Pathogenesis and immune response to Paracoccidioides brasiliensis in the fructivorous bat, Artibeus lituratus

Groups of neotropical bats (Artibeus lituratus) were inoculated by the intraperitoneal or intranasal routes with varying doses of yeast phase Paracoccidioides brasiliensis. Bats infected with 10(6) viable yeast cells intraperitoneally developed fatal, disseminated disease, with delayed hypersensitivity appearing within 2 weeks. No precipitating antibodies were detected up to 7 weeks post-exposure. After intranasal instillation of 10(5) viable P. brasiliensis, the disease spread from the lung to the spleen by 3 weeks and to the liver by 9 weeks. As few as 10 viable cells were capable of causing pulmonary disease. Antibodies were detected at 5 weeks and persisted for several weeks thereafter. No viable P. brasiliensis was recovered from the intestines or fecal contents of any bats. Artibeus lituratus appears to be very susceptible to paracoccidioidomycosis by the respiratory route. The resulting immune response is characterized by delay appearance of precipitating antibodies and a moderate degree of delayed hypersensitivity. The pathogenesis of the resulting disease is similar to that observed in humans. The absence of intestinal involvement, even in chronic systemic disease, suggests that bats do not play a direct role in dissemination of this fungus in nature.