Determination of G and P type diversity of group A rotaviruses in faecal samples of diarrhoeic calves in Kashmir, India

Aims: To determine the genetic diversity of group A rotaviruses in bovine calves in Kashmir, India. Methods and Results: Of 200 diarrhoeic faecal samples collected from calves, aged between 0 and 6 months and screened by polyacrylamide gel electrophoresis (PAGE), 31 were detected positive for group A rotaviruses. On G and P genotyping by reverse transcriptase-polymerase chain reaction (RT-PCR), G10P[11] turned out to be predominant (80 center dot 64%) combination followed by G8P[11] (7 center dot 7%). One (3 center dot 84%) sample carried mixed infection of G8 + G10P[11]. Two (7 center dot 7%) samples belonged to P[11] genotype, but their G genotype specificity could not be established. This study revealed the ambiguity in RT-PCR typing method. All the samples that turned out to be G10 by Isegawa et al. (1993; Mol Cell Probes7, 277) primers could be amplified by G3 specific primers of Gouvea et al. (1990; J Clin Microbiol32, 1338). However, on homology study of their VP7 gene sequence, the strains turned out to be G10. Conclusions: Rotavirus is prevalent in diarrhoeic calves in Kashmir, India, and G10P[11] is the predominant genotype in circulation. There is evidence of mixed infection. Even though RT-PCR method is the quick way to type the strains, there is need to generate more sequence data to improve the specificity of typing primers. Significance and Impact of the Study: Rotavirus is a significant cause of diarrhoea in calves. RT-PCR typing method needs to be supported by the sequence data, and there is need to re-evaluate the primers used for typing.