Open reading frame 3 protein of hepatitis E virus:Multi-function protein with endless potential

Hepatitis E virus (HEV), a fecal-orally transmitted foodborne viral pathogen,causes acute hepatitis in humans and is responsible for hepatitis E outbreaksworldwide. Since the identification of HEV as a zoonotic agent, this virus has beenisolated from a variety of hosts with an ever-expanding host range. HEV-openreading frame (ORF) 3, the smallest ORF in HEV genomes, initially had beenperceived as an unremarkable HEV accessory protein. However, as novel HEVORF3function has been discovered that is related to the existence of a putativethird virion structural form, referred to as “quasi-enveloped” HEV particles, HEVis challenging the conventional virion structure-based classification scheme,which assigns all viruses to two groups, “enveloped” or “non-enveloped”. In thisreview, we systematically describe recent progress that has identified multiplepathogenic roles of HEV-ORF3, including roles in HEV virion release, biogenesisof quasi-enveloped virus, regulation of the host innate immune response, andinterference with host signaling pathways. In addition, implications of HEVORF3-associated quasi-enveloped virions are discussed to guide futuredevelopment of improved vaccines against zoonotic HEV infection.

Hepatitis E virus: Epidemiology, diagnosis, clinical manifestations, and treatment

The hepatitis E virus(HEV)is the fifth known form of viral hepatitis and was first recognized as the cause of an epidemic of unexplained acute hepatitis in the early 1980s.Globally,it is one of the most frequent causes of acute viral hepatitis.The majority of HEV infections are asymptomatic and lead to the spontaneous clearance of the virus.Among the eight different genotypes identified to date,HEV genotype 1(HEV1),HEV2,HEV3,and HEV4 are the most frequent genotypes causing infections in humans.HEV1 and HEV2 are prevalent in developing regions and able to result in large-scale outbreaks originating from contaminated water supplies.They are also responsible for severe hepatitis in pregnant patients and infants.In contrast,HEV3 and HEV4 are zoonotic,and the transmission of these genotypes to humans occurs mainly through the fecal contamination of water and consumption of contaminated meat from infected animals.Their main reservoir is the pig,and they are mostly encountered in developed countries.The major risk groups for HEV infection and its ensuing adverse consequences are pregnant women,infants,older people,immunocompromised individuals,patients with underlying chronic liver diseases,and workers that come into close contact with HEV-infected animals.In the clinical perspective,HEV infections have diverse clinical manifestations including acute and self-limiting hepatitis,acute-on-chronic liver disease,chronic hepatitis,cirrhosis,and liver failure.Although HEV mainly results in acute selflimiting infection,chronic HEV infection may occur among immunocompromised patients(e.g.,solid-organ transplant recipients).Additionally,HEV-associated extrahepatic manifestations involving various organs have been reported in the last decade,although the causal link for many of them still needs to be proven.Ribavirin and interferon-alpha are the most widely used agents for the treatment of HEV infections with a certain level of success.However,ribavirin is contraindicated in pregnant patients,and interferon-alpha cannot be used in most transplant recipients.Therefore,there is an urgent need for novel antiviral compounds that are safe and effective particularly for patients having contraindications for ribavirin or interferon-alpha and infected by the ribavirinresistant HEV.In this review article,a literature search using PubMed and MEDLINE databases was performed,up to March 2020.Only the articles published in English were reviewed.

Hepatitis E virus is a leading cause of acute-on-chronic liver disease:experience from a tertiary centre in Bangladesh

BACKGROUND:Acute-on-chronic liver failure(ACLF) is common in Bangladesh.Acute viral E hepatitis is sporadically encountered in this country each year,with a rising incidence in the rainy season.This study aimed to identify the etiology of ACLF in Bangladesh. METHODS:In this retrospective study,69 ACLF patients were included.They presented to our department at the Bangabandhu Sheikh Mujib Medical University in Dhaka.History of diseases was recorded and appropriate investigations were conducted in all patients. RESULTS:Acute hepatitis E virus(HEV)infection was positive in 21.7%(15/69)of the patients,while 14.5% (10/69)had septicemia.Upper gastrointestinal tract hemorrhage was seen in 4.3%of the patients(3/69),while another 4.3%(3/69)had a positive history for alcohol or drugs.None of the patients tested positive for hepatitis A virus infection and no evidence of hepatitis B virus flare was found in any patient.No specific cause for ACLF could be identified. CONCLUSIONS:Acute HEV infection is a leading cause of ACLF in Bangladesh.Many patients were thought to have decompensation of cirrhosis,but subsequently were recognized as having ACLF by a retrospective review according to the definition of the Asian Pacific Association for the Study of the Liver Working Party Meeting on ACLF in New Delhi in early 2008.

Neurological manifestations of hepatitis E virus infection:An overview

Hepatitis E virus(HEV)is an important cause of repeated waterborne outbreaks of acute hepatitis.Recently,several extrahepatic manifestations(EHMs)have been described in patients with HEV infection.Of these,neurological disorders are the most common EHM associated with HEV.The involvement of both the peripheral nervous system and central nervous system can occur together or in isolation.Patients can present with normal liver function tests,which can often be misleading for physicians.There is a paucity of data on HEV-related neurological manifestations;and these data are mostly described as case reports and case series.In this review,we analyzed data of 163 reported cases of HEV-related neurological disorders.The mechanisms of pathogenesis,clinico-demographic profile,and outcomes of the HEV-related neurological disorders are described in this article.Nerve root and plexus disorder were found to be the most commonly reported disease,followed by meningoencephalitis.

Expression and Characterization of a Recombinant Truncated Capsid Protein of Hepatitis E Virus in Pichia pastoris

Hepatitis E is an enterically transmitted viral disease caused by infection with hepatitis E virus（HEV）. HEV is a nonenveloped virus that bas been classified in the family of Caliciviridae. The virus appears to be a polya-denylated, positive-stranded RNA virus with three major open reading frames（ORFs）. The capsid protein of HEV is encoded by the open reading frame 2（ORF2）. We attempted to produce a truncated capsid protein, designed p293, in Pichia pastoris. The p293 gene encoding amino acids（aa） 382-674 of HEV ORF2 was designed based on the full length of HEV ORF2, cloned into the yeast vector pPIC9K, and expressed in P. pastoris strain GS 115. SDS-PAGE and Western blotting demonstrated that the recombinant protein p293 could well be expressed in P pastoris. Under optimized conditions （culture medium pH, 6.0-6.5; methanol concentration added daily, 3.0%; inoculum density, OD600=60; induction time point, 72-96 h）, the yield of soluble p293 was approximately 80 mg/L. We also observed p293 secretory expressed in P. pastoris to be 30 nm viral like particles by using electron microscopy. These results show that the p293 may has utility in the analysis of cell specific factors in the protein processing and assembly of HEV, and serve as a useful antigen for both diagnostic and vaccine purposes.

Cloning and expression of cDNAs from hepatitis E virus structural gene

OBJECTIVE: To obtain recombinant antigen for development of anti-HEV ELISA kit and vaccine against hepatitis E virus infection. METHODS: A 492 base cDNA was collected from 5'-terminus of open reading frame 2 (ORF2) among epidemic hepatitis E virus (HEV) isolated from Xinjiang, Western China. The fragment was digested with BamH I and EcoR I, and inserted into vector pGEX-4T-3 which was also digested by the same enzyme. The recombinant plasmid was transformed into E. coli TG-1 and the fusion protein expressed was confirmed by Western blot analysis using serum of a patient with hepatitis E. RESULTS: The recombinant plasmid was identified and confirmed with enzyme digestion, polymerase chain reaction (PCR) and sequencing, respectively. A protein band of about 46 kDa was demonstrated by SDS-PAGE and designated GST-pORF2. The result of Western blot analysis suggested that the fusion protein reacted with anti-HEV positive sera at a dilution of 1:100. CONCLUSION: The recombinant protein GST-pORF2 may be useful in developing anti-HEV ELISA kit and vaccine against hepatitis E virus infection.

Insights into hepatitis E virus epidemiology in Croatia

BACKGROUND Hepatitis E virus(HEV)is an emerging virus of global health concern.The seroprevalence rates differ greatly according to geographic region and population group.AIM To analyze the seroprevalence of HEV in exposed(animal-related professions)and nonexposed populations,as well as solid organ and hematopoietic stem cell transplant patients.METHODS Forestry workers(n=93),hunters(n=74),and veterinarians(n=151)represented the exposed population.The general population(n=126)and pregnant women(n=118)constituted the control group.Transplant patients included liver transplant recipients(LTRs)(n=83),kidney transplant recipients(KTRs)(n=43),and hematopoietic stem cell transplant recipients(HSCRs)(n=39).HEV immunoglobulin G antibodies were detected using the enzyme-linked immunosorbent assay and confirmed by the immunoblot test.RESULTS The HEV seroprevalence significantly differed between groups:Veterinarians 15.2%,hunters 14.9%,forestry workers 6.5%,general population 7.1%,and pregnant women 1.7%.In transplant patients,the seropositivity was highest in LTRs(19.3%),while in KTRs and HSCRs,the seroprevalence was similar to the general population(6.9%and 5.1%,respectively).A significant increase in seropositivity with age was observed from 2.9%in individuals less than 30 years to 23.5%in those older than 60 years.Sociodemographic characteristics(sex,educational level,area of residence,and number of household members),eating habits(game meat,offal,and pork products consumption),and environmental and housing conditions(drinking water supply,type of water drainage/sewer,waste disposal,domestic animals)were not associated with HEV seropositivity.However,individuals who reported a pet ownership were more often seropositive compared to those who did not have pet animals(12.5%vs 7.0%).CONCLUSION The results of this study showed that individuals in professional contact with animals and LTRs are at higher risk for HEV infection.In addition,age is a significant risk factor for HEV seropositivity.

Detection and characterization of Hepatitis E virus from commercial rabbit livers in Hebei, China

Rabbit hepatitis E virus(HEV)has been reported for years and is thought to have the potential for zoonotic transmission from rabbits to humans.As reported,HEV genotype 3(gt3)is the most prevalent form of HEV in rabbits.To determine the prevalence of HEV in commercial rabbit livers,176 liver samples were collected from an abattoir in Hebei Province,China.Three(1.7%)samples tested positive for RNA of HEV-0RF2(open reading frames-2).Sequence analysis showed that the three isolates shared high identities with each other(94.08-98.85%).Further analysis showed that all the rabbit strains clustered together in the branch of HEV gt3.Further study by immunohistochemistry(IHC)assays showed that 131(74.4%)liver samples were positive for HEV ORF2 protein.Pathological changes including cell degeneration,inflammatory cell infiltration and bile duct epithelial cell hyperplasia were observed under microscopy.These findings indicated the presence of HEV in commercial livers of rabbits.Additional studies should be conducted to investigate the infectivity of rabbit HEV(rHEV)and the potential risks of zoonotic transmission of rHEV from rabbits to human beings.

Seroprevalence of Hepatitis E Virus in Human and Pigs in Pig Farms from Guangdong Province,Southern China

Hepatitis E is caused by hepatitis E virus （HEV）, which has been classified into four genotypes. Genotypes 3 and 4 are regarded as zoonotic pathogens. Accumulating researches indicate that genotype 4 is the main HEV strain circulating in China, and there are high levels of seropositive pigs and human in some provinces of China. In this study, serum samples from pigs and from human occupationally exposed to pigs were obtained from pig farms in Guangdong Province, in subtropical southern China, in order to investigate for the first time the prevalence of anti-HEV immunoglobulin G （IgG） in the region. Antibodies against HEV were detected by Enzyme-Linked Immunosorbent Assay （ELISA） using a commercially marketed kit. The results showed that high numbers of pigs （74/94; 78.7%） and human （50/94; 53.2%） from three pig farms in Guangdong Province were positive for anti-HEV IgG. The correlation coefficient relating the prevalence in pigs and human on different farms was 0.920. The seropositive rate in males （human） was 48.8% （20/41） and that in females was 47.7% （9/19）, which showed no statistically significant difference. These data indicated that there was a high prevalence of anti-HEV antibodies in pigs and in human with occupational exposure to pigs. The risk of infection with HEV in both human and pigs in Guangdong Province appeared to be age-dependent, to a certain extent. This study provided basic data for further researches on HEV and was a reminder that more attention should be paid to HEV infection both in pigs and workers on pig farms in the study region.

Hepatitis E virus in professionally exposed: A reason for concern?

The zoonotic risk of hepatitis E virus(HEV)is well established.The HEV seroprevalence rates vary according to geographical region,assays used,and study cohorts.HEV infection is still underdiagnosed,implying the need to evaluate the disease's burden in the general population and specific risk groups,such as professionally exposed.Close contact with various animal reservoirs such as pigs,rabbits,sheep,dogs,wild boars,and deer has been associated with higher anti-HEV seroprevalence as a part of occupational exposure.While exact transmission routes remain to be determined,some general preventive measures such as proper hand hygiene,the usage of personal protective equipment,and the thermal processing of food before consumption should be followed.A“One-Health”multisectoral approach should be implemented to achieve optimal health and well-being outcomes,recognizing the interconnections between humans,animals,plants,and their shared environment,in which a vaccine against the zoonotic genotypes 3 and 4 and swine vaccination should be considered as a possible public health measure.This opinion review comprehensively addresses the HEV burden of professional exposure for butchers,slaughterhouse workers,veterinarians,farmers,hunters,and forestry workers delineates the current limits of protective work measures,and tackles future directions.

Construction of Three Nucleic Acid Vaccines of Swine Hepatitis E Virus ORF2 Ger\e Continuous Fragment

In order to develop swine hepatitis E （HE） genetically engineering vaccines, specific primers of genes LB1, LB2, LB3 of swine hepatitis E virus were designed and used for amplification, DNA amplieons generated by PCR assays were directly cloned into T-A plasmid and expressed using pEASY-M1 expression vector. Three recombinant eukaryotic expression plasmids of pEASY-LB1, pEASY-LB2 and pEASY-LB3 were constructed. The eukaryotic expression plasmids of pEASY-LB1, pEASY-LB2, and pEASY-LB3 were transfected into 293T cells, and three target genes were detected by real-time fluorescent quantitative RT-PCR. The results confirmed that three eukaryotic expression plasmids were transfected into 293Teells and target protein was expressed. Analysis by SDS-PAGE electrophoresis and Western-blot indicated that three target proteins were expressed in 293T cells transfected with eukaryotic expression plasmids of pEASY-LB1, pEASY-LB2 and pEASY-LB3. Antigenicity studies indicated good HEV responses. Therefore, three recombinant DNAs of HEV ORF2 nucleic acid vaccine candidates were ob- tained, which might lay the foundation for further studies in the future.

Detection of Hepatitis E Virus and Serum Antibodies against Hepatitis E Virus in Livestock in Heilongjiang Province

[Objective] To observe the distribution of hepatitis E virus （HEV） in livestock in Hailongjiang Province. [Method] The serum samples collected from two regions of Heilongjiang Province included 719 samples from pigs older than 3 months old, 840 samples from pigs younger than 3 months old, 505 bovine serum samples and 515 ovine serum samples. The samples were detected by enzyme-linked immunosorbent assay （ ELISA）. [ Result] The pigs had the highest level of antibodies against HEV, and the positive rate of HEV was 89.71%, indicating pigs were more likely to be infected by HEV than other livestock populations. HEV was detected in 59 porcine serum samples, three bovine serum samples and one ovine serum sample collected from Heilongjiang Province. The positive rate of HEV in pigs was higher in Heilongjiang Province than in Jinlin Province and Liaoning Province. [ Conclusion] HEV infection was wide in pigs in Heilongjiang Province, and the infection rate was higher in the old pigs than in the young pigs.

Hepatitis E virus re-infection accelerates hepatocellular carcinoma development and relapse in a patient with liver cirrhosis:A case report and review of literature

BACKGROUND Hepatitis E virus(HEV)superinfection is a suspected promoting factor for hepatocellular carcinoma(HCC)in patients with chronic hepatitis and cirrhosis.However,to date,very few cases of HEV-related HCC have been reported.Nevertheless,the role of HEV re-infection in cirrhotic liver without other chronic hepatitis infections has rarely been explored.CASE SUMMARY A 53-year-old male farmer was diagnosed with liver cirrhosis and splenomegaly in August 2016,accompanied with negative HEV-IgM and positive HEV-IgG.No evidence of hepatitis B virus or hepatitis C virus infection was found.Since then the patient was evaluated for liver function and viral parameters every 3 mo.In June 2017,the patient presented severe fatigue with whole body itching and was diagnosed with HCC.Afterwards this patient experienced quick HCC development,progression,relapse,and metastasis in the following 8 mo,and presented persistent dual positivity of HEV-IgM and HEV-IgG.This patient had a long history of smoking and alcohol consumption.CONCLUSION This unique case invokes the importance of HEV surveillance and treatment among cirrhotic patients,HCC cases,and blood donors.

Seroprevalence of Hepatitis E Virus among Voluntary Blood Donors in Nairobi County, Kenya: A Pilot Study

Hepatitis E is a common infection caused by the Hepatitis E virus (HEV), a primarily enteric virus. HEV disease is mainly spread via stool contamination of water and food supplies. The virus has recently been identified as a global threat to blood safety. The seroprevalence of HEV among blood donors in Kenya remains unknown. This study was carried out as a pilot study to determine the seroprevalence of the virus among blood donors at Nairobi Blood Transfusion Center during the period from September 2018 to January 2019. A total of three hundred and fifty eight (n = 358) plasma samples were used in this study. The plasma was tested for HEV IgM and IgG antibody using a qualitative membrane-based immunoassay (Biopanda reagents Belfast UK). Demographic characteristics of the blood donors were also collected. The age of the blood donors ranged from 16 to 61 years with a mean age of 29 years (±14). Of the study subjects, 36% (n = 130) were females while 64% (n = 228) were males. Overall, 10.6% (38) and 7.8% (28) of the samples were HEV IgG and IgM seropositive respectively. Anti-HEV was distributed among all age groups;however donors aged 20 - 40 years had the highest prevalence. This study shows a relatively high prevalence of anti-HEV among healthy blood donors in Nairobi, Kenya. Further studies would be needed in other population groups to assess the potential benefit of incorporating HEV screening of blood products to the current blood donor selection criteria. Moreover, further studies to determine the circulating genotypes of HEV among this group are required for epidemiological reasons.

Animal models of hepatitis E infection: Advances and challenges

Hepatitis E virus(HEV)is one of the leading causes of acute viral hepatitis worldwide.Although most of HEV infections are asymptomatic,some patients will develop the symptoms,especially pregnant women,the elderly,and patients with preexisting liver diseases,who often experience anorexia,nausea,vom-iting,malaise,abdominal pain,and jaundice.HEV infection may become chronic in immunosuppressed individuals.In addition,HEV infection can also cause several extrahepatic manifestations.HEV exists in a wide range of hosts in nature and can be transmitted across species.Hence,animals susceptible to HEV can be used as models.The establishment of animal models is of great significance for studying HEV transmission,clinical symptoms,extrahepatic manifestations,and therapeutic strategies,which will help us understand the pathogenesis,prevention,and treatment of hepatitis E.This review summarized the animal models of HEV,including pigs,monkeys,rabbits,mice,rats,and other animals.For each animal species,we provided a concise summary of the HEV genotypes that they can be infected with,the cross-species transmission pathways,as well as their role in studying extrahepatic manifestations,prevention,and treatment of HEV infection.The advantages and disadvantages of these animal models were also emphasized.This review offers new perspectives to enhance the current understanding of the research landscape surrounding HEV animal models.

Partial nucleotide sequencing of hepatitis E viruses detected in sera of patients with hepatitis E from 14 cities in China

OBJECTIVE: To investigate the genotypes of hepatitis E viruses (HEV) detected in sera of patients from different regions of China. METHODS: The partial genome (nt6461-6860, nt5994-6294) of open reading frame 2 (ORF2) of 45 HEV strains detected from 14 cities of China was amplified and sequenced using polymerase chain reaction (PCR) and direct sequencing. RESULTS: Forty-one of 45 strains (91%) share the same genotype with HEV Burma strain (B), with nucleotide identities higher than 98% with the representative HEV Chinese strain. Only 4 HEV strains are significantly divergent from the 3 prototype strains of HEV, with nucleotide identities of 77%-80% with HEV Burmese/Chinese strain, 74%-76% with Mexican strain and 74%-77% with the newly discovered HEV US/swine strain, respectively. Phylogenetic analysis suggests that these 4 strains may represent 2 different subtypes that belong to a novel genotype of HEV, which is significantly divergent from the prototype Mexico, Burmese and US/swine strains. CONCLUSION: Among patients with hepatitis E in China, most are infected by the Chinese prototype HEV, and only a small part by the new genotype HEV.

The Leu477 and Leu613 of ORF2-Encoded Protein Are Critical in Forming Neutralization Antigenic Epitope of Hepatitis E Virus Genotype 4

Hepatitis E virus （HEV） genotype 4 was originally identified in China. Its neutralization antigenic epitopes have not been characterized. Recently, we identified a neutralizing monoclonal antibody （mAb） IG10, which was generated following immunization of mice with p166Chn, a recombinant protein comprising 464-629 amino acids （aa） of the HEV genotype 4 capsid protein. In this study, a panel of 22 N- and/or C-terminal truncated and 6 site-directed mutated p166Chn proteins were prepared. Only those N- or C-terminal truncated proteins containing the region 477-613 aa could react with the mAb 1G10, suggesting the neutralization epitope of HEV genotype 4 is located between aa477 and aa613. However, a both N- and C-terminal truncated protein, pN477-C613, neither reacted to 1G10 nor elicited neutralizing antibodies in mice, while another both terminal truncated protein, pN472-C617, did, suggesting the flanking regions of the pN477-C613 could help to stabilize and allow presentation of the neutralization epitope to the immune system. Substituting Leu477 and/or Leu613 with the polar, uncharged threonine （Thr） caused 〉 50% reduction of the mutants＇ immunoreactivity to IG10, whereas replacement by hydrophobic phenylalanine （Phe） made little impact on the immunoreactivity, revealing functional associations between hydrophobicity of aa at positions 477 and 613 and the antigenicity of p166Chn. These data suggested Leu477 and Leu613 are critical in forming the neutralization epitope of HEV genotype 4. Cellular ＆ Molecular Immunology. 2008;5（6）：447-456.

Recent Advances Towards the Development of a Potent Antiviral Against the Hepatitis E Virus

Hepatitis E virus(HEV)is one of the leading causes of acute viral hepatitis.It also causes acute liver failure and acute-on-chronic liver failure in many patients,such as those suffering from other infections/liver injuries or organ transplant/chemo-therapy recipients.Despite widespread sporadic and epidemic incidents,there is no specific treatment against HEV,justifying an urgent need for developing a potent antiviral against it.This review summarizes the known antiviral candidates and pro-vides an overview of the potential targets for the development of specific antivirals against HEV.

Similarities,differences,and possible interactions between hepatitis E and hepatitis C viruses:Relevance for research and clinical practice

Hepatitis E virus(HEV)and hepatitis C virus(HCV)are both RNA viruses with a tropism for liver parenchyma but are also capable of extrahepatic manifestations.Hepatitis E is usually a viral acute fecal-oral transmitted and self-limiting disease presenting with malaise,jaundice,nausea and vomiting.Rarely,HEV causes a chronic infection in immunocompromised persons and severe fulminant hepatitis in pregnant women.Parenteral HCV infection is typically asymptomatic for decades until chronic complications,such as cirrhosis and cancer,occur.Despite being two very different viruses in terms of phylogenetic and clinical presentations,HEV and HCV show many similarities regarding possible transmission through organ transplantation and blood transfusion,pathogenesis(production of antinuclear antibodies and cryoglobulins)and response to treatment with some direct-acting antiviral drugs.Although both HEV and HCV are well studied individually,there is a lack of knowledge about coinfection and its consequences.The aim of this review is to analyze current literature by evaluating original articles and case reports and to hypothesize some interactions that can be useful for research and clinical practice.

Autochthonous Hepatitis E Virus Infection in Europe:A Matter of Concern for Public Health?

Human hepatitis E virus (HHEV) is the proposed name for a diverse group of RNA viruses from the family Hepeviridae that cause acute hepatitis among humans.Waterborne strains are regularly imported into Europe by international travelers,and virus transmission of zoonotic strains via contaminated aliments is involved in autochthonous cases.Therefore,in Europe,hepatitis E displays a unique dual character,having features of both imported and autochthonous infections.Environmental involvement of waterborne and zoonotic diseases puts alimentary safety at risk.In addition,it may lead to serious health problems derived from persistent infection among patients with immune impairment due to organ transplant,cancer,or human immunodeficiency virus infection.Although the European health authorities know at present that HHEV represents a problem worthy of consideration,the actual incidence of the disease in Europe is unknown,and attempts to ascertain the prevalence of the infection is hampered by unresolved technical issues.In order to determine the burden of hepatitis E in Europe,the World Health Organization Regional Office and the European Centre for Disease Prevention and Control should pay specific attention to hepatitis E,and research efforts in the continent should be transnational and collaborative.Development of a specific European network for hepatitis E would help to achieve these goals.