Direct Exposure of Mice to Soils Known to Contain Histoplasma capsulatum.

Susceptibility of white Swiss mice to infection with H. capsulatum by inhalation of dust aerosol was determined by direct exposure of animals to known positive soil samples. 2. Disseminated histoplasmosis occurred in a large percentage of mice. 3. Naturally contaminated soil samples held 5 and 10 months at room temperature remained highly infectious. 4. Artificially seeded soil cultures were 100% infective to the white mouse at exposures of 1, 2, 4, and 7 days.