Frequency

United States
Prior to 1946, only 200 patients with cryptococcal disease had been reported in the medical literature. The development and use of corticosteroids and improvement in patient survival with some malignancies increased the reported incidence of cryptococcal disease. Since the mid 1980s, most cryptococcal disease has occurred in patients with AIDS. A study published in March 2005 that reviewed data from 1981-2000, the first 2 decades of the AIDS epidemic, showed that the annual incidence per million person-years was 19 cases in men and 2.6 cases in women. The highest incidence occurred from 1981-1992, and the incidence then began to decline. In women, the peak incidence occurred in 1997. The overall incidence in cryptococcal disease decreased and preceded the availability of highly active antiretroviral therapy for AIDS.

Approximately 7-15% of patients with AIDS develop cryptococcal infections. In 1993, the US Centers for Disease Control and Prevention reported that 6% of 274,150 patients with AIDS developed cryptococcal disease. Furthermore, patients with AIDS-associated cryptococcal infections now account for 80-90% of all patients with cryptococcosis.

International
C neoformans has a worldwide distribution and, similar to in the United States, preferentially infects immunosuppressed individuals, especially those with AIDS. In sub-Saharan Africa, 15-30% of all patients with AIDS develop cryptococcal disease. However, in some areas, such as Zimbabwe, 88% of patients with AIDS have cryptococcal infection as their AIDS-defining illness. Overall, most case reports of C neoformans var gattii have been from Australia, with a few case reports from the southern California coast and tropical regions of Central and South America.