Genetic Characterization of Norovirus GII.3 Circulating in Korea

Noroviruses (NoV) are the major viral pathogen that causes epidemic acute gastroenteritis and outbreaks of food-borne illness. The major genotypes responsible for the epidemics of NoV are GII.4 and GII.3. However, most studies of NoV have been associated with GII.4 genotype and only few studies have been done with GII.3 genotype. Here, we selected 18 GII.3 strains, which recently circulated in Korea, and determined the partial sequences of the capsid gene. Phylogenetic analysis comparing these sequences with 29 reference strains from the GenBank database was performed using the MEGA program. All NoV GII.3 strains formed 2 distinct genetic lineages and variant groups. Lineage A showed 94.1~97.6%, 90.2~94.6% nucleotide identities from lineage B and variant group, respectively. Lineage B showed 90.2~94.6% nucleotide identities from variant group. These different genetic lineages based on the phylogenetic analysis of capsid sequences imply that the circulating Korean NoV GII.3 strains have potential antigenic variation.