Consensus proposals for classification of the family Hepeviridae

Assessing Hepatitis E Virus Seroprevalence among Slaughterhouse Workers in Western Saudi Arabia: Zoonotic Threats in Focus

HEV, primarily known for its waterborne transmission, is increasingly recognized for its zoonotic potential, raising public health concerns for individuals in close contact with animals or animal products. This study aims to evaluate the seroprevalence of Hepatitis E Virus (HEV) among slaughterhouse workers in Saudi Arabia and compare it to a control group of blood donors, emphasizing potential occupational risks and associated factors.This comparative cross-sectional study included 239 slaughterhouse workers (study group) and 250 blood donors (control group). HEV IgG antibodies were detected using an in-house ELISA. Sociodemographic data, occupational exposure duration, and animal contact details were analyzed.The HEV seroprevalence was significantly higher in slaughterhouse workers (49.7%) compared to blood donors (22.1%) (p < 0.0001). Age and duration of occupational exposure were strongly predictive of HEV infection, with workers exposed for over one year showing higher odds of seropositivity. Geographic region and type of animal contact showed no significant associations.The findings suggest that prolonged occupational exposure to animals demonstrated increased the risk of HEV infection among slaughterhouse workers. Public health interventions, including improved hygiene measures, health screenings, and potential vaccination, could mitigate the risk of HEV transmission in high-exposure occupations.

Diversity of Hepatitis E Viruses in Rats in Yunnan Province and the Inner Mongolia Autonomous Region of China

Hepatitis E virus (HEV) is one of the most common pathogens causing acute hepatitis. Rat HEV, a member of the genus Rocahepevirus, infects mainly rat but can also cause human zoonotic infection. A survey of the virome of rats via next-generation sequencing (NGS) was performed in Yunnan Province and Inner Mongolia in China. Further screening of rat HEV was conducted by nested PCR. The complete genome of six representative strains were obtained by NGS and RT-PCR. The virome analysis revealed that multiple reads were annotated as Hepeviridae. The screening results showed that HEV was detected in 9.6% (34 of 355) of the rat samples and phylogenetically classified into three lineages. The sequences from Yunnan clustered with Rocahepevirus ratti, named the YnRHEV group, and those from Inner Mongolia were separated into two lineages, named the NmRHEV-1 and NmRHEV-2 groups. Complete sequence analysis showed that YnRHEV had very high sequence identity to a human HEV strain identified in immunosuppressed patients (88.7% to 94.3%), a reminder of the risk of cross-species transmission of rodent HEV. Notably, NmRHEV-1 and the most closely related rat HEV, RtCb-HEV/HeB2014, were divergent from other HEV. The phylogenetic analyses and lower sequence identities of the complete genome suggested the NmRHEV-1 to be a novel putative genus of the subfamily Orthohepevirinae. NmRHEV-2 shared the highest sequence identities (70.6% to 72.0%) with the species Rocahepevirus eothenomi, which may represent a putative novel genotype. This study revealed high genetic diversity of Hepeviridae in rats in China and a potentially zoonotic Rocahepevirus ratti strain.

Biosecurity Risk Factors and Predictive Index for Hepatitis E Virus Serological Status in Belgian Pig Farms: Conventional and Free-Range Systems

Hepatitis E viruses (HEV) cause hepatitis E in humans. In industrialized countries, sporadic HEV infections, typically caused by HEV genotypes 3 or 4, can become chronic and progress to liver cirrhosis in immunocompromised individuals. Pigs are a significant animal reservoir, implicating raw or undercooked pork products as potential sources of human infection. To better understand HEV dissemination in the Belgian pig population, potential risk factors were investigated by linking farm-level HEV serological status to biosecurity questionnaire data. Farrow-to-finish herd type, free-range systems, and poor boot hygiene were significantly associated with higher within-herd prevalences. This enabled an initial risk profiling of various farming types and the development of predictions for all Belgian pig farms. When combined with the census of the Belgian wild boar population, the predicted HEV status of all professional Belgian pig farms (based on these associations) does not suggest that the proximity of wild boars is a main source of HEV in free-ranging herds. Identifying risk factors for increased circulation of HEV between and within pig farms is critical to controlling its spread and reducing human infection.

Avian hepatitis E seroprevalence and its association with production parameters in layer hens

Big Liver and Spleen (BLS) disease in poultry is caused by avian Hepatitis E virus (aHEV) and has been reported in poultry flocks across the world including Australia. BLS was first characterised in Australia in the 1980s but currently the prevalence of aHEV in commercial egg layer flocks is not known. How aHEV effects production performance has also not been investigated. In this study, a cross-sectional epidemiological survey was conducted across several commercial egg producing flocks. Two rearing (5 flocks) and five production farms (19 flocks) were included in the study. Blood samples were collected from 20 birds from each flock. Serum was used to evaluate the seroprevalence of aHEV. The production parameters were also investigated by comparing weekly mean egg production, weekly mortality as well as food and water consumption between seropositive and seronegative sheds. The seroprevalence of aHEV for birds sampled was 14.5 % in production and 1 % in rearing flocks. A decrease in weekly egg production (p < 0.001), increased mortality (p < 0.001) as well as food (p = 0.003) and water (p < 0.001) intake were associated with seropositive sheds. The detection of anti-avian HEV antibodies in this study and its associated influence on production parameters in layer hen flocks highlights the importance of continued surveillance and impacts of aHEV in the egg industry. Further research is required to investigate the pathophysiology of avian hepatitis E viral infection and its impact on egg production and mortality.

RNA Helicase DDX3 Interacts with the Capsid Protein of Hepatitis E Virus and Plays a Vital Role in the Viral Replication

DDX3 is an ATP-dependent RNA helicase that is involved in multiple cellular activities, including RNA metabolism and innate immunity. DDX3 is known to assist the replication of some viruses while restricting others through its direct interaction with viral proteins. However, the role of DDX3 in the replication of the hepatitis E virus (HEV) is unknown. In this study, DDX3 was shown to interact with the HEV capsid protein and provide an important role in HEV replication. The DDX3 C-terminal domain was demonstrated to interact with the capsid protein. The depletion of DDX3 led to a significant reduction in HEV replication. Also, the ATPase motif of DDX3 was shown to be required in HEV replication as an ATPase-null mutant DDX3 failed to rescue the viral replication in the DDX3-depleted cells. These results demonstrate a pro-viral role of DDX3 in HEV replication, providing further insights on the virus-cell interactions.

Endemic maintenance of human-related hepatitis E virus strains in synurbic wild boars, Barcelona Metropolitan Area, Spain

Hepatitis E virus (HEV), shared by humans, domestic animals, and wildlife, is an emerging global public health threat. Because wild boars are a major reservoir of HEV, the new zoonotic interfaces resulting from wild boar population increase and synurbization significantly contribute to increasing the risk of zoonotic transmission of HEV. This study characterizes HEV strains of synurbic wild boars and assesses their relationship with sympatric human and domestic swine HEV strains. We analyzed the faeces of 312 synurbic wild boars collected from 2016 to 2021 in the Barcelona Metropolitan Area (BMA), where there is a high density of wild boars, and found 7 HEV-positive samples among those collected between 2019 and 2020. The molecular analysis of these isolates, along with 6 additional wild boar HEV isolates from a previous study, allowed us to establish a close phylogenetic relationship between these HEV strains and human HEV isolates from sympatric blood donors and domestic pigs from Catalonia. HEV-positive wild boar samples belonged to piglet, juvenile and yearling individuals, but not adults, indicating the endemic maintenance of HEV in the wild boar population of the BMA by naïve young individuals. All wild boar HEV isolates in this study classified within HEV genotype 3. The results show, for the first time, a close molecular similarity between the HEV strains endemically maintained by the synurbic wild boars in the BMA and citizens from the same area and period. The data could also indicate that HEV infection presents a seasonal and interannual variability in wild boars of BMA. Further investigation is required to unveil the HEV transmission routes between synurbic wild boars and sympatric citizens. These findings can serve in other synurbic wildlife-human interfaces throughout the world.

Challenges and global trends in combating enteric hepatitis

Enteric hepatitis, represented by the hepatitis A virus (HAV) and hepatitis E virus (HEV), remains a significant global public health concern. While much progress has been made, many aspects of the biology and pathophysiology of HAV and HEV are still not fully understood. One of the major challenges is the absence of a reliable system for virus replication. Additionally, the lack of standardized and widely accessible diagnostic tests contributes to the underestimation of the true prevalence of these viruses. Factors such as climate change, environmental shifts, globalization and increased population mobility further complicate the spread of these infections by affecting pathogen transmission, water quality and the distribution of vectors. This review approaches the emergent research challenges and trends of enteric hepatitis and focuses on developing more efficient diagnostic tools, exploring the role of zoonotic transmission and addressing the impact of environmental and climate changes on disease dynamics, underscoring the need for collaborative, interdisciplinary efforts to effectively combat enteric hepatitis in a rapidly changing world.

A critique of the use of species and below-species taxonomic terms for viruses-time for change?

The International Committee for the Taxonomy of Viruses (ICTV) regulates assignment and names of virus species and higher taxa through its taxonomy proposal and ratification process. Despite using similar taxonomic ranks to those used elsewhere in biology, the ICTV has maintained the principle that species and other taxa are strictly categories with a formal nomenclature, whereas the viruses as objects are referenced through a parallel inventory of community-assigned virus names. This is strikingly different from common and scientific name synonyms for species used elsewhere in biology. The recent introduction of binomial names for virus species resembling biological scientific names has intensified this confusion in terms within the virology community and beyond. The ICTV taxonomy furthermore does not engage with or regulate classification below species and consequently lacks taxonomic terms or descriptions for important viral pathogens such as polioviruses, severe acute respiratory syndrome coronavirus type 2, HIV-1, and avian influenza as examples. The consequent reliance on community-adopted virus names, genotypes, and other categories often lacks clarity for clinical, biocontainment, and other regulatory purposes. This article proposes a revision of rules and procedures for species and below-species level classification. It recasts virus and virus species names as 'common' and 'scientific' names that are used in other biology nomenclature codes, each with expanded reference to both object and taxon. It further advocates the creation of a formal below-species taxonomic rank to define a new inventory of approved taxa and specified nomenclature below species. Adoption of the proposed changes will realign virus taxonomy with other biological nomenclatural codes and provide greater transparency and clarity in virology, medical, and regulatory fields.

Zoonotic and Food-Related Hazards Due to Hepatitis A and E in Africa: A Systematic Review and Meta-Analysis

Introduction

Foodborne infections are caused by a wide spectrum of microbial pathogens, and they pose a significant global health threat, resulting in millions of cases and thousands of fatalities annually. Among these pathogens, human viruses, including Hepatitis A virus (HAV) and Hepatitis E virus (HEV), play a significant role in foodborne viral outbreaks, especially in Africa. This systematic review determined the prevalence of these viruses in livestock and produce in Africa.

Method

A systematic search strategy was implemented following the PRISMA guidelines. Databases such as African Journal Online, Web of Science, Scopus, and PubMed were searched from their inception until November 30, 2023. Descriptive statistics and a proportional meta-analysis utilising a random-effects model with a 95% confidence interval were employed in the data analysis. The Cochrane risk-of-bias tool (ROB2) was utilised to evaluate the potential for bias in each study.

Results

The search identified 27 articles that met the inclusion criteria, among which seven focused on HAV, comprising a total of 309 samples, whereas 20 studies focused on HEV, comprising a total of 4238 samples. Egypt had the highest number of studies, followed by Cameroon and Nigeria. The meta-analysis revealed an overall prevalence of 33.8% (95% CI: 17.0-50.6) for HAV in ducks and shellfish and 22.0% (95% CI: 12.1-31.8) for HEV in various livestock. Genotype 3 was identified as the predominant genotype, for both HAV and HEV.

Conclusion

This review revealed a high prevalence of HAV and HEV in livestock populations in Africa, shedding light on the potential risks associated with zoonotic and/or food-related infections. There is a need for continued surveillance and monitoring of these viruses in both animals and food products to mitigate the risk of foodborne outbreaks and protect human health.

Cell binding tropism of rat hepatitis E virus is a pivotal determinant of its zoonotic transmission to humans

Classically, all hepatitis E virus (HEV) variants causing human infection belong to the genus Paslahepevirus (HEV-A). However, the increasing cases of rat HEV infection in humans since 2018 challenged this dogma, posing increasing health threats. Herein, we investigated the underlying mechanisms dictating the zoonotic potentials of different HEV species and their possible cross-protection relationships. We found that rat HEV virus-like particles (HEVVLPs) bound to human liver and intestinal cells/tissues with high efficiency. Moreover, rat HEVVLPs and infectious rat HEV particles penetrated the cell membrane and entered human target cells postbinding. In contrast, ferret HEVVLPs showed marginal cell binding and entry ability, bat HEVVLPs and avian HEVVLPs exhibited no binding and entry potency. Structure-based three-dimensional mapping identified that the surface spike domain of rat HEV is crucial for cell binding. Antigenic cartography indicated that rat HEV exhibited partial cross-reaction with HEV-A. Intriguingly, sera of HEV-A infected patients or human HEV vaccine Hecolin® immunized individuals provided partial cross-protection against the binding of rat HEVVLPs to human target cells. In summary, the interactions between the viral capsid and cellular receptor(s) regulate the distinct zoonotic potentials of different HEV species. The systematic characterization of antigenic cartography and serological cross-reactivity of different HEV species provide valuable insights for the development of species-specific diagnosis and protective vaccines against zoonotic HEV infection.

Strain- and Subtype-Specific Replication of Genotype 3 Hepatitis E Viruses in Mongolian Gerbils

Since Mongolian gerbils are broadly susceptible to hepatitis E virus (HEV), including genotypes 1, 4, 5, and 8 (HEV-1, HEV-5, HEV-5, and HEV-8) and rat HEV, they are a useful small animal model for HEV. However, we have observed that the subtypes HEV-3k and HEV-3ra in genotype 3 HEV (HEV-3) were not infected efficiently in the gerbils. A small-animal model for HEV-3 is also needed since HEV-3 is responsible for major zoonotic HEV infections. To investigate whether gerbils can be used as animal models for other subtypes of HEV-3, we injected gerbils with five HEV-3 subtypes (HEV-3b, -3e, -3f, -3k, and -3ra) and compared the infectivity of the subtypes. We detected viral RNA in the gerbils' feces. High titers of anti-HEV IgG antibodies in serum were induced in all HEV-3b/ch-, HEV-3f-, and HEV-3e-injected gerbils. Especially, the HEV-3e-injected animals released high levels of viruses into their feces for an extended period. The virus replication was limited in the HEV-3b/wb-injected and HEV-3k-injected groups. Although viral RNA was detected in HEV-3ra-injected gerbils, the copy numbers in fecal specimens were low; no antibodies were detected in the sera. These results indicate that although HEV-3's infectivity in gerbils depends on the subtype and strain, Mongolian gerbils have potential as a small-animal model for HEV-3. A further comparison of HEV-3e with different genotype strains (HEV-4i and HEV-5) and different genera (rat HEV) revealed different ALT elevations among the strains, and liver damage occurred in HEV-4i- and HEV-5-infected but not HEV-3e- or rat HEV-infected gerbils, demonstrating variable pathogenicity across HEVs from different genera and genotypes in Mongolian gerbils. HEV-4i- and HEV-5-infected Mongolian gerbils might be candidate animal models to examine HEV's pathogenicity.

Hepatitis E virus immunosuppressed animal models

Hepatitis E virus (HEV) is an important emerging pathogen producing significant morbidity in immunosuppressed patients. HEV has been detrimental to solid organ transplant (SOT) patients, cancer patients, and HIV-positive patients, where chronic HEV infections occur. Blood-borne transfusions and multiple cases of chronic HEV infection in transplant patients have been reported in the past few decades, necessitating research on HEV pathogenesis using immunosuppressed animal models. Numerous animal species with unique naturally occurring HEV strains have been found, several of which have the potential to spread to humans and to serve as pathogenesis models. Host immunosuppression leads to viral persistence and chronic HEV infection allows for genetic adaptation to the human host creating new strains with worse disease outcomes. Procedures necessary for SOT often entail blood transfusions placing immunosuppressive patients into a "high risk group" for HEV infection. This scenario requires an appropriate immunosuppressive animal model to understand disease patterns in these patients. Hence, this article reviews the recent advances in the immunosuppressed animal models for chronic HEV infection with emphasis on pathogenesis, immune correlates, and the liver pathology associated with the chronic HEV infections.

Utility of various genome lengths in diversity and evolution analyses of Hepatitis E virus

The aim of this study was to investigate to what extent fragments of the HEV genome could be used for accurate diagnostics and inference of viral population-scale processes. For this, we selected all the published whole genome sequences from the NCBI GenBank and trimmed them to various fragment lengths (ORF1,2,3, ORF1, ORF2, ORF3, 493 nt in ORF2 and 148 nt in ORF2). Each of the fragment lengths was used to infer the richness and diversity of the viral sequence types, typing accuracy, and potential use in phylodynamics. The results obtained from the different fragments were compared. We observed that, generally, the longer the nucleic acid fragment used in typing, the better the accuracy in predicting the viral subtype. However, the dominant HEV subtypes circulating in Europe were relatively well classified even by the 493 nt fragment, with false negative rates as low as 8 in 1000 typed sequences. Most fragments also give comparable results in analyses of population size, albeit with shorter fragments showing a broader 95 % highest posterior density interval and less obvious increase of the viral effective population size. The reconstructed phylogenies of a heterochronous subset indicated a good concordance between all the fragments, with the major clades following similar branching patterns. Furthermore, we have used the HEV sequence data from the Netherlands available in the HEVnet database as a case study for reconstruction of population size changes in the past decades. This data showed that molecular and epidemiological results are concordant and point to an increase in the viral effective population size underlying the observed increase in incidence of acute HEV infection cases. In the absence of whole genome sequencing data, the 493 bp fragment can be used for analyzing HEV strains currently circulating in Europe, as it is informative for describing short term population-scale processes.

A Broad-specificity Neutralizing Nanobody against Hepatitis E Virus Capsid Protein

Hepatitis E virus (HEV) is a worldwide zoonotic and public health concern. The study of HEV biology is helpful for designing viral vaccines and drugs. Nanobodies have recently been considered appealing materials for viral biological research. In this study, a Bactrian camel was immunized with capsid proteins from different genotypes (1, 3, 4, and avian) of HEV. Then, a phage library (6.3 × 108 individual clones) was constructed using peripheral blood lymphocytes from the immunized camel, and 12 nanobodies against the truncated capsid protein of genotype 3 HEV (g3-p239) were screened. g3-p239-Nb55 can cross-react with different genotypes of HEV and block Kernow-C1/P6 HEV from infecting HepG2/C3A cells. To our knowledge, the epitope recognized by g3-p239-Nb55 was determined to be a novel conformational epitope located on the surface of viral particles and highly conserved among different mammalian HEV isolates. Next, to increase the affinity and half-life of the nanobody, it was displayed on the surface of ferritin, which can self-assemble into a 24-subunit nanocage, namely, fenobody-55. The affinities of fenobody-55 to g3-p239 were ∼20 times greater than those of g3-p239-Nb55. In addition, the half-life of fenobody-55 was nine times greater than that of g3-p239-Nb55. G3-p239-Nb55 and fenobody-55 can block p239 attachment and Kernow-C1/P6 infection of HepG2/C3A cells. Fenobody-55 can completely neutralize HEV infection in rabbits when it is preincubated with nonenveloped HEV particles. Our study reported a case in which a nanobody neutralized HEV infection by preincubation, identified a (to our knowledge) novel and conserved conformational epitope of HEV, and provided new material for researching HEV biology.

Oxysterol binding protein (OSBP) contributes to hepatitis E virus replication

Hepatitis E virus (HEV) is a positive-sense, single-stranded RNA virus and causes primarily acute self-limiting infections. The ORF1 of the HEV genome encodes a polyprotein around 190 kDa, which contains several putative domains, including helicase and RNA-dependent RNA polymerase. The HEV-encoded helicase is a member of the superfamily 1 helicase family and possesses multiple enzymatic functions, such as RNA 5'-triphosphatase, RNA unwinding, and NTPase, which are thought to contribute to viral RNA synthesis. However, the helicase interaction with cellular proteins remains less known. Oxysterol binding protein (OSBP) is a lipid regulator that shuffles between the Golgi apparatus and the endoplasmic reticulum for cholesterol and phosphatidylinositol-4-phosphate exchange and controls the efflux of cholesterol from cells. In this study, the RNAi-mediated silencing of OSBP significantly reduced HEV replication. Further studies indicate that the HEV helicase interacted with OSBP, shown by co-immunoprecipitation and co-localization in co-transfected cells. The presence of helicase blocked OSBP preferential translocation to the Golgi apparatus. These results demonstrate that OSBP contributes to HEV replication and enrich our understanding of the HEV-cell interactions.

Acute Viral Hepatitis E Infection Complicating Postliving Liver Donor Hepatectomy Recovery

This study presents a case of a living liver donor who developed a hepatitis E virus (HEV) infection postdonation, complicating his recovery. The donor was a 28-year-old male with no prior health issues who underwent a right lobe hepatectomy. Initially, his postoperative course was uneventful, but on the third postoperative day, he became lethargic and icteric. Laboratory tests showed elevated liver function markers, with peak levels on the 5th day. The HEV infection was confirmed through serological and polymerase chain reaction (PCR) testing. The donor was managed supportively and recovered, with normal liver function at discharge. Unfortunately, the recipient of the liver graft died on the 5th postoperative day due to sepsis, and the impact of HEV infection on the recipient could not be fully assessed due to the complicating factors. This case highlights the importance of considering HEV infection in donors with abnormal postoperative liver functions, especially in regions with high HEV prevalence, and suggests the potential benefit of HEV vaccination for liver donors. Further research is needed to better understand and manage HEV infection in the context of liver donation.

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

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

Prevalence and molecular characterization of hepatitis E virus (HEV) from wild rodents in Hubei Province, China

Hepatitis E, caused by the hepatitis E virus (HEV), is a global public health issue. Low similarity between the gene sequences of mouse and human HEV led to the belief that the risk of human infection was low. Recent reports of chronic and acute hepatitis E caused by murine HEV infection in humans in Hong Kong have raised global concerns. Therefore, it is crucial to investigate the epidemiology and prevalence of HEV in China. We comprehensively analyzed different rodent HEV strains to understand rocahepevirus occurrence in Hubei Province, China. The HEV positivity rate for was 6.43% (73/1136). We identified seven near-full-length rocahepevirus strains and detected rat HEV antigens in tissues from different mouse species. HEV has extensive tissue tropism and a high viral load in the liver. We highlight the genetic diversity of HEVs in rodents and underscore the importance of paying attention to their variation and evolution.

Hepatitis E Virus in the United States and Canada: Is It Time to Consider Blood Donation Screening?

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis in the world and can lead to severe complications in immunocompromised individuals. HEV is primarily transmitted through eating pork, which has led to an increased in anti-HEV IgG seropositivity in the general population of Europe in particular. However, it can also be transmitted intravenously, such as through transfusions. The growing evidence of HEV contamination of blood products and documented cases of transmission have given rise to practice changes and blood product screening of HEV in many European countries. This review covers the abundant European literature and focuses on the most recent data pertaining to the prevalence of HEV RNA positivity and IgG seropositivity in the North American general population and in blood products from Canada and the United States. Currently, Health Canada and the Food and Drug Administration do not require testing of HEV in blood products. For this reason, awareness among blood product prescribers about the possibility of HEV transmission through blood products is crucial. However, we also demonstrate that the province of Quebec has a prevalence of anti-HEV and HEV RNA positivity similar to some European countries. In light of this, we believe that HEV RNA blood donation screening be reevaluated with the availability of more cost-effective assays.

Hepatitis E virus causes apoptosis of ovarian cells in hens and resulting in a decrease in egg production

Previous studies have shown that avian hepatitis E virus (HEV) decreases egg production by 10-40% in laying hens, but have not fully elucidated the mechanism of there. In this study, we evaluated the replication of avian HEV in the ovaries of laying hens and the mechanism underlying the decrease in egg production. Forty 150-days-old commercial laying hens were randomly divided into 2 groups of 20 hens each. A total of 1 mL (104GE) of avian HEV stock was inoculated intravenously into each chicken in the experimental group, with 20 chickens in the other group serving as negative controls. Five chickens from each group were necropsied weekly for histopathological examination. The pathogenicity of avian HEV has been characterized by seroconversion, viremia, fecal virus shedding, ovarian lesions, and decreased egg production. Both positive and negative-strand avian HEV RNA, and ORF2 antigens can be detected in the ovaries, suggesting that avian HEV can replicate in the ovaries and serve as an important extrahepatic replication site. The ovaries of laying hens underwent apoptosis after avian HEV infection. These results indicate that avian HEV infection and replication in ovarian tissues cause structural damage to the cells, leading to decreased egg production.

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, vomiting, 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.

Multi-epitope vaccine design for hepatitis E virus based on protein ORF2 and ORF3

Introduction

Hepatitis E virus (HEV), with heightened virulence in immunocompromised individuals and pregnant women, is a pervasive threat in developing countries. A globaly available vaccine against HEV is currently lacking.

Methods

We designed a multi-epitope vaccine based on protein ORF2 and ORF3 of HEV using immunoinformatics.

Results

The vaccine comprised 23 nontoxic, nonallergenic, soluble peptides. The stability of the docked peptide vaccine-TLR3 complex was validated by molecular dynamic simulations. The induction of effective cellular and humoral immune responses by the multi-peptide vaccine was verified by simulated immunization.

Discussion

These findings provide a foundation for future HEV vaccine studies.

Label-Free Quantitative Analysis of Pig Liver Proteome after Hepatitis E Virus Infection

Hepatitis E represents an emerging zoonotic disease caused by the Hepatitis E virus (HEV), for which the main route of transmission is foodborne. In particular, infection in humans has been associated with the consumption of contaminated undercooked meat of pig origin. The aim of this study was to apply comparative proteomics to determine if porcine liver protein profiles could be used to distinguish between pigs seropositive and seronegative for HEV. Preliminarily, an ELISA was used to evaluate the presence of anti-HEV antibodies in the blood serum of 136 animals sent to slaughter. Among the analyzed samples, a seroprevalence of 72.8% was estimated, and it was also possible to identify 10 animals, 5 positive and 5 negative, coming from the same farm. This condition created the basis for the quantitative proteomics comparison between homogeneous animals, in which only the contact with HEV should represent the discriminating factor. The analysis of the proteome in all samples of liver exudate led to the identification of 554 proteins differentially expressed between the two experimental groups, with 293 proteins having greater abundance in positive samples and 261 more represented in negative exudates. The pathway enrichment analysis allowed us to highlight the effect of the interaction between HEV and the host biological system in inducing the potential enrichment of 69 pathways. Among these, carbon metabolism stands out with the involvement of 41 proteins, which were subjected to interactomic analysis. This approach allowed us to focus our attention on three enzymes involved in glycolysis: glucose-6-phosphate isomerase (GPI), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and fructose-bisphosphate aldolase A (ALDOA). It therefore appears that infection with HEV induced a strengthening of the process, which involves the breakdown of glucose to obtain energy and carbon residues useful for the virus's survival. In conclusion, the label-free LC-MS/MS approach showed effectiveness in highlighting the main differences induced on the porcine liver proteome by the interaction with HEV, providing crucial information in identifying a viral signature on the host metabolism.

Hepatitis E outbreak in the health district of Bocaranga-Koui, Central African Republic, 2018-2019

BACKGROUND

Hepatitis E virus (HEV) is a major public health disease causing large outbreaks and sporadic cases of acute hepatitis. We investigated an outbreak of HEV infection that occurred in September 2018 in the health district (HD) of Bocaranga-Koui, located in the northwestern part of Central African Republic (CAR).

METHODS

Blood samples were collected from 352 patients aged 0-85 years suspected to be infected with yellow fever (YF), according to the World Health Organization YF case definition. The notification forms from recorded cases were used. Water consumed in the HD were also collected. Human samples found negative for anti-YF IgM were then tested by ELISA for anti-HEV IgM and IgG antibodies. Positive anti-HEV (IgM and/or IgG) samples and collected water were then subjected to molecular biology tests using a real time RT-PCR assay, followed by a nested RT-PCR assay for sequencing and phylogenetic analysis.

RESULTS

Of the 352 icterus patients included, anti-HEV IgM was found in 142 people (40.3%) and anti-HEV IgG in 175 (49.7%). Although HEV infection was detected in all age groups, there was a significant difference between the 0-10 age groups and others age groups (P = 0.001). Elevated levels of serum aminotransferase were observed in anti-HEV IgM-positive subjects. Phylogenetic analysis showed HEV genotype 1e in infected patients as well as in the contaminated water.

CONCLUSION

This epidemic showed that CAR remains an HEV-endemic area. The genotype 1e strain was responsible for the HEV outbreak in Bocaranga-Koui HD. It is necessary to implement basic conditions of hygiene and sanitation to prevent further outbreaks of a HEV epidemics, to facilitate access to clean drinking water for the population, to launch intensive health education for basic hygiene measures, to sett up targeted hygiene promotion activities and, finally, to ensure that formal health care is available.

Prevalence, Genetic Diversity, and Quantification of the RNA Genome of the Hepatitis E Virus in Slaughtered Pigs in Serbia

The goal of this study conducted in Serbia was to detect HEV in pig liver samples from slaughterhouses, retail outlets, and environmental swabs over the course of a year. All positive HEV samples were measured and expressed as HEV gene copy numbers per gram of sample, and a representative number of samples were sequenced using the Sanger approach. A total of 45 HEV-positive samples were re-amplified using nested RT-PCR employing CODEHOP primers targeting ORF2 (493 nucleotides). The average prevalence of the HEV genotype 3 in all pig liver samples from the slaughterhouses was 29%, while HEV prevalence was 44% in liver samples from animals younger than 3 months. HEV RNA was found in thirteen out of sixty (22%) environmental swab samples that were taken from different surfaces along the slaughter line. Our findings confirmed seasonal patterns in HEV prevalence, with two picks (summer and winter periods) during the one-year examination. Among HEV-positive samples, the average viral particles for all positive liver samples was 4.41 ± 1.69 log10 genome copies per gram. Phylogenetic analysis revealed the majority of HEV strains (43/45) from Serbia were grouped in the HEV-3a subtype, while two strains were classified into the HEV-3c subtype, and one strain could not be classified into any of the HEV-3 subtypes.

Common and Potential Emerging Foodborne Viruses: A Comprehensive Review

Human viruses and viruses from animals can cause illnesses in humans after the consumption of contaminated food or water. Contamination may occur during preparation by infected food handlers, during food production because of unsuitably controlled working conditions, or following the consumption of animal-based foods contaminated by a zoonotic virus. This review discussed the recent information available on the general and clinical characteristics of viruses, viral foodborne outbreaks and control strategies to prevent the viral contamination of food products and water. Viruses are responsible for the greatest number of illnesses from outbreaks caused by food, and risk assessment experts regard them as a high food safety priority. This concern is well founded, since a significant increase in viral foodborne outbreaks has occurred over the past 20 years. Norovirus, hepatitis A and E viruses, rotavirus, astrovirus, adenovirus, and sapovirus are the major common viruses associated with water or foodborne illness outbreaks. It is also suspected that many human viruses including Aichi virus, Nipah virus, tick-borne encephalitis virus, H5N1 avian influenza viruses, and coronaviruses (SARS-CoV-1, SARS-CoV-2 and MERS-CoV) also have the potential to be transmitted via food products. It is evident that the adoption of strict hygienic food processing measures from farm to table is required to prevent viruses from contaminating our food.

The Protease Domain in HEV pORF1 Mediates the Replicase's Localization to Multivesicular Bodies and Its Exosomal Release

BACKGROUND

A peculiar feature of the hepatitis E virus (HEV) is its reliance on the exosomal route for viral release. Genomic replication is mediated via the viral polyprotein pORF1, yet little is known about its subcellular localization.

METHODS

Subcellular localization of pORF1 and its subdomains, generated and cloned based on a structural prediciton of the viral replicase, was analyzed via confocal laser scanning microscopy. Exosomes released from cells were isolated via ultracentrifugation and analyzed by isopycnic density gradient centrifugation. This was followed by fluorimetry or Western blot analyses or reverse transcriptase-polymerase chain reaction to analyze separated particles in more detail.

RESULTS

We found pORF1 to be accumulating within the endosomal system, most dominantly to multivesicular bodies (MVBs). Expression of the polyprotein's 7 subdomains revealed that the papain-like cysteine-protease (PCP) is the only domain localizing like the full-length protein. A PCP-deficient pORF1 mutant lost its association to MVBs. Strikingly, both pORF1 and PCP can be released via exosomes. Similarly, genomic RNA still is released via exosomes in the absence of pORF2/3.

CONCLUSIONS

Taken together, we found that pORF1 localizes to MVBs in a PCP-dependent manner, which is followed by exosomal release. This reveals new aspects of HEV life cycle, because replication and release could be coupled at the endosomal interface. In addition, this may mediate capsid-independent spread or may facilitate the spread of viral infection, because genomes entering the cell during de novo infection readily encounter exosomally transferred pORF1.

Redeveloping antigen detection kits for the diagnosis of rat hepatitis E virus

The emergence of Rocahepevirus ratti [species HEV ratti (r HEV)] as a causative agent of hepatitis E in humans presents a new potential threat to global public health. The R. ratti genotype 1 (r-1 HEV) variant only shares 50%-60% genomic identity with Paslahepevirus balayani [species HEV balayani (b HEV)] variants, which are the main causes of hepatitis E infection in humans. Here, we report antigen diagnoses for r-1 HEV and b HEV using an enzymatic immunoassay (EIA) method. We detected recombinant virus-like particles protein (HEV 239) of r HEV and b HEV using a collection of hepatitis E virus (HEV)-specific monoclonal antibodies. Two optimal candidates, the capture antibody P#1-H4 and the detection antibodies C145 (P#1-H4*/C145#) and C158 (P#1-H4*/C158#), were selected to detect antigen in infected rat samples and r-1 HEV- or b HEV-infected human clinical samples. The two candidates showed similar diagnostic efficacy to the Wantai HEV antigen kit in b HEV-infected clinical samples. Genomic divergence resulted in low diagnostic efficacy of the Wantai HEV antigen kit (0%, 0 of 10) for detecting r-1 HEV infection. Compared with the P#1-H4*/C145# candidate (80%, 8 of 10), the P#1-H4*/C158# candidate had excellent diagnostic efficacy in r-1 HEV-infected clinical samples (100%, 10 of 10). The two candidates bind to a discrete antigenic site that is highly conserved across r HEV and b HEV. P#1-H4*/C145# and P#1-H4*/C158# are efficacious candidate antibody combinations for rat HEV antigen detection.

Dynamic and Seasonal Distribution of Enteric Viruses in Surface and Well Water in Riyadh (Saudi Arabia)

Enteric viruses are the major cause of gastroenteritis and enteric hepatitis worldwide, but in some areas like Saudi Arabia, little is known about their presence in water sources. The available information from clinical samples is not enough to figure out their actual prevalence. The aim of this study was to gather information for the first time in Saudi Arabia on the presence of the Norovirus (NoV) genogroup GI and GII, hepatitis A virus (HAV), and hepatitis E virus (HEV) in water. For this purpose, thirteen monthly samples were collected from Lake Wadi Hanifa and surrounding wells from December 2014 to November 2015. Viruses were detected and quantified using real-time RT-qPCR. Despite HEV findings being anecdotic, our results highlight interesting behaviors of the other viruses. There was a higher prevalence of noroviruses in Wadi Hanifa samples than in well water samples (46.43% vs. 12.5% of NoV GI; 66.67% vs. 8.33% of NoV GII). On the contrary, similar levels of HAV positivity were observed (40.48% in surface water vs. 43.06% in well water). Also, a strong influence of flooding events on HAV and NoV GI occurrence was observed in both surface and well water samples, with NoV GII apparently not affected.

Point-of-Care Testing for Hepatitis Viruses: A Growing Need

Viral hepatitis, caused by hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), or hepatitis E virus (HEV), is a major global public health problem. These viruses cause millions of infections each year, and chronic infections with HBV, HCV, or HDV can lead to severe liver complications; however, they are underdiagnosed. Achieving the World Health Organization's viral hepatitis elimination goals by 2030 will require access to simpler, faster, and less expensive diagnostics. The development and implementation of point-of-care (POC) testing methods that can be performed outside of a laboratory for the diagnosis of viral hepatitis infections is a promising approach to facilitate and expedite WHO's elimination targets. While a few markers of viral hepatitis are already available in POC formats, tests for additional markers or using novel technologies need to be developed and validated for clinical use. Potential methods and uses for the POC testing of antibodies, antigens, and nucleic acids that relate to the diagnosis, monitoring, or surveillance of viral hepatitis infections are discussed here. Unmet needs and areas where additional research is needed are also described.

Virome of high-altitude canine digestive tract and genetic characterization of novel viruses potentially threatening human health

The majority of currently emerging infectious illnesses are zoonotic infections, which have caused serious public health and economic implications. The development of viral metagenomics has helped us to explore unknown viruses. We collected 1,970 canine feces from Yushu and Guoluo in the plateau region of China for this study to do a metagenomics analysis of the viral community of the canine digestive tract. Our analysis identified 203 novel viruses, classified into 11 known families and 2 unclassified groups. These viruses include the hepatitis E virus, first identified in dogs, and the astrovirus, coronavirus, polyomavirus, and others. The relationship between the newly identified canine viruses and known viruses was investigated through the use of phylogenetic analysis. Furthermore, we demonstrated the cross-species transmission of viruses and predicted new viruses that may cause diseases in both humans and animals, providing technical support for the prevention and control of diseases caused by environmental pollution viruses. IMPORTANCE Most emerging infectious diseases are due to zoonotic disease agents. Because of their effects on the security of human or animal life, agriculture production, and food safety, zoonotic illnesses and livestock diseases are of worldwide significance. Because dogs are closely related to humans and domestic animals, they serve as one of the important links in the transmission of zoonotic and livestock diseases. Canines can contaminate the environment in which humans live such as water and soil through secretions, potentially altering the human gut microbiota or causing diseases. Our study enriched the viral community in the digestive tract microbiome of dogs and found types of viruses that threaten human health, providing technical support for the prevention and control of early warning of diseases caused by environmental contaminant viruses.

Zoonotic diseases transmitted from the camels

BACKGROUND

Zoonotic diseases, infections transmitted naturally from animals to humans, pose a significant public health challenge worldwide. After MERS-CoV was discovered, interest in camels was raised as potential intermediate hosts for zoonotic viruses. Most published review studies pay little attention to case reports or zoonotic epidemics where there is epidemiological proof of transmission from camels to humans. Accordingly, any pathogen found in camels known to cause zoonotic disease in other animals or humans is reported.

METHODS

Here, zoonotic diseases linked to camels are reviewed in the literature, focusing on those with epidemiological or molecular evidence of spreading from camels to humans. This review examines the risks posed by camel diseases to human health, emphasizing the need for knowledge and awareness in mitigating these risks.

RESULTS

A search of the literature revealed that eight (36.4%) of the 22 investigations that offered convincing evidence of camel-to-human transmission involved MERS, five (22.7%) Brucellosis, four (18.2%) plague caused by Yersinia pestis, three (13.6%) camelpox, one (4.5%) hepatitis E, and one (4.5%) anthrax. The reporting of these zoonotic diseases has been steadily increasing, with the most recent period, from 2010 to the present, accounting for 59% of the reports. Additionally, camels have been associated with several other zoonotic diseases, including toxoplasmosis, Rift Valley fever, TB, Crimean-Congo hemorrhagic fever, and Q fever, despite having no evidence of a transmission event. Transmission of human zoonotic diseases primarily occurs through camel milk, meat, and direct or indirect contact with camels. The above-mentioned diseases were discussed to determine risks to human health.

CONCLUSION

MERS, Brucellosis, plague caused by Y. pestis, camelpox, hepatitis E, and anthrax are the main zoonotic diseases associated with human disease events or outbreaks. Transmission to humans primarily occurs through camel milk, meat, and direct contact with camels. There is a need for comprehensive surveillance, preventive measures, and public health interventions based on a one-health approach to mitigate the risks of zoonotic infections linked to camels.

Discovery of Hepatitis E and Its Impact on Global Health: A Journey of 44 Years about an Incredible Human-Interest Story

The story of the discovery of hepatitis E originated in the late 1970s with my extreme belief that there was a hidden saga in the relationship between jaundice and pregnancy in developing countries and the opportunity for a massive epidemic of viral hepatitis, which hit the Gulmarg Kashmir region in November 1978. Based on data collected from a door-to-door survey, the existence of a new disease, epidemic non-A, non-B hepatitis, caused by a hitherto unknown hepatitis virus, was announced. This news was received by the world community with hype and skepticism. In the early 1980s, the world watched in awe as an extreme example of human self-experimentation led to the identification of VLP. In 1990, a cDNA clone from the virus responsible for epidemic non-A, non-B hepatitis was isolated. Over the years, we traversed three eras of ambiguity, hope, and hype of hepatitis E research and conducted several seminal studies to understand the biology of HEV and manifestations of hepatitis E. Many milestones have been reached on the long and winding road of hepatitis E research to understand the structure, biology, and diversity of the agent, changing the behavior of the pathogen in developed countries, and the discovery of a highly effective vaccine.

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

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

Genotype 4 Hepatitis E virus replicates in the placenta, causes severe histopathological damage, and vertically transmits to fetuses

BACKGROUND

Hepatitis E virus (HEV) infection in pregnant women causes adverse pregnancy outcomes, including maternal death, premature delivery, stillbirth, and fetal infection. However, the pathogenesis of maternal and fetal HEV infection is unclear.

METHODS

Placenta and placental appendixes were collected from HEV-4 infected pregnant women to explore the vertical transmission of HEV from mothers to fetuses.

RESULTS

HEV-4 replicated in the placenta, placental membrane, and umbilical cord and was vertically transmitted from mothers to fetuses. HEV-4 placental infection resulted in serious histopathological damage, such as fibrosis and calcification, and severe inflammatory responses. Adverse maternal outcomes were observed in 38.5% of HEV-4 infected pregnant women. The distinct cytokine/chemokine expression patterns of HEV-infected pregnant women and nonpregnant women may contribute to the adverse pregnancy outcomes. Furthermore, the impaired maternal and fetal innate immune responses against HEV-4 facilitated viral replication during pregnancy.

CONCLUSION

HEV-4 replicates in the placenta and is vertically transmitted from mothers to fetuses, causing severe histopathological damage.

Low Replication Efficiency of a Japanese Rabbit Hepatitis E Virus Strain in the Human Hepatocarcinoma Cell Line PLC/PRF/5

A Japanese rabbit hepatitis E virus (HEV) strain, JP-59, has been identified in a feral rabbit. When this virus was transmitted to a Japanese white rabbit, it caused persistent HEV infection. The JP-59 strain shares an <87.5% nucleotide sequence identity with other rabbit HEV strains. Herein, to isolate JP-59 by cell culture, we used a 10% stool suspension recovered from a JP-59-infected Japanese white rabbit and contained 1.1 × 10⁷ copies/mL of the viral RNA and using it to infect a human hepatocarcinoma cell line, PLC/PRF/5. No sign of virus replication was observed. Although long-term virus replication was observed in PLC/PRF/5 cells inoculated with the concentrated and purified JP-59 containing a high titer of viral RNA (5.1 × 10⁸ copies/mL), the viral RNA of JP-59c that was recovered from the cell culture supernatants was <7.1 × 10⁴ copies/mL during the experiment. The JP-59c strain did not infect PLC/PRF/5 cells, but its intravenous inoculation caused persistent infection in rabbits. The nucleotide sequence analyses of the virus genomes demonstrated that a total of 18 nucleotide changes accompanying three amino acid mutations occurred in the strain JP-59c compared to the original strain JP-59. These results indicate that a high viral RNA titer was required for JP-59 to infect PLC/PRF/5 cells, but its replication capability was extremely low. In addition, the ability of rabbit HEVs to multiply in PLC/PRF/5 cells varied depending on the rabbit HEV strains. The investigations of cell lines that are broadly susceptible to rabbit HEV and that allow the efficient propagation of the virus are thus needed.

Structural features stabilized by divalent cation coordination within hepatitis E virus ORF1 are critical for viral replication

Hepatitis E virus (HEV) is an RNA virus responsible for over 20 million infections annually. HEV's open reading frame (ORF)1 polyprotein is essential for genome replication, though it is unknown how the different subdomains function within a structural context. Our data show that ORF1 operates as a multifunctional protein, which is not subject to proteolytic processing. Supporting this model, scanning mutagenesis performed on the putative papain-like cysteine protease (pPCP) domain revealed six cysteines essential for viral replication. Our data are consistent with their role in divalent metal ion coordination, which governs local and interdomain interactions that are critical for the overall structure of ORF1; furthermore, the 'pPCP' domain can only rescue viral genome replication in trans when expressed in the context of the full-length ORF1 protein but not as an individual subdomain. Taken together, our work provides a comprehensive model of the structure and function of HEV ORF1.

Hepatitis E Virus Research in Brazil: Looking Back and Forwards

Hepatitis E virus (HEV) has emerged as a public health concern in Brazil. From the first identification and characterization of porcine and human HEV-3 strains in the 2000s, new HEV subtypes have been identified from animal, human, and environmental isolates. As new potential animal reservoirs have emerged, there is a need to compile evidence on the zoonotic dissemination of the virus in animal hosts and the environment. The increasing amount of seroprevalence data on sampled and randomly selected populations must be systematically retrieved, interpreted, and considered under the One Health concept. This review focused on HEV seroprevalence data in distinct animal reservoirs and human populations reported in the last two decades. Furthermore, the expertise with experimental infection models using non-human primates may provide new insights into HEV pathogenesis, prevention, and environmental surveillance.

Specific Plasma MicroRNA Signatures Underlying the Clinical Outcomes of Hepatitis E Virus Infection

The pathogenic mechanisms determining the diverse clinical outcomes of HEV infection (e.g., self-limiting versus chronic or symptomatic versus asymptomatic) are not yet understood. Because specific microRNA signatures during viral infection inform the cellular processes involved in virus replication and pathogenesis, we investigated plasma microRNA profiles in 44 subjects, including patients with symptomatic acute (AHE, n = 7) and chronic (CHE, n = 6) hepatitis E, blood donors with asymptomatic infection (HEV BDs, n = 9), and anti-HEV IgG+ IgM- (exposed BDs, n = 10) and anti-HEV IgG- IgM- (naive BDs, n = 12) healthy blood donors. By measuring the abundance of 179 microRNAs in AHE patients and naive BDs by reverse transcription-quantitative PCR (RT-qPCR), we identified 51 potential HEV-regulated microRNAs (P value adjusted for multiple testing by the Benjamini-Hochberg correction [PBH] < 0.05). Further analysis showed that HEV genotype 3 infection is associated with miR-122, miR-194, miR-885, and miR-30a upregulation and miR-221, miR-223, and miR-27a downregulation. AHE patients showed significantly higher levels of miR-122 and miR-194 and lower levels of miR-221, miR-27a, and miR-335 than HEV BDs. This specific microRNA signature in AHE could promote virus replication and reduce antiviral immune responses, contributing to the development of clinical symptoms. We found that miR-194, miR-335, and miR-221 can discriminate between asymptomatic HEV infections and those developing acute symptoms, whereas miR-335 correctly classifies AHE and CHE patients. Our data suggest that diverse outcomes of HEV infection result from different HEV-induced microRNA dysregulations. The specific microRNA signatures described offer novel information that may serve to develop biomarkers of HEV infection outcomes and improve our understanding of HEV pathogenesis, which may facilitate the identification of antiviral targets. IMPORTANCE There is increasing evidence that viruses dysregulate the expression and/or secretion of microRNAs to promote viral replication, immune evasion, and pathogenesis. In this study, we evaluated the change in microRNA abundance in patients with acute or chronic HEV infection and asymptomatic HEV-infected blood donors. Our results suggest that different HEV-induced microRNA dysregulations may contribute to the diverse clinical manifestations of HEV infection. The specific microRNA signatures identified in this study hold potential as predictive markers of HEV infection outcomes, which would improve the clinical management of hepatitis E patients, particularly of those developing severe symptoms or chronic infections. Furthermore, this study provides new insights into HEV pathogenesis that may serve to identify antiviral targets, which would have a major impact because no effective treatments are yet available.

Modelling of Hepatitis E virus RNA-dependent RNA polymerase genotype 3 from a chronic patient and in silico interaction analysis by molecular docking with Ribavirin

Hepatitis E Virus (HEV) infection is an emergent zoonotic disease, where chronic hepatitis E associated to solid organ transplant (SOT) recipients, related to genotype 3, is the clinical manifestation of major concern. In this setting, ribavirin (RBV) treatment is the only available therapy, though drug-resistant variants could emerge leading to a therapeutic failure. Crystallographic structures have not been reported for most of the HEV proteins, including the RNA-polymerase (RdRp). Therefore, the mechanism of action of RBV against HEV and the molecular interactions between this drug and RdRp are largely unknown. In this work, we aimed to model in silico the 3 D structure of a novel HEV3 RdRp (HEV_C1_Uy) from a chronically HEV infected-SOT recipient treated with RBV and to perform a molecular docking simulation between RBV triphosphate (RBVT), 7-methyl-guanosine-5'-triphosphate and the modelled protein. The models were generated using I-TASSER server and validated with multiple bioinformatics tools. The docking analysis were carried out with AutoDock Vina and LeDock software. We obtained a suitable model for HEV_C1_Uy (C-Score=-1.33, RMSD = 10.4 ± 4.6 Å). RBVT displayed a binding affinity of -7.6 ± 0.2 Kcal/mol by molecular docking, mediated by 6 hydrogen-bonds (Q195-O14, S198-O11, E257-O13, S260-O2, O3, S311-O11) between the finger's-palm-domains and a free binding energy of 31.26 ± 16.81 kcal/mol by molecular dynamics simulations. We identified the possible HEV RdRp interacting region for incoming nucleotides or analogs and provide novel insights that will contribute to better understand the molecular interactions of RBV and the enzyme and the mechanism of action of this antiviral drug.Communicated by Ramaswamy H. Sarma.

Current Challenges and Future Perspectives of Diagnosis of Hepatitis B Virus

It is estimated that approximately 260 million people worldwide are infected with the hepatitis B virus (HBV), which is one of the leading causes of liver disease and liver cancer throughout the world. Compared with developed countries, low-income and middle-income countries have limited access to resources and advanced technologies that require highly specialized staff for HBV diagnosis. In spite of the heavy burden caused by hepatitis B virus, 90% of people are still undiagnosed. The World Health Organization (WHO) goal of eliminating hepatitis B by 2030 seems very difficult to achieve due to the existing diagnostic infrastructure in low-resource regions. The majority of diagnostic laboratories still use hepatitis B surface antigen (HBsAg)-based tests. WHO's elimination plan is at risk of derailment due to phases like the window period, immune control, and occult HBV infection (OBI) not being detected by standard tests. Here, in this article, we are focusing on various diagnostic platforms for the better diagnosis of HBV. The aim of the elimination of HBV can only be achieved by detecting all phases of HBV infection, which can be executed by a combined approach of using new marker assays along with advanced pretesting and testing methods.

Recent Advances in Protective Vaccines against Hepatitis Viruses: A Narrative Review

Vaccination has been confirmed to be the safest and, sometimes, the only tool of defense against threats from infectious diseases. The successful history of vaccination is evident in the control of serious viral infections, such as smallpox and polio. Viruses that infect human livers are known as hepatitis viruses and are classified into five major types from A to E, alphabetically. Although infection with hepatitis A virus (HAV) is known to be self-resolving after rest and symptomatic treatment, there were 7134 deaths from HAV worldwide in 2016. In 2019, hepatitis B virus (HBV) and hepatitis C virus (HCV) resulted in an estimated 820,000 and 290,000 deaths, respectively. Hepatitis delta virus (HDV) is a satellite virus that depends on HBV for producing its infectious particles in order to spread. The combination of HDV and HBV infection is considered the most severe form of chronic viral hepatitis. Hepatitis E virus (HEV) is another orally transmitted virus, common in low- and middle-income countries. In 2015, it caused 44,000 deaths worldwide. Safe and effective vaccines are already available to prevent hepatitis A and B. Here, we review the recent advances in protective vaccines against the five major hepatitis viruses.

A Randomized Large-Scale Cross-Sectional Serological Survey of Hepatitis E Virus Infection in Belgian Pig Farms

Hepatitis E virus (HEV) is the causative agent of hepatitis E disease in humans. While sporadic HEV infections, which occur in industrialised countries and are typically due to HEV genotypes 3 or 4, are asymptomatic and self-limiting, a chronic form of the disease can lead to liver cirrhosis in immunocompromised individuals. Pigs share HEV 3 and 4 genotypes and are thus considered a major animal reservoir for human infection. A subset of animals has been shown to carry HEV particles at the age of slaughter, rendering raw or undercooked pig products potential vectors for human infection. To provide an overview of the current dissemination of HEV in Belgian pig herds, this study was designed as a randomized, robust, large-scale, cross-sectional, serological survey. HEV genotypes and subtypes recently circulating in Belgium (2020-2021) were investigated. Sample stratification as well as epidemiological investigation through the available demographic data of the sampled herds showed that HEV widely circulated in the Belgian pig population during this time and that a change in the circulating HEV strains may have occurred in the last decade. Herd size and type were identified as risk factors for HEV herd-seropositivity. Identifying farms at risk of being HEV-positive is an important step in controlling HEV spread and human infection.

Puzzles for Hepatitis E Virus

Hepatitis E virus (HEV) is an important but understudied virus that has been the major cause of acute viral hepatitis worldwide. In recent decades, our understanding of this neglected virus has changed greatly: novel forms of viral proteins and their functions have been discovered; HEV can transmit via blood transfusion and organ transplantation; HEV can infect many animal species and the number is still increasing; HEV can induce chronic hepatitis and extra-hepatic manifestations. However, we are short of effective treatment measures to counter the virus. In this chapter we tend to briefly introduce the puzzles and major knowledge gaps existed in the field of HEV research.

Prevalence of hepatitis E virus and its association with adverse pregnancy outcomes in pregnant women in China

BACKGROUND

Hepatitis E virus (HEV) infection has become a global concern, especially in pregnant women. However, the association between HEV prevalence and age, gravidity and parity of pregnant women remains unclear.

METHODS

Pregnant women (n=19,762) were enrolled for HEV prevalence and associated adverse pregnancy outcomes investigation in Qujing City, Yunnan Province of China from May 2019 to December 2020.

RESULTS

The seroprevalence of HEV was 11.6% (2,297/19,762; 95% CI:11.2%-12.1%). About 11.4% (2,247/19,762; 95% CI:10.9%-11.8%) were positive for anti-HEV IgG antibody, 0.1% (22/19,762; 95% CI:0.1%-0.2%) were positive for anti-HEV IgM antibody, and 0.1% (28/19,762; 95% CI:0.1%-0.2%) were positive for both anti-HEV IgM and IgG antibodies. Sixty-one out of 2,297 anti-HEV-antibodies-positive pregnant women were positive for HEV RNA. Phylogenetic analysis revealed that all HEV isolates from pregnant women belong to genotype 4. Age, gravidity and parity are associated with increased prevalence of HEV. Pregnant women positive for HEV-IgG antibody bear a higher risk for an adverse pregnancy history and liver injury with elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels than anti-HEV-negative pregnant women. Furthermore, seropositive pregnant women suffered a higher adverse maternal outcomes risk (crude odds ratio [cOR]=1.29; 95% CI: 1.16-1.43; adjusted odds ratio [aOR]=1.40, 95% CI: 1.25-1.55 for anti-HEV-IgG-positive pregnant women and cOR=1.38, 95% CI: 1.02-1.86; aOR=1.43, 95% CI: 1.05-1.95 for anti-HEV-IgM-positive pregnant women) and fetal outcomes risk (cOR=1.80, 95% CI: 1.61-2.01; aOR=1.77, 95% CI: 1.57-1.99) than anti-HEV-negative pregnant women. Adverse pregnancy outcomes of HEV infection are aggravated by age, gravidity and parity.

CONCLUSION

In this study, we demonstrated high prevalence of HEV in pregnancy women in China, and HEV infection can cause various adverse maternal and neonatal outcomes.

Genetic Evolution of Hepatitis E Virus

Comparative analysis of the genomic sequences of multiple hepatitis E virus (HEV) isolates has revealed extensive genomic diversity among them. Recently, a variety of genetically distinct HEV variants have also been isolated and identified from large numbers of animal species, including birds, rabbits, rats, ferrets, bats, cutthroat trout, and camels, among others. Furthermore, it has been reported that recombination in HEV genomes takes place in animals and in human patients. Also, chronic HEV infection in immunocompromised individuals has revealed the presence of viral strains carrying insertions from human genes. This paper reviews current knowledge on the genomic variability and evolution of HEV.

Animal Models for Hepatitis E Virus

Animal models are one of the most important tools in the study of human hepatitis E virus (HEV) infection. They are particularly important in light of the major limitations of the cell culture system for HEV. Besides nonhuman primates, which are extremely valuable because of their susceptibility to HEV genotypes 1-4, animals like swine, rabbit, and humanized mice are also potential models for studies of pathogenesis, cross-species infection, and the molecular biology of HEV. Identification of a useful animal model for human HEV infection studies is crucial to further investigations into this ubiquitous yet poorly understood virus and facilitate the development of antiviral therapeutics and vaccines.

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.

Hepatitis E prevalence and infection in solid-organ transplant recipients in the United States

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide. An increased risk for HEV infection has been reported in organ-transplant recipients, mainly from Europe. Prospective data on HEV prevalence in the United States (U.S.) organ transplant population are limited. To determine the prevalence and factors associated with HEV infection among solid organ transplant-recipients, we conducted a prospective, cross-sectional, multicentre study among transplant-recipients and age- and organ-matched waitlist patients. Participants answered a risk-exposure questionnaire and were tested for HEV-RNA (in-house PCR), HEV-IgG, and IgM (ELISA, Wantai). Among 456 participants, 224 were transplant-recipients, and 232 were waitlist patients. The mean age was 58 years, 35% female, and 74% White. HEV seroprevalence of the entire cohort was 20.2% and associated with older age (p < 0.0001) and organ transplantation (p = 0.02). The HEV seropositivity was significantly higher among transplant-recipients compared with waitlist patients (24% vs. 16.4%, p = 0.042). Among transplant recipients, relative-risk of being HEV seropositive increased with older age (RR = 3.4 [1.07-10.74] in patients >70 years compared with ≤50 years, p = 0.037); history of graft hepatitis (2.2 [1.27-3.72], p = 0.005); calcineurin inhibitor use (RR = 1.9 [1.03-3.34], p = 0.02); and kidney transplantation (2.4 [1.15-5.16], p = 0.02). HEV-RNA, genotype 3 was detected in only two patients (0.4%), both transplant-recipients. HEV seroprevalence was higher among transplant-recipients than waitlist patients. HEV should be considered in transplant-recipients presenting with graft hepatitis. Detection of HEV-RNA was rare, suggesting that progression to chronic HEV infection is uncommon in transplant-recipients in the U.S.

Detection of Nonenveloped Hepatitis E Virus in Plasma of Infected Blood Donors

BACKGROUND

Transfusion-transmitted hepatitis E virus (HEV) infections have raised many concerns regarding the safety of blood products. To date, enveloped HEV particles have been described in circulating blood, whereas nonenveloped HEV virions have only been found in feces; however, no exhaustive studies have been performed to fully characterize HEV particles in blood.

METHODS

Using isopycnic ultracentrifugation, we determined the types of HEV particles in plasma of HEV-infected blood donors.

RESULTS

Nonenveloped HEV was detected in 8 of 23 plasma samples, whereas enveloped HEV was found in all of them. No association was observed between the presence of nonenveloped HEV and viral load, gender, or age at infection. However, samples with HEV-positive serology and/or increased levels of liver injury markers contained a higher proportion of nonenveloped HEV than samples with HEV-negative serology and normal levels of liver enzymes. These results were further confirmed by analyzing paired donation and follow-up samples of 10 HEV-infected donors who were HEV seronegative at donation but had anti-HEV antibodies and/or increased levels of liver enzymes at follow up.

CONCLUSIONS

The HEV-contaminated blood products may contain nonenveloped HEV, which may pose an additional risk to blood safety by behaving differently to pathogen inactivation treatments or increasing infectivity.