STUDIES ON THE COMMUNICABILITY OF HISTOPLASMOSIS

Abstract

By skin-testing a large series of dogs (2210) with histoplasmin, something less than 1% (18) were found to be positive. In these, 2/3 (12) showed active histoplasmosis. 3 out of 5 skin test negative and apparently uninfected animals placed in contact with infected animals developed histoplasmosis and histoplasmin reactivity within 2-5 months after exposure began. Human beings in either household or laboratory contact with dogs that had active histoplasmosis did not develop active disease although 5 out of 33 showed positive skin reactions. Dog to dog communicability seems established but dog to man transmission is unfounded. Nevertheless since Histoplasma capsulation is discharged in the sputum, saliva, vomitus, feces and urine of the dog, contagion must be considered possible.