RESUMO
Sera from 305 dogs were analyzed by enzyme-linked immunosorbent assay (ELISA) to determine presence of the antibody anti-gp43, which reacts to a specific antigen of Paracoccidioides brasiliensis. The dogs were divided into three groups according to their origin: urban dogs (animals with little or no contact with rural areas); suburban dogs (from the urban outskirts); and rural dogs. There was a significant difference between groups (P < 0.05). Rural dogs reacted positively in 89.5% of cases, followed by suburban (48.8%) and urban dogs (14.8%). There were no differences between male and female dogs. In an attempt to verify the feasibility of skin testing with gp43 to determine sensitization against P. brasiliensis in dogs, suburban (n = 61) and rural (n = 21) dogs were tested, showing positivity of 13.1 and 38.1%, respectively. Six dogs that had higher ELISA titers and also showed strong reactions in skin testing were killed in an attempt to isolate P. brasiliensis. The fungus was not detected by culture or histopathological analysis in these dogs, suggesting that dogs have a natural resistance or that they encounter an inoculum level that is insufficient to cause disease. These results indicate that ELISA and skin testing can be useful in the epidemiological study of paracoccidioidomycosis in dogs and that encounter with the fungus in nature is a frequent event.