Unusual diversity of human rotavirus G and P genotypes in India

Abstract

Between April and December 1993, we determined P and G genotypes of group A rotavirus strains obtained from children admitted to diarrhea treatment centers in five Indian cities. From a total of 63 rotavirus- positive specimens, we identified 10 different strains with five different G genotypes and four distinct P types by using reverse transcription-PCR. The common worldwide strains G₁P₈, G₂P₄, G₃P₈, and G₄P₈ were underrepresented among Indian children (33%), whereas strains of P type 6 (G₁P₆, G₂P₆, G₃P₆, G₄P₆, and G₉P₆), which primarily infect asymptomatic newborns but are rare in children with diarrhea were common in India (43%). Of these, G₉P₆, a strain not previously reported to be found in children with diarrhea, was the most prevalent (22%). Eleven percent of the strains were nontypeable, and another 11% of the specimens had mixed infections. Using digoxigenin-labeled, genotype- specific hybridization probes, we confirmed all G₉ strains and mixed infections tested and identified three nontypeable strains (one G₉ and two P₈). The epidemiological significance of G₉ rotavirus strains, if confirmed in other settings, may have important implications for vaccine development.