Quantitative Methods for the Prioritization of Foods Implicated in the Transmission of Hepatititis E to Humans in Italy

Persistence of hepatitis E virus (HEV) subtypes 3c and 3e: Long-term cold storage and heat treatments

Hepatitis E virus (HEV) is the causative agent of foodborne infections occurring in high income countries mainly by consumption of undercooked and raw pork products. The virus is zoonotic with pigs and wild boars as the main reservoirs. Several studies proved the presence of HEV-RNA in pork liver sausages, pâté and other pork by-products. However, the detection of HEV nucleic acids does not necessary correspond to infectious virus and information on the persistence of the virus in the food is still limited. To which extent and how long the virus can survive after conventional industrial and home-made conservation and cooking procedures is largely unknown. In the present study, we investigated the persistence of two subtypes of HEV-3, by measuring the viral RNA on cell supernatant of infected A549 cells, after long-term storage at +4 °C and -20 °C and after heating for short or long-time span. Results confirmed that either low temperature storage (+4 °C) or freezing (-20 °C) do not influence the survival of the virus, and only a moderate reduction of presence of its RNA after 12 weeks at +4 °C was observed. To the other side, heating at 56 °C for long time (1 h) or at higher temperatures (>65 °C) for shorter time inactivated the virus successfully.

Hepatitis E Virus RNA Detection in Liver and Muscle Tissues Sampled from Home Slaughtered Domestic Pigs in Central Italy

Hepatitis E virus is a worldwide emerging foodborne pathogen; raw or undercooked meats and liver pork products can cause infection through the orofecal route. In Central-Southern Italy, small traditional farming method, associated with the possibility of environmental sharing with wild species, can facilitate HEV diffusion and persistence. The aim of this study was to determine HEV genotype and subtype in Marche region from home slaughtered domestic pigs involved in small and traditional food chains. A total of 236 liver and muscle tissues and 6 pooled salami samples were screened. Laboratory workflow started with homogenization, followed by RNA extraction. Nested reverse transcription PCR and qRT-PCR were used to amplify specific parts of overlapping open reading frames belonging to the HEV genome. A total of 42/236 (17.79%) liver and 8/236 (3.39%) diaphragm specimens were positive; none of the pooled salami specimens showed positive HEV signal. The discovered HEV3c presented high nucleotide similarities with ones amplified from wild boar populations hunted in the same province. Extensive farming methods and environmental sharing with wild animal species support cross-infection infections, as observed in the present study. Although salami resulted negative for HEV RNA detection, the effects of food technologies on viral loads remain unclear. Therefore, further scientific investigations coupled with efficacious standardized laboratory procedures will be the next challenge.

Assessing the efficacy of different bead-based assays in capturing hepatitis E virus

Hepatitis E virus (HEV) generally causes acute liver infection in humans and its transmission could be waterborne, foodborne, bloodborne, or zoonotic. To date, there is no standard method for the detection of HEV from food and environmental samples. Herein, we explored the possibility of using magnetic beads for the capture and detection of HEV. For this purpose, we employed Dynabeads M-270 Epoxy magnetic beads, coated with different monoclonal antibodies (mAbs) against HEV capsid protein, and the Nanotrap Microbiome A Particle magnetic beads, which are coated with chemical affinity baits, to capture HEV-3 particles in suspension. Viral RNA was extracted by heat-shock or QIAamp viral RNA kit and subjected to quantification using digital-droplet RT-PCR (ddRT-PCR). We demonstrated that the mAb-coupled Dynabeads and the Nanotrap particles, both were able to successfully capture HEV-3. The latter, however had lower limit of detection (<140gc compared with <1400 gc) and significantly higher extraction efficiency in comparison to the mAb-coupled Dynabeads (41.1% vs 8.8%). We have also observed that viral RNA extraction by heat-shock is less efficient compared to using highly denaturing reagents in QIAmp viral RNA extraction kit. As such, magnetic beads have the potential to be used to capture HEV virions for research and surveillance purposes.

Hepatitis A Virus and Hepatitis E Virus as Food- and Waterborne Pathogens-Transmission Routes and Methods for Detection in Food

Foodborne viruses are an important threat to food safety and public health. Globally, there are approximately 5 million cases of acute viral hepatitis due to hepatitis A virus (HAV) and hepatitis E virus (HEV) every year. HAV is responsible for numerous food-related viral outbreaks worldwide, while HEV is an emerging pathogen with a global health burden. The reported HEV cases in Europe have increased tenfold in the last 20 years due to its zoonotic transmission through the consumption of infected meat or meat products. HEV is considered the most common cause of acute viral hepatitis worldwide currently. This review focuses on the latest findings on the foodborne transmission routes of HAV and HEV and the methods for their detection in different food matrices.

Cross-sectional study of hepatitis E virus (HEV) circulation in Italian pig farms

Foodborne transmission is considered the main way of spreading zoonotic hepatitis E virus (HEV) infection in Europe. In recent years, the human cases of hepatitis E in subjects without history of travel in endemic areas have raised, suggesting that domestic HEV transmission is increasing. Pork products with or without liver, are often indicated as the source of many human foodborne HEV cases as well as small outbreaks. Pigs are recognized as the main reservoir of the zoonotic HEV-3 genotype, the most frequently detected in human cases in the EU. In the absence of a harmonized surveillance of HEV circulation, data on prevalence are heterogeneous but confirm a widespread circulation of HEV-3 in pig herds across EU. HEV-3 can pass through the food chain from farm to fork when infected animals are slaughtered. In Italy, several studies reported the circulation of HEV-3 in pig farms, but results are heterogeneous due to different methodologies applied. In the present study, we performed a survey over 51 pig herds belonging to three main types of farms: breeding, fattening and farrow-to-finish. HEV-RNA was analyzed by broad range Real-time RT-PCR on 20 samples for each farm, obtained by pooling together feces from 10 individuals. Overall, HEV RNA was confirmed on 150 fecal pooled samples out of 1,032 (14.5%). At least one positive pooled sample was detected from 18 farms out of 51 tested (35.3%). By lowering the number of infected pigs at primary production, the risk of HEV-3 entering into the food chain can be reduced. Hence, information on HEV circulation in herds is highly relevant for choosing preventive measures and deserves development of a monitoring program and further investigations.

Detection of hepatitis E virus RNA from pig bile collected at a slaughterhouse in Japan

Hepatitis E virus (HEV) is a zoonotic pathogen that circulates mainly between pigs and humans. In Japan, the number of confirmed HEV cases has increased over the past decade, with the majority reported as domestic HEV infections. HEV-infected pork products may be associated with this increase, but there is limited information on HEV in pork in Japanese markets. From February to March 2020, gallbladders were collected from 200 slaughtered pigs shipped from 14 farms and were surveyed to detect HEV RNA in bile using reverse transcription quantitative polymerase chain reaction. The samples were then sequenced and genotyped. Twenty pigs were positive for HEV ribonucleic acid, and seven samples had Ct values of less than 30. Among these 20 pigs, virus strains from 14 pigs were determined as genotype 3. This report indicated that HEV-contaminated pork liver was shipped to consumer markets and demonstrated the importance of detection of HEV in meat ready for shipment.

Hepatitis E Virus in Water Environments: A Systematic Review and Meta-analysis

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans, through foodborne, zoonotic, and waterborne transmission routes. This study aimed to assess the prevalence of HEV in water matrices. Six categories were defined: untreated and treated wastewater, surface water (river, lake, and seawater), drinking water, groundwater, and other water environments (irrigation water, grey water, reservoir water, flood water, and effluent of pig slaughterhouse). We searched PubMed, Web of Science, Global Index Medicus, and Excerpta Medica Database. Study selection and data extraction were performed by at least two independent investigators. Heterogeneity (I²) was assessed using the χ² test on the Cochran Q statistic and H parameter. Sources of heterogeneity were explored by subgroup analysis. This study is registered with PROSPERO, number CRD42021289116. We included 87 prevalence studies from 58 papers, 66.4% of which performed in Europe. The overall prevalence of HEV in water was 9.8% (95% CI 6.4-13.7). The prevalence was higher in untreated wastewater (15.1%) and lower in treated wastewater (3.8%) and in drinking water (4.7%). In surface water, prevalence was 7.4%, and in groundwater, the percentage of positive samples, from only one study available, was 8.3%. Overall, only 36.8% of the studies reported the genotype of HEV, with genotype 3 (HEV-3) prevalent (168 samples), followed by HEV-1 (148 sample), and HEV-4 (2 samples). High-income countries were the most represented with 59/87 studies (67.8%), while only 3/87 (3.5%) of the studies were performed in low-income countries. The overall prevalence obtained of this study was generally higher in industrialized countries. Risk of bias was low in 14.9% of the studies and moderate in 85.1%. The results of this review showed the occurrence of HEV in different waters environments also in industrialized countries with sanitation and safe water supplies. While HEV transmission to humans through water has been widely demonstrated in developing countries, it is an issue still pending in industrialized countries. Better knowledge on the source of pollution, occurrence, survival in water, and removal by water treatment is needed to unravel this transmission path.