Wild animals as sentinels of Paracoccidioides brasiliensis in the state of Rio Grande do Sul, Brazil

Paracoccidioides brasiliensis, a dimorphic pathogenic fungus, causes the principal form of systemic mycosis in Brazil. The literature furnishes only limited data on the ecology of this fungus in the state of Rio Grande do Sul, the southernmost state of Brazil. The purpose of this study was to evaluate the prevalence of fungal infection in wild animals, using serological tests and using the animals as sentinels of the presence of P. brasiliensis in three specified mesoregions of Rio Grande do Sul. A total of 128 wild animals from the three mesoregions were included in the study. The serum samples were evaluated by immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) technique to detect anti-gp43 antibodies from P. brasiliensis. Two conjugates were tested and compared with the ELISA technique. Although no positive samples were detected by immunodiffusion, 26 animals (20%), belonging to 13 distinct species, were found to be seropositive by the ELISA technique. The seropositive animals were from two mesoregions of the state. The results were similar according to the gender, age, and family of the animals, but differed significantly according to the conjugate used (p < 0.001), showing more sensitivity to protein A-peroxidase than to protein G-peroxidase. The finding that wild animals from the state of Rio Grande do Sul are exposed to P. brasiliensis suggests that the fungus can be found in this region despite the often-rigorous winters, which frequently include below-freezing temperatures.