Distribution of Human Norovirus in the Coastal Waters of South Korea

RESEARCH ARTICLE Distribution of Human Norovirus in the Coastal Waters of South Korea Man Su Kim1☯, Eung Seo Koo1☯, Yong Seon Choi1, Ji Young Kim1, Chang Hoon Yoo1, Hyun Jin Yoon2, Tae-Ok Kim3, Hyun Bae Choi4, Ji Hoon Kim5, Jong Deok Choi2, KwonSam Park3, Yongsik Shin4, Young-Mog Kim5, GwangPyo Ko6, Yong Seok Jeong1* a11111 1 Department of Biology and Research Institute of Basic Sciences, Kyung Hee University, Seoul, South Korea, 2 Department of Seafood Science and Technology, Institute of Marine Industry, Gyeongsang National University, Tongyeong, Gyeongnam, South Korea, 3 Department of Food Science and Biotechnology, College of Ocean Science and Technology, Kunsan National University, Kunsan, South Korea, 4 Department of Environmental Engineering & Biotechnology, Mokpo National Maritime University, Mokpo, South Korea, 5 Department of Food Science and Technology, Pukyong National University, Busan, South Korea, 6 Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, South Korea ☯ These authors contributed equally to this work. * OPEN ACCESS Citation: Kim MS, Koo ES, Choi YS, Kim JY, Yoo CH, Yoon HJ, et al. (2016) Distribution of Human Norovirus in the Coastal Waters of South Korea. PLoS ONE 11(9): e0163800. doi:10.1371/journal. pone.0163800 Editor: Martyn Kirk, Australian National University, AUSTRALIA Received: June 11, 2016 Accepted: September 14, 2016 Published: September 28, 2016 Copyright: © 2016 Kim et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This study was funded by a grant from the cooperative Research Program from the Ministry of Food and Drug Safety (KFDA, Project No. 14162-973), South Korea (http://www.mfds. go.kr/eng/index.do). KFDA had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. 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. 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]. In particular, human norovirus (HNoV) has been reported as the major cause of non-bacterial PLOS ONE | DOI:10.1371/journal.pone.0163800 September 28, 2016 1 / 17 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 [2–6]. HNoV can infect via multiple routes, and is transmitted through contact with gastroenteric effluents originating from infected individuals [7]. At least 70% of outbreaks have occurred in semi-closed communities [8–10]. Noroviruses (NoVs) are small non-enveloped viruses in the Caliciviridae family with a positive single-stranded RNA genome of 7.5–7.7 kb in length, which is organized into three or four open reading frames (ORFs) [11–14]. 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]. After a viral incubation period of 12 hours to 2 days, a patient generally experiences acute symptoms, such as vomiting, diarrhea, nausea, abdominal cramps, and low-grade fever [10]; immunocompromised patients are susceptible to chronic gastroenteritis [16]. NoVs are genetically diverse and are classified into six established genogroups (GI–GVI) based on VP1 sequences [10, 14]. Of the six genogroups, 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]. To date, nine capsid genotypes have been identified in GI, 22 in GII, and three genotypes of GII (GII.11, GII.18, and GII.19) have been uniquely detected in swine. Of the two genotypes of GIV identified to date, GIV.1 can infect humans [10]. HNoV is known to spread through the fecal-oral route, which can be subdivided into direct person-to-person contact (88%), food ingestion (10%), and drinking water intake (1.5%) [19]. Epidemiological studies show that HNoVs can survive for prolonged periods outside of the host [2]. To date, studies for HNoV detection in water have revealed that HNoVs are present in aquatic environments such as raw/treated sewage [20], rivers [20–26], groundwater [12, 18, 27, 28], ocean water [2, 24, 29, 30], and tap water [31]. In particular, contamination of the marine environment with viruses from the human community increases the potential for outbreaks via recreation and shellfish consumption [32]. The objective of this study was to investigate the distribution over time of the GI and GII genotypes of NoV in estuaries and inflow streams in four different geographical areas in South Korea. This study is the first nationwide study conducted in South Korea focusing on detection of HNoV contamination in coastal environments that are utilized as clam fisheries. Materials and Methods Ethics statement Sample collection was approved by the Korean Food and Drug Administration (KFDA, Project No. 14162–973). This study did not require additional permissions because samples were not collected on private land or in protected areas. We confirm that this study did not involve endangered or protec (...truncated)