Background: Acute gastroenteritis was more prevalent in children under five year-olds, and general etiological agents are norovirus (NoV), group A rotavirus (RoV), enteric adenovirus (AdV), astrovirus (AsV) and sapovirus (SaV). In this study, we analyzed the laboratory surveillance of diarrhea induced sporadically by viral pathogens in Korea in 2015.

Methodology: NoV was screened by real-time RT-PCR and positive samples were performed with RT-PCR. The antigens of RoV and AdV were detected through EIAs method and AdV positive samples were confirmed with PCR. Specific gene of AsV and SaV were detected by duplex RT-PCR method. The genotype was determined by BLAST search and phylogenetic analysis was performed with MegAlign program after nucleotide sequencing.

Results: From the tested samples (13,011 people), 15.1% (1,959 people) of specimens were detected with viral pathogens. NoV was the most prevalent pathogen (8.4%), followed by RoV (4.5%), AdV (1.1%), AsV (0.9%), and SaV (0.2%). NoV was predominant during the winter season, while RoV was at its peak during spring season. The most prevalent genotype of NoV was GII.4, while type 41, type 1a and GI.1 was the most prevalent in AdV, AsV and SaV, respectively

Conclusion: NoV GII.4 was the major cause of viral acute gastroenteritis. However, the incidence of GII.17 infection sharply increased from December 2014, to January 2015. In general, the epidemic strain of norovirus changes every 2-3 years. Comprehensive and continuous surveillance is needed to identify the prevalence of different acute gastroenteritis pathogens.