Development and validation of an improved RT-PCR assay with nested universal primers for detection of hepatitis E virus strains with significant sequence divergence

Recent decline in hepatitis E virus prevalence among wild boars in Japan: Probably due to countermeasures implemented in response to outbreaks of classical swine fever virus infection

Previous studies have emphasized the necessity of surveillance and control measures for hepatitis E virus (HEV) infection in wild boars, an important reservoir of HEV. To assess the current situation of HEV infection in wild boars in Japan, this study investigated the prevalence and genetic diversity of HEV among wild boars captured in 16 prefectures of Japan during 2018-2023. Serum samples from 968 wild boars were examined for anti-HEV IgG antibodies and HEV RNA. The prevalence of anti-HEV IgG varied geographically from 0 % to 35.0 %. HEV RNA was detected in 3.6 % of boars, with prevalence varying by prefecture from 0 % to 22.2 %. Genotype 3 was the most prevalent genotype (91.9 %), followed by genotype 4 (5.4 %), with one strain closely related to genotype 6. The prevalence of HEV infection among wild boars decreased from 2018/2019 to 2022/2023 with significant declines in levels of anti-HEV IgG antibodies (14.5 % vs. 6.2 %, P < 0.0001) and HEV RNA (7.6 % vs. 1.5 %, P < 0.0001). Regional analysis showed varying trends, with no HEV RNA-positive boars found in several regions in recent years. A plausible factor contributing to the decline in HEV infection is the application of countermeasures, including installing fences to prevent intrusion into pig farms, implemented in response to the emergence of classical swine fever virus (CSFV) infection in wild boars and domestic pigs, with incidents reported annually since 2018. Further investigation is warranted to explore the association between countermeasures to CSFV infection and the decrease in HEV infection among wild boars.

Hepatitis E Virus Genotype 3 among Hemodialysis Patients in Mexico: First Identification of Chronic Infection

The global distribution of hepatitis E virus (HEV) is attributed to its capacity to spread through several routes of transmission; hemodialysis has gained increased amounts of attention in recent years. Although Mexico is considered a hyperendemic region for hepatitis E, no HEV surveillance is performed in the country. The frequency of HEV in hemodialysis (HD) patients has not been determined. Herein, we conducted a cross-sectional single-center analytical study including 67 serum samples from HD patients. Anti-HEV IgG and IgM antibodies and the viral genome were determined; partial regions within the HEV genome were sequenced for further phylogenetic analysis. Globally, 14.9% of the tested patients exhibited reactivity for IgG antibodies against HEV, and none showed reactivity to IgM. A total of 5.9% of the samples showed HEV genome amplification, and sequencing confirmed the identity of genotype 3; subsequent analysis of positive cases revealed two acute cases and chronic hepatitis E infection in one patient. Notably, the chronic patient was negative for anti-HEV IgG antibodies. Our findings highlight the importance of viral genome testing in HD patients and the need to establish guidelines for HEV detection in Mexico.

Recent advances in hepatitis E virus research and the Japanese clinical practice guidelines for hepatitis E virus infection

Acute hepatitis E was considered rare until reports emerged affirming the existence of hepatitis E virus (HEV) genotypes 3 and 4 infections in Japan in the early 2000s. Extensive studies by Japanese researchers have highlighted the pivotal role of pigs and wild animals, such as wild boars and deer, as reservoirs for HEV, linking them to zoonotic infections in Japan. Currently, when hepatitis occurs subsequent to the consumption of undercooked or grilled pork, wild boar meat, or offal (including pig liver and intestines), HEV infection should be considered. Following the approval of anti-HEV immunoglobulin A antibody as a diagnostic tool for hepatitis E by Japan's Health Insurance System in 2011, the annual number of diagnosed cases of HEV infection has surged. Notably, the occurrence of post-transfusion hepatitis E promoted nationwide screening of blood products for HEV using nucleic acid amplification tests since 2020. Furthermore, chronic hepatitis E has been observed in immunosuppressed individuals. Considering the significance of hepatitis E, heightened preventive measures are essential. The Japan Agency for Medical Research and Development Hepatitis A and E viruses (HAV and HEV) Study Group, which includes special virologists and hepatologists, held a virtual meeting on February 17, 2024. Discussions encompassed pathogenesis, transmission routes, diagnosis, complications, severity factors, and ongoing and prospective vaccination or treatments for hepatitis E. Rigorous assessment of referenced studies culminated in the formulation of recommendations, which are detailed within this review. This comprehensive review presents recent advancements in HEV research and Japanese clinical practice guidelines for HEV infection.

The Full-Genome Analysis and Generation of an Infectious cDNA Clone of a Genotype 6 Hepatitis E Virus Variant Obtained from a Japanese Wild Boar: In Vitro Cultivation in Human Cell Lines

Hepatitis E virus (HEV) can cause self-limiting acute and chronic hepatitis infections, particularly in immunocompromised individuals. In developing countries, HEV is mainly transmitted via drinking contaminated water, whereas zoonotic transmission dominates the route of infection in developed countries, including Japan. Pigs are an important reservoir for HEV infection. Wild boars, which share the same genus and species as domestic pigs, are also an HEV reservoir. During our nationwide study of HEV infection in wild boar populations in Japan, a genotype 6 (HEV-6) strain, wbJHG_23, was isolated in Hyogo Prefecture in 2023. The genomic length was 7244 nucleotides, excluding the poly(A) tract. The wbJHG_23 strain exhibited the highest nucleotide identity throughout its genome with two previously reported HEV-6 strains (80.3-80.9%). Conversely, it displayed lower similarity (73.3-78.1%) with the HEV-1-5, HEV-7, and HEV-8 strains, indicating that, although closely related, the wbJHG_23 strain differs significantly from the reported HEV-6 strains and might represent a novel subtype. The wbJHG_23 strain successfully infected the human-derived cancer cell lines, PLC/PRF/5 and A549 1-1H8 cells, suggesting that HEV-6 has the potential for zoonotic infection. An infectious cDNA clone was constructed using a reverse genetics system, and a cell culture system supporting the efficient propagation of the HEV-6 strain was established, providing important tools for further studies on this genotype. Using this cell culture system, we evaluated the sensitivity of the wbJHG_23 strain to ribavirin treatment. Its good response to this treatment suggested that it could be used to treat human infections caused by HEV-6.

Detection of human enteric viruses in fresh produce of markets, farms and surface water used for irrigation in the Tehran, Iran

Considering the major role of vegetables in the transmission of gastrointestinal diseases, investigation of the presence of gastrointestinal viruses is particularly important for public health. Additionally, monitoring and investigating potential points of contamination at various stages of cultivation, harvesting, and distribution can be important in identifying the sources of transmission. This study was conducted with the aim of identifying norovirus, adenovirus, hepatitis A virus, hepatitis E virus, rotaviruses, and astroviruses in vegetable samples from the fields and fruit and vegetable centers of Tehran City, and to investigate their presence in irrigation water by RT-qPCR. This study was carried out in two phases: initial and supplementary. During phase I, a total of 3 farms and 5 fruit and vegetable centers and a total of 35 samples from farms, 102 samples from fruit and vegetable centers and 8 agricultural water samples were collected. Zero, 16 and 1 samples were positive for at least one of the viruses from each of the sources, respectively. During phase II, 88 samples from 23 farms, 226 samples from 50 fruit and vegetable centers and 16 irrigation water samples were collected, with 23, 57 and 4 samples were positive for at least one virus, respectively. Rotavirus was the most frequently identified virus among the samples, followed by NoV GII, NoV GI, AstV, and AdV. HAV and HEV were not detected in any of the tested samples. The results of this study suggest that there may be a wide presence of viruses in vegetables, farms, and fruit and vegetable centers in Tehran City, which could have significant consequences considering the fact that many of these foods are consumed raw. Additionally, the detection of some of these viruses in irrigation water suggests that this may be a potential route for viral contamination of produce.

Development of a Sensitive and Specific Quantitative RT-qPCR Method for the Detection of Hepatitis E Virus Genotype 3 in Porcine Liver and Foodstuff

As an international and zoonotic cause of hepatitis, hepatitis E virus (HEV) poses a significant risk to public health. However, the frequency of occurrence and the degree of contamination of food of animal origin require further research. The aim of this study was to develop and validate a highly sensitive quantitative RT-qPCR assay for the detection and quantification of HEV contamination in porcine liver and food. The focus was on genotype 3, which is most common as a food contaminant in developed countries and Europe. The selected assay has its target sequence in the open reading frame 1 (ORF1) of the HEV genome and showed good results in inclusivity testing, especially for HEV genotype 3. The developed assay seems to show high efficiency and a low intercept when compared to other assays, while having a comparable limit of detection (LOD). In addition, a standard curve was generated using artificially spiked liver to provide more accurate quantitative results for contamination assessment and tracking in this matrix. Application of the assay to test 67 pig livers from different origins resulted in a positivity rate of 7.5%, which is consistent with the results of numerous other prevalence studies. Quantitative detection of the viral genome in the food chain, particularly in pig livers, is essential for understanding the presence and evolution of HEV contamination and thus ensures consumer safety.

Seroprevalence and incidence of hepatitis E virus infection in the general population of Iwate prefecture, Japan: A retrospective cohort study

AIM

Hepatitis E virus (HEV) causes subclinical or acute self-limiting hepatitis. We surveyed the current seroprevalence and incidence of HEV infection among the general population in Iwate Prefecture, Japan, where the endemic infection is presumed to be low.

METHODS

Between 2014 and 2016, we recruited individuals from Iwate Prefecture, Japan, who visited a general medical work-up program. Serum anti-HEV antibody and HEV RNA were measured twice, with an interval of 2 years. Anti-HEV antibody was measured with enzyme-linked immunosorbent assay and HEV RNA with reverse transcription-polymerase chain reaction.

RESULTS

Study participants comprised 1284 Japanese (650 men and 634 women) with age ranging 20-89 years. A total of 90 participants were found to be positive for anti-HEV immunoglobulin G on the first visit, with a prevalence of 7.0% (95% confidence interval [CI] 5.6%-8.4%). Seroprevalence was higher in men than in women (10.1% vs. 3.7%, p < 0.001), and in those aged in their 50s-80s than in those aged in their 20s-40s (p = 0.006). Positive seroconversion indicating new HEV infection was found in seven of 1194 seronegative participants (0.59%; 95% CI 0.15%-1.0%), indicating the incidence of HEV infection to be 272 per 100 000 person-years (95% CI 109-561).

CONCLUSIONS

Our observations suggest that the incidence of HEV infection is high and that it is a leading cause of hepatitis virus infection in Iwate Prefecture, Japan.

Infection Dynamics and Genomic Mutations of Hepatitis E Virus in Naturally Infected Pigs on a Farrow-to-Finish Farm in Japan: A Survey from 2012 to 2021

Hepatitis E virus (HEV) causes acute or chronic hepatitis in humans. Pigs are the primary reservoir for zoonotic HEV genotypes 3 and 4 worldwide. This study investigated the infection dynamics and genomic mutations of HEV in domestic pigs on a farrow-to-finish pig farm in Japan between 2012 and 2021. A high prevalence of anti-HEV IgG antibodies was noted among pigs on this farm in 2012, when the survey started, and persisted for at least nine years. During 2012-2021, HEV RNA was detected in both serum and fecal samples, indicating active viral replication. Environmental samples, including slurry samples in manure pits, feces on the floor, floor and wall swabs in pens, and dust samples, also tested positive for HEV RNA, suggesting potential sources of infection within the farm environment. Indeed, pigs raised in HEV-contaminated houses had a higher rate of HEV infection than those in an HEV-free house. All 104 HEV strains belonged to subgenotype 3b, showing a gradual decrease in nucleotide identities over time. The 2012 (swEJM1201802S) and 2021 (swEJM2100729F) HEV strains shared 97.9% sequence identity over the entire genome. Importantly, the swEJM2100729F strain efficiently propagated in human hepatoma cells, demonstrating its infectivity. These findings contribute to our understanding of the prevalence, transmission dynamics, and genetic characteristics of HEV in domestic pigs, emphasizing the potential risks associated with HEV infections and are crucial for developing effective strategies to mitigate the risk of HEV infection in both animals and humans.

The Common Mosquito (Culex pipiens) Does Not Seem to Be a Competent Vector for Hepatitis E Virus Genotype 3

An experimental infection approach was used to estimate the competence of the common mosquito, Culex pipiens, for hepatitis E virus replication and transmission, using an isolate of hepatitis E virus genotype 3 of human origin in varying infectious doses. The experimental approach was carried out in biosafety level 2 conditions on three batches of 120 Cx. pipiens females, each using an artificial feeding system containing the virus in aliquots of fresh avian blood. Mosquitoes from each batch were collected 1, 7, 14, and 21 days post-infection (dpi) and dissected. The proboscis was subjected to forced excretion of saliva to estimate potential virus transmission. HEV RNA presence in abdomen, thorax, and saliva samples was analyzed by PCR at the selected post-infection times. HEV RNA was detected in the abdomens of Cx. pipiens females collected 1 dpi in the two experimentally-infected batches, but not in the saliva or thorax. None of the samples collected 7-21 dpi were positive. Our results show that Cx. pipiens is not a competent vector for HEV, at least for zoonotic genotype 3.

Identification of hepatitis E virus in wild sika deer in Japan

Hepatitis E virus (HEV) is a zoonotic agent mainly transmitted through the consumption of uncooked or undercooked meat products derived from infected animals. In Japan, domestic pigs and wild boars are the major animal reservoirs, and whether or not deer are an HEV reservoir remains controversial. We analyzed 395 serum and 199 liver samples from 405 sika deer (Cervus nippon) caught in the wild between 1997 and 2020 in 11 prefectures of Japan for markers of HEV infection. Overall, 17 deer had anti-HEV IgG (4.3%), while 1 (0.2%) had HEV RNA (genotype 3b), indicating the occurrence of ongoing HEV infection in wild deer in Japan. An analysis of the complete HEV genome (deJOI_14) recovered from a viremic deer in Oita Prefecture revealed only 88.8% identity with the first HEV strain in sika deer (JDEER-Hyo03L) in Japan, being closest (96.3%) to the HEV obtained from a hepatitis patient living in the same prefecture. Of note, the deJOI_14 strain was 8.7-9.0% different from the wild boar HEV strains obtained in the same habitat and the same year, suggesting that difference in infected HEV strains between boar and deer may be explained by the limited possibility of close contact with each other, although boars are a known source of HEV infection. Increased numbers of hepatitis E cases after consumption of raw or undercooked meat products of wild deer have been reported in Japan. These results suggest a low but nonnegligible zoonotic risk of HEV infection in wild deer in this country.

Development of diagnostic systems for wide range and highly sensitive detection of two waterborne hepatitis viruses from groundwater using the conventional reverse transcription nested PCR assay

Waterborne epidemics of human hepatitis virus A and E (HAV and HEV) have been reported worldwide. Molecular biology techniques, such as reverse transcription polymerase chain reaction (RT-PCR), have been widely used to detect the two hepatitis viruses. However, comparative studies of various types of samples are needed, and different environmental factors, including the low copy pathogens, presence of PCR inhibitors in the sample, unknown non-specific reaction with template, and sequence diversity leading to new variants in viruses, should be considered. In addition, standard positive material is required to determine the accuracy of the PCR and should be able to distinguish between false and real positives. In this study, we developed RT-PCR primer sets and optimised standard templates for HAV and HEV detection to address the above concerns associated with test sensitivity and possible PCR inhibition. Finally, previously reported diagnostic methods of HAV and HEV were compared and an applicability test using groundwater was performed. The nested RT-PCR developed in this study is expected to contribute to assess water safety by monitoring HAV and HEV in non-disinfected water, like groundwater.

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.

Variability in molecular characteristics of Hepatitis E virus quasispecies could modify viral surface properties and transmission

Hepatitis E virus (HEV) usually causes self-limited liver diseases but can also result in severe cases. Genotypes 1 (G1) and 2 circulate in developing countries are human-restricted and waterborne, while zoonotic G3 and G4 circulating in industrialized countries preferentially infect human through consumption of contaminated meat. Our aims were to identify amino acid patterns in HEV variants that could be involved in pathogenicity or in transmission modes, related to their impact on antigenicity and viral surface hydrophobicity. HEV sequences from human (n = 37) and environmental origins (wild boar [n = 3], pig slaughterhouse effluent [n = 6] and urban wastewater [n = 2]) were collected for the characterization of quasispecies using ultra-deep sequencing (ORF2/ORF3 overlap). Predictive and functional assays were carried out to investigate viral particle antigenicity and hydrophobicity. Most quasispecies showed a major variant while a mixture was observed in urban wastewater and in one chronically infected patient. Amino acid signatures were identified, as a rabbit-linked HEV pattern in two infected patients, or the S68L (ORF2) / H81C (ORF3) residue mostly identified in wild boars. By comparison with environmental strains, molecular patterns less likely represented in humans were identified. Patterns impacting viral hydrophobicity and/or antigenicity were also observed, and the higher hydrophobicity of HEV naked particles compared with the enveloped forms was demonstrated. HEV variants isolated from human and environment present molecular patterns that could impact their surface properties as well as their transmission. These molecular patterns may concern only one minor variant of a quasispecies and could emerge under selective pressure.

Loss of antibodies to hepatitis E virus in organ transplant patients with hepatitis E

AIM

Studies regarding changes in antibodies to hepatitis E virus (HEV) after HEV infection in organ transplant patients are limited. This study aimed to clarify HEV infection trends in organ transplant patients who contracted HEV using data from a previous Japanese nationwide survey.

METHODS

This study was undertaken from 2012 to 2019. Among 4518 liver, heart, and kidney transplant patients, anti-HEV immunoglobulin G (IgG) antibodies were positive in 164; data were collected from 106 of these patients, who consented to participate in the study. In total, 32 liver transplant patients, seven heart transplant patients, and 67 kidney transplant patients from 16 institutions in Japan were examined for IgG, IgM, and IgM antibodies to HEV and the presence of HEV RNA in the serum. The χ² -test was used to determine the relationship between the early and late postinfection groups in patients with anti-HEV IgG positive-to-negative conversion rates. The Mann-Whitney U-test was used to compare clinical factors.

RESULTS

Anti-HEV IgG positive-to-negative conversion occurred in 25 (23.6%) of 106 organ transplant patients. Of eight patients with hepatitis E who tested positive for HEV RNA, one (14.0%) had anti-HEV IgG positive-to-negative conversion. Twenty-four (24.5%) of 98 patients negative for HEV RNA had anti-HEV IgG positive-to-negative conversion.

CONCLUSIONS

This study revealed, for the first time, the changes in HEV antibodies in organ transplant patients. Loss of anti-HEV IgG could often occur unexpectedly in organ transplant patients with previous HEV infection.

Identification and a full genome analysis of novel camel hepatitis E virus strains obtained from Bactrian camels in Mongolia

Hepatitis E virus (HEV) infects humans and a wide variety of other mammalian hosts. Recently, HEV strains belonging to genotype 8 (G8) within the Orthohepevirus A species of the Hepeviridae family, were identified in Bactrian camels (Camelus bactrianus) in China. The Bactrian camel (also known as the Mongolian camel) is native to the steppes of Central Asia. However, the HEV strains of Mongolian camels have not been examined. Among 200 serum samples from domestic Bactrian camels raised on 6 farms, in 6 soums in 3 provinces; 71 (35.5 %) were positive for anti-HEV IgG, with prevalence differing by farm (soum) (4.2-75.0 %); and 2 camels (1.0 %) that had been raised in Bogd, Bayankhongor Province, which had the highest seroprevalence among the six studied areas, were positive for HEV RNA. The two HEV strains (BcHEV-MNG140 and BcHEV-MNG146) obtained from the viremic camels in the present study shared 97.7 % nucleotide identity. They were closest to the reported G8 Chinese camel HEV strains but differed from them by 13.9-14.3 % over the entire genome, with a nucleotide difference of 24.0-26.5 % from the reported G1-G7 HEV strains. A phylogenetic tree indicated that the BcHEV-MNG140 and BcHEV-MNG146 strains were located upstream of a clade consisting of the Chinese camel HEV strains and formed a cluster with them, with a bootstrap value of 100 %, suggesting that they may represent a novel subtype within G8. These results indicate a high prevalence of HEV infection in Mongolian camels and suggest that the variability of camel HEV genomes is markedly high.

Development and Clinical Validation of a Pangenotypic PCR-Based Assay for the Detection and Quantification of Hepatitis E Virus (Orthohepevirus A Genus)

The objective of this study was to design a pangenotypic PCR-based assay for the detection and quantification of hepatitis E virus (HEV) RNA from across the entire spectrum of described genotypes belonging to the Orthohepevirus A genus. The optimal conditions and the performance of the assay were determined by testing the WHO standard strain (6219/10) and the WHO HEV panel (8578/13). Similarly, performance comparisons were made with two commercial assays (Real Star HEV RT-PCR 2.0 and ampliCube HEV 2.0 Quant) to detect HEV RNA at concentrations below 1,000 IU/ml with viral strains from the WHO and to test samples from 54 patients with acute hepatitis. The assay presented in this study was able to detect the entire spectrum of described genotypes belonging to the Orthohepevirus A genus, demonstrating better performance than both commercial kits. This procedure may represent a significant improvement in the molecular diagnosis of HEV infection.

Serological prevalence and molecular characterization of hepatitis E virus in imported pigs in Singapore (2000-2019)

Hepatitis E is a significant liver disease caused by infection with hepatitis E virus (HEV). The risk factors for hepatitis E in developed countries include blood transfusion and ingestion of undercooked meat or meat products derived from HEV-infected animals. Since 2000, there has been increased human hepatitis E incidence reported in Singapore. Although the causes of this increase have not been established, several studies have linked zoonotic HEV infections in humans to pork consumption. It is therefore important to closely monitor the presence of HEV in food sources for the prevalence and virulence. In this study, we demonstrated the presence of HEV in pigs imported into Singapore for consumption through serological and molecular investigation of live pig and post-slaughter samples collected between 2000 and 2019. Among imported pigs, anti-HEV antibody prevalence remained at a level around 35% until 2017, with a statistically significant increase in 2018. HEV RNA was detected in 8.40% (34/405) of the faecal samples, indicative of an active infection in the pigs. HEV RNA was also detected in 6.67% (4/60) of liver samples obtained post-slaughter. We also report the development of an RT-PCR-based next-generation sequencing (NGS) method that enabled full sequencing of the HEV genome in HEV RNA-positive samples in a relatively short span of time. Phylogenetic analysis identified the HEV in one of the imported pigs (HEV-S28) as genotype 3a, which clustered together with the human HEV strains previously identified in Singapore. We found that the HEV-S28 strain exhibited amino acid substitutions that are associated with reduced HEV replication efficiency. The increase in anti-HEV seroprevalence in the pig population from 2018 is worth further exploration. We will continue to monitor the prevalent HEV strains and assess the genetic diversity of HEV in the imported pigs to confirm the potential association with human infections.

Electrochemical DNA detection of hepatitis E virus genotype 3 using PbS quantum dot labelling

The aim of this study was to develop a highly specific electrochemical DNA sensor using functionalized lead sulphide (PbS) quantum dots for hepatitis E virus genotype 3 (HEV3) DNA target detection. Functionalized-PbS quantum dots (QDs) were used as an electrochemical label for the detection of HEV3-DNA target by the technique of square wave anodic stripping voltammetry (SWASV). The functionalized-PbS quantum dots were characterized by UV-vis, FTIR, XRD, TEM and zeta potential techniques. As-prepared, functionalized-PbS quantum dots have an average size of 4.15 ± 1.35 nm. The detection platform exhibited LOD and LOQ values of 1.23 fM and 2.11 fM, respectively. HEV3-DNA target spiked serum is also reported.Graphical abstract.

A Nationwide Survey of Hepatitis E Virus Infection and Chronic Hepatitis in Heart and Kidney Transplant Recipients in Japan

Background.

Recently, chronic hepatitis E has been reported in solid organ transplant (SOT) recipients in European countries. Previously, we clarified the prevalence of hepatitis E virus (HEV) infection in Japanese liver transplant recipients and identified 2 chronic hepatitis E patients infected by blood transfusion. However, the rate of HEV infection in recipients of SOTs other than liver in Japan remains unclear, so we conducted a nationwide survey to clarify the prevalence of chronic HEV infection in Japanese heart and kidney transplant recipients.

Methods.

A total of 99 heart and 2526 kidney transplant recipients in 17 hospitals in Japan were examined for the presence of the IgG class of anti-HEV antibodies as well as for serum HEV RNA.

Results.

The prevalence of anti-HEV IgG among heart and kidney transplant recipients was 7.07% (7/99) and 4.08% (103/2526), respectively. One heart transplant patient (1.01%) and 11 kidney transplant patients (0.44%) were found to be positive for HEV RNA. The HEV isolates from all viremic patients were typed as genotype 3. Four patients developed chronic hepatitis E after transplantation. Three patients were treated with ribavirin; their liver enzymes normalized, and HEV RNA became negative immediately. Sustained virologic response was achieved in all cases.

Conclusions.

This is the first nationwide survey of HEV infection in Japanese heart and kidney transplant recipients. The prevalence of anti-HEV IgG and HEV RNA in heart and kidney transplant recipients in Japan was lower than that in European countries. Of note, 42% of viremic transplant patients developed chronic hepatitis.

Prevalence and genotype/subtype distribution of hepatitis E virus (HEV) among wild boars in Japan: Identification of a genotype 5 HEV strain

To further investigate the prevalence of hepatitis E virus (HEV) infection and characterize HEV genomes among Japanese wild boars (Sus scrofa leucomystax), 1880 boars captured in 17 prefectures in Japan from 2013 to 2019 were studied. Overall, anti-HEV IgG was detected in 8.9 % and HEV RNA was detected in 3.9 % of boars, which was comparable with our previous studies during 2003-2013 (10.3 % and 3.5 %, respectively). Among 74 boar HEV strains obtained from infected boars in the present study, 50 (68 %) were classified into genotype 3 (3a and 3b), 23 (31 %) were classified into genotype 4 (4i), and the remaining strain (wbJGF_19-1) was classified into genotype 5. The wbGF_19-1 strain shared 92.7 % identity over the entire genome with the prototype genotype 5 strain (JBOAR135-Shiz09). The identification of the second genotype 5 HEV strain in a place that is located only 100 km from the site at which JBOAR135-Shiz09 was identified, suggests that genotype 5 HEV circulates within a relatively close range in Japan. Genetically similar HEV strains forming a clade were identified from wild boars living in each area during the observation period of 11-13 years, although the nucleotide sequence changed gradually, accounting for up to 3.4-3.6 % within the 412-nucleotide ORF2 sequence. Eight groups of boars with a cluster of HEV infections were observed, consisting of two, three or four infected offspring, presumably born to the same mother or offspring with their mother. These results suggest that wild boars continue to be important reservoirs for HEV infection in humans in Japan.

First detection of hepatitis E virus genotype 3 as a common infectious agent in patients with chronic liver damage in Mexico

INTRODUCTION AND OBJECTIVES

To characterize the virological features of hepatitis E virus (HEV) in serum from patients exhibiting chronic liver damage.

METHODS

A data-base of 513 unrelated individuals from West-Mexico with liver-disease determined by clinical and biochemical tests and transient elastography between 2011 and 2016 were retrospectively analyzed. According to infectious etiologies, patients were classified as hepatitis B virus (HBV)-, hepatitis C virus (HCV)-infected patients, and patients exhibiting chronic liver damage with non-identified infectious etiological agent (NIIEA). Available serum samples from NIIEA-patients were tested by RT-nPCR for the presence of HEV-RNA and partially sequenced for genotyping.

RESULTS

Out of the 513 cases, 5.85% were patients infected with HBV, 67.64% with HCV, and 26.51% were NIIEA-patients. Among 76 available samples from NIIEA-cases, 30.26% tested positive for HEV-RNA. Twelve (15.79%) partial HEV sequences allowed phylogenetic analysis, revealing the classification of HEV as HEV-Gt3. Advanced fibrosis (F3-F4 stage) was found in a 26.1% of patients with HEV-active infection.

CONCLUSION

Although HCV is the main infectious agent related to chronic liver disease in Mexico, liver damage without an infectious etiology is common. Our findings reveal that an elevated rate of chronic liver disease might be represented by autochthonous infection of HEV-Gt3, whose detection makes Mexico unique in Latin-America with the circulation of HEV strains belonging to three genotypes (Gt1, Gt2, and Gt3). Thus, HEV infection should be a matter of health concern, and mandates for HEV screening to properly handle this commonly undiagnosed disease.

Occurrence of Staphylococcus spp. and investigation of fecal and animal viral contaminations in livestock, river water, and sewage from Tunisia and Romania

The objective of this study was to determine the occurrence of Staphylococcus spp., Escherichia coli, somatic coliphages, F-specific RNA bacteriophages, hepatitis E virus (HEV), and bovine enterovirus (BEV) in fecal and water samples. The occurrence of Staphylococcus spp. was investigated in treated wastewater samples collected from slaughterhouse of Tunisia. Results showed that Staphylococcus spp. were detected in the totality of collected samples with an average mean of 5.44 Log₁₀ (CFU/100 ml). Regarding fecal indicator bacteria, E. coli was detected in the totality of water samples and was more abundant in Tunisian samples than in samples collected from Romania (P < 0.05). Concerning somatic coliphages and F-specific RNA bacteriophages used as viral indicators, they were detected in all raw and treated wastewaters. Bovine enterovirus (BEV) was detected in 20.1% and 28% of bovine stool samples collected from Tunisia and Romania, respectively. BEV was also detected in 60% of porcine stool samples from Romania. BEV was absent in all treated sewage samples. HEV was detected in raw sewage and bovine fecal sample from Romania with low occurrence and none sample from Tunisia was positive. This study may give us an insight into the monitoring of water quality in Tunisia and Romania.

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

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

Emerging hepatitis E virus compared with hepatitis A virus: A new sanitary challenge

Hepatitis A (HAV) and E (HEV) viruses are able to cause liver disease in humans. Among the five classical hepatotropic viruses, they are mainly transmitted via the fecal-oral route. Historically, many similarities have thus been described between them according to their incidence and their pathogenicity, especially in countries with poor sanitary conditions. However, recent advances have provided new insights, and the gap is widening between them. Indeed, while HAV infection incidence tends to decrease in developed countries along with public health improvement, HEV is currently considered as an underdiagnosed emerging pathogen. HEV autochthonous infections are increasingly observed and are mainly associated with zoonotic transmissions. Extra hepatic signs resulting in neurological or renal impairments have also been reported for HEV, as well as a chronic carrier state in immunocompromised patients, arguing in favor of differential pathogenesis between those two viruses. Recent molecular tools have allowed studies of viral genome variability and investigation of links between viral plasticity and clinical evolution. The identification of key functional mutations in viral genomes may improve the knowledge of their clinical impact and is analyzed in depth in the present review.

Risk assessment for hepatitis E virus infection from domestic pigs introduced into an experimental animal facility in a medical school

Hepatitis E virus (HEV) is known to cause zoonotic infections from pigs, wild boars and deer. Domestic pigs have been used as an experimental animal model in medical research and training; however, the risks of HEV infection from pigs during animal experiments are largely unknown. Here, we retrospectively investigated the seroprevalence and detection rates of viral RNA in 73 domestic pigs (average 34.5 kg) introduced into an animal experimental facility in a medical school during 2012–2016. We detected anti-HEV immunoglobulin G antibodies in 24 of 73 plasma samples (32.9%), though none of the samples were positive for viral RNA. Plasma samples of 18 pigs were sequentially monitored and were classified into four patterns: sustained positive (5 pigs), sustained negative (5 pigs), conversion to positive (6 pigs) and conversion to negative (2 pigs). HEV genomes were detected in 2 of 4 liver samples from pigs that were transported from the same farm during 2016–2017. Two viral sequences of the overlapping open reading frame (ORF) 2/3 region (97 bp) were identical and phylogenetically fell into genotype 3. A 459-bp length of the ORF2 region of an amplified fragment from a pig transported in 2017 was clustered with the wbJYG1 isolate (subgenotype 3b) with 91.5% (420/459 bp) nucleotide identity. Based on our results, we suggest that domestic pigs introduced into animal facilities carry a potential risk of HEV infection to researchers, trainees and facility staff. Continuous surveillance and precautions are important to prevent HEV infection in animal facilities.

Transmission of hepatitis E virus by water: An issue still pending in industrialized countries

Hepatitis E virus (HEV) is an enteric virus divided into eight genotypes. Genotype 1 (G1) and G2 are specific to humans; G3, G4 and G7 are zoonotic genotypes infecting humans and animals. Transmission to humans through water has been demonstrated for G1 and G2, mainly in developing countries, but is only suspected for the zoonotic genotypes. Thus, the water-related HEV hazard may be due to human and animal faeces. The high HEV genetic variability allows considering the presence in wastewater of not only different genotypes, but also quasispecies adding even greater diversity. Moreover, recent studies have demonstrated that HEV particles may be either quasi-enveloped or non-enveloped, potentially implying differential viral behaviours in the environment. The presence of HEV has been demonstrated at the different stages of the water cycle all over the world, especially for HEV G3 in Europe and the USA. Concerning HEV survival in water, the virus does not have higher resistance to inactivating factors (heat, UV, chlorine, physical removal), compared to viral indicators (MS2 phage) or other highly resistant enteric viruses (Hepatitis A virus). But the studies did not take into account genetic (genogroups, quasispecies) or structural (quasi- or non-enveloped forms) HEV variability. Viral variability could indeed modify HEV persistence in water by influencing its interaction with the environment, its infectivity and its pathogenicity, and subsequently its transmission by water. The cell culture methods used to study HEV survival still have drawbacks (challenging virus cultivation, time consuming, lack of sensitivity). As explained in the present review, the issue of HEV transmission to humans through water is similar to that of other enteric viruses because of their similar or lower survival. HEV transmission to animals through water and how the virus variability affects its survival and transmission remain to be investigated.

Prevalence and characteristics of hepatitis E virus infection in kidney transplant recipients: A single-center experience in Japan

BACKGROUND

Hepatitis E virus (HEV) infection can lead to chronic hepatitis in solid organ transplant recipients. To investigate whether HEV infection influences outcomes following kidney transplantation, we examined the prevalence of HEV infection and clinical characteristics of kidney transplant recipients in our hospital.

METHODS

Our cross-sectional study included 184 kidney transplant recipients. Blood samples were obtained from all patients to detect anti-HEV immunoglobulin (Ig)A, IgM, and IgG by enzyme-linked immunosorbent assay and HEV RNA by reverse transcription polymerase chain reaction. Clinical data were collected from medical charts for all patients.

RESULTS

The prevalence of anti-HEV IgG was 8/184 (4.3%). Anti-HEV IgA, anti-HEV IgM, and HEV RNA were not detected in any patients. Compared to their anti-HEV IgG-negative counterparts, anti-HEV IgG-positive patients were significantly older at the time of transplantation, and they were more likely to receive kidneys from deceased donors. No significant differences in other characteristics such as the prevalence of primary cause of end-stage renal disease, blood transfusion, and immunosuppressive therapy use; liver and renal function; and the frequencies of hepatitis B and hepatitis C virus infection were observed according to the patients' anti-HEV IgG status.

CONCLUSION

HEV infection had no significant influence on the outcomes of kidney transplantation at our institution. However, HEV infection should be recognized in kidney transplant recipients similarly as hepatitis B and hepatitis C virus infection in cases of liver dysfunction.

Prevalence of hepatitis E in liver transplant recipients in Greece

Hepatitis E virus (HEV) is a well-known cause of acute hepatitis. Immunocompromised subjects, including liver transplant recipients, are considered to be at risk for HEV infection, which occasionally follows a chronic course. The diagnosis of HEV infection in these patients must be based on HEV RNA testing, as serology has variable performance. The aim of this study was to assess the prevalence of HEV infection in liver transplant recipients in Greece by means of HEV RNA testing. Liver transplant recipients followed in the sole transplant centre in Greece were prospectively included. HEV RNA was detected by real-time RT-PCR. Positive samples were further analysed using a nested reverse transcription RT-PCR kit, which amplifies a 137-nucleotide sequence within the ORF2/ORF3 overlapping region to detect the HEV genotype and perform phylogenetic analysis. The mean age of the included patients (n = 76) was 54 years. The most common indication for liver transplantation was viral hepatitis (57%). The majority of the patients (75%) received a calcineurin inhibitor as part of their immunosuppressive regimen and had normal liver enzymes. HEV RNA was found positive in only 1/76 (1.3%) patient. Phylogenetic analysis showed that the sequence clustered into the HEV genotype 3 clade. This patient experienced an acute hepatitis flare, which nonetheless did not become chronic. The prevalence of HEV infection in liver transplant recipients in Greece is similar (1.3%) to that reported previously in other countries. Transplant physicians should be aware of this condition and its associated consequences.

Prevalence, risk factors and molecular evaluation of hepatitis E virus infection among pregnant women resident in the northern shores of Persian Gulf, Iran

BACKGROUND

Although Iran is reported to be an endemic country for hepatitis E virus (HEV), data on the prevalence of HEV infection among pregnant women are scarce and the epidemiology of HEV is unknown in most parts of the country. Therefore, this study was conducted to elucidate the prevalence, risk factors and genotypic pattern of HEV infection among pregnant women resident in the northern shores of Persian Gulf. This is the first report on the epidemiology of HEV infection among pregnant women in this territory.

METHODS

From October 2016 to May 2017, 1331 pregnant women participated in this study. The mean age ± SD of participants was 27.93±5.7 years with a range of 14-45 years. Serum samples of pregnant women were screened for the presence of anti-HEV total antibodies, anti-HEV IgG and anti-HEV IgM using commercially available ELISA kits (DIA.PRO, Milan, Italy). All anti-HEV IgG and anti-HEV IgM positive samples were tested for HEV RNA using two independent reverse transcriptase polymerase chain reaction (RT-PCR) assays, targeting ORF2 and ORF3 of HEV genome. In addition, 92 anti-HEV seronegative samples as well as 50 pooled seronegative samples were evaluated by two independent RT-PCR assays for validation of results.

RESULTS

Of the 1331 pregnant women, 84 women (6.3%, 95% CI: 5.1%-7.7%) were positive for anti-HEV antibodies, of which 83 women had anti-HEV IgG, and 11 women (0.83%, 95% CI: 0.47%-1.47%) had anti-HEV IgM. The highest rate of HEV seroprevalence was observed among Afghan immigrants (68.0%), uneducated pregnant women (46.51%) and those residents in Bushehr city (8.75%). All anti-HEV IgG and/or IgM positive samples were found to be negative for HEV RNA. In addition, all of the evaluated anti-HEV seronegative samples were negative for HEV RNA. HEV seropositivity among pregnant women was statistically associated with age, ethnicity, place of residence, number of pregnancies, and level of education. So that, low education levels, Afghan, residence in Bushehr city, age group >34 years, and more parities were risk factors for exposure to HEV. In contrast, HEV seropositivity was not associated with stage of gestation, history of abortion, and time of sampling.

CONCLUSION

The northern shores of Persian Gulf in Iran, with HEV seroprevalence of 6.3%, can be classified as an endemic geographical region for hepatitis E, and residents of Bushehr city, Afghan immigrants and uneducated women are the main at-risk populations in this territory.

Familial Hepatitis E Outbreak Linked to Wild Boar Meat Consumption

An HIV-infected patient was diagnosed with acute hepatitis E infection in our hospital. An epidemiological inquiry was performed to collect demographic, food and animal exposure variables in order to identify the potential route of transmission. The patient reported that his family traditionally hunted wild boar for food. All family members were analysed for hepatitis E virus infection. Additionally, route of transmission by wild boar meat consumption and prevalence of HEV infection among wild boar from the same hunting area were investigated. In all-family members (n = 8), HEV-RNA was amplified. Two wild boar meat slices consumed was analysed, showing the presence of HEV. The virus isolated was consistent with genotype 3, revealing 100% homology between family members and meat. Additionally, we tested nine wild boar hunted in the same hunting area. All of them were RNA-HEV positive, isolating the same HEV genotype 3 viral strain. We demonstrated by phylogenetic analysis zoonotic transmission of HEV by wild boar meat consumption. The prevalence of HEV infection among wild boar found in our study suggests that this species is an important route of transmission to human.

Hepatitis E Virus (Genotype 3) in Slurry Samples from Swine Farming Activities in Italy

Hepatitis E virus (HEV) is an emergent causative agent of acute hepatitis, transmitted by fecal-oral route. Infection with HEV is a global cause for morbidity and mortality throughout the world: it mainly causes large outbreaks in endemic areas and sporadic autochthonous cases in industrialized countries where HEV infections seem to be an emergent zoonotic disease. Infection of porcine livestock and its relationship with the human cases have been demonstrated. The present study describes an investigation on the prevalence and diversity of HEV in pig slurry in Italy. Slurry samples (24) were collected from ten farms located in North Italy during 2015 and analyzed for HEV, using four broad-range nested PCR assays targeting ORF1 (MTase), ORF2 (capsid) genes, and ORF2/3 regions. Overall, 18 samples (75%) were positive for HEV RNA, and characterized as genotype 3. Nine samples could be subtyped by ORF2 sequencing: Eight belonged to subtype 3f, while one sequence could not be characterized by blast analysis and phylogenetic analysis and may actually represent a new subtype. Furthermore, similarity of 99% was found between 3f Italian HEV sequences of human and swine origins. Real-Time PCR assay was also performed, in order to obtain quantitative data on positive samples. Two swine slurry samples were positive, containing 600 and 1000 UI per mL of sewage. The results of this study show that HEV strains belonging to zoonotic genotype 3 are widely present in swine excreta, and have high degree of identity with strains detected in autochthonous HEV cases. Improving swine farming operations safety and increasing operators' awareness of the zoonotic potential connected with the handling of swine effluents turn out to be key points in order to reduce the environmental and sanitary problem represented by the possible dissemination of HEV to water bodies.

First evidence of the Hepatitis E virus in environmental waters in Colombia

Hepatitis E virus (HEV) is one of the main causes of acute viral hepatitis of enteric transmission. HEV has been detected in environmental samples in several countries from Europe and Asia, constituting a risk factor for waterborne infection. In Colombia, HEV has been identified in samples obtained from patients as well as from swine, but no environmental studies have been carried out. To determine if HEV is present in environmental waters, samples from the main source of drinking water plant and of wastewater system of eight municipalities and two villages of Antioquia state (North West Colombia), were collected between December 2012 and April 2014. The HEV genome was detected by RT-PCR in 23.3% (7/30) of the samples from the main source of drinking water plants and in 16.7% (5/30) from sewage. Viral concentrates obtained from three positive sewage samples were used to inoculate HepG2 cell cultures that were followed for one month; however, the viral genome was not detected in any cell culture. This study demonstrates the circulation of HEV in both source of drinking water plants and wastewater in Antioquia state, Colombia. The presence of HEV in environmental waters could be a risk for waterborne transmission in this population. The findings of the present study, together with the evidence of HEV circulation in human and swine in Colombia, should be consider by public health authorities for the development of surveillance programs and the inclusion of HEV infection diagnosis in the guidelines of viral hepatitis in the country. This is the first report of HEV in environmental samples in Colombia and the second one in Latin America.

Clinical and virological features of acute hepatitis E in Gunma prefecture, Japan between 2004 and 2015

AIM

To evaluate the clinical and virological features of acute hepatitis E (AH-E) in Gunma prefecture and focus on the hepatitis E virus (HEV) infection in immunocompromised patients.

METHODS

A total of 30 patients with AH-E diagnosed at our Gunma University Hospital, and located in 3-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan, and its affiliated hospitals from 2004 to 2015, were studied. We evaluated the detailed medical histories, laboratory examinations and virological features of these participants.

RESULTS

Of the 30 patients, 21 patients were men, with a median age of 61 years. Three of these patients had a history of recent oversea travel. A total of 14 patients had eaten raw or undercooked meat/viscera from animals, and two patients had contracted transfusion-transmitted AH-E. Eight patients were immunocompromised, including those with hematological disease, cancer receiving systemic chemotherapy and kidney transplant or connective tissue disease undergoing immunosuppressive medications. The alanine aminotransferase and total bilirubin levels were more significantly reduced in these immunocompromised patients than in the non-immunocompromised patients. Severe thrombocytopenia, an extra-hepatic manifestation of AH-E, occurred in one case. Among the 22 HEV strains whose subgenotype was determined, two were imported strains (1a and 1f), and 11 strains formed four distinct phylogenetic clusters within subgenotype 3b. The remaining nine strains differed from each other by 9.8-22.4%, and were classified into four subgenotypes (3a, 3b, 3e and 3f).

CONCLUSION

Markedly divergent HEV strains (3a, 3b, 3e and 3f) were found to circulate in Gunma. Although immunosuppression appears to play a crucial role in establishing chronic sequels, AH-E in eight immunocompromised patients, including transfusion-transmitted HEV infection in two patients, did not become chronic.

Genome Sequence of a Genotype 2 Hepatitis E Virus World Health Organization Reference Strain

We report here the sequence of a genotype 2a reference strain of hepatitis E virus (HEV), developed on behalf of the World Health Organization. The HEV reference strain is intended for use in assays based on nucleic acid amplification for the validation of HEV RNA detection.

A Nationwide Survey of Hepatitis E Virus Infection and Chronic Hepatitis E in Liver Transplant Recipients in Japan

Background

Recently, chronic hepatitis E has been increasingly reported in organ transplant recipients in European countries. In Japan, the prevalence of hepatitis E virus (HEV) infection after transplantation remains unclear, so we conducted a nationwide cross-sectional study to clarify the prevalence of chronic HEV infection in Japanese liver transplant recipients.

Methods

A total of 1893 liver transplant recipients in 17 university hospitals in Japan were examined for the presence of immunoglobulin G (IgG), IgM and IgA classes of anti-HEV antibodies, and HEV RNA in serum.

Findings

The prevalence of anti-HEV IgG, IgM and IgA class antibodies was 2.9% (54/1893), 0.05% (1/1893) and 0% (0/1893), respectively. Of 1651 patients tested for HEV RNA, two patients (0.12%) were found to be positive and developed chronic infection after liver transplantation. In both cases, HEV RNA was also detected in one of the blood products transfused at the perioperative period. Analysis of the HEV genomes revealed that the HEV isolates obtained from the recipients and the transfused blood products were identical in both cases, indicating transfusion-transmitted HEV infection.

Interpretation

The prevalence of HEV antibodies in liver transplant recipients was 2.9%, which is low compared with the healthy population in Japan and with organ transplant recipients in European countries; however, the present study found, for the first time, two Japanese patients with chronic HEV infection that was acquired via blood transfusion during or after liver transplantation.

•

We conducted the multicenter survey for HEV infection in liver transplant recipients.

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Though the chronic HEV infection is rare, transfusion-transmitted cases were detected.

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Blood products can be a risk of chronic HEV infection in transplant recipients.

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 antibody prevalence, RNA frequency, and genotype among blood donors in Cambodia (Southeast Asia)

BACKGROUND

Recent studies conducted in developed countries described hepatitis E virus (HEV) as an emerging infectious threat to blood safety. However, data on HEV among blood donors from southeast Asia are lacking.

STUDY DESIGN AND METHODS

Between July and August 2014, we assessed the presence of HEV immunoglobulin (Ig)G and IgM in 301 Cambodian blood donors. All samples were further tested for the presence of HEV RNA using an in-house reverse transcription-polymerase chain reaction. ORF2/ORF3 phylogenetic analysis was performed on positive HEV RNA specimens.

RESULTS

We found HEV IgG in 28.2% of blood donors from Cambodia. Three blood donors tested positive for HEV IgM with three distinct patterns: IgM(+)/IgG(-)/RNA(-) (n = 1), IgM(+)/IgG(+)/RNA(-) (n = 1), and IgM(+)/IgG(+)/RNA(+) (n = 1). Thus, the prevalence rates of HEV IgM and HEV RNA were 1.0 and 0.3%. Interestingly, the viremic blood donor harbored a HEV strain that belonged to Genotype 3 (HEV-3) and clustered with a Cambodian riverine HEV-3 isolate.

CONCLUSION

Due to the high frequency of Cambodian blood donors with positive HEV IgG, we conclude that HEV is endemic in this country. Large-scale studies must be considered to determine whether Cambodian blood donation screening is warranted to enhance blood safety in regard to HEV. In addition, our findings suggest that river water may be a significant source of exposure to HEV-3.

Characteristics of 20 Patients with Autochthonous Acute Hepatitis E in Hokkaido, Japan: First Report of Bilateral Facial Palsy Following the Infection with Genotype 4 Hepatitis E Virus

Autochthonous hepatitis E is increasingly being recognized in industrialized countries, including Japan. Although neurological abnormalities have been sporadically reported as an extrahepatic manifestation of hepatitis E virus (HEV) infection, it is rare and has not been reported in Japan. The present study aimed to characterize a total of 20 patients consecutively diagnosed with sporadic acute hepatitis E at a city hospital in Hokkaido, Japan, during 2001-2014, focusing on a patient complicated with neuropathy. Seventeen patients were infected with genotype 4 HEV, while the remaining three patients were with genotype 3 HEV. Although a 67-year-old male with severe hepatitis did not have predisposing factors associated with the development of neurological disorders, such as diabetes mellitus and the use of immunosuppressive agents, he developed bilateral peripheral facial palsy six days after admission. A neurological examination revealed the inability to smile, frown, close his eyes completely or puff out his cheeks. MRI brain scans were considered to be normal. Although it took 83 days after admission for the total bilirubin levels to normalize, his neurological symptoms resolved gradually within three weeks without any sequelae following conservative therapy. A full-length genomic analysis of the HEV strain (HE-JA30) isolated from the patient belonged to genotype 4 and was closest to that currently circulating in Hokkaido, Japan. This is the first report of HEV-associated neuropathy in Japan. While all of previous reports on HEV-related neuropathy involve genotype 3 HEV, the present report is unique in that genotype 4 HEV is responsible for the neuropathy.

Hepatitis E Virus Genotype 3 in Colombia: Survey in Patients with Clinical Diagnosis of Viral Hepatitis

Background

Hepatitis E virus is a major cause of outbreaks as well as sporadic hepatitis cases worldwide. The epidemiology of this enterically transmitted infection differs between developing and developed countries. The aims of this study were to describe HEV infection in Colombian patients and to characterize the genotype.

Methods

A prospective study was carried out on 40 patients aged over 15 with a clinical diagnosis of viral hepatitis, recruited from five primary health units in the city of Medellin, Colombia. Fecal samples obtained from the 40 consecutives cases were analyzed for HEV RNA using nested reverse transcription PCR for both ORF1 and ORF2-3. The amplicons were sequenced for phylogenetic analyses.

Results

Nine (22.5%) cases of HEV infection were identified in the study population. Three HEV strains obtained from patients were classified as genotype 3. No significant association was found between cases of Hepatitis E and the variables water drinking source, garbage collection system and contact with pigs.

Conclusions

This is the first prospective study of hepatitis E in Colombian patients. The circulation of the genotype 3 in this population is predictable considering the reports of the region and the identification of this genotype from pigs in the state of Antioquia, of which Medellin is the capital. Further studies are necessary to establish whether zoonotic transmission of HEV is important in Colombia.

Recent Trend of Hepatitis E Virus Infection in Chiba Area, Japan: 3 of 5 Cases with Rheumatoid Arthritis

Hepatitis E virus (HEV) infection is an emerging health concern in developing and developed countries, such as Japan. Five cases have recently been diagnosed as hepatitis E. Of interest, 3 of them had rheumatoid arthritis (RA), although a previous study demonstrated a lack of association between HEV and RA. One of the other patients developed autoimmune hepatitis and was successfully treated with corticosteroids approximately 150 days after the diagnosis of hepatitis E. In RA patients with liver dysfunction, the presence of HEV infection should be evaluated immediately because these patients are often relatively old. Further investigation of the association between HEV and autoimmune hepatitis is needed.

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(®).

Hepatitis E virus and coliphages in waters proximal to swine concentrated animal feeding operations

North Carolina is the second leading state in pork production in the United States, with over 10 million swine. Swine manure in NC is typically collected and stored in open-pit lagoons before the liquid waste is sprayed onto agricultural fields for disposal. Components of this waste may be able to impact surface water quality with the potential for human exposure. This study examined viruses of public health concern in creeks adjacent to swine concentrated animal feeding operation (CAFO) spray fields. Surface water samples (n=154) were collected from public access waters in proximity to swine CAFO spray fields for six months and were tested for hepatitis E virus (HEV) and coliphages. HEV was detected in one sample. Somatic coliphages were detected in 98% of samples (geometric mean 24 ± 4.1 PFU per 100 ml), and F+ coliphages were detected in 85% of samples (geometric mean 6.8 ± 5.0 PFU per 100 ml). Only 3% (21) of the F+ coliphage isolates were RNA phage, and all of the F+ RNA coliphages belonged to genogroup I. Although the pervasiveness of swine CAFOs in this area prevented a comparison with samples from un-impacted sites, the near ubiquity of coliphages, as well as the presence of HEV, suggests that current waste management practices may be associated with the dissemination of viruses of public health concern in waters proximal to CAFO spray fields.

Genome-wide comparisons of phylogenetic similarities between partial genomic regions and the full-length genome in Hepatitis E virus genotyping

Besides the complete genome, different partial genomic sequences of Hepatitis E virus (HEV) have been used in genotyping studies, making it difficult to compare the results based on them. No commonly agreed partial region for HEV genotyping has been determined. In this study, we used a statistical method to evaluate the phylogenetic performance of each partial genomic sequence from a genome wide, by comparisons of evolutionary distances between genomic regions and the full-length genomes of 101 HEV isolates to identify short genomic regions that can reproduce HEV genotype assignments based on full-length genomes. Several genomic regions, especially one genomic region at the 3'-terminal of the papain-like cysteine protease domain, were detected to have relatively high phylogenetic correlations with the full-length genome. Phylogenetic analyses confirmed the identical performances between these regions and the full-length genome in genotyping, in which the HEV isolates involved could be divided into reasonable genotypes. This analysis may be of value in developing a partial sequence-based consensus classification of HEV species.

Hepatitis E virus genotypes 1 and 3 in wastewater samples in Tunisia

Hepatitis E represents an important public-health concern throughout the world. It is one of the leading causes of hepatitis in North Africa, Asia and the Middle East. In Tunisia, the true burden of HEV infection is still unknown. The objectives of the present study were to assess the occurrence of hepatitis E virus in Tunisia through the monitoring of urban sewage and to characterize the strains identified using molecular assays. A total of 150 sewage samples (raw and treated) were collected from three wastewater treatment plants located in the regions of Monastir and Mahdia and analyzed by nested RT-PCR using a qualitative assay targeting the methyltransferase gene in ORF1. Of these, only three samples (2 %) were found to be positive for HEV, one belonging to genotype 1 and two to genotype 3. The results of the present study indicate a low level of virus excretion among the Tunisian population. Both genotypes 1 and 3 are circulating in this country, however, possibly causing sporadic infections. The presence of the zoonotic genotype 3, known to be transmitted to humans mainly by swine and demonstrated in Tunisia for the first time in this work, raises the question of possible reservoir species, since pork products are not consumed in this country, pigs are not bred, and wild boar is not endemic. Further studies will be needed to gather information on the occurrence and diversity of HEV strains circulating among humans and animals in Tunisia, and on possible animal reservoirs.