Pathogenesis of Cryptococcus neoformans

Cryptococcus neoformans (Cn) is a fungal pathogen, commonly found in urban environments (Tampieri, 2006) that primarily affects immunocompromised individuals through inhalation of spores. In healthy individuals Cn infection is usually cleared, or can remain in a latent form for prolonged periods of time. However, in individuals with impaired immune function, the infection may spread to the central nervous system (CNS), causing life-threatening meningitis (Casadevall & Perfect, 1998; Hull & Heitman, 2002). Thus, the disease is relatively common in AIDS patients. A recent study shows that the prevalence of cryptococcosis has declined with the increasing availability of highly active retroviral therapy (HAART) to treat HIV (Lortholary et al., 2006; Mirza et al., 2003). However, the disease continues to be a problem for those with limited access to HAART, especially in the developing world (Banerjee et al., 2001; Marques et al., 2000). Another group of individuals who are susceptible to cryptococcosis are organ transplant recipients receiving immunosuppressive therapy (Husain et al., 2001; Vilchez et al., 2002). However, cryptococcosis is not limited to immunocompromised persons, as shown by the recent outbreak in Vancouver among healthy individuals (Hoang et al., 2004).