Estudo soroepidemiológico da infecção pelo Paracoccidioides brasiliensis em caninos domésticos no sul do Rio Grande do Sul

Abstract

The thermally dimorphic fungus Paracoccidioides brasiliensisis the main agent that triggers the paracoccidioidomycosis (PCM), a systemic infectious disease restricted to Latin America and endemic in Brazil. In southern Brazil, this disease has been diagnosed in humans since the 60s and the number of cases has increased since the 90s. In order to detect the presence of the agent in urban areas and warn about the possibility of the exposion of susceptibles individuals to the disease, this study aimed to investigate the infection by P. brasiliensis in dogs in Rio Grande do Sul, southern state of Brazil. 196 dogs which participated in a program of animal population control in the cities of Pelotas and Capão do Leão were evaluated. The indirect ELISA technique was used in order to detect the presence of anti-gp43 antibodies in the animal serum. Two different conjugates were tested and compared in this serological technique, the dog anti-IgG peroxidase and the protein Gperoxidase, that were evaluated for the concordance of the test results (Kappa index). The sensitivity, specificity, positive and negative predictive value of protein Gperoxidase were calculated considering the specific conjugate of dog as a gold standard. The fungal infection was confirmed in 58 animals (29,6%), and no significant difference was found between the gender, age and breed of the dogs (P>0,05). Seropositive animals could be detected coming from the two cities, both Pelotas and Capão do Leão. The result of the tests made with the different conjugate showed poor concordance (Kappa=0,140; P< 0,001). The protein G-peroxidase presented low sensitivity and occurrence of false negatives regarding to the specific conjugate, what demonstrated not being a viable alternative to realize an immunoassay in dogs. The detection of specific antibodies in the dogs serum in this study proved the presence and a wide distribution of P. brasiliensis in the urban areas of Pelotas and Capão do Leão city and alerted to the occurrence of PCM in susceptible individuals, as well as the possibility of the disease in small animals in the region.