Epidemiological and molecular analysis of a waterborne outbreak of norovirus GII.4

Guangdong Provincial Centre for Disease Control and Prevention, Guangdong, China.
Epidemiology and Infection (Impact Factor: 2.54). 03/2012; 140(12):1-8. DOI: 10.1017/S0950268812000374
Source: PubMed


SUMMARYContaminated water is one of the main sources of norovirus (NoV) gastroenteritis outbreaks globally. Waterborne NoV outbreaks are infrequently attributed to GII.4 NoV. In September 2009, a NoV outbreak affected a small school in Guangdong Province, China. Epidemiological investigations indicated that household use water, supplied by a well, was the probable source (relative risk 1·9). NoV nucleic acid material in concentrated well-water samples was detected using real-time RT-PCR. Nucleotide sequences of NoV extracted from diarrhoea and well-water specimens were identical and had the greatest sequence identity to corresponding sequences from the epidemic strain GII.4-2006b. Our report documents the first laboratory-confirmed waterborne outbreak caused by GII.4 NoV genotype in China. Our investigations indicate that well water, intended exclusively for household use but not for consumption, caused this outbreak. The results of this report serve as a reminder that private well water intended for household use should be tested for NoV.

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Available from: John D Klena, Jan 16, 2014
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    • "NoV are characterized by high environmental stability, and only few infectious viral particles are necessary to induce disease (Teunis et al. 2008). Transmission of these highly infectious viruses occurs mainly via the faecal–oral route, by ingestion of contaminated water and food, particularly shellfish, soft fruits and vegetables, but also through person-to-person contact and exposure to fomites (Beuchat 2006; Hewitt et al. 2007; Le Guyader et al. 2009; Lopman et al. 2012; Matthews et al. 2012; Zhou et al. 2012). NoV outbreaks occur most commonly in semi-closed communities such as restaurants, nursing homes, hospitals, schools, day care centres and cruise chips (Fankhauser et al. 2002). "
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    ABSTRACT: To provide a rapid and sensitive method for detecting NoV GI and NoV GII in water and to evaluate the use of the murine norovirus (MNV-1) as a process control. The method is based on viral concentration by filtration on electropositive filters and direct lysis of adsorbed viruses from filters before RNA extraction and RT-qPCR amplification. A one-step multiplex RT-qPCR assay was developed for the simultaneous detection of NoV GI, NoV GII and MNV-1. Then, water samples were artificially contaminated to determine mean virus recoveries and method sensitivity. The method showed a higher sensitivity for detecting NoV GII (10(3) genome copies /0.5 L) than for NoV GI (10(4) genome copies /0.5 L) in presence of MNV-1 regardless of the type of water. The data also showed that MNV-1 is a robust option as process control. The method described provides a valuable tool for the monitoring of potential public health risks associated with NoV contamination in drinkable water. Given the increasing evidence for NoV involvement in food outbreaks, the one step multiplex RT-qPCR assay we used in this study would be a very useful tool to investigate NoV contamination in other food products. This article is protected by copyright. All rights reserved.
    Journal of Applied Microbiology 09/2013; 116(1). DOI:10.1111/jam.12345 · 2.48 Impact Factor
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    • "Viral gastroenteritis is a major health problem worldwide. Viruses cause both seasonal acute gastroenteritis and occasional outbreaks associated with the consumption of contaminated food or water [1]. These outbreaks involve a number of high-risk groups, particularly young children, the elderly and immunocompromised patients [2-6]; they are frequent in semi-enclosed environments, such as school settings due to the increased number of people and the increased personal contacts among them. "
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    ABSTRACT: Background Two parallel gastroenteritis outbreaks occurred in an elementary school and a neighboring kindergarten in Kilkis, Northern Greece in 2012. The aim of the study was the investigation of these two parallel outbreaks as well as their possible source. Methods Two retrospective cohort studies were performed to identify the mode and the vehicle of transmission as well as the possible connection between them. Results Elementary school and kindergarten populations of 79.9% (119/149) and 51.1% (23/45) respectively, participated in the study. Case definition was satisfied by 65 pupils from the elementary school and 14 from the kindergarten. For elementary school, 53 cases were considered primary cases of the outbreak and were included in the analysis. Based on the results of the multivariate analysis, consumption of tap water was the only statistically significant independent risk factor of gastroenteritis (RR = 2.34, 95% C.I.: 1.55-3.53).; a finding supported by the shape of the epidemic curve which referred to a common point source outbreak with secondary cases. For kindergarten, no statistically significant risk factor was identified, and the epidemic curve supported a person-to-person transmission according univariate analysis. Norovirus GI and GII and human Adenovirus were detected by Real Time PCR in stool samples from seven children of elementary school, but stool samples were not collected by children of the kindergarten. Conclusions Even though the etiological agent of the outbreak was not verified, combined epidemiological and laboratory results were in favor of a waterborne viral gastroenteritis outbreak at the elementary school, followed by a person to person spread at the kindergarten.
    BMC Public Health 03/2013; 13(1):241. DOI:10.1186/1471-2458-13-241 · 2.26 Impact Factor
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    ABSTRACT: RT-PCR, nucleotide sequencing, and phylogenetic analysis were performed for genotyping and molecular characterization of noroviruses isolated from Korean groundwater. Among 160 samples collected from 80 sites between 2008 and 2010, 14 samples (8.7 %) from 12 sites were positive for noroviruses (NoVs). The percentages of NoV-positive samples in 2008, 2009, and 2010 were 22.2, 3.2, and 0 %, respectively, representing a yearly decrease. GII-positive samples (n = 9, 5.6 %) outnumbered GI-positive samples (n = 5, 3.1 %). The genotypes of the GI NoVs were GI.2, GI.5, and GI.6, and the genotypes of the GII NoVs were all GII.4. One sample, HM623465, was very similar to CUK-3 and CBNU2 and two GII.4 sequences isolated from the stool of Korean gastroenteritis patients. A BLASTN search revealed several nucleotide sequences highly similar to those of NoVs isolated in this study. The original isolation sources for these similar NoVs were mostly stool (n = 731, 80.0 %) and groundwater (n = 135, 14.8 %), and all the countries from which they were isolated were almost in Asia (96.0 %); specifically, China (n = 192, 21.0 %), Japan (n = 383, 41.9 %), Korea (n = 296, 32.4 %), and other Asian countries (n = 6, 0.7 %). These results suggest that Korean groundwater might be contaminated with NoVs from the stool of infected patients and that these NoVs in turn cause new cases of gastroenteritis through a typical fecal-oral route with region-specific circulation. Therefore, it is important to properly treat sewage, which may include waterborne viruses and manage point sources in groundwater for national health and sanitation. In addition, continuous molecular surveillance remains important for understanding circulating NoVs.
    Food and Environmental Virology 09/2012; 4(3):115-23. DOI:10.1007/s12560-012-9084-y · 2.36 Impact Factor
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