Serological and molecular diversity of human rotavirus in São Paulo, Brazil

From a total of 187 fecal samples from children with ages between 0 and 5 years, collected in the Hospital Universitário -USP, Brazil, from 1994 to 1996, 54 (28.9%) were positive for rotavirus. Positive samples were characterized by electropherotyping, subgrouping, G serotype and genotype and P genotype. Rotavirus electropherotypes were characterized in four different long genome patterns (38.9%), one short genome pattern (34.0%) and 18.0% were characterized as an unusual pattern. Subgroup I was found in 38.9% strains, subgroup II in 50.0% and 7.7% was subgroup nonI-nonII. For G serotypes, G2 was found in 59.3%, G1 was identified in 33.3% of strains, two samples showed mixtures of G1+G2 and one sample was G1+G3. Ten samples characterized as serotype G2 showed a long eletropherotype. Genotype G2 was the most frequently and was found in 37 (44.0%) samples (23 samples as a single genotype and 14 as mixtures of genotypes). G1 was found in 15 samples. G3 and G4 was detected mainly in mixtures of genotypes and G5, G6 and G9 were identified only in mixtures. A total of 20 (38.5%) samples were characterized as G genotype mixtures and P mixtures were found in 16 (29.6%) samples. P[4] was found in 55.6% of samples, P[8] in 51.9% and P[6-M37 like] in 22.3% of cases. P[6-Gottfried like] and P[11] were detected only in mixtures. One sample with G6 specificity, mixed with a G2 rotavirus and a P[11] strain, mixed with P[4] and P[8]strain was described for the first time in Latin America.