Preliminary Visual Screening of Soil Samples for the Presumptive Presence of Histoplasma Capsulatum

SUMMARY

A filtration technique which permits one to detect visually tuberculate macroconidia in soil substrates in less than 2 h is described. Studies of guano-enriched soils indicate the method can be used in the preliminary screening of soil samples for the presence or absence of Histoplasma capsulatum, the visual evidence correlating well with positive and negative isolations of the fungus from tissues of soil-inoculated mice. Spores concentrated by filtration can also be used for isolating the fungus through mice. The isolation of H. capsulatum from a gull nesting site, after first identifying spores visually, is reported.