A NATURAL FOCUS OF HISTOPLASMA-CAPSULATUM VAR DUBOISII IS A BAT CAVE

The natural reservoir of Histoplasma c apsulatum var. duboisii, the et iological agent of histoplasmosis duboisii (African histoplasmosis) is not yet known. We report the isolation of H. capsulatum var. duboisii from soil admired with bat guano and from the intestinal contents of a bat in a sandstone cave in a rural area, Ogbunike in Anambra State o f Nigeria. Eight of 45 samples of soil admired with bat guano yielded H. capsulatum var. duboisii. Of the 35 bats belonging to the species N ycteris hispida and Tadiridn pumila examined, only one (N. hispida) yi elded this fungus from its intestinal contents. Identification of the isolates as Histoplasma was confirmed by exoantigen tests and by matin g with tester strains of H. capsulatum. In vitro conversion to large y east from suggestive of H. capsulatum var. duboisii was obtained on br ain heart infusion agar supplemented with sheep blood and glutamine or cysteine. Pathogenicity tests with mice for all the isolates confirme d their identity by the demonstration of large yeast forms (8-15 mu m in diameter) within giant cells in the infected tissues. Investigation s on the possible occurrence of human infections in the area are in pr ogress.