Full genomic analysis of human group A rotavirus G2 and non-typable genotype G strains from São Paulo, Brazil: strains classification using new system and variability investigation due to vaccine introduction in the Brazilian public health system.

Abstract

Acute gastroenteritis is one of the most frequent diseases affecting humans and rotaviruses are considered its most important etiologic agent. Members of Reoviridae family, genus Rotavirus, theses viruses have a genome of 11 dsRNA segments, each one coding for at least one protein (six structural proteins - VP - and six non-structural proteins - NSP). Group A rotaviruses are classified into genotypes/serotypes according to antigenic specificity of two outer capsid proteins, VP7 (G) and VP4 (P). Molecular epidemiological studies indicate a great variety of genotypes infecting humans all over the world. As this variety may be explained mostly by occurrence of dsRNA viral segments' reassortments, a new rotavirus classification system was proposed in 2008, based on nucleotide (nt) sequencing of all rotavirus' RNA segments. The present study intends to sequence, classify and phylogenetically analyze nt sequences of all 11 viral segments' ORFs of 113 human rotavirus strains from São Paulo State, Brazil, in order to investigate inter-species viral transmission, reassortments occurrence, strains evolutionary origins and existence of new genotypes. It also intends to analyze G2 strains genotypes' variability as it seems to be an important emerging genotype in the Brazilian population, after monovalent vaccine implementation in 2006. All data will be compared to new rotavirus classification data that are being recently published around the world, and it may also provide information on rising of different, and not so frequently found, genotypes in a population, as a result of monovalent rotavirus vaccines introduction.