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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.

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Ten faecal samples of bovine rotavirus from calves less than 30 days old from an outbreak of diarrhea in Hidrolândia, Goiás, Brazil were submitted to serological and molecular characterization, using enzyme immunoassay for subgrouping and serotyping, PAGE for determination of electropherotypes and PCR for genome typing. Nine samples belonged to group A/subgroup I rotavirus and one sample was group A / subgroup non-I/non-II. Four samples were characterized as G10P[11] (B223-like), four samples showed a mixture of two rotavirus strains (G6G10 and P[5]P[11]), one sample was characterized as G6P [11] and one sample was characterized only by G serotyping/genotyping, and did not react with any P primer used. Two electropherotypes were detected and both were present in the same animal. This study demonstrates that two different electropherotypes and/or serotypes of bovine rotavirus can circulate in the same outbreak.

Accounting for an estimated 600,000 deaths worldwide each year, rotaviruses are recognized as the most important etiologic agents causing severe acute gastroenteritis among children under the age of five years. In Brazil, until rotavirus vaccination was established in the public health system in 2006, acute gastroenteritis striking children under five years and caused by these viruses was clearly associated with 3.5 million episodes of diarrhea, 650,000 visits to outpatient health care facilities, 92,000 hospitalizations, and 850 deaths each year. After the introduction of the rotavirus vaccine in Brazil in March 2006, studies all over the country have been comparing rotavirus genotypes circulating in the recent pre-and postvaccination era. Most of these studies have reported a high prevalence of the G2P[4] genotype and also a decrease in rotavirus detection all over Brazil after the introduction of the vaccine. So far, these are preliminary studies, as a longer period of time is necessary to establish if this high prevalence of G2P[4] is due to selective pressure by the vaccine on the circulating viruses or to a normal genotype fluctuation, and if it will have any impact on vaccine efficacy in the future. This review describes results from the most recent studies addressing this issue and on rotavirus genotypic variability in Brazil.

Group A human rotaviruses (HuRVA) are causative agents of acute gastroenteritis. Six viral structural proteins (VPs) and six nonstructural proteins (NSPs) are produced in RV-infected cells. NSP4 is a diarrhoea-inducing viral enterotoxin and NSP4 gene analysis revealed at least 15 (E1-E15) genotypes. This study analysed the NSP4 genetic diversity of HuRVA G2P[4] strains collected in the state of São Paulo (SP) from 1994 and 2006-2010 using reverse transcription-polymerase chain reaction, sequencing and phylogenetic analysis. Forty (97.6%) G2P[4] strains displayed genotype E2; one strain (2.4%) displayed genotype E1. These results are consistent with the proposed linkage between VP4/VP7 (G2P[4]) and the NSP4 (E2) genotype of HuRVA. NSP4 phylogenetic analysis showed distinct clusters, with grouping of most strains by their genotype and collection year, and most strains from SP were clustered together with strains from other Brazilian states. A deduced amino acid sequence alignment for E2 showed many variations in the C-terminal region, including the VP4-binding domain. Considering the ability of NSP4 to generate host immunity, monitoring NSP4 variations, along with those in the VP4 or VP7 protein, is important for evaluating the circulation and pathogenesis of RV. Finally, the presence of one G2P[4]E1 strain reinforces the idea that new genotype combinations emerge through reassortment and independent segregation.

The G (VP7) and P (VP4) serotype distribution of Brazilian porcine rotaviruses was determined using reverse transcription-PCR genotyping methods. Common porcine G types G3, G4, and G5 were detected in combination with P types [6] and [7]. The detection of nonporcine G types and unusual G-P combinations and the characterization of an atypical virus indicated that interspecies transmission may contribute to the genetic diversity of porcine rotaviruses.

The G (VP7) and P (VP4) serotype distribution of Brazilian porcine rotaviruses was determined using reverse transcription-PCR genotyping methods. Common porcine G types G3, G4, and G5 were detected in combination with P types [6] and [7]. The detection of nonporcine G types and unusual G-P combinations and the characterization of an atypical virus indicated that interspecies transmission may contribute to the genetic diversity of porcine rotaviruses.