PHYLOGENETIC ANALYSIS OF VP7 GENE OF ROTAVIRUS STRAINS CIRCULATING IN CHILDREN WITH ACUTE GASTROENTERITIS IN CHENNAI WITH FOCUS ON G2

Abstract

Background: Group A rotavirus is the leading cause of gastroenteritis among children worldwide and accounts  for  872000  hospitalizations,  3270000  outpatient  visits  and  predictable  78000  deaths annually in India. As the disease burden is more common in low income countries including India, monitoring and detection of the circulating strains of rotavirus needs to be monitored. This study emphasis the genetic relatedness among G2 rotavirus strains that was analyzed during the study period in and around Chennai, Tamilnadu during pre-vaccination era.

Materials and Methods: We collected fresh stool from child < 5 years admitted with acute gastroenteritis (AGE) admitted  to  hospitals.  Rotavirus infections were detected by enzyme immune assay. Positive rotavirus isolates were genotyped using semi-nested type-specific multiplex PCR for G and P types and were sequenced. Phylogenetic analysis of VP7 genes of G2 were carried out and the variations between strains isolated globally were documented.

Results: Group  A  rotaviruses  was  detected  in  77  (39.48%)  samples  and  samples  of  G2  was identified in more percentage and results indicated it would be re-emerging strain/genotype. The deduced amino acid sequences of the antigenic regions of VP7 exposed substitutions at various positions correlated with changes compared to other strains by phylogenetic analysis.

Conclusion: Since rotavirus is transmitted through oral-fecal route and monitoring of environmental cleanliness is of mandatory to cease the spread of this deadliest viral agent and covering single genotype/strains  before  the  pre-vaccination  era  will  have  to  be  modified  with  respect  to  the circulating strains as vaccine candidate.

Keywords: Genetic Diversity, Genotypes, Phylogenetic Analysis, Severity of Diarrhea, RT-PCR, G2.