DAO 70:219-225 (2006)  -  doi:10.3354/dao070219

Mortality and pathology in brown bullheads Amieurus nebulosus associated with a spontaneous Edwardsiella ictaluri outbreak under tank culture conditions

Luke R. Iwanowicz1,2,*, Alison R. Griffin1, Deborah D. Cartwright1,3, Vicki S. Blazer1

1National Fish Health Research Laboratory, US Geological Survey, 11649 Leetown Road, Kearneysville, West Virginia 25430, USA
2Department of Natural Resources Conservation, University of Massachusetts, Amherst, Massachusetts 01003, USA
3Environmental Health Sciences, University of Georgia, Athens, Georgia 30602-2102, USA

ABSTRACT: Brown bullheads Amieurus nebulosus (family Ictaluridae) are commonly used as a sentinel of environmental contamination. These fish are not generally cultured under laboratory conditions and little is known about their disease susceptibility. Here we report an outbreak of disease due to Edwardsiella ictaluri in a laboratory population of tank-reared, wild-caught brown bullheads. The isolate was positively identified as E. ictaluri using standard bacteriological substrate utilization tests and a monoclonal antibody specific for this bacterium. This pathogen causes a significant disease in channel catfish Ictalurus punctatus and is associated with disease in other ictalurid and non-ictalurid fishes. It appears that E. ictaluri is also a significant pathogen in brown bullheads and produces clinical signs and lesions similar but not identical to those observed in channel catfish. Since commercial sources of bullheads for laboratory tank studies are not available, precautions should be taken to prevent potential E. ictaluri disease outbreaks from wild-caught bullheads intended for laboratory research.


KEY WORDS: Amieurus nebulosus · Brown bullhead · Edwardsiella · Enteric septicemia of channel catfish · ESC · Pathology


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