Hepatitis E virus infection in North Italy: high seroprevalence in swine herds and increased risk for swine workers

Zoonoses in dog and cat shelters in North-East Italy: update on emerging, neglected and known zoonotic agents

Introduction

Shelters for stray dogs and cats deserve careful monitoring for zoonotic risk, as they represent a crucial point for prevention and control of infection spread. Data sorting to prioritize zoonotic agents in a geographic area need constant updating, but no regular official programs are ongoing, to allow an efficient risk survey for these animal species. This study aimed to conduct a comprehensive investigation of the prevalence of certain known, potential and emerging zoonoses within the framework of the routine monitoring of dog and cat shelters in North-East Italy.

Methods

A total of 389 cats and 257 dogs housed in public veterinary services shelters and feline colonies were included in the present investigation. The animals originated from the provinces of Padua, Venice, Rovigo, Vicenza, Verona, Trento and Bolzano. Serological, molecular and microbiological diagnostics were implemented to investigate the prevalence of Leptospira sp., Brucella canis, Leishmania infantum, dermatophytes, gastrointestinal parasites, antimicrobial-resistant bacteria, Capnocytophaga sp., Bartonella sp., Norovirus, Rotavirus A, Cowpox virus, Mammalian Orthoreovirus, Hepatitis E virus, SARS-CoV-2 and Influenza A virus.

Results

Data about some known zoonoses (e.g., serological positivity of Leishmania infantum 25% and Leptospira sp. 44.3% in dogs, and Bartonella henselae 70% in cats) resulted aligned with previous research and recent reports, whereas there was a notable occurrence of some potential, emerging and neglected pathogens (e.g., Mammalian Orthoreovirus 0.38% in dogs and 2.83% in cats). For some other agents (e.g., dermatophytes in dogs and in cats) the prevalence resulted lower than expected.

Discussion

The prevention of the zoonotic risk requires a re-examination of the complex interaction between humans, animals, and environment. This is of particular importance in settings like companion animal shelters, which serve as key sites for disease monitoring and zoonotic risk mitigation. The study highlights the need to monitor and prioritize the zoonotic pathogens, to implement and constantly update surveillance and specific training programs for the kennels' operators, and management of epidemiological risks.

Hepatitis E Virus (HEV) in Heavy Pigs in Slaughterhouses of Northern Italy: Investigation of Seroprevalence, Viraemia, and Faecal Shedding

Hepatitis E virus (HEV) is considered an emerging threat in Europe, owing to the increased number of human cases and the widespread presence of the virus in pigs at farms. Most cases in industrialized countries are caused by the zoonotic HEV-3 genotype. The main transmission route of HEV-3 in Europe is foodborne, through consumption of raw or undercooked liver pork and wild boar meat. Pigs become susceptible to HEV infection after the loss of maternal immunity, and the majority of adult pigs test positive for IgG anti-HEV antibodies. Nonetheless, HEV-infected pigs in terms of liver, faeces, and rarely blood are identified at slaughterhouses. The present study aimed to investigate the prevalence of HEV-positive batches of Italian heavy pigs at slaughterhouses, assessing the presence of animals still shedding HEV upon their arrival at the slaughterhouse by sampling faeces collected from the floor of the trucks used for their transport. The occurrence of viraemic animals and the seroprevalence of anti-HEV antibodies were also assessed. The results obtained indicated the presence of anti-HEV IgM (1.9%), and a high seroprevalence of anti-HEV total antibodies (IgG, IgM, IgA; 89.2%, n = 260). HEV RNA was not detected in either plasma or faecal samples. Nevertheless, seropositive animals were identified in all eight batches investigated, confirming the widespread exposure of pigs to HEV at both individual and farm levels. Future studies are needed to assess the factors associated with the risk of HEV presence on farms, with the aim to prevent virus introduction and spread within farms, thereby eliminating the risk at slaughterhouse.

Assessment on the efficacy of methods 2 to 5 and method 7 set out in Commission Regulation (EU) No 142/2011 to inactivate relevant pathogens when producing processed animal protein of porcine origin intended to feed poultry and aquaculture animals

An assessment was conducted on the level of inactivation of relevant pathogens that could be present in processed animal protein of porcine origin intended to feed poultry and aquaculture animals when methods 2 to 5 and method 7, as detailed in Regulation (EU) No 142/2011, are applied. Five approved scenarios were selected for method 7. Salmonella Senftenberg, Enterococcus faecalis, spores of Clostridium perfringens and parvoviruses were shortlisted as target indicators. Inactivation parameters for these indicators were extracted from extensive literature search and a recent EFSA scientific opinion. An adapted Bigelow model was fitted to retrieved data to estimate the probability that methods 2 to 5, in coincidental and consecutive modes, and the five scenarios of method 7 are able to achieve a 5 log10 and a 3 log10 reduction of bacterial indicators and parvoviruses, respectively. Spores of C. perfringens were the indicator with the lowest probability of achieving the target reduction by methods 2 to 5, in coincidental and consecutive mode, and by the five considered scenarios of method 7. An expert knowledge elicitation was conducted to estimate the certainty of achieving a 5 log10 reduction of spores of C. perfringens considering the results of the model and additional evidence. A 5 log10 reduction of C. perfringens spores was judged: 99-100% certain for methods 2 and 3 in coincidental mode; 98-100% certain for method 7 scenario 3; 80-99% certain for method 5 in coincidental mode; 66-100% certain for method 4 in coincidental mode and for method 7 scenarios 4 and 5; 25-75% certain for method 7 scenario 2; and 0-5% certain for method 7 scenario 1. Higher certainty is expected for methods 2 to 5 in consecutive mode compared to coincidental mode.

Epidemiological and genetic evaluation of HEV in swine slaughtered in Sicily region (Italy)

Hepatitis E virus (HEV) is the etiological agent of acute viral hepatitis, a disease transmitted by the oral-faecal route. In Europe, zoonotic transmission of HEV-3 genotype is associated with the consumption of raw or slightly cooked meat of pigs and wild boars that are considered the main reservoirs. This work aims to assess the occurrence of swines' HEV RNA liver samples and rectal swabs slaughtered in Sicily using biomolecular methods. HEV-RNA was detected in 17.5 % (21/120) liver samples analyzed and in 3.7 % (3/81) rectal swabs examined. All positive samples were predicted as genotype 3 and subtype 3c (75 %). These data suggest a potential HEV transmission to humans through close contact with pig breeders, veterinarians, slaughterhouse personnel, and pork meat product consumption. Moreover, there are few scientific data evaluating the HEV spread around pigs and humans in Sicily. Therefore, further studies are necessary to correlate humans with swine serotypes and to assess the HEV presence and persistence in food and the risk during the slaughtering process. These surveys allow to clarify the role of the swine species as a potential source of infection for other domestic or wild animals and humans and to establish possible control measures throughout the food chain.

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.

Serological, Virological Investigation and Hepatic Injury Evaluation for Hepatitis E Virus in Hunting Dogs

Hepatitis E virus (HEV) is a quasi-enveloped single-stranded positive-sense RNA virus belonging to the Orthohepevirus A genus within the Hepeviridae family. The most common transmission route of this virus is fecal–oral, although zoonotic transmission by contact with infected animals has also been described. In this study, 80 sera and rectal swabs were collected from dogs during the 2019/2020 and 2020/2021 wild boar hunting season in Tuscany. All dogs were submitted for serological screening to detect the presence of anti-HEV antibodies. To evaluate the circulation of HEV, rectal swabs from both seropositive dogs and dogs living in the same kennels were examined by One-Step RT-qPCR. In addition, the presence of markers of hepatic damage in dogs’ sera was investigated. Results indicated the presence of anti-HEV antibodies in 4/80 subjects (5%). However, neither HEV RNA nor signs of hepatic damage were found. In conclusion, although HEV can stimulate a specific immuno-response in dogs, this species does not seem to play an important role in HEV epidemiology.

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.

Co-Circulation of Different Hepatitis E Virus Genotype 3 Subtypes in Pigs and Wild Boar in North-East Germany, 2019

Hepatitis E is a major cause of acute liver disease in humans worldwide. The infection is caused by hepatitis E virus (HEV) which is transmitted in Europe to humans primarily through zoonotic foodborne transmission from domestic pigs, wild boar, rabbits, and deer. HEV belongs to the family Hepeviridae, and possesses a positive-sense, single stranded RNA genome. This agent usually causes an acute self-limited infection in humans, but in people with low immunity, e.g., immunosuppressive therapy or underlying liver diseases, the infection can evolve to chronicity and is able to induce a variety of extrahepatic manifestations. Pig and wild boar have been identified as the primary animal reservoir in Europe, and consumption of raw and undercooked pork is known to pose a potential risk of foodborne HEV infection. In this study, we analysed pig and wild boar liver, faeces, and muscle samples collected in 2019 in Mecklenburg-Western Pomerania, north-east Germany. A total of 393 animals of both species were investigated using quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR), conventional nested RT-PCR and sequence analysis of amplification products. In 33 animals, HEV RNA was detected in liver and/or faeces. In one individual, viral RNA was detected in muscle tissue. Sequence analysis of a partial open reading frame 1 region demonstrated a broad variety of genotype 3 (HEV-3) subtypes. In conclusion, the study demonstrates a high, but varying prevalence of HEV RNA in swine populations in Mecklenburg-Western Pomerania. The associated risk of foodborne HEV infection needs the establishment of sustainable surveillance and treatment strategies at the interface between humans, animals, and the environment within a One Health framework.

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.

Seroprevalence and phylogenetic characterization of hepatitis E virus in pig farms in Southern Italy

Hepatitis E virus (HEV) infection is an emerging public health problem in industrialized countries. The infection is associated with waterborne epidemics and transmitted via faecal-oral route. Zoonotic cases of HEV in humans have increased in Europe, and HEV genotype 3 (HEV-3) is the most frequent among humans and animals. Nevertheless, HEV surveillance in the Italian pig farming industry is patchy. Here, HEV prevalence in pig farms located in the Calabria region in Southern Italy was investigated. A total of 692 serum samples were collected from 26 farms and tested for anti-HEV IgG antibody detection. The percentage of HEV-seropositive pigs was 56.8 %. Small farm size, farrow-to-finishing production, and infrequent cleaning procedures were associated with higher HEV seroprevalence. In 12 of the HEV-seropositive farms, 67 faecal samples were collected and 10 of these (10.6 %) tested positive for HEV RNA. Seven of 10 viral RNA sequences were genotyped for phylogenetic analysis, five of which belonged to subtype HEV-3f and two to subtype HEV-3e. The high HEV seroprevalence and the circulation of HEV-3 strains among domestic pigs in the Calabria region pose a risk for the zoonotic transmission of HEV from pigs to occupational exposed workers.

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.

Hepatitis E Virus RNA Presence in Wild Boar Carcasses at Slaughterhouses in Italy

Simple Summary

Hepatitis E virus (HEV) is a worldwide diffused pathogen responsible for acute hepatitis of humans. Transmission of the pathogen is mostly related to the consumption of contaminated food and water. Although initially the disease was contained in developing countries, in recent years autochthonous infections have been reported in several industrialised countries. A different epidemiological pattern of transmission has been highlighted; while in Africa and Asia transmission is mainly due to waterborne outbreaks caused by low sanitation standards, in Europe and other industrialised countries, the disease has mainly spread due to consumption of raw or undercooked meat and seafood. Although HEV has been identified in several domestic and wild animal species, pigs and wild boar, appear to play a distinct role mainly acting as a reservoir of the pathogen. In this study, we monitored the presence of HEV in carcasses and livers of wild boar sampled in Tuscany at the slaughterhouse following hunting activities. Our data indicate the presence of the pathogen in the liver and the carcasses, suggesting cross-contamination. This evidence highlights the importance of maintaining safety control measures to avoid the spreading of HEV infection.

Abstract

Hepatitis E virus (HEV) is a waterborne and foodborne pathogen largely spread around the world. HEV is responsible for acute hepatitis in humans and it is also diffused in domestic and wild animals. In particular, domestic pigs represent the main reservoir of the infection and particular attention should be paid to the consumption of raw and undercooked meat as a possible zoonotic vehicle of the pathogen. Several studies have reported the presence of HEV in wild boar circulating in European countries with similar prevalence rates. In this study, we evaluated the occurrence of HEV in wild boar hunted in specific areas of Tuscany. Sampling was performed by collecting liver samples and also by swabbing the carcasses at the slaughterhouses following hunting activities. Our data indicated that 8/67 (12%) of liver samples and 4/67 (6%) of swabs were positive for HEV RNA. The presence of HEV genome on swabs indicates the possible cross-contamination of carcass surfaces during slaughtering procedures. Altogether, our data indicated that it is essential to promote health education programmes for hunters and consumers to limit the diffusion of the pathogen to humans.

Global infectious disease risks associated with occupational exposure among non-healthcare workers: a systematic review of the literature

Objectives

Employees in non-healthcare occupations may be in several ways exposed to infectious agents. Improved knowledge about the risks is needed to identify opportunities to prevent work-related infectious diseases. The objective of the current study was to provide an updated overview of the published evidence on the exposure to pathogens among non-healthcare workers. Because of the recent SARS-CoV-2 outbreaks, we also aimed to gain more evidence about exposure to several respiratory tract pathogens.

Methods

Eligible studies were identified in MEDLINE, Embase and Cochrane between 2009 and 8 December 2020. The protocol was registered with International Prospective Register of Systematic Reviews (CRD42019107265). An additional quality assessment was applied according to the Equator network guidelines.

Results

The systematic literature search yielded 4620 papers of which 270 met the selection and quality criteria. Infectious disease risks were described in 37 occupational groups; 18 of them were not mentioned before. Armed forces (n=36 pathogens), livestock farm labourers (n=31), livestock/dairy producers (n=26), abattoir workers (n=22); animal carers and forestry workers (both n=16) seemed to have the highest risk. In total, 111 pathogen exposures were found. Many of these occupational groups (81.1%) were exposed to respiratory tract pathogens.

Conclusion

Many of these respiratory tract pathogens were readily transmitted where employees congregate (workplace risk factors), while worker risk factors seemed to be of increasing importance. By analysing existing knowledge of these risk factors, identifying new risks and susceptible risk groups, this review aimed to raise awareness of the issue and provide reliable information to establish more effective preventive measures.

Long-term surveillance for hepatitis E virus in an Italian two-site farrow-to-finish swine farm

In humans, hepatitis E virus (HEV) is responsible for an acute enterically transmitted hepatitis, which can become chronic in immune-compromised patients. Genotypes 3 and 4 (HEV-3 and HEV-4) are zoonotic, and domestic pigs and wild boar are the main reservoirs. The occurrence of autochthonous cases in Europe, which have been increasing over the last 10 years, has been associated with food-borne zoonotic transmission of HEV-3, mainly linked to consumption of undercooked or raw pork products (sausages containing liver) and wild boar meat. Zoonotic HEV-3 strains are widespread on pig farms, but little information is available on the dynamic of HEV-3 infection within farms, among pigs. The aims of this study were to evaluate the prevalence of the infection among pigs of different ages along the production chain by the zoonotic HEVs, and to evaluate how long the virus may persist in the farm environment. The presence of HEV-RNA was investigated by real-time reverse transcription PCR (RT-PCR) in 281 test faecal pools over 19 months (2017-2019) on a two-site farrow-to-finish farm (about 1,000 sows), in Northern Italy. A total of 67/281 test faecal pools (23.8%) resulted positive for the presence of HEV-RNA (site 1: 59/221, 26.7%; site 2: 8/60, 13.3%). Nucleotide sequencing revealed a unique HEV-3 viral variant circulating during 19 months of surveillance. The same HEV-3 strain was detected in the same farm on 2012, indicating the persistence of the same virus over 7 years, and highlighting the role of the environment as a continuous source of infection on pig farms. The results confirmed the circulation of the zoonotic genotype HEV-3 in pigs before slaughtering.

Hepatitis E Virus Occurrence in Pigs Slaughtered in Italy

Simple Summary

Hepatitis E is now recognized as an emerging zoonotic disease in Europe caused by an RNA virus (HEV) and foodborne is the main route of transmission. Human cases have been linked to the consumption of contaminated pig liver sausages, raw venison, or undercooked wild boar meat. The zoonotic genotype HEV-3 is widespread in pigs at farm level but little information is available on the occurrence of HEV-positive pigs at the slaughterhouse. The aim of this study was to investigate the prevalence of HEV-positive pigs during slaughtering, to understand which biological samples (feces and organs) were more frequently HEV positive. Our results showed that pigs positive for HEV can be slaughtered and that the percentage of positive animals depends on the age of animals. The other main result is the presence of the virus in the plasma of animals, which may contribute to the contamination of meat (muscle). Nevertheless, muscles are rarely contaminated by HEV-RNA compared to liver, which is the organ of replication.

Abstract

In Europe, foodborne transmission has been clearly associated to sporadic cases and small clusters of hepatitis E in humans linked to the consumption of contaminated pig liver sausages, raw venison, or undercooked wild boar meat. In Europe, zoonotic HEV-genotype 3 strains are widespread in pig farms but little information is available on the prevalence of HEV positive pigs at slaughterhouse. In the present study, the prevalence of HEV-RNA positive pigs was assessed on 585 animals from 4 abattoirs located across Italy. Twenty-one pigs (3.6%) tested positive for HEV in either feces or liver by real-time RT-PCR. In these 21 pigs, eight diaphragm muscles resulted positive for HEV-RNA. Among animals collected in one abattoir, 4 out of 91 plasma tested positive for HEV-RNA. ELISA tests for the detection of total antibodies against HEV showed a high seroprevalence (76.8%), confirming the frequent exposure of pigs to the virus. The phylogenetic analyses conducted on sequences of both ORF1 and ORF2 fragments, shows the circulation of HEV-3c and of a novel unclassified subtype. This study provides information on HEV occurrence in pigs at the slaughterhouse, confirming that muscles are rarely contaminated by HEV-RNA compared to liver, which is the most frequently positive for HEV.

Seroprevalence of Hepatitis E Virus in Forestry Workers from Trentino-Alto Adige Region (Northern Italy)

People with some occupational or recreational activities, such as hunters and veterinarians, may have increased risk to be infected by the hepatitis E virus (HEV). The aim of the present study was to establish whether forestry workers could be considered at a higher risk of HEV infection than a control group. One hundred and fifty sera from forestry workers and a control group of 85 sera were analysed by anti-HEV IgG antibodies detection using a commercial ELISA kit. The anti-HEV IgG seroprevalence was 14% for forestry workers and 9.4% for the control group. Comparing the risk of HEV infection in the two groups, there was no difference in the odds ratio. However, the seroprevalence in older subjects was higher in the forestry workers than in the control group. Two sera from forestry workers were also positive for anti-HEV IgM, and, in one of them, HEV-RNA was detected. Our findings showed an increase of seroprevalence with age, which is likely to reflect cumulative exposure to HEV over time. The occupation of forestry workers did not seem to be associated with a higher risk of HEV infection. The study provided new insights into the risk of acquiring HEV in occupational exposure workers with open-air activities.

High Predictive Power of Meat Juice Serology on the Presence of Hepatitis E Virus in Slaughter Pigs

Hepatitis E virus (HEV) as a zoonotic agent can be responsible for an acute hepatitis in humans, which is usually self-limiting. Progression toward a chronic stage is possible, especially in immunocompromised patients. In the past decade, the number of hepatitis E cases in humans in Germany has increased enormously to 3491 cases in 2018. Domestic pigs have been identified as a main animal reservoir and the consumption of raw and undercooked pork products, that is, livers or liver products, meat or meat products, is known as a potential risk of foodborne HEV infection. The aim of this study was to determine whether serological tests are appropriate to predict the occurrence of HEV in the liver and muscle of domestic pigs in Germany. In 2018, samples of meat juice, liver, and ham muscle were collected from 250 fattening pigs at an abattoir in North West Germany. Samples were analyzed for the presence of HEV antibodies using enzyme-linked immunosorbent assay respectively for the presence of HEV RNA using real-time reverse transcription-polymerase chain reaction. In total, 62% (155/250) of the meat juice samples were positive for HEV antibodies at a single animal basis. At herd level, 72% (18/25) of the herds were seropositive. The HEV prevalence in the liver was 17.2% (43/250). Each positive liver sample originated from seropositive herds respectively from HEV seropositive pigs. This study demonstrates for the first time the significant correlation between a positive HEV serology and the occurrence of HEV RNA in the liver of slaughter pigs (χ² = 31.83; p < 0.001), highlighting the significant predictive power of positive serological results on the occurrence of HEV RNA in the liver.

Screening and Molecular Characterization of Hepatitis E Virus in Slaughter Pigs in Serbia

Hepatitis E virus (HEV) is a zoonotic virus that can cause acute hepatitis in humans. Besides the fecal-oral route, transmission can occur by consumption of undercooked pig liver. Genotype 3 is the most frequent genotype found in Europe. Studies on HEV in slaughter-age pigs have not been conducted in Serbia so far. Pork meat production and consumption in Serbia is on average, higher than in the rest of Europe. With the aim to identify the circulating HEV genotypes, pig livers and swab samples from three pig slaughterhouses located in three different sub-regions of Serbia were collected. A nested RT-PCR was used to amplify the hypervariable HEV ORF-1 region (334 bp). The amplicons yielded in this study were sequenced, and a molecular phylogeny analysis based on the maximum likelihood method, including HEV sequences reported in several other countries, was performed. The average prevalence of HEV genotype 3 in 3-month-old pigs was 34%. Phylogenetic analysis revealed the majority of HEV amplification fragments from Serbia were grouped in four clades within sub-genotype 3a and were also genetically related to German, Italian, Slovenian, and American HEV sequences. Sub-genotypes 3b and 3j were also found in a single pig each. This study provides the first analysis of the genetic diversity and circulation dynamics of HEV in pigs at slaughterhouses in Serbia.

Clinical presentations of Hepatitis E: A clinical review with representative case histories

Hepatitis E virus (HEV) typically causes an acute, self-limiting hepatitis and is among the commonest cause of such presentations. Hepatitis E viral infection is also increasingly recognized as a cause of chronic hepatitis amongst the immunocompromised, particularly amongst solid organ transplant recipients. Chronic HEV infection remains an underdiagnosed disease and chronic infection can lead to rapidly progressive liver fibrosis and cirrhosis. This review examines current understanding of the HEV. We illustrate typical clinical presentations, management strategies [(based upon guidelines from both the British Transplant Society (BTS) and European Association for the study of liver (EASL)] and outcomes of HEV infection in different cohorts of patients by highlighting select transplant and non-transplant patient cases, from one of the largest tertiary Hepatology centres in Europe.

Design and immunogenicity analysis of the combined vaccine against zoonotic hepatitis E and foot-and-mouth disease

AIM

Design and immunogenicity assessment of the combined vaccine candidate against zoonotic hepatitis E virus (HEV) and foot-and-mouth disease virus (FMDV).

METHODS

Using the molecular cloning technology, we produced and purified 9 HEV ORF2-truncated proteins (HEV genotype 4). Then, we compared their thermal stability, antigenicity, and immunogenicity to select the best HEV immunogen. Next, we used the adjuvant Montanide ISA-206 to prepare different formulations of HEV vaccine alone, FMDV vaccine alone and HEV-FMDV combined vaccine. The formulations were injected into mice and the induced humoral immune responses were monitored up 12 weeks post-immunization.

RESULTS

The HEV p222 protein could self-assemble into VLPs (∼34 nm) and showed higher stability and better antigenicity/immunogenicity than the other HEV antigens, thus it was selected as the best HEV immunogen. Mice immunization with the FMDV vaccine alone induced high FMDV-specific antibody titers in a dose-dependent manner; the HEV p222 protein also induced high levels of anti-HEV antibodies but in a dose-independent manner. The HEV-FMDV combination induced anti-FMDV antibody titers 7-16-fold higher than the titers induced by the FMDV vaccine alone, and HEV-specific antibody titers 2.4-fold higher than those induced by the HEV p222 antigen alone.

CONCLUSION

Herein, we proposed a new approach for the control of zoonotic HEV infection through its control in its main host (pig). We also designed the first HEV-FMDV combined vaccine and the preliminary analyses revealed a synergistic effect on the immunogenicity of both HEV and FMDV antigens.

Hepatitis E in pigs in Israel: seroprevalence, molecular characterisation and potential impact on humans

IntroductionThe zoonotic hepatitis E virus (HEV) genotype 3 (HEV-G3) has become a common cause of acute and chronic hepatitis among humans worldwide. In Israel, while HEV-3 sequences have previously been detected in sewage, only the non-zoonotic HEV-G1 genotype has been found in samples from human patients.AimIn this pilot study, we aimed to assess the status of HEV in a sample of the swine population and among swine farm workers in Israel.MethodsPig blood (n = 141) and faecal samples (n = 39), pig farm sewage samples (n = 8) and blood from farm workers (n = 24) were collected between February 2016 and October 2017. Anti-HEV IgG was detected using the Wantai assay. HEV RNA was analysed with the RealStar HEV kit. HEV open reading frame 1 fragments amplified from representative HEV RNA-positive samples were used for phylogenetic analysis.ResultsOverall prevalence of HEV antibodies in pigs was 75.9% (107/141). HEV RNA was detected in plasma (2.1%, 3/141), faecal (22.8%, 18/79) and pig sewage (4/8) samples. Pig and sewage-derived viral sequences clustered with previously identified human sewage HEV-G3 sequences. Most pig farms workers (23 of 24) were HEV-seropositive; none was viraemic or reported previous clinical signs.ConclusionsThis study showed that domestic pigs in Israel are infected with HEV-G3. The high HEV seropositivity of the farm workers together with the previous identification of this virus in human sewage suggests circulation to humans. The clinical impact of these findings on public health should be further explored.

Detection of hepatitis E virus RNA in rats caught in pig farms from Northern Italy

Hepatitis E virus (HEV) strains belonging to the Orthohepevirus genus are divided into four species (A-D). HEV strains included in the Orthohepevirus A species infect humans and several other mammals. Among them, the HEV-3 and HEV-4 genotypes are zoonotic and infect both humans and animals, of which, pigs and wild boar are the main reservoirs. Viruses belonging to the Orthohepevirus C species (HEV-C) have been considered to infect rats of different species and carnivores. Recently, two studies reported the detection of HEV-C1 (rat HEV) RNA in immunocompromised and immunocompetent patients, suggesting a possible transmission of rat HEV to humans. The role of rats and mice as reservoir of HEV and the potential zoonotic transmission is still poorly known and deserves further investigation. To this purpose, in this study, the presence of HEV RNA was investigated in the intestinal contents and liver samples from 47 Black rats (Rattus rattus) and 21 House mice (Mus musculus) captured in four pig farms in Northern Italy. The presence of both Orthohepevirus A and C was investigated by the real-rime RT-PCR specific for HEV-1 to HEV-4 genotypes of Orthohepevirus A species and by a broad spectrum hemi-nested RT-PCR capable of detecting different HEV species including rat HEV. The intestinal content from two Black rats resulted positive for HEV-C1 RNA and for HEV-3 RNA, respectively. None of the House mice was HEV RNA positive. Sequence analyses confirmed the detection of HEV-C1, genotype G1 and HEV-3 subtype e. The viral strain HEV-3e detected in the rat was identical to swine HEV strains detected in the same farm. Liver samples were negative for the detection of either rat HEV or HEV-3.

Cross-sectional Seroprevalence and Genotype of Hepatitis E Virus in Humans and Swine in a High-density Pig-farming Area in Central China

Hepatitis E virus (HEV) infection is a common public health problem in developing countries. However, the current prevalence of HEV and the relationship of HEV genotype between swine and human within high-density pig-farming areas in central China are still inadequately understood. Here, cross-sectional serological and genotypic surveys of HEV among the 1232 general population, 273 workers occupationally exposed to swine, and 276 pigs in a high-density pig-breeding area, were undertaken by ELISA and nested RT-PCR methods. Anti-HEV IgG was detected in 26.22% of general population and 48.35% of occupational workers. The prevalence of swine serum HEV-Ag was 6.52%. The prevalence of anti-HEV IgG was significantly higher among the workers occupationally exposed to swine than among the general population. An increased HEV seropositivity risk among the general population was associated with either being a peasant or male and was very strongly associated with the increase of age. Among the occupationally exposed group, the prevalence of anti-HEV IgG antibodies increased with age and working years. Among the 30 HEV-IgM-positive people, the infection rates of clerks in the public, peasants, pork retailers, and pig farmers were higher than those of others. A phylogenetic analysis revealed that all the isolates belonged to subgenotype 4_d, and four people and four pigs shared 97.04%-100% sequence homology. This study revealed a high HEV seroprevalence among the general population and workers occupationally exposed to swine in the Anlu City, and supports the notion that swine are a source of human HEV infection.

Prevalence of hepatitis E virus infection among people and swine in mainland China: A systematic review and meta-analysis

Hepatitis E virus (HEV) infection remains an important public health problem, and it is endemic primarily in developing countries. This study aimed to evaluate the seroprevalence of HEV among the general population, occupational population and swine in mainland China and its risk factors based on a systematic review and meta-analysis. Systematic search from EMBASE, PubMed, Web of Science, Cochrane Library and several Chinese databases, such as Wanfang (WF) Data, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP) and SINOMED, was searched from inception up to 25 April 2018. The overall seroprevalence of HEV and its corresponding 95% confidence interval (CI) as well as the correlation coefficients between different groups were estimated using stata 12.0 and r-3.4.1 software. Potential sources of heterogeneity were explored using subgroup and sensitivity analyses. Twenty-eight studies with 57,274 participants (including human and swine) were included. The seroprevalence of anti-HEV immunoglobulin G (IgG) among the general population, occupational population and swine was 27.3% (95% CI: 22.4-32.2), 47.4% (95% CI: 40.1-54.8) and 66.4% (95% CI: 61.7-71.1), respectively. The overall prevalence of IgM among the general population was 1.8% (95% CI: 0.7-2.9). The odds ratio for the occupational population, as compared to the general population, was 2.63. The highest anti-HEV IgG prevalence (59%) was observed in East China, whereas the lowest (34.8%) was noted in Northeast and North China. In the occupational population, the highest prevalence (77.0%) was observed among swine vendors. Seven studies included 30,392 participants (humans and swine); the correlation coefficient for the prevalence of anti-HEV IgG between the professional population and adult pigs was 0.88. Sensitivity analyses showed that the stability of results was not considered significant. This research found that HEV is common in China, and contact with pork or other pig products may be an important mode of HEV transmission.

Emerging zoonotic viral infections of occupational health importance

Emerging viral infections represent a public health risk pointed out by the spreading of pathogens with potential zoonotic risk. Moreover, the risk of zoonosis has probably been underestimated in occupational settings. A literature review between 2007 and 2018 was performed to identify evidences concerning the epidemiological associations between some emerging viruses and occupational diseases. Observational studies and case-reports were selected and analyzed. West Nile Virus (WNV) disease, Crimean-Congo Hemorrhagic Fever (CCHF) disease and Hepatitis E virus (HEV) infection were included in the review for their potential zoonotic transmission. The most important risk factor for acquiring WNV infection and CCHF infection is the exposure to infected mosquitoes and ticks, respectively; therefore, outdoor workers are at risk of infection. HEV is responsible for epidemics and endemics of acute hepatitis in humans, that can become infected through waterborne, foodborne and zoonotic transmission routes. A total of 10, 34 and 45 eligible studies for WNV, CCHF virus (CCFHV) and HEV, respectively, were analyzed by year, country, study design, risk group and outcomes. The occupational risk groups mainly included farm and agricultural workers, veterinarians, slaughterers, animal handlers, healthcare workers and soldiers. These findings support the need to develop effective interventions to prevent transmission of emerging viruses.

Hepatitis E virus: reasons for emergence in humans

Hepatitis E virus (HEV) infects both humans and other animal species. Recently, we have seen a steady increase in autochthonous cases of human HEV infection in certain areas especially in Europe, and large outbreaks in several African countries among the displaced population. This mini-review critically analyzes potential host, environmental, and viral factors that may be associated with the emergence of hepatitis E in humans. The existence of numerous HEV reservoir animals such as pig, deer and rabbit results in human exposure to infected animals via direct contact or through animal meat consumption. Contamination of drinking, irrigation and coastal water by animal and human wastes lead to emergence of endemic cases in industrialized countries and outbreaks in displaced communities especially in war-torn countries.

Hepatitis E virus: zoonotic and foodborne transmission in developed countries

Hepatitis E virus (HEV), together with hepatitis A virus, transmits via the fecal–oral route. The number of domestic hepatitis E cases among Europeans has grown alarmingly during the past 5 years. Surveillance studies suggest that the number of foodborne HEV infections is increasing most rapidly. Zoonotic HEV genotype HEV-3 is prevalent among pigs and wild boars in Europe and many developed countries, whereas zoonotic genotype HEV-4 is more common in pigs in some Asian countries. This review presents the most recent data about possible foodborne transmission of HEV via pigs and other production animals and about the presence of HEV in high-risk foods, such as ready-to-eat meat products. Possible solutions about how to tackle this problem are discussed here.