Naturally occuring histoplasmosis in guinea pigs.

Histoplasmosis naturally occurring in laboratory guinea pigs is described in its clinical, necropsy, histological and mycological aspects.The animals if adult show a chronic disease with progressive emaciation and lameness of the hind legs. The young below three months of age died in 2 to 4 weeks presenting ruffled fur, great dorsal curvature and sometimes closed eyelids and catarrhal conjunctivitis. At necropsy the principal lesions were ulcerative gastritis, hemorrhagic and catarrhal enteritis, enlarged spleen and mesenteric lymph nodes. Sometimes the liver, lungs, mediastinal lymph nodes and other organs showed lesions. Histological and mycological demonstration of the fungus completed the diagnosis and the surviving animals were burned and sanitation measures instituted. Histological evidence of histoplasmosis in a cow's lung from the area from which the grass was obtained for the feeding of the guinea pigs suggests an epidemiological link. Efforts will be made to isolate and demonstrate H. capsulatum in wild animals on the same area.