Increased frequency of rotavirus G3P[8] and G12P[8] in Argentina during 2008–2009: Whole-genome characterization of emerging G12P[8] strains

Abstract Background Group A rotaviruses are the leading cause of non-bacterial severe diarrhea disease in infants and young children. In humans, the most common genotypes are G1–G4 and G9. Recently, G12 strains have been sporadically reported in several countries, including Argentina, Brazil and Paraguay. Objectives To analyze rotavirus strain diversity in Argentina during 2008–2009 and to describe the whole genome-based classification of emerging G12P[8] strains detected in our country. Study design Rotavirus positive-samples ( n = 544) were collected from Argentinean children during 2008–2009, as a part of the National Surveillance Network for Viral Diarrheas. Specimens were genotyped by reverse transcription-polymerase chain reaction (RT-PCR) followed by nested-multiplex PCR. Sequencing of 11 genome segments was performed in 3 randomly selected G12P[8] strains. Results G9P[8] was the most frequent strain in 2008, but in 2009 G3P[8] and G12P[8] were the most frequent strains in different geographical regions of the country. The novel emerging G12P[8] strains presented the following combination of genes: G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1 (i.e. genotype1, Wa-like strains). The phylogenetic analysis of the VP7 gene of the G12P[8] strains grouped them within lineage III. Previously reported Argentinean G12P[9] strains presented genes from genotype 3 (AU-1-like strains) with a VP7 gene from lineage II. Conclusions The emergence of G12P[8] rotaviruses was due to the introduction of a new strain, rather than to a reassortment of the G12P[9] strains previously circulating in our country. This study assesses the temporal and geographical changes in genotypes prevalence as well as the periodic emergence of unusual G genotypes.