Evidence for Occurrence of Human group B rotavirus in Central India Based on Characterization of NSP2 Gene

Human group B rotavirus (HuGBR) was first described as the causative agent of severe gastroenteritis, affecting millions of people in China during 1982-1983. In spite of serological evidences for the presence of HuGBR in many countries of the world, the virus has only been detected from China, Bangladesh and some parts of India. The present study describes a HuGBR (designated as MP-1 isolate) which was confirmed in an adult patient suffering from gastroenteritis in 2008 in Madhya Pradesh, central India. The RNA electrophoresis in polyacrylamide gel (RNA-PAGE) and NSP2 gene based RT-PCR assays and later sequencing was used to confirm the isolate. The nucleotide and deduced amino acid sequences of this HuGBR (MP-1) isolate were analyzed and their relationship with corresponding gene of other Indian, Bangladeshi and Chinese HuGBR and animal group B rotaviruses (AnGBR) was determined. The isolate showed a typical RNA banding pattern of 4:2:2:3 in RNA-PAGE which was indicative of group B rotaviruses (GBR). The sequence comparison of MP-1 isolate with NSP2 gene revealed that MP-1 isolate had 98.6 and 97.7% nucleotide sequence homology and 93.8% amino acid similarity with Bang373 and CAL-1 strains, respectively. The nucleotide and amino acid sequence similarity of MP-1 isolate with one of the Chinese ADRV (WH-1) strain was 92.8 and 92.5%, respectively. While sequence homology with another Chinese strain ADRV (J19) was considerably lower (45.6 and 48.3%, respectively). The percent identity with AnGBRs (porcine and murine) was also lower at nucleotide and amino acid level (66 to 80%). The phylogenetic analysis suggested that MP-1 isolate is closer to Bangladeshi (Bang373) as compared to Indian strain (CAL-1). Our findings indicated that MP-1 isolate might have originated from a common ancestral HuGBR virus but distinct from AnGBR lineage. Occurrence of GBR in other parts of India warrants further epidemiological and molecular studies to develop effective control strategies for GBR infection in adults as well as children.