Scientific Opinion on an update on the present knowledge on the occurrence and control of foodborne viruses

dHepatitis E virus (HEV), an enteric pathogen of both humans and animals, is excreted by infected individuals and is therefore present in wastewaters and coastal waters. As bivalve molluscan shellfish are known to concentrate viral particles during the process of filter feeding, they may accumulate this virus. The bioaccumulation efficiencies of oysters (Crassostrea gigas), flat oysters (Ostrea edulis), mussels (Mytilus edulis), and clams (Ruditapes philippinarum) were compared at different time points during the year. Tissue distribution analysis showed that most of the viruses were concentrated in the digestive tissues of the four species. Mussels and clams were found to be more sensitive to sporadic contamination events, as demonstrated by rapid bioaccumulation in less than 1 h compared to species of oysters. For oysters, concentrations increased during the 24-h bioaccumulation period. Additionally, to evaluate environmental occurrence of HEV in shellfish, an environmental investigation was undertaken at sites potentially impacted by pigs, wild boars, and human waste. Of the 286 samples collected, none were contaminated with hepatitis E virus, despite evidence that this virus is circulating in some French areas. It is possible that the number of hepatitis E viral particles discharged into the environment is too low to detect or that the virus may have a very short period of persistence in pig manure and human waste.

mentioning

confidence: 99%

Bioaccumulation Efficiency, Tissue Distribution, and Environmental Occurrence of Hepatitis E Virus in Bivalve Shellfish from France

Grodzki

Schaeffer

Piquet

et al. 2014

“…Infected food handler contamination and exposure to fecally contaminated water are thought to be the most frequent modes of human NoV contamination of foods (2,5,10,18). The use of irrigation water that is contaminated with fecal matter is considered a significant cause of viral contamination in soft berries (19)(20)(21)(22). A multicountry study conducted in Europe investigating human NoV prevalence in soft red fruit obtained directly from processing companies or retail markets found viral RNA in 7 to 34% of samples (2,22).…”

mentioning

confidence: 99%

Evidence of the Internalization of Animal Caliciviruses via the Roots of Growing Strawberry Plants and Dissemination to the Fruit

DiCaprio

Culbertson

Lǐ

2015

Human norovirus (NoV) is the leading cause of foodborne disease in the United States, and epidemiological studies have shown that fresh produce is one of the major vehicles for the transmission of human NoV. However, the mechanisms of norovirus contamination and persistence in fresh produce are poorly understood. The objective of this study is to determine whether human NoV surrogates, murine norovirus (MNV-1) and Tulane virus (TV), can attach and become internalized and disseminated in strawberries grown in soil. The soil of growing strawberry plants was inoculated with MNV-1 and TV at a level of 10 8 PFU/plant. Leaves and berries were harvested over a 14-day period, and the viral titer was determined by plaque assay. Over the course of the study, 31.6% of the strawberries contained internalized MNV-1, with an average titer of 0.81 ؎ 0.33 log 10 PFU/g. In comparison, 37.5% of strawberries were positive for infectious TV, with an average titer of 1.83 ؎ 0.22 log 10 PFU/g. A higher percentage (78.7%) of strawberries were positive for TV RNA, with an average titer of 3.15 ؎ 0.51 log 10 RNA copies/g as determined by realtime reverse transcriptase quantitative PCR (RT-qPCR). In contrast, no or little virus internalization and dissemination were detected when TV was inoculated into bell peppers grown in soil. Collectively, these data demonstrate (i) virally contaminated soils can lead to the internalization of virus via plant roots and subsequent dissemination to the leaf and fruit portions of growing strawberry plants and (ii) the magnitude of internalization is dependent on the type of virus and plant.H uman norovirus (NoV) is the major cause of nonbacterial gastroenteritis, contributing to over 95% of the cases of nonbacterial acute gastroenteritis and an estimated 58% of all foodborne illnesses reported annually in the United States (1-4). In recent years, fresh produce has been identified as a leading cause of foodborne illness in the United States (3, 5, 6). Human NoV alone accounts for over 40% of the fresh produce-related illnesses reported each year in the United States (1, 2, 4-8). Human NoV has been attributed to outbreaks in many diverse types of produce, including fresh cut fruit, lettuce, tomatoes, melons, salads, green onions, strawberries, blueberries, raspberries, and salsa, as well as many others (5-7, 9-15). Human NoV is resistant to common disinfectants, has a low infectious dose, and is highly stable in the environment, which contributes to the high prevalence of foodborne outbreaks associated with the virus and its presence and persistence in food commodities (3,16,17).Foods can become contaminated with human NoV at any point from farm to fork, including production, processing, and preparation. Infected food handler contamination and exposure to fecally contaminated water are thought to be the most frequent modes of human NoV contamination of foods (2, 5, 10, 18). The use of irrigation water that is contaminated with fecal matter is considered a significant cause of viral contamination in soft b...

“…NoVs have been detected on berries, tomatoes, and shellfish from the European, Canadian, American, and Japanese markets with prevalence frequencies ranging from less than 4% to more than 76% (31,35,(45)(46)(47) A review performed by an expert panel on the biology, epidemiology, detection, and public health importance of food-borne viruses identified NoVs (as well as HAV) to be the most frequent causes of food-borne illness among all virus-food commodity combinations (8). One recommendation of this expert panel was to obtain more data on NoV food contamination to develop a risk assessment and to evaluate the impact of food on NoV epidemiology.…”

Section: Discussionmentioning

confidence: 99%

“…The large amount of virus shed by infected persons and the high level of resistance to inactivation in the environment are likely factors associated with virus prevalence in environmental waters (5)(6)(7). Although food handlers have been implicated as the source of food contamination in some outbreaks, it is clear that foods such as berries, green vegetables, and shellfish can be contaminated during production (8)(9)(10).…”

mentioning

confidence: 99%

Environmental Detection of Genogroup I, II, and IV Noroviruses by Using a Generic Real-Time Reverse Transcription-PCR Assay

Miura

Parnaudeau

Grodzki

et al. 2013

Norovirus is the most common agent implicated in food-borne outbreaks and is frequently detected in environmental samples. These viruses are highly diverse, and three genogroups (genogroup I [GI], GII, and GIV) infect humans. Being noncultivable viruses, real-time reverse transcription-PCR (RT-PCR) is the only sensitive method available for their detection in food or environmental samples. Selection of consensus sequences for the design of sensitive assays has been challenging due to sequence diversity and has led to the development of specific real-time RT-PCR assays for each genogroup. Thus, sample screening can require several replicates for amplification of each genogroup (without considering positive and negative controls or standard curves). This study reports the development of a generic assay that detects all three human norovirus genogroups on a qualitative basis using a one-step real-time RT-PCR assay. The generic assay achieved good specificity and sensitivity for all three genogroups, detected separately or in combination. At variance with multiplex assays, the choice of the same fluorescent dye for all three probes specific to each genogroup allows the levels of fluorescence to be added and may increase assay sensitivity when multiple strains from different genogroups are present. When it was applied to sewage sample extracts, this generic assay successfully detected norovirus in all samples found to be positive by the genogroup-specific RT-PCRs. The generic assay also identified all norovirus-positive samples among 157 archived nucleic acid shellfish extracts, including samples contaminated by all three genogroups.