Cryptococcus neoformans: Latency and Disease
This chapter reviews the evidence of disease after acute infection and reactivation of latent infection, considering the newer epidemiological and serological studies and the older anatomical evidence. Cryptococcal meningitis was diagnosed in an HIV-infected patient who helped dismantle an aviary, and another patient had pigeons nesting in the ceiling above his desk. Cryptococcal infection occurs in children as demonstrated by the existence of antibodies to Cryptococcus neoformans in children. Primary pulmonary cryptococcosis may be asymptomatic or confused with viral infections frequently observed during childhood. The high incidence of disease reported in the Vancouver Island outbreak may not be the norm, even though it appears from epidemiological studies that C. neoformans has a greater potential for reactivation of infection leading to disease than C. gattii. The overwhelming majority of individuals with persistent/latent infection would remain asymptomatic as long as they retained an intact immune system. In murine inhalational models acute pulmonary infection with C. neoformans is rapidly followed by the appearance of cryptococci both free and within macrophages in the lymphoid sinuses of hilar (draining) lymph nodes. The best animal model available for the study of latency and reactivation is experimental rat pulmonary cryptococcosis.
