GROWTH AND SURVIVAL OF HISTOPLASMA CAPSULATUM IN SOIL

Abstract

Growth and survival of Histoplasma capsulatum, a fungus pathogen of man, in sterilized and non-sterile soil was determined. Growth in sterilized soil, as determined by plate counts, was favored by increasing moisture levels up to 85% of the water-holding capacity of the soil, and by the addition of several organic materials, including peptone, grass clippings, purified chitin, and chicken feces. The fungus survived for at least 8 weeks when introduced into non-sterile soil as conidia. Addition of organic amendments were not necessary for survival, and may, in fact, have been deleterious. Disappearance of the fungus from unsterile soil in some experiments suggests that it is sensitive to antagonistic biological effects. The fact that non-amended soils were as favorable for survival as were soils amended with chicken feces, or other organic materials, suggests that the search for natural habitats of this fungus should not be limited to bird roosting sites.