Paracoccidioidomycosis: a model for evaluation of the effects of human immunodeficiency virus infection on the natural history of endemic tropical diseases.

The interaction of human immunodeficiency virus (HIV) infection with endemic tropical diseases has become a major concern, but its mechanisms are still poorly understood. Paracoccidioidomycosis (PCM), a South America endemic deep mycosis, may provide an interesting model to investigate this interaction, as clinical-epidemiological features of most HIV-PCM-coinfected patients are difficult to classify into the standard acute and chronic forms of PCM. Such patients have presented clinical features indicative of an uncontrolled infection with lymphohematogenous dissemination, similar to the more severe, acute form. However, this infection probably resulted from reactivated latent foci that, in nonimmunocompromised hosts, leads to the less severe chronic form, characterized by mucosal lesions. We propose that a new outcome of the Paracoccidioides brasiliensis-host interaction is induced by concomitant HIV infection. This outcome probably reflects an impaired anti-P. brasiliensis immune response during coinfection that is similar to that seen in the acute form, although the patients have a chronic P. brasiliensis infection.