Genetic diversity of noroviruses detected in oysters in Jinhae Bay, Korea

Norovirus (NoV) is considered the major causative agent of food poisoning outbreaks in Korea. Most such outbreaks originate from vegetables or drinking water, but bivalves are known to be an important NoV vector. Environmental contamination of NoV in ground and river water has been reported in Korea, but the NoV contamination status of shellfish-growing areas based on regular surveys is not available. In this study, we investigated the NoV contamination status of oyster-growing areas in the Jinhae Bay of Korea to evaluate the circulation of various NoV genotypes. A total of 39 NoV-positive samples detected from February, 2010 to February, 2011 were sequenced and evaluated. Based on the sequencing results, five genotypes (GI.1, GI.2, GI.5, GI.6, and GI.7) were identified in NoV GI, and seven genotypes (GII.2, GII.3, GII.4, GII.7, GII.12, GII.13, and GII.17) in NoV GII. GI.1 (52.6%; 10 of 19). Both GII.3 and GII.4 (30.0%; 6 of 20, respectively) were identified as the most prevalent GI and GII strains in oyster during the investigation period.