Retrospective seroepidemiological analysis of patients with suspicion of paracoccidioidomycosis in São Paulo State, Brazil

The geographic distribution of paracoccidioidomycosis (PCM) in the Brazilian state of São Paulo was evaluated in a retrospective study using secondary data from serological analyses, carried out by double immunodiffusion assay of patients with PCM suspicion, from January 1999 to May 2010. Sixty percent of 10,176 patients, from 239 cities, were serologically reactive to P. brasiliensis. The cities that showed the most serological reactivity among patients were São João da Boa Vista (85%), Piracicaba (75%), Sorocaba (73%), Campinas (72%) and São Paulo (62%). São Paulo state has an area of 248,209.4 km²; the climate is tropical and sub-tropical with annual temperatures between 18 and 24ºC, high rainfall (900 to 1800 mm/year), rainy summers and mild winters. It also features large areas composed of acidic soils, and is one of the greatest contributors to Brazilian agricultural production and, separately, the largest producer of orange juice and, the ninth greatest producer of soy and sugar cane and the fourth largest coffee producer. We suggest that the climatic characteristics associated with soil type and development of primary activities can contribute to the endemic potential of PCM in São Paulo state.

Use of immunoblotting assay improves the sensitivity of paracoccidioidomycosis diagnosis

The purpose of this work was to evaluate two serological assays: double immunodiffusion (DI) and immunoblotting (IB) in immunodiagnosis of paracoccidioidomycosis (PCM). We evaluated by IB assay 23 sera samples from patients with clinical confirmation of PCM, all of them with negative DI results against culture filtrate from Paracoccidioides brasiliensis isolate 113. For IB, as well as for comparative DI assay, we employed soluble components of the cell wall outer surface (SCCWOS) from P. brasiliensis isolate 113 cultivated at 36°C in Fava-Neto's agar medium for 5 and 10 days. Among the 20 sera samples analyzed by DI, 13 (65 percent) were negative and 7 (35 percent) were positive against SCCWOS obtained on the 5th and 10th days. By IB assay, 95.4 percent and 100 percent of sera reacted against gp43 and gp70 present in SCCWOS from the 5th day and 95.6 percent recognized these fractions when evaluated against SCCWOS from the 10th day. Our results demonstrated that the use of an immunoenzymatic assay significantly improves the sensitivity of PCM immunodiagnosis and also suggests that at least two serological tests for antibody detection should be adopted in cases of questionable diagnosis.