Histoplasma capsulatum Prevalence in Bat Roosting Sites Compared to Non-bat Roosting Sites

Indianapolis, IN

Histoplasma capsulatum is a dimorphic fungus that thrives in damp soil enriched with bat and bird guano. This fungus causes the disease known as histoplasmosis in humans. The research objective was to determine the prevalence of H. capsulatum in potential bat roosting sites compared to non-bat roosting sites. Motion sensor cameras were used to determine if bats were using the potential bat-roosting boxes. Sample sites were in Spencer, Woodford, and Franklin counties in Kentucky. At each site, soil samples were collected to determine the presence of H. capsulatum. After being dried, samples were cultured on rose bengal agar with streptomycin at 22oC and 30oC. Fungal samples that resembled H. capsulatum macroscopically were then sub-cultured on the same media. Microscopy was used to distinguish H. capsulatum from similar fungal colonies. There were no bats detected at any of the bat boxes. Histoplasma capsulatum was not cultured from any of the soil samples collected under the bat boxes or from non-bat-roosting sites. Since neither bats nor H. capsulatum were found at any location, I was unable to conclude that there was a difference in prevalence between site types.