Endemic canine and feline histoplasmosis in El Paso, Texas.

Seventeen cases of histoplasmosis involving 2 dogs and 15 cats have occurred in the Upper Rio Grande Valley of El Paso since 1978. The diagnosis, based on clinical signs and radiographic findings, was confirmed by one or more of the following laboratory procedures: demonstration of intracellular Histoplasma capsulatum yeast cells in tissue, positive serology, or isolation of H. capsulatum from various organs of necropsied animals. H. capsulatum was isolated also from a bat cave and soil in the vicinity of some of the houses where the affected animals had resided. Skin-tests of 97 persons for histoplasmosis indicated a 14% positive prevalance in this locale.