A natural focus ofHistoplasma capsulatum var.duboisii is a bat cave

Abstract

The natural reservoir of Histoplasma capsulatum var. duboisii, the etiological agent of histoplasmosis duboisii (African histoplasmosis) is not yet known. We report the isolation of H. capsulatum var. duboisii from soil admixed with bat guano and from the intestinal contents of a bat in a sandstone cave in a rural area, Ogbunike in Anambra State of Nigeria. Eight of 45 samples of soil admixed with bat guano yielded H. capsulatum var. duboisii. Of the 35 bats belonging to the species Nycteris hispida and Tadirida pumila examined, only one (N. hispida) yielded this fungus from its intestinal contents. Identification of the isolates as Histoplasma was confirmed by exoantigen tests and by mating with tester strains of H. capsulatum. In vitro conversion to large yeast from suggestive of H. capsulatum var. duboisii was obtained on brain heart infusion agar supplemented with sheep blood and glutamine or cysteine. Pathogenicity tests with mice for all the isolates confirmed their identity by the demonstration of large yeast forms (8-15 microns in diameter) within giant cells in the infected tissues. Investigations on the possible occurrence of human infections in the area are in progress.

African histoplasmosis: the first report of an indigenous case in India

“…duboisii, was first described by Dubois et al 9 in 1952. 10 The disease has been detected in about 20 countries in tropical Africa between the tropics of Cancer and Capricorn. Cases of African histoplasmosis reported in the literature up to 2007 number fewer than 300.…”

Extracellular proteolytic enzyme activity ofHistoplasma capsulatum var.duboisii

“…Five isolates of H. capsulatum var. duboisii recovered from soil admixed with bat guano [16] were investigated. These included two isolates deposited in ATCC with accesion numbers as 76543 and 76544, and three others, viz.…”

African histoplasmosis: report of four cases from northeastern Nigeria

“…Three of the four cases included in the present report were autochthonous to Borno State and werc not known to have travelled outside this Statc, whereas the fourth case originated from Anambra State in Eastern Nigeria, where the disease is well known [6] and a natural focus of the aetiological agent H. cupsulatum var. duboisii has been discovered recently [9]. None of our cases had been clinically diagnosed as having African histoplasmosis, possibly because of lack of awareness about the disease in this part of Nigeria.…”