CLINICAL AND HOST DIFFERENCES BETWEEN INFECTIONS WITH THE 2 VARIETIESOF CRYPTOCOCCUS-NEOFORMANS

A population-based register of cases of cryptococcosis in patients tre ated in Victoria, Australia, over a 10-year period was established for studying the epidemiologic and clinical features of infection with Cr yptocaccus neoformans and its two varieties, gattii and neoformans. On e hundred thirty-three cases of cryptococcosis were entered on the reg ister; the incidence was 3.0 cases per 1 million population per year, a rate that increased to 5.0 cases per 1 million population per year o ver the decade as a result of the AIDS epidemic. There was a distinct association between immune status and C. neoformans variety: all C. ne oformans variety gattii infections occurred in healthy hosts and 90% o f C. neofarmans variety neoformans infections occurred in immunosuppre ssed hosts. Meningitis was the commonest manifestation, with focal CNS and pulmonary lesions occurring primarily in healthy hosts with C. ne oformans variety gattii infection; isolation of C. neoformans from blo od and urine was associated with immunosuppression and C. neaformans v ariety neofarmans infection. The mortality among patients with C. neof ormans variety neoformans infection was high, while none of those pati ents with C. neoformans variety gattii died but often had neurological sequelae that required surgery and prolonged therapy. These findings appear to be related to variety-specific interactions between host and parasite and warrant further epidemiologic and immunologic study.