PIP: The incidence of disseminated cryptococcosis among Central Africans with acquired immunodeficiency syndrome (AIDS) may exceed 35%. Of the 2 varieties of Cryptococcus neoformans--neoformans and gattii--it appears that the neoformans variant is the one most frequently associated with AIDS. This assumption is based on the investigation of 47 cryptococcosis isolates into white mice to determine their ability (variety gattii) or inability (variety neoformans) to produce the elongated cells characteristic of the former variety. Of the 7 isolates collected in 1951-1969, 6 were of the gattii biovar. On the other hand, all of the 40 isolates collected after 1969 were of the biovar neoformans, suggesting that the biovar gattii is disappearing from Central Africa.