G1P[8] Rotavirus in children with severe diarrhea in the post-vaccine introduction era in Brazil: Evidence of reassortments and structural modifications of the antigenic VP7 and VP4 regions

摘要

Worldwide rotaviruses A (RVA) are responsible for approximately 215,000 deaths annually among children aged & 5 years. RVA G1P[8] remains associated with & 50% of gastroenteritis cases in this age group. The aim of this study was to assess the genetic variability of G1P[8] strains detected in children with severe diarrhea in Belem, Para, Brazil, during the post-rotavirus vaccine introduction era. Phylogenetic analysis clustered the VP4 and VP7 genes of 40 samples selected between 2009 and 2011 into lineages found to be different from the Rotarix (R) vaccine strain. A detailed investigation of their complete genotype constellations identified 2 reassortant viruses (5%), resulting from reassortments between the genogroups Wa-like and DS-1-like (G1-P[8]-I1-R2-C1-M1-A1-N1-T2-E1-H1) and Wa-like and AU-1-like (G1-P[8]-I1-R3-C1-M1-A1-N1-T1-E1-H1) genotype constellations. A comparison of the amino acid residues presents in the antigenic epitopes of VP7 and VP4, showed differences in the electrostatic charges distribution, between wild type Brazilian strains and the Rotarix (R) and RotaTeq (R) vaccine strains. These findings reflect the structural analyses of the antigenic regions of VP7 and VP4 of the RVA G1P[8] in children with gastroenteritis in Northern Brazil raising the hypothesis that structural modifications at these sites over time may account for the emergence of new strains that could possibly pose a challenge to current vaccines.