Molecular characterization of G1 human rotaviruses detected in children from Belém, Pará, Brazil Caracterização molecular de rotavírus humanos do tipo G1 detectados em crianças de Belém, Pará, Brasil Caracterización molecular de rotavirus humano tipo G1 detectado en niños de Belém (Estado de Pará, Brasil)

Rotavirus is responsible for 40% of gastroenteritis infections worldwide, resulting in 611 thousand deaths annually among infants and young children. The aim of the present study was to perform molecular characterization of strains of the most common circulating rotavirus genotype (G1), which was obtained from children participating in studies previously conducted in Belem, northern Brazil over a 21-year period (1982 to 2003). G1 type rotavirus was detected by polyacrylamide gel electrophoresis, enzyme immunoassay and by reverse transcription polymerase chain reaction for the VP7 and VP4 genes. Of 798 specimens that were found to be positive for rotavirus, 330 (41%) had G1-specificity by EIA using monoclonal antibodies. A total of 148 G1 strains were analyzed by reverse transcription polymerase chain reaction. Electropherotypes and P genotypes characterization of G1 rotavirus occurred at frequencies of 78% and 88%, respectively. Three long electropherotype varieties were identified, with the L1 variety the most frequently found (79%). The G1P[8] combination was the most frequent, responsible for 64% of cases. Mixed infections of G1P[6]+P[8], G1P[4]+P[8], G1P[4]+P[6] and G1P[4]+P[6]+P[8] were found in 11 (7%), 11 (7%), 3 (2%) and 1 (0.6%) samples, respectively. One sample displaying a mixed G1+G4 infection was found. To our knowledge, this is the first study to focus on G1 rotavirus molecular characterization in Brazil. Our findings provide information that will allow a better understanding of the molecular diversity of G1 rotavirus infections in our region.