Rosenthal, Montana Fish, Wildlife & Parks, 490 North Meridian Road, Kalispell, MT 59901
Kenneth D. Staigmiller, Montana Fish, Wildlife & Parks, 4801 Giant Springs Road, Great Falls, MT
59405
Kevin R. Snekvik, Washington Animal Disease Diagnostic Laboratory and the Department of Veterinary
Microbiology and Pathology, College of Veterinary Medicine, Washington State University,
Pullman, WA 99164
Daniel S. Bradway, Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine,
Washington State University, Pullman, WA 99164

Abstract
An angler-caught bull trout (Salvelinus confluentus) from Hungry Horse Reservoir, MT
with noticeably poor condition was examined to reveal liver nodules. Further investigation
discovered acid-fast bacteria present in these granulomas making this a unique finding
requiring further diagnostics. Molecular diagnostics revealed the infectious agent to be
Mycobacterium fortuitum. This is a range and species expansion for this pathogen in fish.
Further examination of additional fish from this water body did not reveal cases similar to this
one, allowing for the possibility of this being a lone occurrence.

Click to read the entire manuscript: IJS-2012-v18-n1-4-Manuscript-Terrazas-Rosenthal-Staigmiller-Snekvik-Bradway-pp20-25