Rotavirus strain diversity in Rio de Janeiro, Brazil: characterization of VP4 and VP7 genotypes in hospitalized children.

Rotavirus strains from 91 patients treated at a children's hospital from 1996 to 1998 in Rio de Janeiro, Brazil, were characterized by electropherotyping, reverse transcription-PCR amplification for P and G genotypes, and Southern hybridization. Results obtained showed that following predominant [P],G type combination: P[4], G2 (21 per cent), P[8], G1 (17 per cent), P[8], G3 (13 per cent), which are prevalent throughout the world. However, an unexpected number of cases were associated with uncommon genotypes: P[8], G2 (13 per cent), P[8], G5 (11 per cent), P[8], G9 (7 per cent), P[8], G10 (4 per cent), P[6], G4 (3 per cent), P[6], G3 (1 per cent), P[4], G9 (1 per cent), and P[6], G9 (1 per cent). Mixed infections with more than one type were identified in only two cases and 16 per cent of the samples were not G and/or P typeable. A subset of G types was confirmed by Southern hybridization and chemiluminescent detection. Rotavirus seasonal distribution was observed between April and July. The contribution of the results obtained in the present investigation corroborates the required epidemiological surveillance for rotavirus infection in Brazil.