High Proportion of Asymptomatic Infections in an Outbreak of Hepatitis E Associated With a Spit-Roasted Piglet, France, 2013

Hepatitis E and Potential Public Health Implications from a One-Health Perspective: Special Focus on the European Wild Boar (Sus scrofa)

The hepatitis E virus (HEV) has become increasingly important in recent years in terms of risk for public health, as the main causative agent of acute viral hepatitis. It is a foodborne disease transmitted to humans through the consumption of contaminated water or contaminated food. Human-to-human transmission is sporadic and is linked to transfusions or transplants. The main reservoirs of the hepatitis E virus are domestic pigs and wild boars, although, compared to pigs, wild boars represent a lesser source of risk since their population is smaller and the consumption of derived products is more limited. These peculiarities often make the role of the wild boar reservoir in the spread of the disease underestimated. As a public health problem that involves several animal species and humans, the management of the disease requires an interdisciplinary approach, and the concept of "One Health" must be addressed. In this direction, the present review intends to analyze viral hepatitis E, with a particular focus on wild boar. For this purpose, literature data have been collected from different scientific search engines: PubMed, MEDLINE, and Google scholar, and several keywords such as "HEV epidemiology", "Extrahepatic manifestations of Hepatitis E", and "HEV infection control measures", among others, have been used. In the first part, the manuscript provides general information on the disease, such as epidemiology, transmission methods, clinical manifestations and implications on public health. In the second part, it addresses in more detail the role of wild boar as a reservoir and the implications related to the virus epidemiology. The document will be useful to all those who intend to analyze this infectious disease from a "One-Health" perspective.

Large-scale HEV genotype 3 outbreak on New Caledonia Island

BACKGROUND AND AIMS

Several symptomatic cases of HEV infections were reported to the New Caledonia Island Public Health Service between August and December 2023. This prompted epidemiological and virological investigations to identify the source of infection.

APPROACH AND RESULTS

HEV RNA was assessed in symptomatic patients, various food items, and pig farms on the Island. HEV strains were characterized by sequencing. A seroprevalence study was also conducted on asymptomatic blood donors before and after the outbreak. One hundred twenty-seven symptomatic cases were reported. Hospitalization was required for 29/127 patients (22.8%). Hospitalized patients presented more frequently with comorbidities, including liver and cardiovascular diseases (80.7% vs. 27%, p < 0.01), and 3 persons died (2.3%). Among the 100 HEV RNA-positive samples received at the French National Reference Centre for HEV, viral sequencing was possible for 76 samples. All strains were identified as HEV genotype 3, and 74/76 strains were grouped together (nucleotide identity: 98%-100%). Full-length sequencing indicated a new HEV-3 subtype within HEV-3 subclade abk. Only genotype 3f strains were detected on the Island's pig farms. No food items tested positive for HEV RNA. The seroprevalence of HEV IgG and IgM in blood donors was 9.2% (9/98) and 0%, respectively, in 2020, rising to 17.3% (17/98) and 2% (2/98) in 2024.

CONCLUSIONS

Although all previous large-scale epidemics in Asia and Africa were associated with HEV-1 or 2, the New Caledonia outbreak was linked to HEV-3. A high number of symptomatic cases were admitted to the hospital, with a case-fatality rate of 2.3%.

Near full-length genome analysis of HEV 4b subtype in pigs showed a similarity up to 99.944% compared to a patient in Guangdong province, China

Hepatitis E virus (HEV) is a prevalent pathogen responsible for acute viral hepatitis, HEV genotypes 3 and 4 infections causing zoonotic infections. Currently, the nucleotide similarity analysis between humans and pigs for HEV genotype 4 is limited. In this study, stool samples from an HEV-infected patient who is a pig farmer and from pigs were collected to obtain the near full-length genome of HEV, phylogenetic trees were constructed for genotyping, and similarity of HEV sequences was analyzed. The results showed that HEV-RNA was detected in the stool samples from the patient and six pigs (6/30, 20.0%). Both HEV subtype in the patient and pigs was 4b. Additionally, similarity analysis showed that the range was 99.875%-99.944% between the patient and pigs at the nucleotide level. Four isolates of amino acid sequences (ORFs 1-3) from pigs were 100% identical to the patient. Phylogenetic tree and similarity analysis of an additional nine HEV sequences isolated from other patients in this region showed that the HEV sequence from the pig farmer had the closest relationship with the pigs from his farm rather than other sources of infection in this region. This study provides indirect evidences for HEV subtype 4b can be transmitted from pigs to humans at the nucleotide level. Further research is needed to explore the characteristics of different HEV subtypes.

Prevalence of Paslahepevirus balayani in commercial swine food products from Spain

Paslahepevirus balayani (formerly known as hepatitis E virus) is an emerging cause of foodborne disease in Europe, transmitted mainly by the consumption of raw or undercooked pork. Since little is known about the presence of the virus in several pork products that are eaten uncooked, our aim was to evaluate the prevalence of Paslahepevirus balayani in groups of commercial pork products intended for human consumption subjected to different processing techniques. A total of 1265 samples of pork products from Spain were divided into four groups and tested for the presence of Paslahepevirus balayani RNA: unprocessed pig and wild boar meat frozen at -20 °C (n = 389), dry-cured pork products (n = 391), dry-cured and salted pork products (n = 219), and boiled products (n = 266) (none of these products contained pork liver). Five samples were positive for Paslahepevirus balayani RNA (overall prevalence: 0.4%; 95% CI: 0.17% - 0.92%). All positive samples were from unprocessed meat stored at -20 °C, with a prevalence in this group of 1.3% (95% CI: 0.42-3.44); two samples came from pigs (1.1%; 95% CI: 0.13-3.81) and three from wild boar (1.5%; 95% CI: 0.31-4.28). None of the pork samples in the other groups was positive. In conclusion, Paslahepevirus balayani was found in unprocessed swine products form Spain, but not in processed products intended to be consumed undercooked, demonstrating that transmission of this zoonotic virus by eating these pork products should be more seriously considered.

Metabarcoding of Hepatitis E Virus Genotype 3 and Norovirus GII from Wastewater Samples in England Using Nanopore Sequencing

Norovirus is one of the largest causes of gastroenteritis worldwide, and Hepatitis E virus (HEV) is an emerging pathogen that has become the most dominant cause of acute viral hepatitis in recent years. The presence of norovirus and HEV has been reported within wastewater in many countries previously. Here we used amplicon deep sequencing (metabarcoding) to identify norovirus and HEV strains in wastewater samples from England collected in 2019 and 2020. For HEV, we sequenced a fragment of the RNA-dependent RNA polymerase (RdRp) gene targeting genotype three strains. For norovirus, we sequenced the 5' portion of the major capsid protein gene (VP1) of genogroup II strains. Sequencing of the wastewater samples revealed eight different genotypes of norovirus GII (GII.2, GII.3, GII.4, GII.6, GII.7, GII.9, GII.13 and GII.17). Genotypes GII.3 and GII.4 were the most commonly found. The HEV metabarcoding assay was able to identify HEV genotype 3 strains in some samples with a very low viral concentration determined by RT-qPCR. Analysis showed that most HEV strains found in influent wastewater were typed as G3c and G3e and were likely to have originated from humans or swine. However, the small size of the HEV nested PCR amplicon could cause issues with typing, and so this method is more appropriate for samples with high CTs where methods targeting longer genomic regions are unlikely to be successful. This is the first report of HEV RNA in wastewater in England. This study demonstrates the utility of wastewater sequencing and the need for wider surveillance of norovirus and HEV within host species and environments.

The Re-Emergence of Hepatitis E Virus in Europe and Vaccine Development

Hepatitis E virus (HEV) is one of the leading causes of acute viral hepatitis. Transmission of HEV mainly occurs via the fecal-oral route (ingesting contaminated water or food) or by contact with infected animals and their raw meat products. Some animals, such as pigs, wild boars, sheep, goats, rabbits, camels, rats, etc., are natural reservoirs of HEV, which places people in close contact with them at increased risk of HEV disease. Although hepatitis E is a self-limiting infection, it could also lead to severe illness, particularly among pregnant women, or chronic infection in immunocompromised people. A growing number of studies point out that HEV can be classified as a re-emerging virus in developed countries. Preventative efforts are needed to reduce the incidence of acute and chronic hepatitis E in non-endemic and endemic countries. There is a recombinant HEV vaccine, but it is approved for use and commercially available only in China and Pakistan. However, further studies are needed to demonstrate the necessity of applying a preventive vaccine and to create conditions for reducing the spread of HEV. This review emphasizes the hepatitis E virus and its importance for public health in Europe, the methods of virus transmission and treatment, and summarizes the latest studies on HEV vaccine development.

Clustered Cases of Waterborne Hepatitis E Virus Infection, France

The identification of seven cases of hepatitis E virus infection in a French rural hamlet in April 2015 led to investigations confirming the clustering and identifying the source of the infection. Laboratories and general practitioners in the area actively searched for other cases based on RT-PCR and serological tests. The environment, including water sources, was also checked for HEV RNA. Phylogenetic analyses were performed to compare HEV sequences. No other cases were found. Six of the seven patients lived in the same hamlet, and the seventh used to visit his family who lived there. All HEV strains were very similar and belonged to the HEV3f subgenotype, confirming the clustering of these cases. All the patients drank water from the public network. A break in the water supply to the hamlet was identified at the time the infection probably occurred; HEV RNA was also detected in a private water source that was connected to the public water network. The water flowing from the taps was quite turbid during the break. The private water supply containing HEV RNA was the likely source of the contamination. Private water supplies not disconnected from the public network are still frequent in rural areas, where they may contribute to public water pollution.

Food safety incidents in the red meat industry: A review of foodborne disease outbreaks linked to the consumption of red meat and its products, 1991 to 2021

Red meat is a significant source of human nutrition, and the red meat industry contributes to the economy of nations. Nonetheless, there is a widespread global concern about public health issues posed by severe food safety incidents within the red meat industry. Most of these incidents are associated with foodborne disease outbreaks that impact individual consumers, food businesses and society. This study adopts a systematic search and review approach to identify three decades of published investigation reports of global foodborne disease outbreaks linked with the consumption of red meat and products made from them. The review aims to evaluate the critical features of these outbreak incidents to get insight into their contributing factors and root causes. In particular, this review discusses the transmission setting (origin of pathogenic agents), the food vehicles mostly incriminated, the causative pathogens (bacteria, viruses, and parasites) causing the most illnesses, and the most commonly reported contributing factors to the outbreaks. This information can help researchers and food business operators (FBOs) inform future risk assessment studies and support risk management activities in developing risk-mitigating strategies for the industry. Findings from this study suggest that implementing food safety management strategies which include adequate control measures at all stages of the food chain, from farm to fork, is imperative in preventing outbreak incidents. Of equal importance is the need for enhanced and sustained public education about the risk of foodborne illnesses associated with meat and its products whilst discouraging the consumption of raw meat products, especially by high-risk groups.

Looking into sewage: how far can metagenomics help to detect human enteric viruses?

The impact of human sewage on environmental and food contamination constitutes an important safety issue. Indeed, human sewage reflects the microbiome of the local population, and a variety of human viruses can be detected in wastewater samples. Being able to describe the diversity of viruses present in sewage will provide information on the health of the surrounding population health and will help to prevent further transmission. Metagenomic developments, allowing the description of all the different genomes present in a sample, are very promising tools for virome analysis. However, looking for human enteric viruses with short RNA genomes which are present at low concentrations is challenging. In this study we demonstrate the benefits of performing technical replicates to improve viral identification by increasing contig length, and the set-up of quality criteria to increase confidence in results. Our approach was able to effectively identify some virus sequences and successfully describe the viral diversity. The method yielded full genomes either for norovirus, enterovirus and rotavirus, even if, for these segmented genomes, combining genes remain a difficult issue. Developing reliable viromic methods is important as wastewater sample analysis provides an important tool to prevent further virus transmission by raising alerts in case of viral outbreaks or emergence.

The first reported hepatitis E outbreak in a food manufacturing factory: Korea, 2022

OBJECTIVES

On February 16, 2022, 12 cases of hepatitis E virus (HEV) infection were reported in a food manufacturing factory in Korea. The aim of this study was to identify additional cases and to determine the source of this HEV outbreak.

METHODS

This study was an in-depth investigation of 12 HEV immunoglobulin M (IgM)-positive cases and their demographic, clinical, and epidemiological characteristics. On-site specimens were collected from the environment and from humans, and a follow-up investigation was conducted 2 to 3 months after the outbreak.

RESULTS

Among 80 production workers in the factory, 12 (15.0%) had acute HEV infection, all of whom were asymptomatic. The follow-up investigation showed that 3 cases were HEV IgMpositive, while 6 were HEV IgG-positive. HEV genes were not detected in the HEV IgM-positive specimens. HEV genes were not detected in the food products or environmental specimens collected on-site. HEV was presumed to be the causative pathogen. However, it could not be confirmed that the source of infection was common consumption inside the factory.

CONCLUSIONS

This was the first domestic case of an HEV infection outbreak in a food manufacturing factory in Korea. Our results provide information for the future control of outbreaks and for the preparation of measures to prevent domestic outbreaks of HEV infection.

Hepatitis E as a Zoonosis

Hepatitis E viruses in the family of Hepeviridae have been classified into 2 genus, 5 species, and 13 genotypes, involving different animal hosts of different habitats. Among all these genotypes, four (genotypes 3, 4, 7, and C1) of them are confirmed zoonotic causing sporadic human diseases, two (genotypes 5 and 8) were likely zoonotic showing experimental animal infections, and the other seven were not zoonotic or unconfirmed. These zoonotic HEV carrying hosts include pig, boar, deer, rabbit, camel, and rat. Taxonomically, all the zoonotic HEVs belong to the genus Orthohepevirus, which include genotypes 3, 4, 5, 7, 8 HEV in the species A and genotype C1 HEV in the species C. In the chapter, information of zoonotic HEV such as swine HEV (genotype 3 and 4), wild boar HEV (genotypes 3-6), rabbit HEV (genotype 3), camel HEV (genotype 7 and 8), and rat HEV (HEV-C1) was provided in detail. At the same time, their prevalence characteristics, transmission route, phylogenetic relationship, and detection technology were discussed. Other animal hosts of HEVs were introduced briefly in the chapter. All these information help peer researchers have basic understanding of zoonotic HEV and adopt reasonable strategy of surveillance and prevention.

Epidemiology of Hepatitis E

Hepatitis E virus (HEV) is globally prevalent with relatively high percentages of anti-HEV immunoglobulin G-positive individuals in the populations of developing and developed countries. There are two distinct epidemiological patterns of hepatitis E. In areas with high disease endemicity, primarily developing countries in Asia and Africa, this disease is caused mainly by genotypes HEV-1 or HEV-2; both genotypes transmit predominantly through contaminated water and occur as either outbreaks or sporadic cases of acute hepatitis. The acute hepatitis has the highest attack rate in young adults and is particularly severe among pregnant women. In developed countries, sporadic cases of locally acquired HEV-3 or HEV-4 infection are observed. The reservoir of HEV-3 and HEV-4 is believed to be animals, such as pigs, with zoonotic transmission to humans. The affected persons are often elderly, and persistent infection has been well documented among immunosuppressed persons. A subunit vaccine has been shown to be effective in preventing clinical disease and has been licensed in China.

Research needs for optimising wastewater-based epidemiology monitoring for public health protection

Wastewater-based epidemiology (WBE) is an unobtrusive method used to observe patterns in illicit drug use, poliovirus, and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The pandemic and need for surveillance measures have led to the rapid acceleration of WBE research and development globally. With the infrastructure available to monitor SARS-CoV-2 from wastewater in 58 countries globally, there is potential to expand targets and applications for public health protection, such as other viral pathogens, antimicrobial resistance (AMR), pharmaceutical consumption, or exposure to chemical pollutants. Some applications have been explored in academic research but are not used to inform public health decision-making. We reflect on the current knowledge of WBE for these applications and identify barriers and opportunities for expanding beyond SARS-CoV-2. This paper critically reviews the applications of WBE for public health and identifies the important research gaps for WBE to be a useful tool in public health. It considers possible uses for pathogenic viruses, AMR, and chemicals. It summarises the current evidence on the following: (1) the presence of markers in stool and urine; (2) environmental factors influencing persistence of markers in wastewater; (3) methods for sample collection and storage; (4) prospective methods for detection and quantification; (5) reducing uncertainties; and (6) further considerations for public health use.

Repeated cross-sectional sampling of pigs at slaughter indicates varying age of hepatitis E virus infection within and between pig farms

Humans can become infected with hepatitis E virus (HEV) by consumption of undercooked pork. To reduce the burden of HEV in humans, mitigation on pig farms is needed. HEV is found on most pig farms globally, yet within-farm seroprevalence estimates vary considerably. Understanding of the underlying variation in infection dynamics within and between farms currently lacks. Therefore, we investigated HEV infection dynamics by sampling 1711 batches of slaughter pigs from 208 Dutch farms over an 8-month period. Four farm types, conventional, organic, and two types with strict focus on biosecurity, were included. Sera were tested individually with an anti-HEV antibody ELISA and pooled per batch with PCR. All farms delivered seropositive pigs to slaughter, yet batches (resembling farm compartments) had varying results. By combining PCR and ELISA results, infection moment and extent per batch could be classified as low transmission, early, intermediate or late. Cluster analysis of batch infection moments per farm resulted in four clusters with distinct infection patterns. Cluster 1 farms delivered almost exclusively PCR negative, ELISA positive batches to slaughter (PCR⁻ELISA⁺), indicating relatively early age of HEV infection. Cluster 2 and 3 farms delivered 0.3 and 0.7 of batches with intermediate infection moment (PCR⁺ELISA⁺) respectively and only few batches with early infection. Cluster 4 farms delivered low transmission (PCR⁻ELISA⁻) and late infection (PCR⁺ELISA⁻) batches, demonstrating that those farms can prevent or delay HEV transmission to farm compartments. Farm type partly coincided with cluster assignment, indicating that biosecurity and management are related to age of HEV infection.

Sheet, Surveillance, Strategy, Salvage and Shield in global biodefense system to protect the public health and tackle the incoming pandemics

The pandemic of COVID-19 challenges the global health system and raises our concerns on the next waves of other emerging infectious diseases. Considering the lessons from the failure of world's pandemic warning system against COVID-19, many scientists and politicians have mentioned different strategies to improve global biodefense system, among which Sheet, Surveillance, Strategy, Salvage and Shield (5S) are frequently discussed. Nevertheless, the current focus is mainly on the optimization and management of individual strategy, and there are limited attempts to combine the five strategies as an integral global biodefense system. Sheet represents the biosafety datasheet for biohazards in natural environment and human society, which helps our deeper understanding on the geographical pattern, transmission routes and infection mechanism of pathogens. Online surveillance and prognostication network is an environmental Surveillance tool for monitoring the outbreak of pandemic diseases and alarming the risks to take emergency actions, targeting aerosols, waters, soils and animals. Strategy is policies and legislations for social distancing, lockdown and personal protective equipment to block the spread of infectious diseases in communities. Clinical measures are Salvage on patients by innovating appropriate medicines and therapies. The ultimate defensive Shield is vaccine development to protect healthy crowds from infection. Fighting against COVID-19 and other emerging infectious diseases is a long rocky journey, requiring the common endeavors of scientists and politicians from all countries around the world. 5S in global biodefense system bring a ray of light to the current darkest and future road from environmental and geographical perspectives.

Epidemiological survey and risk factors associated with hepatitis E virus in small ruminants in southern Spain

Autochthonous cases of hepatitis E (HE) associated with zoonotic genotypes HEV-3 and HEV-4 have significantly increased in industrialized countries over the last decade. Suidae are generally recognized as the main reservoirs of these genotypes. Susceptibility to HE virus (HEV) infection and zoonotic potential have also been confirmed in other species, including sheep and goat. However, the information about their role in the epidemiology of HEV remains very scarce. The objective of this study was to assess the prevalence, spatial distribution and risk factors associated with HEV exposure in sheep and goats in southern Spain, the country with the highest census of small domestic ruminants in the European Union. Blood samples from 240 sheep and 240 goats were collected between 2015 and 2017. Sera were analysed in parallel using a commercial double-antigen ELISA and real-time PCR. A total of 38 (7.9%; 95%CI: 5.5-10.3) out of 480 sampled animals showed anti-HEV antibodies. By species, the seroprevalences found in sheep and goats were 2.1% (5/240; 95%CI: 0.3-3.9) and 13.8% (33/240; 95%CI: 9.4-18.1) respectively. Anti-HEV antibodies were found on 19 (59.4%; 95%CI: 42.4-76.4) of the 32 sampled farms. The GEE model showed that species (goat) and number of small ruminants in the farm (≤348 animals and ≥538 animals) were risk factors potentially associated with HEV exposure in small ruminants in the study area. HEV RNA was not detected in any of the 480 (0.0%; 95%CI: 0.0-0.8) tested animals. Our results confirm that sheep and goats are naturally, but not equally exposed to HEV and indicate the widespread spatial distribution of HEV among small ruminant populations in southern Spain. Further studies are required to elucidate the role of sheep and goat in the epidemiology of HEV and their potential implications for public health.

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

Hepatitis E is considered an emerging foodborne disease in Europe. Several types of foods are implicated in the transmission of the hepatitis E virus (HEV) to humans, in particular, pork and wild boar products. We developed a parametric stochastic model to estimate the risk of foodborne exposure to HEV in the Italian population and to rank the relevance of pork products with and without liver (PL and PNL, respectively), leafy vegetables, shellfish and raw milk in HEV transmission. Original data on HEV prevalence in different foods were obtained from a recent sampling study conducted in Italy at the retail level. Other data were obtained by publicly available sources and published literature. The model output indicated that the consumption of PNL was associated with the highest number of HEV infections in the population. However, the sensitivity analysis showed that slight variations in the consumption of PL led to an increase in the number of HEV infections much higher than PNL, suggesting that PL at an individual level are the top risky food. Uncertainty analysis underlined that further characterization of the pork products preparation and better assessment of consumption data at a regional level is critical information for fine-tuning the most risky implicated food items in Italy.

Hepatitis E Virus Infection: Neurological Manifestations and Pathophysiology

Hepatitis E virus (HEV) is the first cause of viral hepatitis in the world. While the water-borne HEV genotypes 1 and 2 are found in developing countries, HEV genotypes 3 and 4 are endemic in developed countries due to the existence of animal reservoirs, especially swine. An HEV infection produces many extra-hepatic manifestations in addition to liver symptoms, especially neurological disorders. The most common are neuralgic amyotrophy or Parsonage–Turner syndrome, Guillain–Barré syndrome, myelitis, and encephalitis. The pathophysiology of the neurological injuries due to HEV remains uncertain. The immune response to the virus probably plays a role, but direct virus neurotropism could also contribute to the pathophysiology. This review describes the main neurological manifestations and their possible pathogenic mechanisms.

Estimating the burden and modeling mitigation strategies of pork-related hepatitis E virus foodborne transmission in representative European countries

Hepatitis E virus (HEV) is an emerging zoonotic pathogen posing global health burden, and the concerns in Europe are tremendously growing. Pigs serve as a main reservoir, contributing to pork-related foodborne transmission. In this study, we aim to specifically simulate this foodborne transmission route and to assess potential interventions. We firstly established a dose-response relationship between the risk of transmission to human and the amount of ingested viruses. We further estimated the incidence of HEV infection specifically attributed to pork-related foodborne transmission in four representative European countries. Finally, we demonstrated a proof-of-concept of mitigating HEV transmission by implementing vaccination in human and pig populations. Our modeling approach bears essential implications for better understanding the transmission of pork-related foodborne HEV and for developing mitigation strategies.

Global molecular diversity of Hepatitis E virus in wild boar and domestic pig

Our study aim was to describe and characterize the global Hepatitis E virus (HEV) molecular and genotype geographical distribution in domestic pig and wild boar, which could facilitate the traceability of human cases. We performed a systematic sequence search for HEVs identified in domestic pig and wild boar from the available data in GenBank. Only sequences with lengths greater than 300 nt were included. For all sequences, the sequence length, host (i.e., domestic pig or wild boar), country of origin, and HEV genotype/subtype were recorded. Genotypes were assigned by the HEVnet typing tool. The genotype distributions were described by country and host. In countries with sequences available for both species, the genotype coincidences between both animal populations were analyzed. A total of 1404 viral sequences were included: 32.6% from wild boar and 67.4% from domestic pig. Most sequences were consistent with HEV genotype 3 (n = 1165). Genotype 4 was represented by 193 sequences, while genotypes 5 and 6 were represented by only 6 sequences. Sequences were identified in 39 countries, which included all continents except Antarctica. The genotypes with a wide distribution were 3a and 3f. Twenty-five countries had sequences that were found only in domestic pig, three countries only in wild boar, and 11 countries had sequences in both populations. In all countries with available sequences in both populations, the same viral genotype was identified. Our study shows that the number of swine HEV sequences is small, which limits direct comparisons with the sequences identified in humans. The global distribution of genotype 3, together with the wide distribution of genotype 4 in Asia, strongly limits the interpretation of the molecular analysis in the absence of an epidemiological survey of the cases. Increased HEV sequencing in swine should be a priority.

•

Our study shows that the number of swine HEV sequences is small.

•

The global distribution of genotype 3 strongly limits the interpretation of the molecular analysis.

•

Increased HEV sequencing in swine should be a priority.

Porcine Blood and Liver as Sporadic Sources of Hepatitis E Virus (HEV) in the Production Chain of Offal-Derived Foodstuffs in Poland

Pig's blood and liver are valuable edible slaughter by-products which are also the major ingredients of offal-derived foodstuffs. The aim of the study was an evaluation of the occurrence of hepatitis E virus (HEV) and porcine adenovirus (pAdV) as an index virus of faecal contamination in pig's blood and liver for human consumption. In total, 246 samples of retail liver (n = 100) and pooled pig's blood (n = 146) were analysed for the presence of HEV and pAdV. Blood samples were individually collected from 1432 pigs at slaughter age. Viral genomic material, including RNA of a sample process control virus was isolated from food samples using a QIAamp® Viral RNA Mini Kit. Virus-specific IAC-controlled real-time PCR methods were used for detection of target viruses. HEV RNA was found in 6 (2.4%; 95% CI: 0.9-5.2) out of 246 samples of tested foodstuffs. The virus was detected in pig's blood (3.4%; 95% CI: 1.1-7.8) and liver (1.0%; 95% CI: 0.0-5.0) with no significant differences observed in the frequency of its occurrence between the two by-products (t = 1.33; p = 0.182 > 0.05); however PAdV was detected more frequently in pig's blood than in liver (t = 4.65; p = 0.000 < 0.05). The HEV strains belonged to the 3f and 3e subtype groups and the pAdV strains were assigned to serotype 5. PAdV was detected in pigs regardless of the farm size from which they originated. The number of animals raised on the farm (the farm size) had no influence on the occurrence of HEV or pAdV infections in pigs (F = 0.81, p = 0.447 > 0.05 for HEV; F = 0.42, p = 0.655 > 0.05 for pAdV). Although HEV was detected in pig's offal only sporadically, consumers cannot treat its occurrence with disregard as it demonstrates that HEV-contaminated pig tissues can enter the food chain.

Hepatitis E Outbreak in the Central Part of Italy Sustained by Multiple HEV Genotype 3 Strains, June-December 2019

In European countries, autochthonous acute hepatitis E cases are caused by Hepatitis E Virus (HEV) genotype 3 and are usually observed as sporadic cases. In mid/late September 2019, a hepatitis E outbreak caused by HEV genotype 3 was recognized by detection of identical/highly similar HEV sequences in some hepatitis E cases from two Italian regions, Abruzzo and Lazio, with most cases from this latter region showing a link with Abruzzo. Overall, 47 cases of HEV infection were finally observed with onsets from 8 June 2019 to 6 December 2019; they represent a marked increase as compared with just a few cases in the same period of time in the past years and in the same areas. HEV sequencing was successful in 35 cases. The phylogenetic analysis of the viral sequences showed 30 of them grouped in three distinct molecular clusters, termed A, B, and C: strains in cluster A and B were of subtype 3e and strains in cluster C were of subtype 3f. No strains detected in Abruzzo in the past years clustered with the strains involved in the present outbreak. The outbreak curve showed partially overlapped temporal distribution of the three clusters. Analysis of collected epidemiological data identified pork products as the most likely source of the outbreak. Overall, the findings suggest that the outbreak might have been caused by newly and almost simultaneously introduced strains not previously circulating in this area, which are possibly harbored by pork products or live animals imported from outside Abruzzo. This possibility deserves further studies in this area in order to monitor the circulation of HEV in human cases as well as in pigs and wild boars.

The Foodborne Transmission of Hepatitis E Virus to Humans

Globally, Hepatitis E virus (HEV) causes over 20 million cases worldwide. HEV is an emerging and endemic pathogen within economically developed countries, chiefly resulting from infections with genotype 3 (G3) HEV. G3 HEV is known to be a zoonotic pathogen, with a broad host range. The primary source of HEV within more economically developed countries is considered to be pigs, and consumption of pork products is a significant risk factor and known transmission route for the virus to humans. However, other foods have also been implicated in the transmission of HEV to humans. This review consolidates the information available regarding transmission of HEV and looks to identify gaps where further research is required to better understand how HEV is transmitted to humans through food.

Mechanism of Cross-Species Transmission, Adaptive Evolution and Pathogenesis of Hepatitis E Virus

Hepatitis E virus (HEV) is the leading cause of acute hepatitis worldwide. While the transmission in developing countries is dominated by fecal-oral route via drinking contaminated water, the zoonotic transmission is the major route of HEV infection in industrialized countries. The discovery of new HEV strains in a growing number of animal species poses a risk to zoonotic infection. However, the exact mechanism and the determinant factors of zoonotic infection are not completely understood. This review will discuss the current knowledge on the mechanism of cross-species transmission of HEV infection, including viral determinants, such as the open reading frames (ORFs), codon usage and adaptive evolution, as well as host determinants, such as host cellular factors and the host immune status, which possibly play pivotal roles during this event. The pathogenesis of hepatitis E infection will be briefly discussed, including the special forms of this disease, including extrahepatic manifestations, chronic infection, and fulminant hepatitis in pregnant women.

Lower Levels of Transaminases but Higher Levels of Serum Creatinine in Patients with Acute Hepatitis E in Comparison to Patients with Hepatitis A

In patients with hepatitis E virus (HEV) infections, extrahepatic, particularly renal and hematological manifestations, are increasingly reported in the medical literature but have never been studied compared to a control cohort. We retrospectively analyzed medical records of consecutive patients that were diagnosed with acute hepatitis E (AHE) (n = 69) or acute hepatitis A (AHA) (n = 46) at the University Medical Center Hamburg Eppendorf from January 2009 to August 2019 for demographical, clinical, and laboratory information. Patients with AHE had significantly lower median levels of ALAT (798 U/L) and total bilirubin (1.8 mg/dL) compared to patients with AHA (2326 U/L; p < 0.001 and 5.2 mg/dL; p < 0.001), suggesting a generally less severe hepatitis. In contrast, patients with AHE had significantly higher median serum creatinine levels (0.9 mg/dL vs. 0.8 mg/dL; p = 0.002) and lower median estimated glomerular filtration rate (eGFR) (91 mL/min/1.73 m² vs. 109 mL/min/1.73 m²; p < 0.001) than patients with AHA. Leucocyte, neutrophil and lymphocyte count, hemoglobin, platelets, red cell distribution width (RDW), neutrophil to lymphocyte ratio (NLR), and RDW to lymphocyte ratio (RLR) did not differ between patients with AHE and those with AHA. Our observations indicate that renal but not hematological interference presents an underrecognized extrahepatic feature of AHE, while inflammation of the liver seems to be more severe in AHA.

Presence of hepatitis E virus in commercially available pork products

An increasing number of hepatitis E virus (HEV) infections in industrialized countries have been foodborne and linked to the consumption of undercooked pork products. To date, data on the prevalence of HEV in pork products sold in the United States is limited and no standard processing method exists for the detection of HEV in foods. In order to develop a processing method for the detection of HEV in pork products, ground pork and pork liver were selected for method development. Murine norovirus (MNV) was used as a process control. A filtration step prior to RNA detection was shown to reduce the level of PCR inhibitors in ground pork and an additional ultracentrifugation process was successful in removing PCR inhibitors in pork liver. MNV RNA was detected in ground pork and liver samples inoculated with 4.7 log₁₀ PFU/g and 3.0 log₁₀ PFU/g, respectively. Using the developed method for viral RNA detection in ground pork and pork liver, 20 packages of ground pork (six 1 g sub-samples per package) and 14 pork livers (four 1 g sub-samples per liver) were screened for the presence of HEV RNA. Fifteen out of 119 (12.6%) ground pork samples tested positive for HEV RNA and 13 out of 20 packages (65%) contained at least one positive sample. Twenty-five of 56 (45%) of pork liver samples were positive for HEV RNA and 6 of 14 livers (43%) had all sub-samples test positive for HEV RNA. Overall, the results indicate ground pork and pig liver as a potential source of HEV.

Full-length genome sequencing of RNA viruses-How the approach can enlighten us on hepatitis C and hepatitis E viruses

Among the five main viruses responsible for human hepatitis, hepatitis C virus (HCV) and hepatitis E virus (HEV) are different while sharing similarities. Both viruses can be transmitted by blood or derivatives whereas HEV can also follow environmental or zoonotic routes. These highly variable RNA viruses can cause chronic hepatitis potentially leading to hepatocarcinoma. HCV and HEV can develop new structures and functions under selective pressure to adapt to host immunity, human tissues, treatments or even various animal reservoirs. Elsewhere, with directly acting antiviral treatments, HCV can be eradicated whereas HEV is an emerging pathogen against which specific treatments have to be improved. As a unique molecular tool able to explore viral genomic plasticity, full-length genome (FLG) sequencing has become easier, faster and cheaper. The present review will show how FLG sequencing can explore these RNA viruses with the aim to investigate key genomics data to improve basic knowledge, patients' healthcare and preventive tools.

Seroprevalence of hepatitis E virus among blood donors on Corsica, France, 2017

Background

Hepatitis E virus (HEV) is an emerging zoonotic pathogen and an important cause of acute viral hepatitis in European countries. Corsica Island has been previously identified as a hyperendemic area for HEV.

Aim

Our aim was to characterise the prevalence and titres of IgG antibodies to HEV among blood donors on Corsica and establish a model of the annual force of infection.

Methods

Between September 2017 and January 2018, 2,705 blood donations were tested for anti-HEV IgG using the Wantai HEV IgG enzyme immunoassay.

Results

The overall seroprevalence was 56.1%. In multivariate analysis, seroprevalence was higher in men than in women (60.0% vs 52.2%; p < 0.01), increased with age and was significantly higher among donors born on Corsica (60.6% vs 53.2%; p < 0.01). No significant difference was observed between the five districts of the island. IgG anti-HEV titres were mostly low (70% of positive donors had titres < 3 IU/mL). In Corsican natives, increasing seroprevalence by age could be explained by models capturing a loss of immunity (annual probability of infection: 4.5%; duration of immunity: 55 years) or by age-specific probabilities of infection (3.8% for children, 1.3% for adults).

Conclusion

We confirmed the high HEV seroprevalence on Corsica and identified three aspects that should be further explored: (i) the epidemiology in those younger than 18 years, (ii) common sources of contamination, in particular drinking water, that may explain the wide exposure of the population, and (iii) the actual protection afforded by the low IgG titres observed and the potential susceptibility to secondary HEV infection.

Hepatitis A and Hepatitis E: Clinical and Epidemiological Features, Diagnosis, Treatment, and Prevention

Hepatitis A and E are both ancient diseases but have only been properly recognized as being caused by distinct pathogens in modern times. Despite significantly different genomic structures, both viruses employ remarkably similar strategies to avoid host detection and increase environmental transmission. There are millions of cases of acute viral hepatitis due to hepatitis A virus (HAV) and hepatitis E virus (HEV) each year, resulting in tens of thousands of deaths. The presentations can be clinically indistinguishable, but each virus also has a range of less common but more specific phenotypes. The epidemiology of HAV is complex, and is shifting in countries that are making improvements to public health and sanitation. HEV presents a significant public health challenge in resource-limited settings but has historically been incorrectly regarded as having little clinical relevance in industrialized countries.

Clinical Characteristics of Acute Hepatitis E and Their Correlation with HEV Genotype 3 Subtypes in Italy

Genotype 3 (GT3) is responsible for most European autochthonous hepatitis E virus (HEV) infections. This study analyzed circulating genotypes and GT3 subtypes in the Lazio region, Italy, between 2011 and 2019, as well as their pathogenic characteristics. Of the 64 evaluable HEV GT3 patient-derived sequences, identified subtypes included GT3f (n = 36), GT3e (n = 15), GT3c (n = 9), GT3a (n = 1) and three unsubtyped GT3 sequences. GT3c strains were similar to Dutch sequences (96.8–98.1% identity), GT3e strains showed high similarity (96.8%) with a United Kingdom sequence, while the most related sequences to GT3f Italian strains were isolated in France, Belgium and Japan. One sequence was closely related to another Italian strain isolated in raw sewage in 2016. The liver functioning test median values for 56 evaluable GT3 patients were: alanine aminotransferase (ALT), 461 (range 52–4835 U/L); aspartate aminotransferase (AST), 659 (range 64–6588 U/L); and total bilirubin, 3.49 (range 0.4–33 mg/dL). The median HEV RNA viral load for 26 evaluable GT3 patients was 42,240 IU/mL (range 5680–895,490 IU/mL). Of the 37 GT3 patients with available clinical information, no correlation was observed between HEV clinical manifestations and GT3 subtype. HEV symptoms were comparable among GT3c/e/f patients across most analyzed categories except for epigastric pain, which occurred more frequently in patients with HEV GT3e (75%) than in patients with GT3c (50%) or GT3f (19%) (p = 0.01). Additionally, patients with HEV GT3c exhibited significantly higher median international normalized ratio (INR) than patients with GT3e and GT3f (p = 0.033). The severity of GT3 acute hepatitis E was not linked to HEV RNA viral load or to the GT3 subtype.

A between-herd data-driven stochastic model to explore the spatio-temporal spread of hepatitis E virus in the French pig production network

Hepatitis E virus is a zoonotic pathogen for which pigs are recognized as the major reservoir in industrialised countries. A multiscale model was developed to assess the HEV transmission and persistence pattern in the pig production sector through an integrative approach taking into account within-farm dynamics and animal movements based on actual data. Within-farm dynamics included both demographic and epidemiological processes. Direct contact and environmental transmission routes were considered along with the possible co-infection with immunomodulating viruses (IMVs) known to modify HEV infection dynamics. Movements were limited to 3,017 herds forming the largest community on the swine commercial network in France and data from the national pig movement database were used to build the contact matrix. Between-herd transmission was modelled by coupling within-herd and network dynamics using the SimInf package. Different introduction scenarios were tested as well as a decrease in the prevalence of IMV-infected farms. After introduction of a single infected gilt, the model showed that the transmission pathway as well as the prevalence of HEV-infected pigs at slaughter age were affected by the type of the index farm, the health status of the population and the type of the infected farms. These outcomes could help design HEV control strategies at a territorial scale based on the assessment of the farms' and network's risk.

Virological analyses in collective catering outbreaks in France between 2012 and 2017

Enteric viruses cause the majority of foodborne illnesses and common symptoms of many foodborne illnesses include vomiting, diarrhea, abdominal pain, and fever. Among the enteric viruses, human Norovirus (NoV) and hepatitis virus (HAV and HEV) are the main viruses suspected to cause foodborne outbreaks and represent a serious public health. The study presents survey tools of viruses in a wide variety of foodstuffs and results obtained during 56 foodborne outbreaks investigation in France between 2012 and 2017. 246 suspected foods were examined for the presence of four human enteric viruses (NoV GI and NoV GII, HAV or HEV) either using methods described in the EN ISO 15216-1 or in house methods. All viral analysis of food samples were performed with the implementation of process control and an external amplification controls. Eighteen of 56 foodborne outbreaks investigated included at least one positive food sample (16/18 NoV, 1/18 HAV and 1/18 HEV). The genomic levels of four viruses detected ranged from < 10² to 10⁷ genome copies per g or per L. This study showed the interest to develop methods for the extraction of viruses in different foodstuffs to increase the possibility to identify the association between viral illness and food consumption.

Mortality and morbidity of locally acquired hepatitis E in the national Scottish cohort: a multicentre retrospective study

BACKGROUND

Hepatitis E virus (HEV) is the most common acute viral hepatitis in Scotland. Little is known about the burden of morbidity and mortality, which can be high in chronic liver disease or immunocompromised states.

AIMS

To record the morbidity and mortality of HEV in Scotland.

METHODS

Demographic, clinical and laboratory data were collected retrospectively from all cases of HEV reported to virology departments across nine NHS health boards, between January 2013 and January 2018.

RESULTS

Five hundred and eleven cases were included (Mean age 62, 64% male). 58 (11%) cases had pre-existing cirrhosis and 110 (21%) had diabetes. Three hundred and three patients required admission (59%), totalling 2747 inpatient bed days. Seventeen (3.3%) HEV-related deaths were recorded. Factors that predicted mortality included haematological malignancy (OR 51.56, 95% CI 3.40-782.83, P = 0.005), cirrhosis (OR 41.85, 95% CI 2.85-594.16, P = 0.006), higher serum bilirubin (OR 1.01, 95% CI 1.01-1.02, P = 0.011) and chronic HEV infection (OR 0.02, 95% CI 0.02-0.28, P < 0.001). HEV infection affected 35 transplant patients of 106 total immunosuppressed patients (21%). Of these, 25 patients received Ribavirin therapy with a sustained virological remission of 76%. Thirty-five (6.7%) patients developed acute or acute-on-chronic liver failure with two requiring transplant. Thirty-seven (7.2%) patients reported neurological complications with 10 developing neuralgic amyotrophy, 6 Guillain-Barré and 2 encephalitis. Forty-four (8.6%) patients developed acute kidney injury.

CONCLUSION

In Scotland, HEV causes a significant burden of inpatient admissions, organ failure and death. Cirrhosis and haematological malignancy are significant predictors of mortality. Neurological and renal complications occur in a significant minority.

Swine hepatitis E virus: Cross-species infection, pork safety and chronic infection

Swine hepatitis E virus (swine HEV) belongs to the species Orthohepevirus A within the genus Orthohepevirus in the family Hepeviridae. Four different genotypes of swine HEV within the species Orthohepevirus A have been identified so far from domesticated and wild swine population: genotypes 3 (HEV-3) and 4 (HEV-4) swine HEVs are zoonotic and infect humans, whereas HEV-5 and HEV-6 are only identified from swine. As a zoonotic agent, swine HEV is an emerging public health concern in many industrialized countries. Pigs are natural reservoir for HEV, consumption of raw or undercooked pork is an important route of foodborne HEV transmission. Occupational risks such as direct contact with infected pigs also increase the risk of HEV transmission in humans. Cross-species infection of HEV-3 and HEV-4 have been documented under experimental and natural conditions. Both swine HEV-3 and swine HEV-4 infect non-human primates, the surrogates of man. Swine HEV, predominantly HEV-3, can establish chronic infection in immunocompromised patients especially in solid organ transplant recipients. The zoonotic HEV-3, and to lesser extent HEV-4, have also been shown to cause neurological diseases and kidney injury. In this review, we focus on the epidemiology of swine HEV, host and viral determinants influencing cross-species HEV infection, zoonotic infection and its associated pork safety concern, as well as swine HEV-associated chronic infection and neurological diseases.

Hepatitis E: an expanding epidemic with a range of complications

BACKGROUND

Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Previously considered a disease of the developing world, it is increasingly recognized that locally acquired HEV infection is common in industrialized countries.

OBJECTIVES

The aim was to highlight the changing epidemiology of HEV infection, particularly in the developed world, and inform clinicians of the diverse clinical presentations and extra-hepatic complications associated with the virus.

SOURCES

References for this review were identified through searches of MEDLINE/PubMed, and Google Scholar, up to January 2020. Searches were restricted to articles published in English.

CONTENT

Hepatitis E virus is an under-recognized, emerging pathogen with important implications for public health in both the developing and developed world. The number of cases reported in resource-rich settings is increasing, in part due to improved case ascertainment but also as a result of increased incidence in some countries. The reasons behind these epidemiological shifts are not currently known. Chronic HEV infection has been reported in immunocompromised patients. A range of extra-hepatic manifestations have also been reported, most notably neurological and renal complications. There is evidence to suggest a causal link with Guillain-Barré syndrome, neuralgic amyotrophy and encephalitis/myelitis. Glomerular disease has been reported in the context of both acute and chronic infection.

IMPLICATIONS

HEV should be included in non-invasive liver screens and considered in the differentials for patients presenting with alanine aminotransferase elevation, suspected drug-induced liver injury or decompensated liver disease. Any patients with acute neurological injury and deranged liver function should be tested for hepatitis E, and all patients presenting with Guillain-Barré syndrome or neuralgic amyotrophy should be tested regardless of liver enzymes. Immunocompromised patients with persistently raised liver enzymes should be tested with molecular techniques and offered annual routine screening.

Individual animal and herd level seroprevalence and risk factors of Hepatitis E in ruminants in Jordan

OBJECTIVES

Hepatitis E virus (HEV) is zoonotic and endemic in several countries. There are no data on the farm level-prevalence and risk factors of HEV in ruminant farms in Jordan or elsewhere. This study aimed to estimate the seroprevalence and risk factors of HEV in ruminant farms in all regions of Jordan.

MATERIAL AND METHODS

A total of 460 apparently healthy ruminants from 115 (31 cow, 51 sheep and 33 goat) farms were tested for HEV antibodies using a double antigen sandwich enzyme linked immunosorbent test. A validated questionnaire was used to collect data on animal health and husbandry practices.

RESULTS

The results showed that 37.4% of the dairy farms under study (51.6%, 37.2% and 24.2% of dairy cow, sheep and goat farms; respectively) had at least one HEV seropositive animal. At the individual animal level, 12.1% of the tested animals were HEV positive; 14.5% (n = 18), 12.7% (n = 26) and 8.3% (n = 11) of cows, sheep and goats; respectively. Infrequent cleaning of feeders was associated with a significantly greater odds of HEV seropositivity in both large and small dairy ruminant farms (AOR = 16.0, p-val = 0.03, AOR = 3.4, p-val = 0.02, respectively). Farms which reported that small ruminants (sheep and goats) were mixed together had a greater odds of farm-level HEV seroprevalence (AOR = 3.1, p-val = 0.04).

CONCLUSIONS

This study shows widespread and high farm-level HEV seroprevalence in dairy farms in Jordan. Husbandry practices and off-abattoir carcass processing in Jordan could amplify emergence and transmission of zoonotic HEV. Future studies should include HEV genotyping in ruminants, their products and humans to better understand HEV epidemiology in Jordan.

Hepatitis E virus is an infrequent but potentially serious infection in allogeneic hematopoietic stem cell transplant recipients

Hepatitis E virus (HEV) can cause chronic infection and liver cirrhosis in immunocompromised individuals. The frequency and clinical importance of HEV was studied retrospectively in a cohort of 236 Swedish allogeneic hematopoietic stem cell transplantation (HSCT) recipients. In blood samples collected at 6 months after HSCT, HEV RNA was identified in 8/236 (3.4%) patients, and 11/236 (4.7%) patients had detectable anti-HEV IgG and/or IgM, eight of whom were HEV RNA negative. Two of the patients with positive HEV RNA died with ongoing signs of hepatitis: one of acute liver and multiple organ failure, the other of unrelated causes. The remaining six patients with HEV RNA had cleared the infection at 7-24 (median 8.5) months after HSCT. HEV infection was associated with elevated alanine aminotransferase at 6 months after HSCT (OR 15, 1.3-174, p = 0.03). Active graft-versus-host disease of the liver at 6 months after HSCT was present in 3/8 (38%) patients with HEV RNA, but was not significantly associated with HEV infection. In conclusion, HEV infection is an important differential diagnosis in patients with elevated liver enzymes after HSCT. Although spontaneous clearance was common, the clinical course may be severe.

Hepatitis E: a largely underestimated, emerging threat

Hepatitis E virus has two distinct clinical and epidemiological patterns based on the varying genotypes. Genotypes 3 and 4 cause widespread, sporadic infection in high-income countries and are emerging as the most common type of viral hepatitis in much of Europe. These infections carry significant morbidity and mortality in the growing numbers of immunosuppressed patients or in patients with established liver disease. Furthermore the growing extra-hepatic associations of the virus, including neurological and kidney injury, suggest that it may have been misnamed as a 'hepatitis' virus. This review explores current understanding of the epidemiology, virology and clinical presentations of hepatitis E infection and identifies vulnerable patient groups, who are at serious risk from infection. Guidance is offered regarding the diagnosis, treatment and prevention of this growing public health hazard.

Clinical Manifestations, Pathogenesis and Treatment of Hepatitis E Virus Infections

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis throughout the world. Most infections are acute but they can become chronic in immunocompromised patients, such as solid organ transplant patients, patients with hematologic malignancy undergoing chemotherapy and those with a human immunodeficiency virus (HIV) infection. Extra-hepatic manifestations, especially neurological and renal diseases, have also been described. To date, four main genotypes of HEV (HEV1-4) were described. HEV1 and HEV2 only infect humans, while HEV3 and HEV4 can infect both humans and animals, like pigs, wild boar, deer and rabbits. The real epidemiology of HEV has been underestimated because most infections are asymptomatic. This review focuses on the recent advances in our understanding of the pathophysiology of acute HEV infections, including severe hepatitis in patients with pre-existing liver disease and pregnant women. It also examines the mechanisms leading to chronic infection in immunocompromised patients and extra-hepatic manifestations. Acute infections are usually self-limiting and do not require antiviral treatment. Conversely, a chronic HEV infection can be cleared by decreasing the dose of immunosuppressive drugs or by treating with ribavirin for 3 months. Nevertheless, new drugs are needed for those cases in which ribavirin treatment fails.

Detection and genomic characterization of hepatitis E virus genotype 3 from pigs in Ghana, Africa

BACKGROUND

Hepatitis E virus (HEV) is a major cause of human hepatitis worldwide. Zoonotic genotypes of the virus have been found in diverse animal species with pigs playing a major role. Putative risk of zoonotic infection from livestock particularly swine in Sub-Saharan Africa including Ghana is poorly understood due to scarcity of available data, especially HEV sequence information.

METHODS

Serum samples were collected from cattle, sheep, goats and pigs from Kumasi in the Ashanti region of Ghana. Samples were subjected to nested RT-PCR screening and quantification of HEV RNA-positive samples using real-time RT-PCR and the World Health Organization International Standard for HEV. Testing of all pig samples for antibodies was done by ELISA. Sanger sequencing and genotyping was performed and one representative complete genome was generated to facilitate genome-wide comparison to other available African HEV sequences by phylogenetic analysis.

RESULTS

A total of 420 samples were available from cattle (n = 105), goats (n = 124), pigs (n = 89) and sheep (n = 102). HEV Viral RNA was detected only in pig samples (10.1%). The antibody detection rate in pigs was 77.5%, with positive samples from all sampling sites. Average viral load was 1 × 10⁵ (range 1.02 × 10³ to 3.17 × 10⁵) International Units per mL of serum with no statistically significant differences between age groups (≤ 6 month, > 6 months) by a T-test comparison of means (t = 1.4272, df = 7, p = 0.1966). Sequences obtained in this study form a monophyletic group within HEV genotype 3. Sequences from Cameroon, Ghana, Burkina Faso and Madagascar were found to share a most recent common ancestor; however this was not the case for other African HEV sequences.

CONCLUSION

HEV genotype 3 is highly endemic in pigs in Ghana and likely poses a zoonotic risk to people exposed to pigs. HEV genotype 3 in Ghana shares a common origin with other virus strains from Sub-Saharan Africa.

Controlling hepatitis E virus in the pig production sector: Assessment of the technical and behavioural feasibility of on-farm risk mitigation strategies

Hepatitis E virus (HEV) is a zoonotic agent with pigs as the main reservoir in industrialised countries. Recent studies conducted on pig farms, in experimental conditions or through modelling approaches, have led to a better understanding of the spread of HEV on pig farms. The findings have also made it possible to define a set of measures to reduce HEV prevalence and the risk of marketing contaminated products. The objective of this study was to assess the feasibility of a set of HEV control strategies on pig farms. Individual semi-structured interviews were conducted with farmers, veterinarians and farming advisors to collect general data, their level of knowledge of HEV, their opinion on the technical feasibility of certain changes in practices, their perception of the respective responsibilities of the different stakeholders, and their feelings about the importance of the issue, following the framework of the Theory of Planned Behaviour. The interviews made it possible to highlight potential barriers and preferred motivators for the implementation of on-farm risk mitigation strategies. Barriers included lack of knowledge, scientific gaps, perceived inability to control HEV, and low perception of the importance of the issue. Motivators included professional satisfaction, family recognition, and the opportunity to achieve higher quality standards. Three clusters of stakeholders were also identified, with a group of leaders who could help unlock reluctance and disseminate innovations. This type of behavioural approach appeared useful to help risk managers facilitate zoonotic control on pig farms.

Hepatitis E virus genotype 3 is associated with gallstone-related disease

Objective: Hepatitis E virus (HEV) genotype 3 is endemic in Northern Europe and despite a high seroprevalence of anti-HEV IgG antibodies among blood donors (≈17%), few clinical cases are notified in Sweden. Low awareness of hepatitis E and its possible symptoms may contribute to this discrepancy. The aim of this study was to investigate the prevalence of acute HEV infection among hospital admitted patients with abdominal pain and elevated liver enzymes.Materials and methods: During 2016-2017, 148 adult patients with serum alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > twice normal levels were prospectively enrolled at surgical wards at three Swedish hospitals. Serum samples were analyzed for HEV RNA as well as anti-HEV IgM and IgG, and medical records were reviewed.Results: Six (6/148, 4.1%) patients were HEV infected confirmed by detectable HEV RNA, but only one of these patients had detectable anti-HEV antibodies. Four of the HEV infected patients were diagnosed with gallstone-related disease: three with biliary pancreatitis and one with biliary colic. The remaining two were diagnosed with bowel obstruction and pancreatic malignancy. Four HEV strains were typed by sequencing to genotype 3.Conclusions: This study identified acute HEV3 infection in 4% of the patients with elevated liver enzymes admitted to a surgical ward. HEV infection was not the solitary disease leading to hospitalization, instead it was found to be associated with other surgical conditions such as gallstone-related disease including biliary pancreatitis. Additionally, HEV RNA might be the preferential diagnostic tool for detecting ongoing HEV infection.

Hepatitis E virus (HEV) in Scotland: evidence of recent increase in viral circulation in humans

BackgroundPrevious studies showed low levels of circulating hepatitis E virus (HEV) in Scotland. We aimed to reassess current Scottish HEV epidemiology. Methods: Blood donor samples from five Scottish blood centres, the minipools for routine HEV screening and liver transplant recipients were tested for HEV antibodies and RNA to determine seroprevalence and viraemia. Blood donor data were compared with results from previous studies covering 2004-08. Notified laboratory-confirmed hepatitis E cases (2009-16) were extracted from national surveillance data. Viraemic samples from blood donors (2016) and chronic hepatitis E transplant patients (2014-16) were sequenced. Results: Anti-HEV IgG seroprevalence varied geographically and was highest in Edinburgh where it increased from 4.5% in 2004-08) to 9.3% in 2014-15 (p = 0.001). It was most marked in donors < 35 years. HEV RNA was found in 1:2,481 donors, compared with 1:14,520 in 2011. Notified laboratory-confirmed cases increased by a factor of 15 between 2011 and 2016, from 13 to 206. In 2011-13, 1 of 329 transplant recipients tested positive for acute HEV, compared with six cases of chronic infection during 2014-16. Of 10 sequenced viraemic donors eight and all six patients were infected with genotype 3 clade 1 virus, common in European pigs. Conclusions: The seroprevalence, number of viraemic donors and numbers of notified laboratory-confirmed cases of HEV in Scotland have all recently increased. The causes of this change are unknown, but need further investigation. Clinicians in Scotland, particularly those caring for immunocompromised patients, should have a low threshold for testing for HEV.

Tackling hepatitis E virus spread and persistence on farrow-to-finish pig farms: Insights from a stochastic individual-based multi-pathogen model

Hepatitis E virus (HEV) is a zoonotic agent of which domestic pigs have been recognised as the main reservoir in industrialised countries. The great variability in HEV infection dynamics described on different pig farms may be related to the influence of other pathogens, and in particular viruses affecting pigs' immune response. The objective of this study was to develop a multi-pathogen modelling approach to understand the conditions under which HEV spreads and persists on a farrow-to-finish pig farm taking into account the fact that pigs may be co-infected with an intercurrent pathogen. A stochastic individual-based model was therefore designed that combines a population dynamics model, which enables us to take different batch rearing systems into account, with a multi-pathogen model representing at the same time the dynamics of both HEV and the intercurrent pathogen. Based on experimental and field data, the epidemiological parameters of the HEV model varied according to the pig's immunomodulating virus status. HEV spread and persistence was found to be very difficult to control on a farm with a 20-batch rearing system. Housing sows in smaller groups and eradicating immunomodulating pathogens would dramatically reduce the prevalence of HEV-positive livers at slaughter, which would drop from 3.3% to 1% and 0.2% respectively (p-value < 0.01). It would also decrease the probability of HEV on-farm persistence from 0.6 to 0 and 0.34 respectively (p-value < 0.01) on farms with a 7 batch rearing system. A number of farming practices, such as limiting cross-fostering, reducing the size of weaning pens and vaccinating pigs against immunomodulating viruses, were also shown to be pivotal factors for decreasing HEV spread and persistence.

Hepatitis E Virus Infection in Blood Donors and Risk to Patients in the United States and Canada

Hepatitis E virus (HEV) is the most common cause of acute hepatitis worldwide including large water-borne outbreaks, zoonotic infections and transfusion transmissions. Several countries have initiated or are considering blood donor screening in response to high HEV-RNA donation prevalence leading to transfusion-transmission risk. Because HEV transmission is more common through food sources, the efficacy of blood donor screening alone may be limited. HEV-nucleic acids in 101 489 blood donations in the United States and Canada were studied. A risk-based decision-making framework was used to evaluate the quantitative risks and cost-benefit of HEV-blood donation screening in Canada comparing three scenarios: no screening, screening blood for all transfused patients or screening blood for only those at greatest risk. HEV-RNA prevalence in the United States was one per 16 908 (95% confidence interval [CI], 1:5786-1:81987), whereas Canadian HEV-RNA prevalence was one per 4615 (95% CI, 1:2579-1:9244). Although 4-fold greater, Canadian HEV-RNA prevalence was not significantly higher than in the United States. Viral loads ranged from 20 to 3080 international units per mL; all successfully typed infections were genotype 3. No HEV-RNA false-positive donations were identified for 100 percent specificity. Without donation screening, heart and lung transplant recipients had the greatest HEV-infection risk (1:366962) versus kidney transplant recipients with the lowest (1:2.8 million) at costs of $225 546 to $561 810 per quality-adjusted life-year (QALY) gained for partial or universal screening, respectively. Higher cost per QALY would be expected in the United States. Thus, HEV prevalence in North America is lower than in countries performing blood donation screening, and if implemented, is projected to be costly under any scenario.

Comparative Seroprevalence of Hepatitis A And E Viruses in Blood Donors from Wielkopolska Region, West-Central Poland

The objective of the present study was to investigate the seroprevalence of HAV and HEV in Polish blood donors (BDs). One hundred and ten randomly selected healthy BDs, living in Wielkopolska Region were tested for anti-HAV IgG and anti-HEV IgG with commercial assays. The seroprevalence of anti-HAV was 11.8%; anti-HEV were detected in 60.9% of BDs (p < 0.0001). Consumption of risky food was more common in anti-HEV-positive BDs (59.1% vs. 33.3%; p = 0.01). Twelve out of 20 BDs (60%) with no history of travel abroad were exposed to HEV. Wielkopolska Region, Poland should be regarded as a new HEV infection-hyperendemic area in Europe.

Impact of porcine circovirus type 2 (PCV2) infection on hepatitis E virus (HEV) infection and transmission under experimental conditions

Hepatitis E virus is a zoonotic pathogen for which pigs have been identified as the main reservoir in industrialised countries. HEV infection dynamics in pig herds and pigs are influenced by several factors, including herd practices and possibly co-infection with immunomodulating viruses. This study therefore investigates the impact of porcine circovirus type 2 (PCV2) on HEV infection and transmission through experimental HEV/PCV2 co-infection of specific-pathogen-free pigs. No statistical difference between HEV-only and HEV/PCV2-infected animals was found for either the infectious period or the quantity of HEV shed in faeces. The HEV latency period was shorter for HEV/PCV2 co-infected pigs than for HEV-only infected pigs (11.6 versus 12.3 days). Its direct transmission rate was three times higher in cases of HEV/PCV2 co-infection than in cases of HEV-only infection (0.12 versus 0.04). On the other hand, the HEV transmission rate through environmental accumulation was lower in cases of HEV/PCV2 co-infection (4.3·10^-6 versus 1.5·10^-5 g/RNA copies/day for HEV-only infected pigs). The time prior to HEV seroconversion was 1.9 times longer in HEV/PCV2 co-infected pigs (49.4 versus 25.6 days for HEV-only infected pigs). In conclusion, our study shows that PCV2 affects HEV infection and transmission in pigs under experimental conditions.

Hepatitis E virus strains infecting Swedish domestic pigs are unique for each pig farm and remain in the farm for at least 2 years

Hepatitis E virus (HEV) genotype 3 (HEV3) is distributed globally and infects both humans and animals, mainly domestic pigs and wild boars, which are the major reservoirs. In this study, the prevalence of HEV among Swedish pigs was investigated by HEV RNA analysis in 363 faecal samples from 3-month-old piglets sampled twice (2013 and 2014) in 30 Swedish pig farms. Four different types of farms were investigated; organic, conventional closed (keeping the sow), satellites in a sow pool (conventional farms sharing sows) and conventional non-closed farms (purchasing gilts). More than two-thirds (77%) of the farms had HEV-infected pigs. HEV RNA was found in faeces from 79 pigs (22%). Partial ORF1 could be sequenced in 46 strains. Phylogenetic analysis revealed a unique HEV3 strain for each farm. Strains sampled more than a year apart from the same farm were closely related, indicating that the same HEV strain is present for several years on the farm. Despite that only 4% of the Swedish pig farms were investigated, two farms had strains similar to those from humans, another had strains similar to wild boar HEV. The uniqueness of strains from each farm indicates a possibility to identify a source of infection down to farm level. This knowledge may be used by the farms to investigate the effectiveness of good hygiene routines to reduce the amount of HEV and thus the infection risk in the farm, and for Swedish public health authorities to identify cases of HEV transmissions from consumption of uncooked pork.

Hepatitis E virus (HEV)-The Future

Hepatitis (HEV) is widely distributed in pigs and is transmitted with increasing numbers to humans by contact with pigs, contaminated food and blood transfusion. The virus is mostly apathogenic in pigs but may enhance the pathogenicity of other pig viruses. In humans, infection can lead to acute and chronic hepatitis and extrahepatic manifestations. In order to stop the emerging infection, effective counter-measures are required. First of all, transmission by blood products can be prevented by screening all blood donations. Meat and sausages should be appropriately cooked. Elimination of the virus from the entire pork production can be achieved by sensitive testing and elimination programs including early weaning, colostrum deprivation, Caesarean delivery, embryo transfer, treatment with antivirals, protection from de novo infection, and possibly vaccination. In addition, contaminated water, shellfish, vegetables, and fruits by HEV-contaminated manure should be avoided. A special situation is given in xenotransplantation using pig cells, tissues or organs in order to alleviate the lack of human transplants. The elimination of HEV from pigs, other animals and humans is consistent with the One Health concept, preventing subclinical infections in the animals as well as preventing transmission to humans and disease.

Genetically similar hepatitis E virus strains infect both humans and wild boars in the Barcelona area, Spain, and Sweden

Hepatitis E virus (HEV) is a hepatotropic virus, endemic in Europe where it infects humans and animals, with domestic pigs and wild boars as main reservoirs. The number of HEV-infected cases with unknown source of infection increases in Europe. There are human HEV strains genetically similar to viruses from domestic pigs, and zoonotic transmission via consumption of uncooked pork meat has been shown. Due to continuous growth of the wild boar populations in Europe, another route may be through direct or indirect contacts with wild boars. In the Collserola Natural Park near Barcelona, Spain, the wild boars have spread into Barcelona city. In Sweden, they are entering into farmlands and villages. To investigate the prevalence of HEV and the risk for zoonotic transmissions, the presence of antibodies against HEV and HEV RNA were analysed in serum and faecal samples from 398 wild boars, 264 from Spain and 134 from Sweden and in sera from 48 Swedish patients with HEV infection without known source of infection. Anti-HEV was more commonly found in Spanish wild boars (59% vs. 8%; p < 0.0001) while HEV RNA had similar prevalence (20% in Spanish vs. 15% in Swedish wild boars). Seven Swedish and three Spanish wild boars were infected with subtype 3f, and nine Spanish with subtype 3c/i. There were three clades in the phylogenetic tree formed by strains from wild boars and domestic pigs; another four clades were formed by strains from humans and wild boars. One strain from a Spanish wild boar was similar to strains from chronically infected humans. The high prevalence of HEV infections among wild boars and the similarity between wild boar HEV strains and those from humans and domestic pigs indicate that zoonotic transmission from wild boar may be more common than previously anticipated, which may develop into public health concern.