Genetic diversity of genotype G1 rotaviruses co-circulating in western India.

The rotavirus (RV) G1 strains represent the common genotype that causes diarrhea in humans. The aim of this study was to determine the genetic lineages of G1 RV strains circulating in western India during two different time periods, 1991-1994 and 2006 by molecular characterization of VP7 genes. The phylogenetic analysis of VP7 genes showed clustering of G1 strains into lineages I (96.4%) and VIII (3.6%) in 1991-1994 and I (96.2%) and II (3.8%) in 2006. The sublineage IA was predominant (96.4%) in the years 1991-1994, however, was detected only in 44.4% of the strains in 2006 co-circulating with other sublineages IB (44.4%), IC (3.7%), IE (3.7%) and IIB (3.7%). The amino acid substitutions were noted in the previously identified signature codes of sublineages IB and IIB at positions 75 and 55, respectively. The differentiation marker (Q) described for sublineage IB at position 16 was replaced by I in all Indian strains clustered in sublineage IB. The study reports the characterization of G1 RV strains on the basis of distinct lineages and sublineages from India and emphasizes continuous monitoring on the diversity of G1 strains across the Indian population.