Hepatitis E: current status

Vital role of autophagy flux inhibition of placental trophoblast cells in pregnancy disorders induced by HEV infection

Hepatitis E virus (HEV) has become one of the important pathogens that threaten the global public health. Type 3 and 4 HEV are zoonotic, which can spread vertically and cause placental damage. At the same time, autophagy plays an important role in the process of embryo development and pregnancy maintenance. However, the relationship between HEV and autophagy, especially in the placenta tissue, has not been clarified. We found lower litter rates in HEV-infected female mice, with significant intrauterine abortion of the embryo (24.19%). To explore the effects of HEV infection on placenta autophagy, chorionic cells (JEG-3) and mice placenta have been employed as research objects, while the expression of autophagy-related proteins (ATGs) has been detected in JEG-3 cells with different times of HEV inoculation. The results demonstrated that the expression of protein LC3 decreased and p62 accumulated, meanwhile ATGs such as ATG4B, ATG5, and ATG9A in JEG-3 cells have decreased significantly. In addition, the maturation of autophagosomes, which referred to the process of the combination of autophagosomes and lysosomes was prevented by HEV infection as well. All processes of autophagic flux, which include the initiation, development, and maturation three stages, were suppressed in JEG-3 cells after HEV infection. Similarly, the protein and gene expression of LC3 were significantly decreased in the placenta of pregnant mice with HEV infection. In summary, our results suggested that HEV inhibited autophagy in JEG-3 cells and placenta of pregnant mice, which might be the important pathogenic mechanisms of HEV infection leading to embryo abortion.

Knowledge about Hepatitis E and Influencing Factors among Residents in Qingdao: a Cross-Sectional Study

Hepatitis E infection poses a serious health problem in developing countries. Hepatitis E vaccination is important for prevention, but it is influenced by residents' knowledge. Qingdao residents' knowledge of hepatitis E remains unknown. This study used an online survey on the WeChat platform. The chi-square test was used to compare the hepatitis E influencing factors between the subgroups. Binary logistic regression was used for multiple factor analysis to explore the hepatitis E influencing factors. The total awareness rate of hepatitis E was 60.51%. Females aged between 51 and 60, aged 61 and above, and working in government-affiliated departments were found to have higher awareness rates than other subgroups. Participants with family members infected with hepatitis E had a lower awareness rate. The government and relevant departments should focus on education regarding the hepatitis E vaccination and disease process.

Hepatitis E virus in Cuba: A cross-sectional serological and virological study in pigs and people occupationally exposed to pigs

Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination.

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.

Hepatitis E virus infection among patients with altered levels of alanine aminotransferase

Hepatitis E virus (HEV) affects 20 million people worldwide, with 3.3 million cases and 56,000 deaths. The transmission is mainly by the fecal-oral route. Several studies have reported increased alanine aminotransferase (ALT) levels in association with viral hepatitis. This study evaluated the diagnosis of HEV infection among patients attending the emergency room (ER) of Hospital Beneficência Portuguesa (HBP) and Hospital São Paulo (HSP) in São Paulo, Brazil increased ALT levels (≥ 200 IU/L). From October 2018 to July 2019, 400 sera samples were collected from patients treated at the ER of HBP (n=200) and HSP (n=200). All samples were screened for HEV by RT-qPCR. 200 samples from HSP were tested for IgM of anti-Hepatitis A (HAV) and B (HBV) viruses, and total antibodies of Hepatitis C virus (HCV). Ninety samples (45 from each hospital), were tested for anti-HEV IgM antibodies. Patients aged under 1 to 91 years (mean = 46.29 ± 24.17, median = 48). ALT levels varied from 200 to 8,974 IU/l. 16 patients (4%) turned out positive for HEV by RT-qPCR (ALT levels = 299 to 698 IU/L). Of the 200 HSP patients, 18 (9%) were anti-HAV IgM reactive, 9 (4.5%) for anti-HBV IgM, and 7 (3.5%) for anti-HCV antibodies (ALT levels = 833 to 1918 IU/L). Two of 90 BPH patients (2.22%) were anti-HEV IgM reactive (ALT levels = 1502 to 3831 IU/L). This is the first Brazilian study evaluating patients with suspected HEV infection with increased ALT levels, which were higher than 12 and 60 times the normal upper limit, in the acute phase or for patients reactive for antibody detection, respectively. Liver damage could be minimized by implementing molecular diagnostic tests in the hospital routine.

Pigs Immunized with the Virus-like Particle Vaccine Are Protected against the Hepatitis E-3 Virus

In this study, we generated the HEV virus-like particle (VLP) vaccine expressing 239 amino acids (367–605 aa) of the HEV-3 ORF2 using the baculovirus expression system. The HEV-3-239-VLP vaccine efficacy was evaluated by dividing 12 pathogen-free pigs into four groups: negative control, positive control, 100 μg VLP-, and 200 μg VLP-vaccinated groups for 10 weeks. The pigs in either of the vaccinated groups were administered the corresponding first and booster doses on weeks 0 and 2. At week 4, the positive control and two vaccinated groups were challenged with 10⁶ HEV-3 genomic equivalent copies; viremia and fecal shedding of the virus were identified in pigs in the positive control and 100 μg VLP-vaccinated pigs showed transient viremia and fecal viral shedding. However, no viruses were detected in the serum or fecal samples of the 200 μg VLP-vaccinated pigs. The 100 and 200 μg VLP-vaccinated pigs had significantly higher (p < 0.01) anti-HEV antibodies than the negative control pigs from weeks 6–10 with normal levels of liver enzymes. The 200 μg VLP-vaccinated pigs showed statistically less liver tissue fibrosis (p < 0.05) than that of the positive control pigs. Thus, the novel baculovirus expression system-generated VLP vaccine dose-dependently protects against HEV-3 challenge and may be useful in other animal species, including humans.

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

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

Characterization of hepatitis E virus natural infection in farmed rabbits

Rabbit hepatitis E virus (HEV3-ra) is widely distributed in rabbits worldwide and several recent reports found that HEV3-ra can infect humans. Therefore, people exposed to rabbits are at high risk of HEV infection. This study was conducted to investigate the characteristics and outcomes of HEV3-ra natural infection in rabbits. Seventy farmed rabbits (3-month-old) were surveyed in a farm in Beijing, China. Rabbits tested positive for HEV RNA were followed weekly for testing of HEV RNA, antigen, antibody and alanine aminotransferase (ALT) level. Liver and kidney tissue was collected for histopathology. Complete genome sequencing of the isolated HEV3-ra strain was performed (CHN-BJ-r4, GenBank: MT364355). The infectivity of CHN-BJ-r4 was tested in ten naïve rabbits by intravenous injection or gavage. Anti-HEV antibody and HEV RNA were tested positive in 7.14% (5/70) and 11.4% (8/70) of rabbits, respectively. Eight naturally infected rabbits were followed, and 37.5% (3/8) of the observed rabbits were found to have fecal shedding of HEV ranging from 3-22 weeks with high viral load (10⁵ -10⁷ copies/g). Two out of eight rabbits showed temporary viremia. Naturally infected rabbits presented elevated ALT level, seroconversion, and liver histopathology. Complete genome of HEV3-ra isolated in this study shared 84.61%-94.36% nucleotide identity with known HEV3-ra complete genomes. The isolated HEV3-ra strain was infectious and could infect other rabbits through intravenous and fecal-oral route. Naturally infected rabbits showed up to 22-week fecal virus shedding with high viral load. These features increased the risk of rabbit-to-rabbit and rabbit-to-human transmission.

Experimental infection of hepatitis E virus induces pancreatic necroptosis in miniature pigs

Infection by hepatitis E virus (HEV) via the oral route causes acute hepatitis. Extra-hepatic manifestations of HEV infection may stem from various causes; however, its distribution in organs such as the liver, as well as the mechanisms underlying HEV-induced cell injury, remain unclear. The objective of this study was to determine the chronological distribution of HEV in various tissues of HEV-challenged miniature pigs and to investigate the mechanisms underlying HEV-induced cell death in the pancreas and liver. Virological and serological analyses were performed on blood and faecal samples. Histopathology of the liver and extra-hepatic tissues was analysed. Cell death pathways and immune cell characterisation in inflammatory lesions were analysed using immunohistochemistry. The liver and pancreas displayed inflammation and cellular injury, and a large amount of HEV was observed in the lesions. The liver was infiltrated by T and natural killer cells. HEV was identified in all organs except the heart, and was associated with immune cells. Although the liver and the pancreas strongly expressed TNF-α and TRAIL, TUNEL assay results were negative. RIP3 and pMLKL were expressed in the pancreas. RIP3, but not pMLKL, was expressed in the liver. Pancreatitis induced in HEV-infected miniature pigs is associated with necroptosis.

Hepatitis E in Italy: 5 years of national epidemiological, virological and environmental surveillance, 2012 to 2016

Increasing numbers of hepatitis E cases are being reported in several European countries, including Italy, but the burden of hepatitis E virus (HEV) infection is largely unknown in the latter. To gain a better understanding of HEV epidemiology at national level in Italy, we piloted a strengthened and integrated human (epidemiological and virological) and environmental HEV surveillance system between 2012 and 2016. Over the 5-year period, 169 confirmed hepatitis E cases were identified, with a national annual incidence of 0.72 cases per 1,000,000. Of 65 HEV-RNA positive samples of sufficient quality for molecular analysis, 66% were genotype HEV3, 32% HEV1 and 1% HEV4. The most frequent risk factor reported by all HEV3 infected cases, was the consumption of undercooked pork and sausage. For the environmental surveillance, 679 urban sewage samples were collected from 53 wastewater treatment plants and HEV-RNA was detected in 38/679 of the samples. Among these, 25 (66%) were genotype HEV3 and the remaining were HEV1. We demonstrate that autochthonous transmission and environmental circulation of genotype HEV3 is adding to travel-related HEV transmission in Italy. We recommend the ‘One Health’ approach to integrated surveillance, and to include HEV-related messages within health information campaigns focussing on food security.

A guide to the management of hepatitis E infection during pregnancy

Hepatitis E virus (HEV) infection has distinct features, depending upon the genotype and geographical area. HEV genotypes 1 and 2 are endemic to various developing countries causing epidemics of acute viral hepatitis with human to human transmission. On the other hand, HEV genotypes 3 and 4 prevalent in developed countries commonly lead to subclinical infection and are transmitted zoonotically. HEV infection typically causes acute self-limiting illness associated with low morbidity and mortality. Infection with HEV genotype 1 or 2 in pregnancy, especially in the third trimester may lead to severe illness and fulminant liver failure. Poor maternal and fetal outcomes have been reported. Areas covered: This review highlights the various aspects of HEV infection in pregnancy including diagnosis, management, and prevention. Expert commentary: Treatment is mainly supportive with diligent monitoring and intensive care. Therapeutic termination of pregnancy cannot be recommended based to the available literature. Early liver transplantation (LT) should be considered in these patients although the indications and timing of LT are still controversial. Prevention of HEV infection or illness by improved sanitation and active/passive immunization needs further research.

Development of new hepatitis E vaccines

Hepatitis E virus (HEV) infection is an emerging zoonotic disease posing a severe threat to public health in the world, especially to pregnant women. Currently, no specific treatments are available for HEV infection. Therefore, it is crucial to develop vaccine to prevent this infection. Although several potential candidate vaccines against HEV have been studied for their immunogenicity and efficacy, only Hecolin® which is developed by Xiamen Innovax Biotech Co., Ltd. and approved by China Food and Drug Administration (CFDA) in 2012, is the licensed HEV vaccine in the world so far. Extensive studies on safety, immunogenicity and efficacy in phase III clinical trials have shown that Hecolin® is a promising vaccine for HEV prevention and control. In this article, the advances on HEV vaccine development and research are briefly reviewed.

Seroprevalence of Hepatitis E Virus in Roma Settlements: A Comparison with the General Population in Slovakia

Hepatitis E infection is one of the most frequent causes of acute hepatitis in the world. Currently five human genotypes with different geographical distributions and distinct epidemiologic patterns are identified. In Slovakia, only rare cases of hepatitis E have been reported in past years. Because the most important risk factors associated with HEV infection include consumption of contaminated pork meat and poor hygienic standards, the aim of the study was to evaluate the prevalence of anti-HEV total antibodies and the main risk factors for HEV in the population living in separated and segregated Roma settlements (n = 195), which represent places with increased risk of infection in Slovakia and to compare it with the prevalence in the general population (n = 69). Of 264 respondents included in the study, 47 (17.8%) showed positivity for anti-HEV antibodies, 42 of whom were Roma (21.5%, n = 195) and 5 (7.2%, n = 69) non-Roma. The population living in Roma settlements lives in poorer conditions and are at higher risk of HEV in comparison to the general population. However, differences in living conditions within the settlements do not contributed to lower risk of HEV antibody prevalence between Roma living in settlements.

Chevrier's Field Mouse (Apodemus chevrieri) and Père David's Vole (Eothenomys melanogaster) in China Carry Orthohepeviruses that form Two Putative Novel Genotypes Within the Species Orthohepevirus C

Hepatitis E virus (HEV) is the prototype of the family Hepeviridae and the causative agent of common acute viral hepatitis. Genetically diverse HEV-related viruses have been detected in a variety of mammals and some of them may have zoonotic potential. In this study, we tested 278 specimens collected from seven wild small mammal species in Yunnan province, China, for the presence and prevalence of orthohepevirus by broad-spectrum reverse transcription (RT)-PCR. HEV-related sequences were detected in two rodent species, including Chevrier's field mouse (Apodemus chevrieri, family Muridae) and Père David's vole (Eothenomys melanogaster, family Cricetidae), with the infection rates of 29.20% (59/202) and 7.27% (4/55), respectively. Further four representative full-length genomes were generated: two each from Chevrier's field mouse (named RdHEVAc14 and RdHEVAc86) and Père David's vole (RdHEVEm40 and RdHEVEm67). Phylogenetic analyses and pairwise distance comparisons of whole genome sequences and amino acid sequences of the gene coding regions showed that orthohepeviruses identified in Chinese Chevrier's field mouse and Père David's vole belonged to the species Orthohepevirus C but were highly divergent from the two assigned genotypes: HEV-C1 derived from rat and shrew, and HEV-C2 derived from ferret and possibly mink. Quantitative real-time RT-PCR demonstrated that these newly discovered orthohepeviruses had hepatic tropism. In summary, our work discovered two putative novel genotypes orthohepeviruses preliminarily named HEV-C3 and HEV-C4 within the species Orthohepevirus C, which expands our understanding of orthohepevirus infection in the order Rodentia and gives new insights into the origin, evolution, and host range of orthohepevirus.

Knowledge gaps and research priorities in the prevention and control of hepatitis E virus infection

Hepatitis E virus (HEV), family Hepeviridae, is a main cause of epidemic hepatitis in developing countries and sporadic and cluster cases of hepatitis in industrialized countries. There are an increasing number of reported cases in humans especially in industrialized countries, and there is a high potential for transboundary spread of zoonotic genotypes of the virus through the transport of pigs, pig products and by-products. Bloodborne transmission of the virus has been reported with a significant medical concern. To better coordinate HEV research and design better control measures of HEV infections in animals, a group of HEV experts reviewed the current knowledge on the disease and considered the existing disease control tools. It was concluded that there is a lack of in-depth information about the spread of the virus from pigs to humans. The role of animals other than pigs in the zoonotic transmission of the virus to humans and the extent of foodborne transmission are poorly understood. Factors involved in development of clinical disease such as infectious dose, susceptibility and virulence of virus strains need to be studied more extensively. However, such studies are greatly hindered by the absence of a broadly applicable, efficient and sensitive in vitro cell culture system for HEV. Diagnostic tools for HEV are available but need to be further validated, harmonized and standardized. Commercially available HEV vaccines for the control of HEV infection in animal populations are needed as such vaccines can minimize the zoonotic risk for humans. Anti-HEV drugs for treatment of HEV-infected patients need to be studied more extensively. The detailed expert review can be downloaded from the project website at http://www.discontools.eu/.

Epidemiology of Hepatitis E

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

Hepatitis E virus seroprevalence among the general population in a livestock-dense area in the Netherlands: a cross-sectional population-based serological survey

Background

Recent serological studies indicate that hepatitis E virus (HEV) is endemic in industrialised countries. The increasing trend in the number of autochthonous cases of HEV genotype 3 in Western European countries, stresses the importance to get insight in the exact routes of exposure. Pigs are the main animal reservoir, and zoonotic food-borne transmission of HEV is proven. However, infected pigs can excrete large amounts of virus via their faeces enabling environmental transmission of HEV to humans. This might pose a risk for of neighbouring residents of livestock farming.

Methods

Within a large study on the health of people living in the vicinity of livestock farming we performed a cross-sectional population-based serological survey among 2,494 non-farming adults from the general population in a livestock-dense area in the south of the Netherlands. Participants completed risk factor questionnaires and blood samples of 2,422 subjects (median age 58 years, range 20–72) were tested for anti-HEV IgG using an enzyme immune assay (Wantai). The aim of this study was to determine the HEV seroprevalence and to assess whether seropositivity in adults was associated with living in the vicinity of pig farms.

Results

The average seroprevalence of HEV was 28.7% (95% CI: 26.9–30.5). Determinants associated with an increased risk for HEV seropositivity were male gender and low level of education. There was a clear trend of increasing prevalence with increasing age (Chi-square test for linear trend, X² = 83.1; p < 0.001). A high number of pigs within 1,000 m of the residential address was not a risk factor for seropositivity.

Conclusions

This study confirmed the high HEV seroprevalence (29%) in the general population of the Netherlands, but presence of antibodies was not associated with residential proximity to pig farms. The prevalence increased with age from 10% in adolescents to 33% among those aged 50 and above, supporting the assumption of a cumulative lifetime exposure to HEV in the Netherlands as well as a higher infection pressure in the past. Our findings cannot refute the assumption that transmission is primarily food-borne.

Preparation and evaluation of MS2 bacteriophage-like particles packaging hepatitis E virus RNA

Hepatitis E virus (HEV) is the pathogen causing hepatitis E (HE). It arouses global public health concern since it is a zoonotic disease. The objective of this letter is to report a cost-effective internal control prepared for monitoring procedures of HEV reverse transcriptase (RT)-PCR detection. A selected conserved HEV RNA fragment was integrated into the downstream of the truncated MS2 bacteriophage genome based on Armored RNA technology. The resulting MS2-HEV gene harbored by the pET-28b-MS2-HEV plasmid was transformed into E. coli BL21(DE3) for expression analysis by SDS-PAGE. The expression products were purified and concentrated by ultrasonication and ultrafiltration separation. The morphology and stability properties of the virus-like particles (VLPs) were evaluated by electron microscopy scanning and nuclease challenges, respectively. SDS-PAGE results showed that the constructed MS2-HEV gene expressed efficiently and the purity of the VLPs was highly consistent with the result in electron microscopy. Stability evaluation results demonstrated that the prepared VLPs exhibited strong resistance to DNase I and RNase A attacks and also performed long-lasting protection of coated HEV RNA for at least 4 months at -20°C. These data revealed that the prepared VLPs meet the basic requirements of use as internal control material in the HEV RNA amplification assay.

Hepatitis E Virus Mutations: Functional and Clinical Relevance

Hepatitis E virus (HEV) infection is a major cause of acute hepatitis and affects more than 20 million individuals, with three million symptomatic cases and 56,000 recognized HEV-related deaths worldwide. HEV is endemic in developing countries and is gaining importance in developed countries, due to increased number of autochthone cases. Although HEV replication is controlled by the host immune system, viral factors (especially specific viral genotypes and mutants) can modulate HEV replication, infection and pathogenesis. Limited knowledge exists on the contribution of HEV genome variants towards pathogenesis, susceptibility and to therapeutic response. Nonsynonymous substitutions can modulate viral proteins structurally and thus dysregulate virus-host interactions. This review aims to compile knowledge and discuss recent advances on the casual role of HEV heterogeneity and its variants on viral morphogenesis, pathogenesis, clinical outcome and antiviral resistance.

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HEV causes acute hepatitis and recently comes into focus because of persistent infection in immunocompromised patients.

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HEV variability can be associated with clinical pathogenesis and transmission dynamics.

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Mutations in the HEV genome can influence HEV physiology and virus-host interaction.

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HEV mutations and variability are likely associated with fulminant hepatic failure and chronic hepatitis E.

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The Y1320H and G1634R/K mutations in the RdRp domain contribute to antiviral resistance through enhancing HEV replication.

We searched MEDLINE database and PubMed for articles from 1980 through June 30, 2016. Search terms used in various combinations were “hepatitis E”, “hepatitis E virus”, “hepatitis E virus infection”, “hepatitis E virus mutation”, “HEV variability”, “HEV genotype”, “HEV drug resistance”, “HEV replication” and “ribavirin”. Articles resulting from these searches and relevant references cited in those articles were selected based on their related topics and were reviewed. Abstracts and reports from meetings were also included. Articles published in English were included.

Identification of Distribution Characteristics and Epidemic Trends of Hepatitis E in Zhejiang Province, China from 2007 to 2012

Hepatitis E virus is a common hepatotropic virus that causes serious gastrointestinal symptoms. Data of reported HEV cases in Zhejiang Province was collected between 2007 and 2012. Descriptive epidemiological methods and spatial-temporal epidemiological methods were used to investigate the epidemiological trends and identify high-risk regions of hepatitis E infection. In this study, the average morbidity of hepatitis E infection was 4.03 per 100,000 in Zhejiang Province, peaking in winter and spring. The ratio between the male and the female was 2.39:1, and the high-risk population was found to be aged between 40 and 60. Trend surface analysis and IDW maps revealed higher incidences in the northwestern counties. The spatial-temporal analysis showed comparable incidences in the counties at the basins of three rivers, mostly under administration of Hangzhou Municipality. Besides, the seasonal exponential smoothing method was determined as the better model for the retrieved data. The epidemiological characteristics of HEV suggested the need of strengthened supervision and surveillance of sanitary water, sewage treatment and food in high-risk areas especially around the Spring Festival. Additionally, time series model could be useful for forecasting the epidemics of HEV in future. All these findings may contribute to the prevention and control of HEV epidemics.

Full coding hepatitis E virus genotype 3 genome amplification method

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A new amplification method for the complete HEV coding genome was described.

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HEV genome organization and function were reviewed.

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Polymorphic amino acids of each HEV genome region were analyzed in reference sequences.

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Complete coding HEV sequence of an immunocompromised patient with acute infection was analyzed.

Hepatitis E virus (HEV) genotype 3 produces zoonotic infection associated with the consumption of infected animals. HEV infections can become chronic in immunocompromised (IC) patients. The viral genome has three well defined open reading frames (ORF1, ORF2 and ORF3) within which various domains and functions have been described. This paper (i) describes a new method of complete sequencing of the HEV coding region through overlapping PCR systems, (ii) establishes a consensus sequence and polymorphic positions (PP) for each domain, and (iii) analyzes the complete coding sequence of an IC patient. With regard to the consensus, a high percentage of PP was observed in protease (PP = 19%) and the X domain (PP = 22%) within ORF1, the N-terminal region of the S domain (PP = 22%) in ORF2, and the P1 (PP = 35%) and P2 (PP = 25%) domains in ORF3. In contrast, the ORF1 Y, ORF2 S, ORF2 M and ORF3 D1 domains were conserved in the reference sequences (0.40, 1, 0.70 and 0% of PP, respectively). The sequence from the IC patient had more mutations in the RpRp (D1235G, Q1242R, S1454T, V1480I, I1502 V, K1511R, G1373 V, E1442D, V1693 M), the terminal ORF2 S- domain (F10L, S26T, G36S, S70P, A105 V, I113 V), the X domain (T938 M, T856 V, S898A) and the helicase (S1014N, S975T, Q1133 K).

Current Knowledge on Hepatitis E

Although only a single serotype of hepatitis E virus (HEV), the causative agent of hepatitis E, has been identified, there is great genetic variation among the different HEV isolates reported. There are at least four major recognized genotypes of HEV: genotypes 1 and 2 are mainly restricted to humans and linked to epidemic outbreaks in nonindustrialized countries, whereas genotypes 3 and 4 are zoonotic in both developing and industrialized countries. Besides human strains, genotype 3 and 4 strains of HEV have been genetically characterized from swine, sika deer, mongooses, sheep, and rabbits. Currently, there are approximately 11,000 human and animal sequences of HEV available at the International Nucleotide Sequence Database Collaboration. HEV is the major cause of waterborne outbreaks of hepatitis in areas of poor sanitation. Additionally, it is responsible for sporadic cases of viral hepatitis in not only endemic but industrialized countries as well. Transmission of HEV occurs predominantly by the fecal-oral route, although parenteral and perinatal routes have been reported. HEV infection develops in most individuals as a self-limiting, acute, icteric hepatitis; with mortality rates around 1%. However, some affected individuals will develop fulminant hepatic failure, a serious condition that is frequently fatal without a liver transplant. This complication is particularly common when the infection occurs in pregnant women, where mortality rates rise dramatically to up to 25%. Among the preventive measures available to avoid HEV infection, two separate subunit vaccines containing recombinant truncated capsid proteins of HEV have been shown to be highly effective in the prevention of disease. One of them, HEV 239, was approved in China, and its commercialization by Innovax began in November 2012 under the name Hecolin(®).

Activation of CXCL-8 Transcription by Hepatitis E Virus ORF-1 via AP-1

Hepatitis E virus (HEV) is a small nonenveloped single-stranded positive-sense RNA virus and is one of the major causes for acute hepatitis worldwide. CXCL-8 is a small multifunctional proinflammatory chemokine. It was reported recently that HEV infection significantly upregulates CXCL-8 gene expression. In this study, we investigated the mechanism of HEV-induced CXCL-8 transcriptional activation. Using CXCL-8 promoter reporters of different lengths ranging from −1400 to −173, we showed that −173 promoter has the highest promoter activity in the presence of HEV genomic RNA, indicating that the −173 promoter contains sequences responsible for CXCL-8 activation by HEV. Ectopic expression of the ORF-1 protein can upregulate the −173 CXCL-8 promoter activity. In contrast, expression of the ORF-2 protein suppresses the CXCL-8 promoter activity and expression of the ORF-3 protein has no effect on the CXCL-8 promoter activity. We further showed that AP-1 is required for CXCL-8 activation because neither HEV genomic RNA nor the ORF-1 protein can upregulate the −173 CXCL-8 promoter in the absence of the AP-1 binding sequence. Taken together, our results showed that HEV and HEV ORF-1 protein activate the CXCL-8 promoter via AP-1. This novel function of HEV ORF-1 protein should contribute to our understanding of HEV-host interactions and HEV-associated pathogenesis.

Chronic hepatitis E resolved by reduced immunosuppression in pediatric kidney transplant patients

At present, transient asymptomatic hepatitis E virus (HEV) infection is common among healthy adults in Western Europe, as reported by blood transfusion services. In immune-suppressed patients HEV infection is often without clinical symptoms, but without therapeutic intervention it may become chronic and lead to cirrhosis. This report describes the course of chronic HEV infection after kidney transplantation in 2 children, who cleared the virus after reduction in immunosuppressive therapy. If aminotransferase levels continue to be moderately elevated after transplantation, HEV infection should be excluded.

First detection of hepatitis E virus in Central Argentina: environmental and serological survey

BACKGROUND

The hepatitis E virus (HEV) is an emergent causative agent of acute hepatitis worldwide, transmitted by fecal-oral route. In Argentina it is considered rare, so differential laboratory testing is not routinely performed. Besides, in Argentina's central area epidemiological and molecular characteristics of HEV are still unknown.

OBJECTIVES

Provide evidence of local circulation of HEV by molecular detection on environmental samples and by serological survey in healthy adult population of Córdoba city, Argentina.

STUDY DESIGN

Environmental surveillance was conducted in river and sewage samples collected between 2007 and 2009-2011. Viral detection was performed by RT-Nested PCR of ORF-1 and ORF-2 partial regions. Anti-HEV IgG was determined by EIA in 433 serum samples collected between 2009 and 2010.

RESULTS

HEV was detected in 6.3% of raw sewage samples and in 3.2% of riverine samples. Nucleotide sequencing analyses revealed that all isolates belonged to genotype 3, subtypes a, b and c. The prevalence of IgG anti-HEV was 4.4%. Seroprevalence increased with the age of the individuals (OR: 3.50; 95% CI 1.39-8.87; p=0.0065) and, although the prevalence was higher in low income population, no statistical relation was found between anti-HEV and socioeconomic level.

CONCLUSIONS

The environmental findings added to serological results, demonstrate that HEV circulates in central Argentina. Contamination of water with HEV could represent a route of transmission for local populations, which have a high number of susceptible individuals. This fact alerts local health care systems in order to include detection of HEV in the diagnostic algorithm of viral hepatitis.

Hepatitis E: an emerging disease

Currently, the infection with the hepatitis E virus represents the most frequent cause for acute hepatitis and jaundice in the world. According to WHO estimations, around two billion people, representing one third of the world's population, live in endemic areas for HEV and, therefore, are at risk of infection. In developed countries, the circulation of the virus in both human and animal (swine, boar, deer) sewage has been confirmed; however, the incidence rate is low compared to that of developing countries where outbreaks of acute hepatitis transmitted via the fecal-oral route are originated, more frequently in the flooding season or after natural disasters, combined with deficient sanitary conditions. There are currently 4 known genotypes of HEV. Genotypes 1 and 2 are isolated in all human epidemic outbreaks in developing countries, while genotypes 3 and 4 are isolated not only in humans but also in animals, in both developing and industrialized countries. These data support genotypes 3 and 4 having zoonotic nature. The diagnosis of this disease is based in the detection of anti-HEV IgG and IgM in blood serum using enzyme-linked immunosorbent methods. However, the method that best confirms the diagnosis is the RT-PCR, which detects HEV RNA in blood serum and also provides the genotype. The clinical course is generally that of an acute hepatitis which in some cases may require hospitalization and that, in transplant patients or HIV infected individuals can become a chronic hepatitis. Furthermore, the virus constitutes an important risk for pregnant women. The hepatitis E can present a wide range of symptoms, from a subclinical case to chronic liver disease with extrahepatic manifestations. For this reason, the diagnostic is challenging if no differential diagnosis is included. There is no specific antiviral drug for hepatitis E, but satisfactory results have been observed in some patients treated with pegylated interferon alfa2a and/or ribavirin. This revision is an update of all the molecular, epidemiological, clinic and preventive knowledge on this emergent disease up to date.