Distribution of Human Norovirus in the Coastal Waters of South Korea.

Man Su Kim,Tae-Ok Kim,Ji Young Kim,Hyun Bae Choi,Gwangpyo Ko,Yongsik Shin,Yong Seon Choi,Hyun Jin Yoon,Young-Mog Kim,Kwon-Sam Park,Eung Seo Koo,Yong Seok Jeong,Ji Hoon Kim,Chang Hoon Yoo,Jong Deok Choi,Martyn Kirk

doi:10.1371/journal.pone.0163800

Abstract

The presence of human norovirus in the aquatic environment can cause outbreaks related to recreational activities and the consumption of norovirus-contaminated clams. In this study, we investigated the prevalence of norovirus genogroups I (GI) and II (GII) in the coastal aquatic environment in South Korea (March 2014 to February 2015). A total of 504 water samples were collected periodically from four coastal areas (total sites = 63), of which 44 sites were in estuaries (clam fisheries) and 19 were in inflow streams. RT-PCR analysis targeting ORF2 region C revealed that 20.6% of the water samples were contaminated by GI (13.3%) or GII (16.6%). The prevalence of human norovirus was higher in winter/spring than in summer/fall, and higher in inflow streams (50.0%) than in estuaries (7.9%). A total of 229 human norovirus sequences were identified from the water samples, and phylogenetic analysis showed that the sequences clustered into eight GI genotypes (GI.1, 2, 3, 4, 5, 6, 7, and 9) and nine GII genotypes (GII.2, 3, 4, 5, 6, 11, 13, 17, and 21). This study highlighted three issues: 1) a strong correlation between norovirus contamination via inflow streams and coastal areas used in clam fisheries; 2) increased prevalence of certain non-GII.4 genotypes, exceeding that of the GII.4 pandemic variants; 3) seasonal shifts in the dominant genotypes of both GI and GII.

Highlights

Acute gastroenteritis causes the second greatest burden of all infectious diseases, estimated at 89.5 million disability-adjusted life-years and 1.45 million deaths worldwide every year [1]
From March 2014 to February 2015, we collected a total of 504 water samples (352 estuary samples and 152 inflow stream samples) from a total of 63 sites in four coastal areas in South Korea (Fig 1)
The rates of human norovirus (HNoV) detection revealed regional differences within each of the two water types. Those from area B showed the highest rate of HNoV detection (11.6%), followed by area D (8.0%), area A (6.2%), and area C (4.5%)

Summary

Introduction

Acute gastroenteritis causes the second greatest burden of all infectious diseases, estimated at 89.5 million disability-adjusted life-years and 1.45 million deaths worldwide every year [1]. Human norovirus (HNoV) has been reported as the major cause of non-bacterial. Human Norovirus in Water Samples from South Korea acute gastroenteritis in patients of all ages, responsible for approximately 90% of all outbreaks of viral gastroenteritis in the world [2,3,4,5,6]. ORF1 encodes six non-structural proteins, including the viral RNA-dependent RNA polymerase, while ORF2 and ORF3 encode the major (VP1) and minor (VP2) capsid proteins, respectively [15]. GI, GII, and GIV infect humans, and GII is the most common threat, causing 75–90% of all HNoV-related outbreaks [11, 12, 17, 18]. Of the two genotypes of GIV identified to date, GIV. can infect humans [10]

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