Molecular characterization of serotype G9 rotaviruses circulating in South Korea between 2005 and 2010

A total of 18 rotavirus G9 strains in South Korea were collected during five rotavirus seasons between 2005 and 2010. The relationship between these strains was examined by analyzing the genetic variation of two major structural genes, VP7 and VP4. All the rotavirus isolates were of the G9P[8] genotype. The VP7 phylogenetic analysis demonstrated that all of the G9 rotaviruses circulating in South Korea belonged to lineage IIId and were within three single clusters. The amino acid comparison of the antigenic regions of the VP7 gene suggests possible common progenitors of these strains. Phylogenetic analysis of P[8] VP4 genotypes indicated three lineages, P[8]-2, P[8]-3, and P[8]-4, with P[8]-3 being the most common. The results of this study provide information on the genetic relatedness of rotavirus G9 strains circulating in South Korea over recent years and can be utilized for the development of effective vaccines and the identification of reference strains for future efficacy studies.