The Dog as a Natural Host for Histoplasma Capsulatum

Summary 1. A generalized infection in a dog by a fungus proven to be identical with Histoplasma capsulatum of Darling in all of its phases in both the tissues of its host, and in cultures is reported. 2. The fungus was cultivated and found to fulfil all of Koch's postulates. 3. This is the first report of Histoplasmosis occurring in any natural host other than man. 4. The disease was also transmitted to dogs and puppies by feeding them cultures of the fungus. 5. The infected dog might possibly transmit the infectious agent to man in infected excreta and secretions, or it might be possible that the flea or the tick acts as a transmitting agent. 6. Histoplasmosis is probably more common than is indicated by the medical literature. 7. In obscure cases of splenomegaly and lymphadenopathy, Histoplasma capsulatum should be searched for in blood films, biopsies of lymph nodes, and in cultures of blood and lymph nodes.