Flavobacterium indologenes infection in leopard frogs

An investigation of an epidemic of infectious disease in a frog (Rana pipiens) colony was conducted. Six of 40 frogs in a continuous (once through) water flow housing system had weight loss, swollen abdomen, corneal edema, uveitis, subcutaneous edema, petechial hemorrhage, incoordination, and respiratory distress. The frogs had lesions consistent with bacterial septicemia. A gram-negative, nonfermenting bacillus, Flavobacterium indologenes (Flavobacterium sp biovar IIb), was isolated in pure culture from tissues and blood. The clinical isolate was used to inoculate healthy frogs sc. An isolate identical to the one isolated from the sick frogs was recovered from tissues and blood of the inoculated frogs. Inoculation of the housing water in a nonflow-through system did not result in disease, despite proliferation of the Flavobacterium spp in the water; therefore, it is likely that establishment of infection requires the presence of the organism in sufficient numbers and a portal of entry into the body.