Avaliação sorológica a antígenos do Paracoccidioides brasiliensis pelo teste de ELISA e prova intradérmica na região rural de Alfenas, MG

Abstract

Paracoccidioidomycosis (PCM), a chronic granulomatous systemic mycosis, endemic in Latin America, is caused by the thermo-dimorphic fungus Paracoccidioides brasiliensis. The endemicity is associated with agricultural areas where the fungus has favorable ecological conditions for its development. If the disease is not diagnosed and treated in time, it can lead to severe and lethal dissemination with rapid involvement of the lung, integument, lymph nodes, spleen, liver and lymphoid organs of the digestive tract. The emergence of the disease depends on the interaction between the fungus and the host immune response, which may progress to spontaneous cure or it may spread through the body causing chronic granulomatous reaction. The diagnosis of PCM is made by clinical examination and laboratory tests. The latter are used as a diagnostic aid. Among these stand out biopsy and culture, aimed at identifying the fungus in biological samples. However, the occurrence of false negative is high. In turn, these serological tests as double immunodiffusion (DID), counterimmunoelectrophoresis (CIE), indirect immunofluorescence (IIF), enzyme linked immunosorbent assay (ELISA) and immunoblotting (IB) are auxiliary in the diagnosis and allows to indirectly assessing the presence of antibodies against the host fungus antigens. DID, the reference test has high sensitivity and specificity, but requires that the patient has high levels of antibodies, a period when the disease is already installed. The ELISA assay is sensitive, fast, and suitable for large sample analysis. It has the disadvantage of crossreactivity between different species of fungi. The project aims to carry out ELISA assays using sera samples from residents of rural areas in Alfenas, Minas Gerais, in the presence or absence of 6M urea solution. Comparing the results of ELISA in the presence or absence of urea we can observe a reduction in the number of positives cases in all age groups, both female as male and an increasing number of negative outcomes in both sexes, and in all age groups. When evaluating the rural of Alfenas, MG using the ELISA treated with 6M urea, the seraprevalence obtained was 55.75%.