Public health risks associated with hepatitis E virus (HEV) as a food‐borne pathogen

Abstract

Hepatitis E virus (HEV) is an important infection in humans in EU/EEA countries, and over the last 10 years more than 21,000 acute clinical cases with 28 fatalities have been notified with an overall 10-fold increase in reported HEV cases; the majority (80%) of cases were reported from France, Germany and the UK. However, as infection in humans is not notifiable in all Member States, and surveillance differs between countries, the number of reported cases is not comparable and the true number of cases would probably be higher. Food-borne transmission of HEV appears to be a major route in Europe; pigs and wild boars are the main source of HEV. Outbreaks and sporadic cases have been identified in immune-competent persons as well as in recognised risk groups such as those with preexisting liver damage, immunosuppressive illness or receiving immunosuppressive treatments. The opinion reviews current methods for the detection, identification, characterisation and tracing of HEV in food-producing animals and foods, reviews literature on HEV reservoirs and food-borne pathways, examines information on the epidemiology of HEV and its occurrence and persistence in foods, and investigates possible control measures along the food chain. Presently, the only efficient control option for HEV infection from consumption of meat, liver and products derived from animal reservoirs is sufficient heat treatment. The development of validated quantitative and qualitative detection methods, including infectivity assays and consensus molecular typing protocols, is required for the development of quantitative microbial risk assessments and efficient control measures. More research on the epidemiology and control of HEV in pig herds is required in order to minimise the proportion of pigs that remain viraemic or carry high levels of virus in intestinal contents at the time of slaughter. Consumption of raw pig, wild boar and deer meat products should be avoided.

Viability RT-qPCR to Distinguish Between HEV and HAV With Intact and Altered Capsids

“…Last year, the European Food Safety authority published recommendations for research needs regarding HEV and food, recommending that the average level of contamination in foods be quantitatively estimated and the correlation between HEV RNA detection and the infectivity of the virus be determined (Ricci et al, 2017). Currently, RT-qPCR is the gold standard method for HEV detection in food (van der Poel and Rzezutka, 2017); however, RT-qPCR does not always correlate with the number of infectious virus particles.…”

“…The World Health Organization estimates 20 million HEV infections worldwide yearly with over three million acute cases and 57,000 deaths 1 . In Europe, the number of confirmed cases of HEV has increased 10 times in the last decade (EFSA, 2017), making HEV issue a trending topic (Kupferschmidt, 2016; van der Poel and Rzezutka, 2017). …”

“…Molecular methods, particularly real-time reverse transcriptase polymerase chain reaction (RT-qPCR), have demonstrated high sensitivity, specificity, and ability to deliver reliable quantitative data in food and environmental samples (Martin-Latil et al, 2014, 2016; Di Bartolo et al, 2015; Mesquita et al, 2016), although such results do not indicate at the infectivity of detected viruses. In addition, alternative strategies to directly study infectivity such as cell culture systems and animal models do not seem to be reliable or practical yet (Ricci et al, 2017; Van der Poel et al, 2018), although promising results have been reported (Emerson et al, 2005; Johne et al, 2016; Imagawa et al, 2018). To enable the differentiation between infectious and inactivated viral particles, different approaches based on capsid integrity have been reported:…”

HEVnet: a One Health, collaborative, interdisciplinary network and sequence data repository for enhanced hepatitis E virus molecular typing, characterisation and epidemiological investigations

“…In Europe, hepatitis E is considered a zoonosis transmitted via contaminated pork meat or other pork food products. Genotype 3 and, to a lesser degree, genotype 4 are prevalent in the animal reservoir (pigs, wild boar and deer), as well as in humans [2]. There are occasional reports of HEV transmission through other routes, such as shellfish, salad or vegetables contaminated by sewage water carrying HEV from infected animals or humans [2-7].…”

“…Genotype 3 and, to a lesser degree, genotype 4 are prevalent in the animal reservoir (pigs, wild boar and deer), as well as in humans [2]. There are occasional reports of HEV transmission through other routes, such as shellfish, salad or vegetables contaminated by sewage water carrying HEV from infected animals or humans [2-7]. Infection through contaminated blood products or other substances of human origin have been reported, and some European countries (the United Kingdom, followed by Ireland and the Netherlands) have implemented comprehensive testing of blood donations to reduce infections among patients who are vulnerable to developing chronic hepatitis E [8].…”