Cryptococcosis is a serious an potentially fatal disease caused by members of the Cryptococcus neoformans species complex, comprising the two species Cryptococcus neoformans and Cryptococcus gattii with C. neoformans further divided into two variaties (var. neoformans and var grubii). It is believed to be acquired by inhalation of the infectous propagule from the environment. Although the exact nature of the infectious propagule is unknown, the leading hypothesis is the basidiospore created through sexual or asexual reproduction. (fungus) Cryptococcus neoformans.