Serologic and Molecular Survey of Hepatitis E Virus in German Deer Populations

Serological survey on Hepatitis E virus in Namibian dogs, cats, horses, and donkeys

The present study investigated the seropositivity rate of Hepatitis E virus (HEV) in domestic and working animals in Namibia, which included dogs, cats, horses, and donkeys. HEV poses a growing threat as a significant cause of human hepatitis globally and has several genotypes of varying zoonotic potential. As epidemiological data on the seroprevalence of HEV in Namibia is scarce, a serosurvey was conducted on archived serum samples of 374 dogs, 238 cats, 98 horses, and 60 donkeys collected between 2018 and 2022 from different regions, to assess the potential of these animals as sources of HEV infection. The findings revealed that 10.43% (n = 39/374) canine and 5.88% (n = 14/238) feline samples tested positive for HEV antibodies, whereas no seropositivity was detected in horses and donkeys. The study further examined the risk factors associated with HEV seropositivity, including animal sex, age, and geographical region, and noted a higher prevalence in dogs living in areas with intensive pig farming. Although there is no direct evidence indicating that these animals served as major reservoirs for HEV transmission to humans, the study underscores the importance of preventive measures to minimize contact exposure with pets considering the potential zoonotic risk, especially for susceptible risk groups. Further research is needed to explore the zoonotic potential of domestic animals and the epidemiological links between animal and human HEV transmissions in Namibia.

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.

Hepatitis E Virus

Since the sequence of hepatitis E virus (HEV) was determined from a patient with enterically transmitted non-A, non-B hepatitis in 1989, similar sequences have been isolated from many different animals, including pigs, wild boars, deer, rabbits, bats, rats, chicken, and trout. All of these sequences have the same genomic organization, which contains open reading frames (ORFs) 1, 2, and 3, although their genomic sequences are variable. Some have proposed that they be classified as new family, Hepeviridae, which would be further divided into different genera and species according to their sequence variability. The size of these virus particles generally ranged from 27 to 34 nm. However, HEV virions produced in cell culture differ in structure from the viruses found in feces. Those from cell culture have a lipid envelope and either lack or have a little ORF3, whereas the viruses isolated from feces lack a lipid envelope but have ORF3 on their surfaces. Surprisingly, most of the secreted ORF2 proteins from both these sources are not associated with HEV RNA.

Current Knowledge of Hepatitis E Virus (HEV) Epidemiology in Ruminants

Hepatitis E virus (HEV) infection represents an emerging public health concern worldwide. In industrialized countries, increasing numbers of autochthonous cases of human HEV infection are caused by zoonotic transmission of genotypes 3 and 4, mainly through the consumption of contaminated raw or undercooked meat of infected pigs and wild boars, which are considered the main reservoirs of HEV. However, in the last few years, accumulating evidence seems to indicate that several other animals, including different ruminant species, may harbor HEV. Understanding the impact of HEV infection in ruminants and identifying the risk factors affecting transmission among animals and to humans is critical in order to determine their role in the epidemiological cycle of HEV. In this review, we provide a summary of current knowledge on HEV ecology in ruminants. A growing body of evidence has revealed that these animal species may be potential important hosts of HEV, raising concerns about the possible implications for public health.

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.

Molecular and Pathological Detection of Hepatitis E Virus in Roe Deer (Capreolus capreolus) and Fallow Deer (Dama dama) in Central Italy

Hepatitis E virus (HEV) is a common causative agent of acute hepatitis in the world, with a serious public health burden in both developing and industrialized countries. Cervids, along with wild boars and lagomorphs, are the main wild hosts of HEV in Europe and constitute a documented source of infection for humans. The aim of this study was to evaluate the presence of HEV in roe deer (Capreolus capreolus) and fallow deer (Dama dama) living in Tuscany, Central Italy. Liver samples from 48 roe deer and 60 fallow deer were collected from carcasses during the hunting seasons. Following the results obtained from molecular and histopathologic studies, 5/48 (10.4%) roe deer and 1/60 (1.7%) fallow deer liver samples were positive for the presence of HEV RNA. All PCR-positive livers were also IHC-positive for viral antigen presence, associated with degenerative and inflammatory lesions with predominantly CD3+ cellular infiltrates. This study represents the first identification in Italy of HEV RNA in roe and fallow deer and the first study in literature describing liver alterations associated with HEV infection in cervids. These results demonstrate that HEV is present in wild cervid populations in Italy and confirm the potential zoonotic role of these species.

Nationwide survey of hepatitis E virus infection among wildlife in Japan

In Japan, hepatitis E virus (HEV) causes hepatitis in humans through the consumption of raw or undercooked meat, including game meat. In the present study, nationwide surveillance of HEV infection among a total of 5,557 wild animals, including 15 species, was conducted in Japan. The prevalence of anti-HEV antibodies in wild boar was 12.4%, with higher positive rates in big boars (over 50 kg, 18.4%) than in small individuals (less than 30 kg, 5.3%). Furthermore, HEV RNA was more frequently detected in piglets than in older boars. Interestingly, the detection of HEV among wildlife by ELISA and RT-PCR suggested that HEV infection in Sika deer was a very rare event, and that there was no HEV infection among wild animals except for wild boar, Sika deer and Japanese monkeys. In conclusion, wild boar, especially piglets, are at high risk of HEV infection, while other wild animals showed less risk or no risk of HEV transmission.

Cellular Organelles Involved in Hepatitis E Virus Infection

Hepatitis E virus (HEV), a major cause of acute hepatitis worldwide, infects approximately 20 million individuals annually. HEV can infect a wide range of mammalian and avian species, and cause frequent zoonotic spillover, increasingly raising public health concerns. To establish a successful infection, HEV needs to usurp host machineries to accomplish its life cycle from initial attachment to egress. However, relatively little is known about the HEV life cycle, especially the functional role(s) of cellular organelles and their associated proteins at different stages of HEV infection. Here, we summarize current knowledge regarding the relation of HEV with the different cell organelles during HEV infection. Furthermore, we discuss the underlying mechanisms by which HEV infection is precisely regulated in infected cells and the modification of host cell organelles and their associated proteins upon HEV infection.

Long-Term Determinants of the Seroprevalence of the Hepatitis E Virus in Wild Boar (Sus scrofa)

Simple Summary

The hepatitis E virus (HEV) is an emerging multi-host pathogen whose main reservoir is suids, and the leading cause of acute viral hepatitis in humans. This study evaluates the main long-term drivers of the exposure to HEV are in the wild boar population from Doñana National Park (southwestern Spain) during a 13-year period (2005–2018). For this purpose, we assay sera from 700 wild boar in which anti-HEV antibodies are widely distributed (46.7 ± 3.8%, 327 out of 700 sampled). The observed marked interannual fluctuations could be explained by the variations in the population control of the wild boar during the study period and its impact on abundance rates. Several factors operating in the medium and long-term (individual, environmental, populational and stochastic) and their interplay explained the exposure to HEV in wild boar. The preferential use of certain areas by wild boar together with its abundance and the meteorological conditions may be behind the level of exposure. Wild boar population control remains a challenge at the international level, and an increase of shared pathogen-related conflicts associated with this species is expected, as exemplified by HEV.

Abstract

The hepatitis E virus (HEV) is an emerging zoonotic pathogen whose main reservoir is suids. Most of the ecological and epidemiological aspects of its sylvatic cycle remain unknown. Thus, in this work, we study the drivers of HEV exposure in the wild boar population of Doñana National Park (DNP, southwest Spain) operating in the medium and long-term (2005–2018). Anti-HEV antibodies are widely distributed throughout the wild boar (46.7 ± 3.8%, 327 out of 700 sampled), showing a statistically significant age-increasing pattern. The temporal pattern displayed important interannual fluctuations. This could be mediated by marked variations in the population control of the wild boar, and subsequent changes in abundance rates, and its interplay with climatic conditions; as wet years together with a low abundance of wild boar led to the lowest seroprevalence. The fact that seroprevalence is high during conditions of high abundance, and not affected by rainfall level, is probably due to the increased interactions among the animals, and possibly, the subsequent higher environmental contamination with HEV particles. The proximity to the marshland (the main water body of the study area) is associated with a higher risk of testing positive, which is probably mediated by the preferential use of this area during the dry season and the favourable environmental conditions for the survival of HEV particles. A deeper understanding of the epidemiology of HEV in host communities deserves future research concerning other susceptible species. Most importantly, wild boar population control remains a challenge at the international level, and an increase of shared pathogen-related conflicts associated with this species is expected, as exemplified by HEV. Therefore, surveillance of wild boar diseases, including integrated population monitoring and sustainable population control programmes, will be essential to control the associated risks.

Hepatitis E Virus (HEV) Spread and Genetic Diversity in Game Animals in Northern Italy

Hepatitis E virus (HEV) is the causative agent of hepatitis E, an emerging public health infection which has an increasing incidence across Europe. Because of the apparent lack of species barriers, HEV was characterized as a zoonotic agent. Swine are recognized as the main reservoir, but HEV is also found in wild animals such as ungulates, lagomorphs, and bats. Our work aimed at detecting the HEV presence in wild fauna in two hunting areas of Northern Italy (Parma and Sondrio areas) with different environmental and anthropic characteristics to investigate its possible role as reservoir. Liver samples were collected from wild boars, red deer, roe deer and chamois, and viral identification was carried out by One-Step RT Real-time PCR. Positive samples were genotyped, and phylogenetic analysis was performed. The virus was found only in the wild boar population, with different prevalence and subtypes in the two areas (14% HEV3a and 1.2% close to HEV3f in Parma and Sondrio, respectively). Wild ruminants seem otherwise to pose a marginal risk. Given the high pig farm density in the Parma area, and expansion of the wild boar population, continuous monitoring of the strains circulating in wildlife is crucial.

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.

Serological Evidence of Hepatitis E Virus Circulation Among Reindeer and Reindeer Herders

Various deer species are infected with hepatitis E virus (HEV) and may be a source of zoonotic infection for humans. So far, HEV has not been isolated from reindeer and the role of this domesticated deer species in HEV transmission is unknown. We tested serum samples from 191 reindeer (Rangifer tarandus) and 86 adult reindeer herders from the circumpolar regions of Yakutia (Russian Federation) for anti-HEV and HEV RNA. Anti-HEV IgG prevalence was 12.0% (95% confidence interval [95% CI]: 8.1-17.5) in reindeer and 4.7% (95% CI: 1.5-11.7) in reindeer herders. The latter was similar to the positivity rate observed in adult residents of the city of Yakutsk, the capital of Yakutia, who do not have routine contact with reindeer (3.7% [19/519, 95% CI: 2.3-5.7]). No samples positive for HEV RNA were identified. The study provides evidence of HEV circulation in reindeer. Nevertheless, the low seroprevalence in reindeer herders indicate a low risk of zoonotic HEV infection.

Seroprevalence of Hepatitis E Virus in Moose (Alces alces), Reindeer (Rangifer tarandus), Red Deer (Cervus elaphus), Roe Deer (Capreolus capreolus), and Muskoxen (Ovibos moschatus) from Norway

Hepatitis E virus (HEV), a major cause of viral hepatitis worldwide, is considered an emerging foodborne zoonosis in Europe. Pigs (Sus scrofa domestica) and wild boars (S. scrofa) are recognized as important HEV reservoirs. Additionally, HEV infection and exposure have been described in cervids. In Norway, HEV has been identified in pigs and humans; however, little is known regarding its presence in wild ungulates in the country. We used a species-independent double-antigen sandwich ELISA to detect antibodies against HEV in the sera of 715 wild ungulates from Norway, including 164 moose (Alces alces), 186 wild Eurasian tundra reindeer (Rangifer tarandus tarandus), 177 red deer (Cervus elaphus), 86 European roe deer (Capreolus capreolus), and 102 muskoxen (Ovibos moschatus). The overall seroprevalence was 12.3% (88/715). Wild reindeer had the highest seropositivity (23.1%, 43/186), followed by moose (19.5%, 32/164), muskoxen (5.9%, 6/102), and red deer (4%, 7/177). All roe deer were negative. According to our results, HEV is circulating in wild ungulates in Norway. The high seroprevalence observed in wild reindeer and moose indicates that these species may be potential reservoirs of HEV. To the authors’ knowledge, this is the first report of HEV exposure in reindeer from Europe and in muskoxen worldwide.

Surveillance Study of Hepatitis E Virus (HEV) in Domestic and Wild Ruminants in Northwestern Italy

Simple Summary

Hepatitis E virus (HEV) infection can cause both acute and chronic hepatitis in humans and represents an emerging public health concern worldwide. In developed countries, zoonotic transmission of HEV genotypes 3 and 4 is caused by ingestion of raw or undercooked meat of infected swine or wild boars, the main reservoirs of HEV. However, in the last few years, molecular and serological evidence seem to indicate that several other animal species may act as HEV host, including domestic and wild ruminants. In this study, serum and fecal specimens from sheep, goats, red deer, roe deer, chamois, and Alpine ibex collected in two northwestern Italian regions (Piemonte and Valle d’Aosta) were screened molecularly and serologically. With the exception of chamois, HEV antibodies were found both in the domestic and wild ruminant species investigated with the highest rates in sheep and goats. These findings demonstrate that wild also domestic ruminants may be implicated in the viral cycle transmission.

Abstract

In industrialized countries, increasing autochthonous infections of hepatitis E virus (HEV) are caused by zoonotic transmission of genotypes (Gts) 3 and 4, mainly through consumption of contaminated raw or undercooked pork meat. Although swine and wild boar are recognized as the main reservoir for Gt3 and Gt4, accumulating evidence indicates that other animal species, including domestic and wild ruminants, may harbor HEV. Herein, we screened molecularly and serologically serum and fecal samples from two domestic and four wild ruminant species collected in Valle d’Aosta and Piemonte regions (northwestern Italy. HEV antibodies were found in sheep (21.6%), goats (11.4%), red deer (2.6%), roe deer (3.1%), and in Alpine ibex (6.3%). Molecular screening was performed using different primer sets targeting highly conserved regions of hepeviruses and HEV RNA, although at low viral loads, was detected in four fecal specimens (3.0%, 4/134) collected from two HEV seropositive sheep herds. Taken together, the data obtained document the circulation of HEV in the geographical area assessed both in wild and domestic ruminants, but with the highest seroprevalence in sheep and goats. Consistently with results from other studies conducted in southern Italy, circulation of HEV among small domestic ruminants seems to occur more frequently than expected.

Antibodies Against Hepatitis E Virus (HEV) in European Moose and White-Tailed Deer in Finland

The main animal reservoirs of zoonotic hepatitis E virus (HEV) are domestic pigs and wild boars, but HEV also infects cervids. In this study, we estimated the prevalence of HEV in Finnish cervid species that are commonly hunted for human consumption. We investigated sera from 342 European moose (Alces alces), 70 white-tailed deer (Odocoileus virginianus), and 12 European roe deer (Capreolus capreolus). The samples had been collected from legally hunted animals from different districts of Finland during 2008-2009. We analysed the samples for total anti-HEV antibodies using a double-sandwich ELISA assay. Seropositive sera were analysed with RT-qPCR for HEV RNA. HEV seroprevalence was 9.1% (31/342) in moose and 1.4% (1/70) in white-tailed deer. None of the European roe deer were HEV seropositive (0/12). No HEV RNA was detected from samples of seropositive animals. HEV seropositive moose were detected in all districts. Statistically, HEV seroprevalence in moose was significantly higher (p < 0.05) in the North-East area compared to the South-West area. The highest HEV seroprevalence (20.0%) in district level was more than six times higher than the lowest (3.1%). We demonstrated the presence of total anti-HEV antibodies in European moose and white-tailed deer in Finland. Our results suggest that HEV is circulating among the moose population. Infections may occur also in white-tailed deer. We were the first to report a HEV seropositive white-tailed deer from Europe. Further studies are needed to demonstrate the HEV genotypes in cervids in Finland and to evaluate the importance of the findings in relation to food safety.

No Evidence of Hepatitis E Virus Infection in Farmed Deer in Germany

Hepatitis E virus (HEV) is a zoonotic agent, which is mainly transmitted by consumption of undercooked meat products originating from infected animals. Domestic pigs and wild boars are the major animal reservoirs, but HEV infections have been also repeatedly described in wild deer species. However, farmed deer has been only sparsely investigated so far. Here, 108 blood and 106 liver samples from fallow deer, red deer, and sika deer strictly hold in game enclosures from 11 farms in Germany were analyzed for markers of HEV infection. Using a commercial double antigen sandwich ELISA, 3/108 (2.7%) serum samples were scored borderline for HEV-specific antibodies, whereas the remaining samples were negative. No HEV-RNA (0%) was detected in the 106 liver samples. The results suggest a low risk of HEV infection in farmed deer in Germany.

Spatial-Temporal Dynamics of Hepatitis E Virus Infection in Foxes (Vulpes vulpes) in Federal State of Brandenburg, Germany, 1993-2012

Hepatitis E virus (HEV) is the main course for acute hepatitis in humans throughout the world. Human associated genotypes 1 and 2 as well as zoonotic genotypes 3 and 4 are grouped in the species Orthohepevirus A. In addition, a large variety of HEV-related viruses has been found in vertebrates including carnivores, rats, bats, and chickens, which were classified in species Orthohepevirus B-D. In 2015, partial genome sequences of a novel hepevirus were detected in feces of red foxes (Vulpes vulpes). However, no further information about virus circulation and the prevalence in foxes was available. We therefore assayed a unique panel of 880 transudates, which was collected from red foxes over 19 years (1993–2012) in Brandenburg, Germany, for HEV-related viral RNA and antibodies. Our results demonstrate a high antibody prevalence of HEV in red foxes, which oscillated annually between 40 and 100%. Molecular screening of the transudates revealed only a single RNA-positive sample, which was assigned to the carnivore species Orthohepevirus C based on the amplified partial sequence. These data indicate that the virus is circulating widely in the fox population and that foxes are carriers of this virus.

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.

Preliminary serological and molecular investigation of selected viral pathogens in Croatian cervid species

A total of 131 blood samples and 175 spleen samples were collected from three cervid species: roe deer (Capreolus capreolus), red deer (Cervus elaphus) and fallow deer (Dama dama) inhabiting the continental part of Croatia. Serum samples were tested for antibodies against bovine herpesvirus 1, parainfluenza-3 virus, bluetongue virus, bovine respiratory syncytial virus, hepatitis E virus, bovine viral diarrhoea virus and enzootic bovine leukosis virus. The tested sera were negative for bovine viral diarrhoea virus, enzootic bovine leukosis virus, bluetongue virus, bovine respiratory syncytial virus and hepatitis E virus antybodies. The antibody prevalence in roe deer and red deer samples was 21.11% for bovine herpesvirus 1 and 75.55% for parainfluenza-3 virus. Sera from bovine herpesvirus 1 positive animals were subsequenty tested with comparative virus neutralization test and bovine herpesvirus 1 neutralising antibodies were found in 18 (out of 19) sera. In fallow deer, no antibodies against any of the viral pathogens were detected. All spleen samples tested for bovine viral diarrhoea virus and enzootic bovine leukosis virus came back negative, except for one red deer spleen sample found to be weakly diarrhoea virus-positive. Our findings provide the first information on the exposure of Croatia-inhabiting cervid species to viral pathogens, and could serve as valuable baseline data for future investigations regarding deer exposure to various pathogens and the distribution of diseases shared between wildlife and livestock. As of now, the epidemiology of these viruses in the Croatian cervid population has been only poorly understood, so that further research is recommended.

Prevalence and phylogenetic analysis of hepatitis E virus in pigs, wild boars, roe deer, red deer and moose in Lithuania

Background

Hepatitis E virus (HEV) is one of the major causes of acute viral hepatitis worldwide. In Europe, food-borne zoonotic transmission of HEV genotype 3 has been associated with domestic pigs and wild boar. Controversial data are available on the circulation of the virus in animals that are used for human consumption, and to date, no gold standard has yet been defined for the diagnosis of HEV-associated hepatitis. To investigate the current HEV infection status in Lithuanian pigs and wild ungulates, the presence of viral RNA was analyzed by nested reverse transcription polymerase chain reaction (RT-nPCR) in randomly selected samples, and the viral RNA was subsequently genotyped.

Results

In total, 32.98 and 22.55% of the domestic pig samples were HEV-positive using RT-nPCR targeting the ORF1 and ORF2 fragments, respectively. Among ungulates, 25.94% of the wild boar samples, 22.58% of the roe deer samples, 6.67% of the red deer samples and 7.69% of the moose samples were positive for HEV RNA using primers targeting the ORF1 fragment. Using primers targeting the ORF2 fragment of the HEV genome, viral RNA was only detected in 17.03% of the wild boar samples and 12.90% of the roe deer samples. Phylogenetic analysis based on a 348-nucleotide-long region of the HEV ORF2 showed that all obtained sequences detected in Lithuanian domestic pigs and wildlife belonged to genotype 3. In this study, the sequences identified from pigs, wild boars and roe deer clustered within the 3i subtype reference sequences from the GenBank database. The sequences obtained from pig farms located in two different counties of Lithuania were of the HEV 3f subtype. The wild boar sequences clustered within subtypes 3i and 3h, clearly indicating that wild boars can harbor additional subtypes of HEV. For the first time, the ORF2 nucleotide sequences obtained from roe deer proved that HEV subtype 3i can be found in a novel host.

Conclusion

The results of the viral prevalence and phylogenetic analyses clearly demonstrated viral infection in Lithuanian pigs and wild ungulates, thus highlighting a significant concern for zoonotic virus transmission through both the food chain and direct contact with animals. Unexpected HEV genotype 3 subtype diversity in Lithuania and neighboring countries revealed that further studies are necessary to understand the mode of HEV transmission between animals and humans in the Baltic States region.

Hepatitis E Virus in Wild Boars and Spillover Infection in Red and Roe Deer, Germany, 2013-2015

To determine animal hepatitis E virus (HEV) reservoirs, we analyzed serologic and molecular markers of HEV infection among wild animals in Germany. We detected HEV genotype 3 strains in inner organs and muscle tissues of a high percentage of wild boars and a lower percentage of deer, indicating a risk for foodborne infection of humans.

Detection and Characterization of Hepatitis E Virus in Goats at Slaughterhouse in Tai'an Region, China

Background

Hepatitis E virus (HEV) is a significant pathogen of viral hepatitis and can be transmitted through fecal-oral route. Epidemiological data concerning HEV in goats, however, are relatively sparse to date. Here, the prevalence and characteristics of HEV isolated from goats at slaughterhouse were investigated in Tai'an region, China.

Methods

Anti-HEV immunoglobulin G (IgG) in blood samples and HEV RNA in the liver samples were determined by using an enzyme-linked immunosorbent assay (ELISA) and a nested reverse transcription polymerase chain reaction (RT-PCR), respectively. In addition, partial nucleotide sequences of open reading frame 2 (ORF-2) of HEV isolates were analyzed.

Results

Fifty goat blood samples (46.7%, 50/120) were masculine for anti-HEV IgG. HEV RNA was detected in 2 liver samples (4.0%, 2/50) and belonged to genotype 4 subtype 4 h, with high identity (91.2-93%) with cow HEV strains detected in the same province, China.

Conclusions

These findings demonstrated that goats may be an important reservoir for HEV and can become a major source of HEV infection in humans via food chain.

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

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

Hepatitis E virus in wild rabbits and European brown hares in Germany

Recently, a change of hepatitis E from being a typical travel-associated disease to an autochthonous zoonosis in Germany was observed. An increasing number of autochthonous infections with the hepatitis E Virus (HEV) have been recognized in developed countries. Venison from wild boar is already known to be a potential source of infection, if not prepared properly by the consumer. In Germany, certain wild animals are known to be a reservoir for HEV. However, current information is missing about European brown hares (Lepus europaeus) and wild rabbits (Oryctolagus cuniculus). Thus, a total of 833 hunting-harvested animals (European brown hares n = 669; wild rabbits n = 164) were tested for the occurrence of HEV RNA and HEV antibodies. For this, liver and blood specimens were taken after hunts in six German federal states. HEV antibodies were found by ELISA in 2.2% (624/14) of European brown hares, but no HEV RNA was detectable by nested real-time RT-PCR. In contrast, a seroprevalence of 37.3% (126/47) was observed for wild rabbits, and 17.1% (164/28) of the samples were HEV RNA positive. Genomic analysis revealed that these partial sequences clustered within the rabbit clade of HEV-3 genotype. In addition, one rabbit sequence segregated into subtype 3g of HEV-3. Highest seroprevalences for hares and rabbits were detected in the federal states of Bavaria and of Schleswig-Holstein, respectively. Comparing urban, rural and insular areas, the highest seroprevalence was shown for wild rabbits in rural areas and for European brown hares on the northern island Fehmarn. This study provides evidence that European brown hares and wild rabbits from Germany can be infected with HEV. The different prevalences indicate that wild rabbits are a potential reservoir for HEV in Germany, whereas European brown hares seem to be only of minor importance for the epidemiology of HEV.

Hepatitis E Virus in Industrialized Countries: The Silent Threat

Hepatitis E virus (HEV) is the main cause of acute viral hepatitis worldwide. Its presence in developing countries has been documented for decades. Developed countries were supposed to be virus-free and initially only imported cases were detected in those areas. However, sporadic and autochthonous cases of HEV infection have been identified and studies reveal that the virus is worldwide spread. Chronic hepatitis and multiple extrahepatic manifestations have also been associated with HEV. We review the data from European countries, where human, animal, and environmental data have been collected since the 90s. In Europe, autochthonous HEV strains were first detected in the late 90s and early 2000s. Since then, serological data have shown that the virus infects quite frequently the European population and that some species, such as pigs, wild boars, and deer, are reservoirs. HEV strains can be isolated from environmental samples and reach the food chain, as shown by the detection of the virus in mussels and in contaminated pork products as sausages or meat. All these data highlight the need of studies directed to control the sources of HEV to protect immunocompromised individuals that seem the weakest link of the HEV epidemiology in industrialized regions.

Excretion of infectious hepatitis E virus into milk in cows imposes high risks of zoonosis

Hepatitis E virus (HEV) represents the main cause of acute hepatitis worldwide. HEV infection in immunocompromised patients involves a high risk for the development of chronic hepatitis. Because HEV is recognized as a zoonotic pathogen, it is currently believed that swine is the primary reservoir. However, this is not sufficient to justify the strikingly high seroprevalence of HEV in both developing and Western countries. Thus, this study aimed to identify new zoonotic sources that bear a high risk of transmission to humans. We collected fecal, blood, and milk samples of cows in a typical rural region of Yunnan Province in southwest China, where mixed farming of domestic animals is a common practice. HEV RNA was quantified by quantitative real-time polymerase chain reaction, and the whole genome was sequenced. HEV infectivity was assessed in rhesus macaques. We found a high prevalence of active HEV infection in cows as determined by viral RNA positivity in fecal samples. Surprisingly, we discovered that HEV is excreted into milk that is produced by infected cows. Phylogenetic analysis revealed that all HEV isolates from cow/milk belong to genotype 4 and subtype 4h. Gavage with HEV-contaminated raw and even pasteurized milk resulted in active infection in rhesus macaques. Importantly, a short period of boiling, but not pasteurization, could completely inactivate HEV.

CONCLUSION

Infectious HEV-contaminated cow milk is recognized as a new zoonotic source that bears a high risk of transmission to humans; these results call attention to understanding and establishing proper measurement and control of HEV zoonotic transmission, particularly in the setting of mixed farming of domestic animals. (Hepatology 2016;64:350-359).

Hepatitis E as a Zoonosis

Hepatitis E (HE) virus infection is not limited to spread from human to human but also occurs between animals and more importantly as zoonotic spread from animals to humans. Genotyping of strains from hepatitis E virus-infected patients has revealed that these infections are not all caused by genotypes 1 or 2 but often by genotypes 3 or 4. Therefore, it is important to understand the striking difference between the spread of genotypes 1 and 2 in countries with poor sanitary standards and the spread of genotypes 3 and 4 in countries with good sanitary standards. The number of animal species known to be infected with HEV is expanding rapidly. The finding of HEV in new host species always raises the question regarding the zoonotic potential of these newfound strains. However, as new strains are found, the complexity increases.Certain genotypes are known to have the ability of zoonotic spread from certain animal species and these animals may even constitute an infection reservoir. Some animal species may contribute to zoonotic infections albeit on a smaller scale, while others are believed to be of minor or no importance at all. This chapter reviews possible sources of zoonotic hepatitis E virus infection.