G and P genotypes of group A rotavirus strains circulating in calves in Brazil, 1996-1999.

Fifty fecal samples from calves with diarrhea, positive for group A rotavirus by enzyme immunoassay (EIA) and polyacrylamide gel electrophoresis (PAGE) were analyzed by a nested multiplex reverse transcription/polymerase chain reaction (Nested multiplex/RT-PCR) for identification of P and G genotypes. Samples were collected between 1996 and 1999 from eight dairy and/or beef cattle herds located in the Mato Grosso do Sul, São Paulo, Goiás and Paraná States, Brazil. Complete genotyping was possible in 44 (88%) of the calf fecal samples. The VP7 gene could not be identified in six (12%) of the samples. Whilst the VP4 (P) gene was identified in 100% of samples. The genotypes of 35 (70%) samples corresponded to the NCDV-like (12%), UK-like (40%), B223-like (16%) and KN-4 (2%) reference rotavirus strains, which are commonly found in cattle. Mixed infections were detected in seven (14%) samples, and genotypes observed in two (4%) samples presented unusual combinations, carrying VP4 and VP7 gene of the bovine group A rotavirus (P[11],G8), in other one carrying a VP4 gene of bovine origin (P[1]) and a VP7 gene of swine origin (G5).