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