TWENTY-SECOND ANNUAL EASTERN FISH HEALTH WORKSHOP ROYAL PAVILLION RESORT, ATLANTIC BEACH, NC MARCH 18 - 20, 1997 Virulence Ranking of Fish Mycobacteriosis Using Goldfish, Carassius auratus Adel M. Talaat, Renate Reimscheussel and Michele Trucksis Center for Vaccine Development and Departments of Medicine and Pathology, University of Maryland, Baltimore, MD Fish mycobacteriosis is a worldwide problem to which more than 150 species of fish are susceptible. Three species, Mycobacterium marinum, M. fortuitum, and M. chelonae have been associated with fish disease. Until now, the study of infection with these organisms depended upon a mouse model developed to study M. tuberculosis. We have developed a fish model for mycobacterial disease using the goldfish (Carassius auratus). Three species of mycobacteria, M. marinum, M. fortuitum, and M. smegmatis were inoculated into goldfish and compared for pathology and the time taken for them to cause death. Median survival time (MST) of fish after inoculation with mycobacteria was dose dependent and mycobacterial species dependent. Histological examination revealed the presence of moderate to severe peritonitis in most fish inoculated with M. marinum. In contrast, the fish inoculated with M. smegmatis were more likely to demonstrate either giant cell formation or moderate peritonitis. Fish infected with M. fortuitum revealed the presence of mild peritonitis and granuloma formation. We believe that this fish model will be a useful tool to study virulence factors in fish mycobacteria. Return to 22nd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page