EASL Clinical Practice Guidelines on hepatitis E virus infection

Viral hepatitis: A narrative review of hepatitis A–E

Viral hepatitis continues to be a major health concern leading to hepatic decompensation ranging from acute hepatitis to cirrhosis and hepatocellular carcinoma. The hepatic and extrahepatic manifestations are not only debilitating but also associated with a significant economic burden. Over the last two decades, the field of virology has made significant breakthroughs leading to a better understanding of the pathophysiology of viral hepatitis, which in turn has led to new therapeutic options. The advent of direct-acting antiviral agents changed the landscape of hepatitis C virus (HCV) therapy, and new drugs are in the pipeline for chronic hepatitis B virus (HBV) treatment. There has also been a significant emphasis on screening and surveillance programs, widespread availability of vaccines, and linkage of care. Despite these efforts, significant gaps persist in care, and there is a pressing need for increased collaboration and teamwork across the globe to achieve a reduction of disease burden and elimination of HBV and HCV.

The diagnostic and prognostic value of serum exosome-derived carbamoyl phosphate synthase 1 in HEV-related acute liver failure patients

BACKGROUND

Early diagnosis and prognosis evaluation are of great significance to HEV-related acute liver failure (HEV-ALF) patients METHODS: We collected serum samples from 200 health controls (HCs), 200 patients with acute hepatitis E (AHE) and 200 HEV-ALF patients to evaluate serum exosome-derived carbamoyl phosphate synthase 1 (CPS1) levels and determine its diagnostic and prognostic value.

RESULTS

The exosome-derived CPS1 levels in the HEV-ALF group were significantly higher than those in the AHE and HCs groups. The AUC of exosome-derived CPS1 to predict the occurrence of HEV-ALF was 0.850 (0.811-0.883). Both logistical regression and orthogonal partial least squares discriminant analysis (OPLS-DA) showed that exosome-derived CPS1 is independent risk factor for HEV-ALF. The exosome-derived CPS1 levels were positively correlated with organ failure, and the outcomes in HEV-ALF patients. The exosome-derived CPS1 levels in the worsening group were significantly higher than those in the fluctuating and the improving groups. The AUC of serum exosome-derived CPS1 to predict 30-day mortality was 0.829 (0.770-0.879), which was significantly greater than that of the Child-Pugh, KCH, and MELD model.

CONCLUSIONS

The level of serum exosome-derived CPS1 might serve as promising diagnostic and prognostic biomarker for HEV-ALF patients, which may provide better guidance for the diagnosis, prognosis and treatment of HEV-ALF patients. This article is protected by copyright. All rights reserved.

A Less Common Cause of Acute Hepatitis in Kidney Transplant Recipients: A Case Series

BACKGROUND

Hepatitis E virus (HEV) is a cause of significant morbidity and mortality, representing an important global public health problem. Immunocompetent patients with acute hepatitis E can clear the infection spontaneously; however, in approximately two thirds of cases, immunosuppressed patients, such as kidney transplant (KT) recipients, fail to clear the HEV infection and develop chronic hepatitis.

PATIENTS AND METHODS

We report 3 cases of HEV infection in KT patients. Two presented only with laboratory abnormalities and elevated liver enzymes, and 1 presented with symptomatic disease motivating hospital admission. None was able to clear the infection spontaneously, and they were all treated with ribavirin, accompanied with reduction of immunosuppressive drugs. Adverse effects of the treatment were reported in 2 patients, and in 1 case, a dose reduction was necessary. All patients responded to the treatment and have no current evidence of active disease. No alterations of basal kidney function during or related to the treatment were registered.

DISCUSSION

HEV screening in KT patients presenting with abnormal liver function of undetermined cause is fundamental, as it might have poorer outcomes in this specific population. The treatment with ribavirin seems to be safe and effective, although we must always be alert to potential side effects, maintaining a close follow-up of these patients.

Serology versus nucleic acid amplification to diagnose acute hepatitis E, United Kingdom, 2014-18

OBJECTIVES

Diagnosing hepatitis E infection usually involves specific IgM testing, but sensitivity/specificity concerns mean many guidelines and practices include confirmatory tests. We studied whether additional information confirmatory tests provide justifies their use.

METHODS

We examined 9,131 records of anti-hepatitis E IgM assays, 7,615 of IgG assays, and 1,726 of RT-PCR assays from our regional laboratory, spanning October 2014-October 2018. We paired 495 IgM assay results with a RT-PCR result. We examined whether IgM results predicted PCR results, reviewed discrepant pairs, and investigated the correlation between IgG and PCR results in patients with strongly reactive IgM assays.

RESULTS

Anti-hepatitis E IgM titres are bimodal. A high cut-off value optimises prediction of RNA detectability. 7/404 low-IgM samples had detectable RNA, 6 from immunosuppressed patients. 26/91 high-IgM samples did not have detectable RNA. In high-IgM samples, RNA detectability was not associated with IgG titre (one-tailed Mann-Whitney U test, p=0.14).

CONCLUSIONS

In immunocompetent patients, tests beyond IgM seldom add clinically useful information. In patients with immunocompromise, IgM and RNA could contribute information. Additional tests' extra costs/intervention delays cannot be justified. IgM assay cut-offs should reflect titres' bimodal distribution, with values standardised using international units.

Assessment of simple sequence repeats signature in hepatitis E virus (HEV) genomes

Background

Hepatitis E virus (HEV) is small (27–34 nm diameter) non-enveloped with positive sense ssRNA genome. Microsatellites or simple sequence repeats (SSR) are short tandem repeat sequences present across coding and non-coding regions of both prokaryotes and eukaryotes. They are involved with genome function and evolution at multiple levels.

Results

The complete genome sequences of 22 HEV genomes of the family Hepeviridae and genus Orthohepevirus (21 species) and Piscihepevirus (1 species) were extracted from NCBI database (http://www.ncbi.nlm.nih.gov/). The extraction of microsatellites was done using Imperfect Microsatellite Extractor (IMEx) in ‘Advance-Mode’. The average genome size of the studied HEV genomes was 7003nt and it ranged from 6649nt (HEV11) to 7310nt (HEV22). The average GC content of the genomes was ~ 55%. A total of 519 SSRs and 21 cSSRS were extracted from the HEV genomes with an average incidence of 24 per genome ranging from 14 (HEV13) to 34 (HEV19). The cSSR incidence ranged from 0 (eight species) to 4 (HEV19). The genomes with no cSSR incidence had an SSR incidence range from 14 to 28. There were just four hexa-nucleotide repeat motifs and 5 penta-nucleotide repeat motifs observed. The most prevalent mono-, di-, and tri-nucleotide repeat motifs were “C”, “GT/TG”, and “GAC/CTG” respectively. The studied genomes had a minimum of ~ 90% incident SSRs present in the coding regions. Viruses with same or similar hosts are placed together on the phylogenetic tree implicating viral host being one of the driving forces for evolution. Conclusions

Host range in viruses is being decided by multiple factors aided by the unique genome SSR signature and genomes of varied compositions need to be analyzed to forge a widely acceptable rule for predicting the same.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00365-w.

Diagnostic Performance of an Automated System for Assaying Anti-Hepatitis E Virus Immunoglobulins M and G Compared with a Conventional Microplate Assay

To evaluate the diagnostic performance of the Liaison® Murex anti-HEV IgM and IgG assays running on the Liaison® instrument and compare the results with those obtained with Wantai HEV assays. We tested samples collected in immunocompetent and immunocompromised patients during the acute (HEV RNA positive, anti-HEV IgM positive) and the post-viremic phase (HEV RNA negative, anti-HEV IgM positive) of infections. The specificity was assessed by testing HEV RNA negative/anti-HEV IgG-IgM negative samples. The clinical sensitivity of the Liaison® IgM assay was 100% for acute-phase samples (56/56) and 57.4% (27/47) for post-viremic samples from immunocompetent patients. It was 93.8% (30/32) for acute-phase (viremic) samples and 71%% (22/31) for post-viremic samples from immunocompromised patients. The clinical sensitivity of the Liaison® IgG assay was 100% for viremic samples (56/56) and 94.6% (43/47) for post-viremic samples from immunocompetent patients. It was 84.3% (27/32) for viremic samples and 93.5% (29/31) for post-viremic samples from immunocompromised patients. Specificity was very high (>99%) in both populations. We checked the limit of detection stated for the Liaison® IgG assay (0.3 U/mL). The clinical performance of the Liaison® ANTI-HEV assays was good. These rapid, automated assays for detecting anti-HEV antibodies will greatly enhance the arsenal for diagnosing HEV infections.

Hepatitis E virus is highly resistant to alcohol-based disinfectants

BACKGROUND & AIMS

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide and is mainly transmitted via the fecal-oral route or through consumption of contaminated food products. Due to the lack of efficient cell culture systems for the propagation of HEV, limited data regarding its sensitivity to chemical disinfectants are available. Consequently, preventive and evidence-based hygienic guidelines on HEV disinfection are lacking.

METHODS

We used a robust HEV genotype 3 cell culture model which enables quantification of viral infection of quasi-enveloped and naked HEV particles. For HEV genotype 1 infections, we used the primary isolate Sar55 in a fecal suspension. Standardized quantitative suspension tests using end point dilution and large-volume plating were performed for the determination of virucidal activity of alcohols (1-propanol, 2-propanol, ethanol), WHO disinfectant formulations and 5 different commercial hand disinfectants against HEV. Iodixanol gradients were conducted to elucidate the influence of ethanol on quasi-enveloped viral particles.

RESULTS

Naked and quasi-enveloped HEV was resistant to alcohols as well as alcohol-based formulations recommended by the WHO. Of the tested commercial hand disinfectants only 1 product displayed virucidal activity against HEV. This activity could be linked to phosphoric acid as an essential ingredient. Finally, we observed that ethanol and possibly non-active alcohol-based disinfectants disrupt the quasi-envelope structure of HEV particles, while leaving the highly transmissible and infectious naked virions intact.

CONCLUSIONS

Different alcohols and alcohol-based hand disinfectants were insufficient to eliminate HEV infectivity with the exception of 1 commercial ethanol-based product that included phosphoric acid. These findings have major implications for the development of measures to reduce viral transmission in clinical practice.

LAY SUMMARY

Hepatitis E virus (HEV) showed a high level of resistance to alcohols and alcohol-based hand disinfectants. The addition of phosphoric acid to alcohol was essential for virucidal activity against HEV. This information should be used to guide improved hygiene measures for the prevention of HEV transmission.

Renal manifestations of hepatitis E among immunocompetent and solid organ transplant recipients

Hepatitis E virus (HEV) infections are generally self-limited. Rare cases of hepatitis E induced fulminant liver failure requiring liver transplantation are reported in the literature. Even though HEV infection is generally encountered among developing countries, a recent uptrend is reported in developed countries. Consumption of unprocessed meat and zoonosis are considered to be the likely transmission modalities in developed countries. Renal involvement of HEV generally holds a benign and self-limited course. Although rare cases of cryoglobulinemia are reported in immunocompetent patients, glomerular manifestations of HEV infection are frequently encountered in immunocompromised and solid organ transplant recipients. The spectrum of renal manifestations of HEV infection include pre-renal failure, glomerular disorders, tubular and interstitial injury. Kidney biopsy is the gold standard diagnostic test that confirms the pattern of injury. Management predominantly includes conservative approach. Reduction of immunosuppressive medications and ribavirin (for 3-6 mo) is considered among patients with solid organ transplants. Here we review the clinical course, pathogenesis, renal manifestations, and management of HEV among immunocompetent and solid organ transplant recipients.

Epidemiological Characteristics and Clinical Manifestations of Hepatitis E in a Tertiary Hospital in China: A Retrospective Study

Background

Hepatitis E virus (HEV) infection is the most common cause of acute viral hepatitis worldwide and one of the main causes of death in the last decade, causing chronic hepatitis and liver failure in some populations. The aging population and obesity are two major factors threatening human health. Therefore, we want to understand the relationship between these two groups and HEV infection.

Objectives

The study aimed to analyze the epidemiological, clinical, and laboratory features of HEV infection and evaluate probable high-risk factors for disease progression and the current diagnostic strategies of hepatitis E infection.

Study Design

Patients diagnosed with acute hepatitis E with symptoms and liver dysfunction were enrolled. For statistical analysis, clinical features and laboratory findings were collected between the elderly and non-elderly and HEV+ fatty liver disease (FLD) groups. Statistical analysis was performed using Excel and the platform VassarStats, and statistical significance was taken as P < 0.05.

Results

Jaundice and the bilirubin peak were significantly deeper, the duration of hospitalization was significantly longer, and the proportion of ascites and liver failure was significantly higher in the elderly group. The aging population is one of the risk factors of severe hepatitis E. Hepatitis E becomes more serious in the HEV + FLD group, although the results did not reach statistical significance.

Conclusion

The aging and FLD were suggested to aggravate HEV infection. However, the diagnosis of HEV infection remains a challenge. A prospective study with sufficient sample size is needed to confirm this conclusion.

Viral Interference of Hepatitis C and E Virus Replication in Novel Experimental Co-Infection Systems

Background: Hepatitis C virus (HCV) constitutes a global health problem, while hepatitis E virus (HEV) is the major cause of acute viral hepatitis globally. HCV/HEV co-infections have been poorly characterized, as they are hampered by the lack of robust HEV cell culture systems. This study developed experimental models to study HCV/HEV co-infections and investigate viral interference in cells and humanized mice. Methods: We used state-of-the art human hepatocytes tissue culture models to assess HEV and HCV replication in co- or super-transfection settings. Findings were confirmed by co- and super-infection experiments in human hepatocytes and in vivo in human liver chimeric mice. Results: HEV was inhibited by concurrent HCV replication in human hepatocytes. This exclusion phenotype was linked to the protease activity of HCV. These findings were corroborated by the fact that in HEV on HCV super-infected mice, HEV viral loads were reduced in individual mice. Similarly, HCV on HEV super-infected mice showed reduced HCV viral loads. Conclusion: Direct interference of both viruses with HCV NS3/4A as the determinant was observed. In vivo, we detected reduced replication of both viruses after super-infection in individual mice. These findings provide new insights into the pathogenesis of HCV-HEV co-infections and should contribute to its clinical management in the future.

Distribution and phylogenetics of hepatitis E virus genotype 4 in humans and animals

BACKGROUND

Worldwide, hepatitis E virus (HEV) infection is considered a significant public health concern. In particular, HEV genotype 4 (HEV-4) has spread to more areas and host species. In this study, we describe the global distribution of HEV-4 and characterize HEV-4 subtypes by host, country and year of isolation.

METHODS

We retrospectively collected HEV-4 sequences available before December 31, 2019, in GenBank. HEV-4 and its subtypes were determined using phylogenetic comparison with HEV reference sequences. Information on the isolation of the sequences was extracted from the GenBank or original publications. Temporal, spatial and host characteristics of the sequences were summarized and nucleotide similarity was calculated based on five amplified fragments within HEV genome, stratified by host, country and year.

RESULTS

A total of 2295 HEV-4 complete and partial nucleotide sequences were studied. The majority (92.7%) was isolated in China's mainland, Japan, Hong Kong and France. A total of 20 animal hosts were documented, though swine remained predominant (71.7%). Globally, prevalent HEV-4 subtypes changed remarkably over the last 18 years. Subtypes 4a, 4b, 4d and 4h were most commonly isolated (80.3%). Subtypes 4c, 4e, 4f, 4g and 4i remained limited in temporal distribution. High nucleotide similarities were observed between the sequences amplified in HEV ORF2, in the same and neighbouring countries, and in similar animal hosts.

CONCLUSION

China and Japan are endemic for HEV-4, and have all the subtypes. In Europe, France has a high prevalence of HEV-4. Increases in affected areas and animal hosts imply consistent cross-border and cross-species transmission.

High dose sofosbuvir and sofosbuvir-plus-ribavirin therapy inhibit Hepatitis E Virus (HEV) replication in a rabbit model for acute HEV infection

Hepatitis E virus (HEV) is an important cause of viral hepatitis worldwide and there is currently no FDA-approved anti-HEV drug. The commonly used drug ribavirin (RBV) could not achieve viral clearance in all patients and can induce drug resistance. Recent studies showed sofosbuvir (SOF) can inhibit HEV replication in vitro and has add-on effect when combined with RBV, but the effect of SOF against HEV infection remains controversial and the dosage of SOF warrants further exploration. In this study, a rabbit model for acute HEV infection was used to evaluate the effect of SOF at different doses against HEV genotype 3 and 4, and to compare the antiviral effect of SOF-plus-RBV therapy with RBV monotherapy. Virological parameters on fecal, serological and intrahepatic level were tested by real-time PCR and ELISA. Liver function tests and histopathological assays were performed. Both 200 mg/d and 300 mg/d SOF treatment inhibits HEV replication with relieved liver inflammation and declined levels of fecal HEV RNA, viremia and antigenemia. 300 mg/d SOF eliminated HEV replication while a short viral rebound was observed after 200 mg/d SOF treatment. The SOF-plus-RBV therapy also showed stronger anti-HEV effect than RBV monotherapy. Our study suggests that high dose of SOF showed better anti-HEV effect in the rabbit model. Moreover, the de novo SOF-plus-RBV therapy which eliminated acute HEV infection more efficiently than RBV monotherapy may serve as an alternative treatment strategy.

Nosocomial transmission of hepatitis E virus and development of chronic infection: The wider impact of COVID-19

Background

Transmission of hepatitis E virus (HEV) within the healthcare setting is extremely rare. Additionally, the development of chronic HEV infection in association with severe acute respiratory syndrome coronavirus disease 2 (SARS-CoV-2) infection and/or its immunomodulatory therapy has not been reported previously.

Aims

To describe the investigation and management of a nosocomial HEV transmission incident during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Epidemiological and molecular investigation of two individuals hospitalised with COVID-19 who were both diagnosed with HEV infection.

Results

Findings from our investigation were consistent with transmission of HEV from one patient with a community-acquired HEV infection to another individual (identical HEV sequences were identified in the two patients), most likely due to a breach in infection control practices whilst both patients shared a bed space on the intensive care unit (ICU). Chronic HEV infection requiring treatment with ribavirin developed in one patient with prolonged lymphopaenia attributable to COVID-19 and/or the immunomodulators received for its treatment. Further investigation did not identify transmission of HEV to any other patients or to healthcare workers.

Conclusions

The extraordinary demands that the COVID-19 pandemic has placed on all aspects of healthcare, particularly within ICU settings, has greatly challenged the ability to consistently maintain optimal infection prevention and control practices. Under the significant pressures of the COVID-19 pandemic a highly unusual nosocomial HEV transmission incident occurred complicated further by progression to a chronic HEV infection in one patient.

Rational development and application of biomarkers in the field of autoimmunity: A conceptual framework guiding clinicians and researchers

Clear guidance is needed in the development and implementation of laboratory biomarkers in medicine. So far, no standardized phased approach is established that would pilot researchers and clinicians in this process. This leads to often incompletely validated biomarkers, which can bear the consequence of wrong applications, misinterpretation and inadequate management in the clinical context.

In this conceptual article, we describe a stepwise approach to develop and comprehensively validate laboratory biomarkers. We will delineate basic steps including technical performance, pre-analytical issues, and biological variation, as well as advanced aspects of biomarker utility comprising interpretability, diagnostic and prognostic accuracy, and health-care outcomes. These aspects will be illustrated by using well-known examples from the field of immunology.

The application of this conceptual framework will guide researchers in conducting meaningful projects to develop and evaluate biomarkers for the use in clinical practice. Furthermore, clinicians will be able to adequately interpret pre-clinical and clinical diagnostic literature and rationally apply biomarkers in clinical practice. Improvement in the implementation and application of biomarkers might relevantly change the management and outcomes of our patients for the better.

Study of Hepatitis E Virus-4 Infection in Human Liver-Chimeric, Immunodeficient, and Immunocompetent Mice

The hepatitis E virus (HEV) is responsible for 20 million infections worldwide per year. Although, HEV infection is mostly self-limiting, immunocompromised individuals may evolve toward chronicity. The lack of an efficient small animal model has hampered the study of HEV and the discovery of anti-HEV therapies. Furthermore, new HEV strains, infectious to humans, are being discovered. Human liver-chimeric mice have greatly aided in the understanding of HEV, but only two genotypes (HEV-1 and HEV-3) have been studied in this model. Moreover, the immunodeficient nature of this mouse model does not allow full investigation of the virus and all aspects of its interaction with the host. Recent studies have shown the susceptibility of regular and nude Balb/c mice to a HEV-4 strain (KM01). This model should allow the investigation of the interplay between HEV and the adaptive immune system of its host, and potential immune-mediated complications. Here, we assess the susceptibility of human liver-chimeric and non-humanised mice to a different HEV-4 strain (BeSW67HEV4-2008). We report that humanised mice could be readily infected with this isolate, resulting in an infection pattern comparable to HEV-3 infection. Despite these results and in contrast to KM01, non-humanised mice were not susceptible to infection with this viral strain. Further investigation, using other HEV-4 isolates, is needed to conclusively determine HEV-4 tropism and mouse susceptibility.

Response to the Letter to the Editor in response to "Hepatitis E virus and Bell's palsy"

In a comment to our recently published article investigating the frequency of Hepatitis E Virus (HEV) infection in patients with Bell's palsy two important questions have been raised with regards to the timeline of inclusion and with regards to the definition of the infection status. In this Letter to the Editor we would like to comment on these.

Advanced sequencing approaches detected insertions of viral and human origin in the viral genome of chronic hepatitis E virus patients

The awareness of hepatitis E virus (HEV) increased significantly in the last decade due to its unexpectedly high prevalence in high-income countries. There, infections with HEV-genotype 3 (HEV-3) are predominant which can progress to chronicity in immunocompromised individuals. Persistent infection and antiviral therapy can select HEV-3 variants; however, the spectrum and occurrence of HEV-3 variants is underreported. To gain in-depth insights into the viral population and to perform detailed characterization of viral genomes, we used a new approach combining long-range PCR with next-generation and third-generation sequencing which allowed near full-length sequencing of HEV-3 genomes. Furthermore, we developed a targeted ultra-deep sequencing approach to assess the dynamics of clinically relevant mutations in the RdRp-region and to detect insertions in the HVR-domain in the HEV genomes. Using this new approach, we not only identified several insertions of human (AHNAK, RPL18) and viral origin (RdRp-derived) in the HVR-region isolated from an exemplary sample but detected a variant containing two different insertions simultaneously (AHNAK- and RdRp-derived). This finding is the first HEV-variant recognized as such showing various insertions in the HVR-domain. Thus, this molecular approach will add incrementally to our current knowledge of the HEV-genome organization and pathogenesis in chronic hepatitis E.

Drug-induced liver injury: A management position paper from the Latin American Association for Study of the liver

Idiosyncratic drug-induced liver injury (DILI) caused by xenobiotics (drugs, herbals and dietary supplements) is an uncommon cause of liver disease presenting with a wide range of phenotypes and disease severity, acute hepatitis mimicking viral hepatitis to autoimmune hepatitis, steatosis, fibrosis or rare chronic vascular syndromes. Disease severity ranges from asymptomatic liver test abnormalities to acute liver failure. DILI has been traditionally classified in predictable or intrinsic (dose-related) or unpredictable (not dose-related) mechanisms. Few prospective studies are assessing the real prevalence and incidence of hepatotoxicity in the general population. DILI registries represent useful networks used for the study of liver toxicity, aimed at improving the understanding of causes, phenotypes, natural history, and standardized definitions of hepatotoxicity. Although most of the registries do not carry out population-based studies, they may provide important data related to the prevalence of DILI, and also may be useful to compare features from different countries. With the support of the Spanish Registry of Hepatotoxicity, our Latin American Registry (LATINDILI) was created in 2011, and more than 350 DILI patients have been recruited to date. This position paper describes the more frequent drugs and herbs-induced DILI in Latin America, mainly focusing on several features of responsible medicaments. Also, we highlighted the most critical points on the management of hepatotoxicity in general and those based on findings from our Latin American experience in particular.

Development of recombinant infectious hepatitis E virus harboring the nanoKAZ gene and its application in drug screening

Hepatitis E virus (HEV) is a quasi-enveloped virus with a single-stranded positive-sense RNA genome belonging to family Hepeviridae. Studies on molecular aspects of HEV and drug screening have benefited from the discovery of bioluminescent reporter genes. However, the stability of large foreign genes is difficult to maintain after insertion into the viral genome. Currently, ribavirin is used to treat HEV-infected patients who require antiviral therapy. This has several major drawbacks. Thus, the development of novel anti-HEV drugs is of great importance. We developed a system consisting of recombinant infectious HEV harboring small luciferase gene (nanoKAZ) in the hypervariable region (HVR) of the open reading frame 1 (ORF1) (HEV-nanoKAZ). It replicated efficiently in cultured cells, was genetically stable, and had morphological characteristics similar to the parental virus. Both membrane-associated (eHEV-nanoKAZ) and membrane-unassociated (neHEV-nanoKAZ) particles were infectious. HEV particles circulating in the blood stream and attaching to hepatocytes in HEV-infected patients are membrane-associated, thus, eHEV-nanoKAZ was applied in drug screening. The eHEV-nanoKAZ system is able to cover at least the inhibitor of HEV entry and inhibitor of HEV RNA replication. Four drugs with anti-HEV activity were identified. Their effectiveness in cultured cells was confirmed in naïve and HEV-producing PLC/PRF/5 cells. Two hit drugs (azithromycin and ritonavir) strongly inhibited HEV production in culture supernatants, as well as intracellular expression of ORF2 protein, and may therefore be candidate novel anti-HEV drugs. The HEV-nanoKAZ system was developed and applied in drug screening, and is expected to be useful for investigating the HEV life cycle. IMPORTANCE Bioluminescent reporter viruses are essential tools in molecular virological research. It has been widely used to investigate viral life cycles and in the development of antiviral drugs. For drug screening, the use of a bioluminescent reporter virus helps shorten the time required to perform the assay. A system, consisting of recombinant infectious HEV harboring the nanoKAZ gene in the HVR of ORF1 (HEV-nanoKAZ), was developed in this study, and was successfully applied to drug screening in which four hit drugs with anti-HEV activity were identified. The results of this study provide evidence supporting the use of this system in more variable HEV studies. In addition, both forms of viral particles (eHEV-nanoKAZ and neHEV-nanoKAZ) are infectious, which will enable their application in HEV studies requiring both forms of viral particles, such as in the investigation of unknown HEV receptors and the elucidation of host factors important for HEV entry.

[Vaccines against hepatitis E virus: state of development]

In Europa ist aktuell kein Impfstoff gegen das Hepatitis-E-Virus (HEV) zugelassen. Demgegenüber steht in China bereits seit 10 Jahren mit HEV-239 (Hecolin®, Xiamen Innovax Biotech Co., Xiamen, China) ein Vakzin gegen den HEV-Genotyp 4 zur Verfügung. Herausforderungen für die Entwicklung von Impfstoffen ergeben sich v. a. aus den Unterschieden zwischen den Genotypen bezüglich Verbreitung, Übertragungswege und Risikogruppen. Weitere Hindernisse sind die Umhüllung von HEV im Blut durch Wirtsmembranen, die Replikation in verschiedenen Organen außerhalb der Leber sowie schwächere Immunantworten in vulnerablen Gruppen. In diesem Artikel wird der aktuelle Stand der verfügbaren und in fortgeschrittener präklinischer Evaluation befindlichen Vakzine gegen HEV mit Fokus auf Strategien der Impfstoffentwicklung dargestellt. Herausforderungen und Limitationen werden beschrieben.

Aktuelle Impfkandidaten fokussieren auf proteinbasierte Immunisierungen mit dem Ziel der Induktion von schützenden, neutralisierenden Antikörperantworten. Das Ziel der HEV-239-Zulassungsstudie mit mehr als 100.000 Studienteilnehmern war die Verhinderung von akuten symptomatischen Infektionen. Es ist jedoch unklar, inwieweit asymptomatische Infektionen durch das Vakzin verhindert wurden und ob es in Risikopatienten für einen komplizierten Verlauf, wie Patienten mit Leberzirrhose, Immunsupprimierten und Schwangeren, effektiv genug wirkt. Effiziente In-vitro-Modelle ermöglichen zunehmend die Entwicklung von monoklonalen neutralisierenden Antikörpern zur passiven Immunisierung oder Therapie.

Zukünftige Vakzine sollten neben einem sehr guten Sicherheitsprofil eine eindeutige Protektion gegenüber allen Genotypen demonstrieren. Die Entwicklung einer effizienten passiven Immunisierungsstrategie, insbesondere für immunsupprimierte Personen, ist wünschenswert.

Viral hepatitis in 2021: The challenges remaining and how we should tackle them

Viral hepatitis results in 1.4 million deaths annually. The World Health Organization (WHO) set an ambitious target to eliminate viral hepatitis by 2030, but significant challenges remain. These include inequalities in access to healthcare, reaching at risk populations and providing access to screening and effective treatment. Stigma around viral hepatitis persists and must be addressed. The WHO goal of global elimination by 2030 is a worthy aim, but remains ambitious and the coronavirus 2019 pandemic undoubtedly has set back progress. This review article will focus on hepatitis A to E, highlighting problems that have been resolved in the field over the past decade, those that remain to be resolved and suggest directions for future problem solving and research.

Hepatocellular Carcinoma in Chronic Viral Hepatitis: Where Do We Stand?

Hepatocellular carcinoma (HCC) is one of the major causes of cancer-related death. Although the burden of alcohol- and NASH-related HCC is growing, chronic viral hepatitis (HBV and HCV) remains a major cause of HCC development worldwide. The pathophysiology of viral-related HCC includes liver inflammation, oxidative stress, and deregulation of cell signaling pathways. HBV is particularly oncogenic because, contrary to HCV, integrates in the cell DNA and persists despite virological suppression by nucleotide analogues. Surveillance by six-month ultrasound is recommended in patients with cirrhosis and in "high-risk" patients with chronic HBV infection. Antiviral therapy reduces the risks of development and recurrence of HCC; however, patients with advanced chronic liver disease remain at risk of HCC despite virological suppression/cure and should therefore continue surveillance. Multiple scores have been developed in patients with chronic hepatitis B to predict the risk of HCC development and may be used to stratify individual patient's risk. In patients with HCV-related liver disease who achieve sustained virological response by direct acting antivirals, there is a strong need for markers/scores to predict long-term risk of HCC. In this review, we discuss the most recent advances regarding viral-related HCC.

Effect of Hepatitis E Virus RNA Universal Blood Donor Screening, Catalonia, Spain, 2017‒2020

Hepatitis E virus (HEV) is the major cause of acute viral hepatitis in several countries in Europe. HEV is acquired mainly by consumption of contaminated pork but can also be transmitted through blood transfusion. HEV infection is usually self-limited but can become persistent in immunocompromised persons. During the first 30 months of HEV RNA universal screening of blood donations in Catalonia, Spain, we identified 151 HEV RNA-positive donations (1/4,341 blood donations). Most infected donors reported consumption of pates and sausages, and 58% were negative for HEV IgM and IgG. All HEV isolates belonged to genotype 3. All infected donors spontaneously resolved the infection, and no neurologic symptoms and reinfections were observed after 1 year of follow-up. Since the implementation of HEV RNA universal screening, no new cases of transfusion-transmitted HEV infection were reported. Our data indicate HEV screening of blood donations provides safer blood for all recipients, especially for immunosuppressed persons.

Hepatitis E virus RNA-dependent RNA polymerase is involved in RNA replication and infectious particle production

BACKGROUND AND AIMS

Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis worldwide. Its positive-strand RNA genome encodes three open reading frames (ORF). ORF1 is translated into a large protein composed of multiple domains and is known as the viral replicase. The RNA-dependent RNA polymerase (RDRP) domain is responsible for the synthesis of viral RNA.

APPROACH AND RESULTS

Here, we identified a highly conserved α-helix located in the RDRP thumb subdomain. Nuclear magnetic resonance demonstrated an amphipathic α-helix extending from amino acids 1628 to 1644 of the ORF1 protein. Functional analyses revealed a dual role of this helix in HEV RNA replication and virus production, including assembly and release. Mutations on the hydrophobic side of the amphipathic α-helix impaired RNA replication and resulted in the selection of a second-site compensatory change in the RDRP palm subdomain. Other mutations enhanced RNA replication but impaired virus assembly and/or release.

CONCLUSIONS

Structure-function analyses identified a conserved amphipathic α-helix in the thumb subdomain of the HEV RDRP with a dual role in viral RNA replication and infectious particle production. This study provides structural insights into a key segment of the ORF1 protein and describes the successful use of reverse genetics in HEV, revealing functional interactions between the RDRP thumb and palm subdomains. On a broader scale, it demonstrates that the HEV replicase, similar to those of other positive-strand RNA viruses, is also involved in virus production.

Sofosbuvir in the Treatment of Hepatitis E virus Infection: A Review of in vitro and in vivo Evidence

Chronic hepatitis E virus (HEV) infection, which occurs almost exclusively in immunocompromised patients, if untreated may progress to cirrhosis and possibly hepatocellular carcinoma. The reduction of immunosuppression and/or administration of ribavirin is frequently curative but there remain many immunocompromised individuals whose HEV infection is refractory to these therapeutic strategies. Moreover, the haematological toxicity of ribavirin limits its use. Pegylated interferon has demonstrated success in a small number of patients with chronic HEV infection; however, the potentially increased risk of graft rejection associated with its use renders it unsuitable for many transplant recipients. Alternative therapeutic strategies are therefore required. This article reviews the in vitro and in vivo literature to date of the antiviral agent sofosbuvir (well established in the treatment of hepatitis C) in the treatment of HEV infection.

Hepatitis E virus infection activates NOD-like receptor family pyrin domain-containing 3 inflammasome antagonizing interferon response but therapeutically targetable

BACKGROUND AND AIMS

HEV infection is the most common cause of liver inflammation, but the pathogenic mechanisms remain largely unclear. We aim to explore whether HEV infection activates inflammasomes, crosstalk with antiviral interferon response, and the potential of therapeutic targeting.

APPROACH AND RESULTS

We measured IL-1β secretion, the hallmark of inflammasome activation, in serum of HEV-infected patients and rabbits, and in cultured macrophage cell lines and primary monocyte-derived macrophages. We found that genotypes 3 and 4 HEV infection in rabbits elevated IL-1β production. A profound increase of IL-1β secretion was further observed in HEV-infected patients (1,733 ± 1,234 pg/mL; n = 70) compared to healthy persons (731 ± 701 pg/mL; n = 70). Given that macrophages are the drivers of inflammatory response, we found that inoculation with infectious HEV particles robustly triggered NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation in primary macrophages and macrophage cell lines. We further revealed that the ORF2 capsid protein and the formed integral viral particles are responsible for activating inflammasome response. We also identified NF-κB signaling activation as a key upstream event of HEV-induced NLRP3 inflammasome response. Interestingly, inflammasome activation antagonizes interferon response to facilitate viral replication in macrophages. Pharmacological inhibitors and clinically used steroids can effectively target inflammasome activation. Combining steroids with ribavirin simultaneously inhibits HEV and inflammasome response without cross-interference.

CONCLUSIONS

HEV infection strongly activates NLRP3 inflammasome activation in macrophages, which regulates host innate defense and pathogenesis. Therapeutic targeting of NLRP3, in particular when combined with antiviral agents, represents a viable option for treating severe HEV infection.

Nationwide survey of hepatitis E virus infection among wildlife in Japan

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

Zoonotic transmission of hepatitis E virus in a pig farmer from Argentina: A case report

Hepatitis E virus (HEV) is a public health concern due to its zoonotic transmission to human, being pigs a highly recognized reservoir. We previously demonstrated HEV genotype 3 infections in pig herds from the highest commercial active region from Argentina. Here, we present a case of acute symptomatic hepatitis E in an elderly man with occupational exposure to pigs who referred regular consumption of pork and sausages. HEV infection in this patient was demonstrated by serological methods, as well as by HEV RNA detection in serum and stool samples using the HEV/MS2 duplex RT-qPCR, formerly optimized in our laboratory. We further detected HEV RNA in pig faeces from the patient´s farm. To confirm the potential role of swine in the transmission, we performed a phylogenetic analysis of all HEV RNA derived from both, the patient and the pig samples. A 303 nt region within the HEV 5 'ORF2 was amplified by nested RT-PCR and subsequently sequenced. Phylogenetic analysis showed that the strains isolated from the farmer and from his pigs presented a nucleotide identity of 100%. These results support the zoonotic transmission of circulating HEV strains and confirm this epidemiological association for the first time in Argentina.

Present and future management of viral hepatitis

Viral hepatitis can result in important morbidity and mortality, with its impact on health conditioned by the specific type of hepatitis, the geographical region of presentation and the development and access to new drugs, among other factors. Most acute presentation forms are self-limiting and may even go unnoticed, with just a small percentage of cases leading to acute liver failure that may necessitate transplantation or even cause the death of the patient. However, when they become chronic, as in the case of hepatitis B virus and C virus, unless they are diagnosed and treated adequately they may have severe consequences, like cirrhosis or hepatocarcinoma. Understanding of the mechanisms of transmission, the pathogenesis, the presence of vaccinations and the development over recent years of new highly-efficient, potent drugs have meant that we are now faced with a new scenario in the management of viral hepatitis, particularly hepatitis B virus and hepatitis C virus. The spectacular advances in hepatitis C virus treatment have led the World Health Organization to propose the objective of its eradication by 2030. The key aspect to achieving this goal is to ensure that these treatments reach all the more vulnerable population groups, in whom the different types of viral hepatitis have a high prevalence and constitute a niche that may perpetuate infection and hinder its eradication. Accordingly, micro-elimination programs assume special relevance at the present time.

Hepatitis E Virus Infection: Neurological Manifestations and Pathophysiology

Hepatitis E virus (HEV) is the first cause of viral hepatitis in the world. While the water-borne HEV genotypes 1 and 2 are found in developing countries, HEV genotypes 3 and 4 are endemic in developed countries due to the existence of animal reservoirs, especially swine. An HEV infection produces many extra-hepatic manifestations in addition to liver symptoms, especially neurological disorders. The most common are neuralgic amyotrophy or Parsonage–Turner syndrome, Guillain–Barré syndrome, myelitis, and encephalitis. The pathophysiology of the neurological injuries due to HEV remains uncertain. The immune response to the virus probably plays a role, but direct virus neurotropism could also contribute to the pathophysiology. This review describes the main neurological manifestations and their possible pathogenic mechanisms.

Treatment induced clearance of hepatitis E viruses by interferon-lambda in liver-humanized mice

BACKGROUND

Hepatitis E viruses (HEV) are an underestimated global cause of enterically transmitted viral hepatitis, which may persist in immunocompromised hosts, posing a risk for progressive liver fibrosis with limited treatment options. We previously established liver-humanized mice as a model for chronic HEV infections, which can be cleared by a 2-week pegylated (peg)-Interferon(IFN)α treatment course. However, severe side effects may hamper the use of IFNα in immunocompromised transplant recipient patients. IFNλ may be a valuable alternative, as its receptor is less ubiquitously expressed.

AIMS

In this study, we assess the in vitro and in vivo potency of pegIFNλ to induce innate immune signalling in liver cells and to clear a persistent HEV infection in liver-humanized mice.

METHODS & RESULTS

We found that human liver cells expressed the IFNλ receptor (IFNLR1) and are responsive to pegIFNλ. Treatment with pegIFNλ of liver-humanized mice persistently infected with HEV genotype 3 showed that pegIFNλ was well tolerated. Dose escalation studies showed that although HEV was not cleared at pegIFNλ doses up to 0.12 mg/kg for a maximum of 8 weeks, a dose of 0.3 mg/kg pegIFNλ treatment resulted in complete clearance of HEV antigen and HEV RNA from the liver in 8 out of 9 liver-humanized mice.

CONCLUSIONS

PegIFNλ is well tolerated in mice and leads to clearance of a persistent HEV infection in liver-humanized mice.

Beyond the Usual Suspects: Hepatitis E Virus and Its Implications in Hepatocellular Carcinoma

Hepatitis E virus infections are the leading cause of viral hepatitis in humans, contributing to an estimated 3.3 million symptomatic cases and almost 44,000 deaths annually. Recently, HEV infections have been found to result in chronic liver infection and cirrhosis in severely immunocompromised patients, suggesting the possibility of HEV-induced hepatocarcinogenesis. While HEV-associated formation of HCC has rarely been reported, the expansion of HEV's clinical spectrum and the increasing evidence of chronic HEV infections raise questions about the connection between HEV and HCC. The present review summarizes current clinical evidence of the relationship between HEV and HCC and discusses mechanisms of virus-induced HCC development with regard to HEV pathogenesis. We further elucidate why the development of HEV-induced hepatocellular carcinoma has so rarely been observed and provide an outlook on possible experimental set-ups to study the relationship between HEV and HCC formation.

Clinical features of sporadic hepatitis E virus infection in pregnant women in Shanghai, China

OBJECTIVES

Hepatitis E virus (HEV) infection causes high mortality in pregnant women of developing regions during large outbreaks. The aim of this study was to investigate the clinical features of HEV-infected pregnant women in Shanghai, China where the epidemiology of HEV has shifted from large outbreaks to the sporadic form.

METHODS

Clinical data of 516 pregnant and nonpregnant child-bearing age women diagnosed with HEV infection during 2009-2020 was collected at the Shanghai Public Health Clinical center. Patients' data were analysed for clinical features and laboratory parameters accordingly.

RESULTS

Most of the hospitalized HEV-infected pregnant women (85.23%, 127/149) showed no obvious clinical symptoms and the disease outcome was generally benign with no liver failure or maternal mortality observed in the patients. By comparison, fewer (37.21%, 32/86) of the HEV-infected nonpregnant women were asymptomatic, and five cases (5.81%, 5/86) of liver failure were observed among them. The levels of serum alanine aminotransferase, aspartate aminotransferase, total bilirubin (TBiL), direct bilirubin (DBiL) and total bile acids (TBA) were significantly higher (P < 0.05) in nonpregnant women than those of the pregnant women. We found 42.99% (46/107) births had adverse foetal/neonatal outcome. Mothers who presented with adverse foetal/neonatal outcome showed higher (P < 0.05) serum TBiL, DBiL and TBA levels than those without.

CONCLUSION

We found that the clinical features of sporadic HEV infection in pregnant women in Shanghai, China are generally mild and no maternal mortality occurred. However foetal/neonatal adverse outcomes including preterm births and stillbirths were observed in HEV-infected pregnant women.

Hepatitis E virus and Bell's palsy

BACKGROUND AND PURPOSE

Acute hepatitis E virus (HEV) infections have been associated with various neurological disorders, including individual cases with Bell's palsy. Nonetheless, systematic studies in the latter are lacking. Therefore, this retrospective study systematically screened a cohort of patients with Bell's palsy for an acute HEV infection.

METHODS

Overall, 104 patients with Bell's palsy treated in our clinic between 2008 and 2018 were identified. Serum samples were analyzed for anti-HEV immunoglobulin (Ig)M and IgG antibodies by enzyme-linked immunosorbent assay. Additionally, serum samples were tested for HEV RNA by polymerase chain reaction in 92 of these 104 patients presenting within the first 7 days from symptom onset. A large group of 263 healthy individuals served as controls.

RESULTS

None of the patients with Bell's palsy but two healthy controls (0.8%) had an acute HEV infection. Anti-HEV IgG seroprevalence indicating previous infection was unexpectedly high in patients with Bell's palsy (34%) and revealed an age-dependent increase.

CONCLUSIONS

In this first systematic study, no cases of Bell's palsy in association with an acute HEV infection were identified. However, based on previous case descriptions, rare associations cannot be excluded. Therefore, large prospective multicenter studies will be necessary for conclusions that are more definitive.

An RNA Interference/Adeno-Associated Virus Vector-Based Combinatorial Gene Therapy Approach Against Hepatitis E Virus

Hepatitis E virus (HEV) is a major public health problem with limited therapeutic options. Here, we engineered adeno-associated viral vectors of serotype 6 (AAV6) to express short hairpin RNAs (shRNAs) against HEV transcripts with the prospect of down-regulating HEV replication in vivo. We designed 20 different shRNAs, targeting the genome of the HEV genotype 3 (GT3) Kernow-C1 p6 strain, for delivery upon AAV6 transduction. Using an original selectable HEV GT3 reporter replicon, we identified three shRNAs that efficiently down-regulated HEV replication. We further confirmed their inhibitory potency with full-length HEV infection. Seventy-two hours following transduction, HEV replication in both systems decreased by up to 95%. The three most potent inhibitory shRNAs identified were directed against the methyltransferase domain, the junction region between the open reading frames (ORFs), and the 3´ end of ORF2. Targeting all three regions by multiplexing the shRNAs further enhanced their inhibitory potency over a prolonged period of up to 21 days following transduction. Conclusion: Combining RNA interference and AAV vector-based gene therapy has great potential for suppressing HEV replication. Our strategy to target the viral RNA with multiplexed shRNAs should help to counteract viral escape through mutations. Considering the widely documented safety of AAV vector-based gene therapies, our approach is, in principle, amenable to clinical translation.

Hepatitis E virus species C infection in humans, Hong Kong

BACKGROUND

Hepatitis E virus (HEV) variants belonging to Orthohepevirus species A (HEV-A) are the primary cause of human hepatitis E. However, we previously reported that Orthohepevirus C (HEV-C1), a divergent HEV variant commonly found in rats, also causes hepatitis in humans. Here, we present a clinical-epidemiological investigation of human HEV-C1 infections detected in Hong Kong, with an emphasis on outcomes in immunocompromised individuals..

METHODS

A surveillance system for detecting human HEV-C1 infections was established in Hong Kong. Epidemiological and clinical characteristics of HEV-C1 cases identified via this system between August 1, 2019 and December 31, 2020 were retrieved. Phylogenetic analysis of HEV-C1 strain sequences was performed. Infection outcomes of immunocompromised individuals with HEV-A and HEV-C1 infections were analyzed.

RESULTS

HEV-C1 accounted for 8/53 (15.1%) RT-PCR confirmed hepatitis E infections in Hong Kong during the study period, raising the total number of HEV-C1 infections detected in the city to 16. Two distinct HEV-C1 strain groups caused human infections. Patients were elderly and/or immunocompromised; half tested negative for HEV IgM. Cumulatively, HEV-C1 accounted for 9/21 (42.9%) cases of hepatitis E recorded in immunocompromised patients in Hong Kong. Immunocompromised HEV-C1 patients progressed to persistent hepatitis at similar rates (7/9; 77.8%) as HEV-A patients (10/12; 75%). HEV-C1 patients responded to oral ribavirin although response to first course was sometimes poor or delayed.

CONCLUSIONS

Dedicated RT-PCR-based surveillance detected human HEV-C1 cases that evade conventional hepatitis E diagnostic testing. Immunosuppressed HEV-C1-infected patients frequently progress to persistent HEV-C1 infection for which ribavirin is a suitable treatment option.

HEV infection in stem cell transplant recipients-retrospective study of EBMT Infectious Diseases Working Party

HEV infection is an emerging cause of acute and chronic hepatitis in stem cell transplant (SCT) recipients. We performed a retrospective observational study among EBMT centers with the aim of describing characteristics, management and outcome of HEV after SCT. There were 34 cases of HEV infection from 12 centers in 6 countries, diagnosed in median 4.5 months after SCT; 20 of acute and 14 of chronic infection. Non-hepatic findings possibly associated with HEV infection were present in 9 (26%). Patients with chronic infection had more characteristics associated with severely immunocompromised status. Ribavirin was provided to 16 patients (47%; 40% with acute and 57% with chronic infection), in median for 75 days. Three (19%) patients discontinued it due to side effects. HEV-RNA clearance occurred in 29 patients (85%; 85% in acute and 86% in chronic infection). HEV was considered a cause of death in 3 (9%), with 2 cases with late diagnosis. Reduction of immunosuppression in those receiving it, and ribavirin treatment in those with chronic infection were associated with shorter time to HEV-RNA clearance. Policy on HEV testing varied between the centers. In conclusion, acute and chronic HEV hepatitis should be promptly diagnosed and managed in SCT recipients.

Hepatitis E: Genotypes, strategies to prevent and manage, and the existing knowledge gaps

Hepatitis E virus (HEV) is considered an emergent source of viral hepatitis worldwide, with an increasing burden of jaundice, liver failure, extrahepatic illnesses, and deaths in developed countries. With the scarcity of data from efficient animal models, there are still open-ended questions about designing new models to study pathogenesis, types, virology, and evolution of these viruses. With an emphasis on available data and updates, there is still enough information to understand the HEV life cycle, pathogen interaction with the host, and the valuation of the role of vaccine and new anti-HEV therapies. However, the World Health Organization (WHO) and the European Association for the Study of the Liver (EASL) preferred to stress prevention and control measures of HEV infections in animals, zoonotic transmission, and foodborne transmission. It is being reviewed that with current knowledge on HEV and existing prevention tools, there is an excellent room for in-depth information about the virus strains, their replication, pathogenicity, and virulence. The current knowledge set also has gaps regarding standardized and validated diagnostic tools, efficacy and safety of the vaccine, and extrahepatic manifestations specifically in pregnant females, immunocompromised patients, and others. This review highlights the areas for more research exploration, focusing on enlisted research questions based on HEV infection to endorse the need for significant improvement in the current set of knowledge for this public health problem.

Molecular characterisation of Hepatitis E virus isolates from north India

PURPOSE

Hepatitis E virus (HEV) is responsible for >50% of acute viral hepatitis (AVH) in developing countries. It has 4 major genotypes and various subtypes which vary in geographical distribution, clinical manifestations and epidemiological patterns. This study was conducted to characterise HEV isolates from north India to study the effect of host and viral factors on HEV infection.

METHODS

Serum samples collected from 536 AVH patients admitted to Department of Medicine, King George's Medical University, Lucknow from July 2016 to June 2017 were screened for anti HEV IgM, anti HAV IgM, HBsAg and anti HCV antibodies using commercial ELISA kits. Samples either positive for anti HEV IgM antibodies (n ​= ​204) or negative for all 4 hepatotropic viruses (n ​= ​37) were enrolled and tested by real time PCR for HEV RNA. HEV RNA positive samples with high viral load were further subjected to nested PCR for amplification of capsid gene. Sequencing and phylogenetic analysis were performed. HEV strains isolated from this study were deposited to GenBank under accession numbers MG571274 to MG571283.

RESULTS

Anti HEV IgM positivity was observed among 38% clinically suspected AVH cases. HEV RNA was detected in 31.8% seropositive HEV cases and additional 3 seronegative cases. Males outnumbered females and the most affected age group was of young adults. Maximum number of cases were seen during the months of June to September. Phylogenetic analysis showed that HEV strains in our study belonged to genotype 1a. Mortality in HEV infected pregnant females was 23.5% as compared to 2.4% in non-pregnant females. Adverse fetal outcome was recorded in 51% of HEV infected pregnancies.

CONCLUSIONS

HEV genotype 1a is prevalent in our setting. HEV during pregnancy is associated with adverse maternal and fetal outcome.

Hepatitis E Virus Infection-Immune Responses to an Underestimated Global Threat

Infection with the hepatitis E virus (HEV) is one of the main ubiquitous causes for developing an acute hepatitis. Moreover, chronification plays a predominant role in immunocompromised patients such as transplant recipients with more frequent severe courses. Unfortunately, besides reduction of immunosuppression and off-label use of ribavirin or pegylated interferon alfa, there is currently no specific anti-viral treatment to prevent disease progression. So far, research on involved immune mechanisms induced by HEV is limited. It is very difficult to collect clinical samples especially from the early phase of infection since this is often asymptomatic. Nevertheless, it is certain that the outcome of HEV-infected patients correlates with the strength of the proceeding immune response. Several lymphoid cells have been identified in contributing either to disease progression or achieving sustained virologic response. In particular, a sufficient immune control by both CD4⁺ and CD8⁺ T cells is necessary to prevent chronic viral replication. Especially the mechanisms underlying fulminant courses are poorly understood. However, liver biopsies indicate the involvement of cytotoxic T cells in liver damage. In this review, we aimed to highlight different parts of the lymphoid immune response against HEV and point out questions that remain unanswered regarding this underestimated global threat.

Global burden of acute viral hepatitis and its association with socioeconomic development status, 1990-2019

BACKGROUND & AIMS

Acute viral hepatitis (AVH) represents an important global health problem; however, the progress in understanding AVH is limited because of the priority of combating persistent HBV and HCV infections. Therefore, an improved understanding of the burden of AVH is required to help design strategies for global intervention.

METHODS

Data on 4 major AVH types, including acute hepatitis A, B, C, and E, excluding D, were collected by the Global Burden of Disease (GBD) 2019 database. Age-standardized incidence rates and disability-adjusted life year (DALY) rates for AVH were extracted from GBD 2019 and stratified by sex, level of socio-demographic index (SDI), country, and territory. The association between the burden of AVH and socioeconomic development status, as represented by the SDI, was described.

RESULTS

In 2019, there was an age-standardized incidence rate of 3,615.9 (95% CI 3,360.5-3,888.3) and an age-standardized DALY rate of 58.0 (47.3-70.0) per 100,000 person-years for the 4 major types of AVH. Among the major AVH types, acute hepatitis A caused the heaviest burden. There was a significant downward trend in age-standardized DALY rates caused by major incidences of AVH between 1990 and 2019. In 2019, regions or countries located in West and East Africa exhibited the highest age-standardized incidence rates of the 4 major AVH types. These rates were stratified by SDI: high SDI and high-middle SDI locations recorded the lowest incidence and DALY rates of AVH, whereas the low-middle SDI and low SDI locations showed the highest burden of AVH.

CONCLUSIONS

The socioeconomic development status and burden of AVH are associated. Therefore, the GBD 2019 data should be used by policymakers to guide cost-effective interventions for AVH.

LAY SUMMARY

We identified a negative association between socioeconomic development status and the burden of acute viral hepatitis. The lowest burden of acute viral hepatitis was noted for rich countries, whereas the highest burden of acute viral hepatitis was noted for poor countries.

Hepatitis E virus as a trigger for Guillain-Barré syndrome

Background

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide. An association with neuralgic amyotrophy and Guillain-Barré syndrome (GBS) was previously described. Concerning GBS, studies from other countries found an acute HEV infection in 5–11% of cases. However, HEV prevalence shows considerable regional variations. Therefore, we retrospectively analyzed the frequency of HEV infections in association with GBS in a monocentric cohort in Southwestern Germany.

Methods

Overall, 163 patients with GBS treated in our clinic between 2008 and 2018 of whom serum and/or cerebrospinal fluid (CSF) samples were available, were identified. Serum samples were analyzed for anti-HEV immunoglobulin (Ig)M and IgG antibodies by ELISA. Additionally, both serum and cerebrospinal fluid (CSF) samples were tested for HEV RNA by PCR if IgM was positive or patients presented within the first 7 days from GBS symptom onset. A group of 167 healthy volunteers and 96 healthy blood donors served as controls.

Results

An acute HEV infection was found in two GBS patients (1.2%) with anti-HEV IgM and IgG antibodies. HEV PCR in serum and CSF was negative in these two patients as well as in all other tested cases. Seroprevalences indicated that acute infection did not differ significantly from controls (0.8%). Anti-HEV IgG seroprevalence indicating previous infection was unexpectedly high (41%) and revealed an age-dependent increase to more than 50% in patients older than 60 years.

Conclusion

In this study, serological evidence of an acute HEV infection in patients with GBS was rare and not different from controls. Comparing our data with previous studies, incidence rates show considerable regional variations.

Ribavirin monotherapy for the treatment of chronic hepatitis E in an immunosuppressed patient

We herein report the case of a 54-year-old male patient with a human immunodeficiency virus 1 (HIV-1) infection, usually with low viral loads and CD4 cells < 200-100/mm3 due to thymic exhaustion. He was referred to our clinic because of hypertransaminasemia and cholestasis of a duration of 58 months and liver cirrhosis on FibroScan® without esophageal varices. Nonspecific manifestations included weight loss. Liver disease stigmata and generalized amyotrophy were also present.

Significant compartment-specific impact of different RNA extraction methods and PCR assays on the sensitivity of hepatitis E virus detection

BACKGROUND

RNA detection in plasma/stool is the gold-standard for diagnosis of hepatitis E virus (HEV) infection. The impact of viral extraction methods on HEV RNA detection is poorly investigated.

METHODS

We determined the limit of detection of the RealStar HEV RT-PCR V2.0 Kit (altona Diagnostics, RS) utilizing 3 RNA extraction methods (COBAS^® AmpliPrep Total Nucleic Acid Isolation Kit, TNAi Roche; MagNA Pure 96 DNA, Viral NA SV Kit, MgP; QIAamp Viral RNA mini Kit Qiagen; VRK) in plasma and stool. The most sensitive method was evaluated in a total of 307 longitudinal samples of patients with HEV infection (acute = 18/chronic = 36) and compared to results with the former diagnostic standard of our centre (TNAi/FastTrack Diagnostic; FTD).

RESULTS

The plasma-LOD was 49, 94 and 329 IU/mL for extraction with MgP, VRK and TNAi respectively. In stool, the LOD was 21 IU/mL, 528 IU/mL and indefinable for extraction with TNAi, VRK and MgP respectively. Utilizing longitudinal patient plasma samples, MgP/RS revealed 56 HEV RNA-positive samples in 158 negative samples as determined by TNAi/FTD. In stool, from 37 HEV negative samples (TNAi/FTD), 15 were positive with TNAi/RS. At end of treatment, 8 out of 27 chronically infected patients were RNA positive with MgP/RS, while classified negative with TNAi/FTD. A relapse occurred in 3 of these patients.

CONCLUSION

Different methods for RNA extraction and quantification have a significant, compartment-specific impact on the sensitivity of HEV detection. Knowledge about the favourable combinations of extraction and quantification has important implications for diagnosis and patients receiving antiviral therapy.

Viral hepatitis: Milestones, unresolved issues, and future goals

In this review the current overall knowledge on hepatitis A, B, C, D, and E will be discussed. These diseases are all characterized by liver inflammation but have significant differences in distribution, transmission routes, and outcomes. Hepatitis B virus and hepatitis C virus are transmitted by exposure to infected blood, and in addition to acute infection, they can cause chronic hepatitis, which in turn can evolve into cirrhosis. It is estimated that more than 300 million people suffer from chronic hepatitis B or C worldwide. Hepatitis D virus, which is also transmitted by blood, only affects hepatitis B virus infected people, and this dual infection results in worse liver-related outcomes. Hepatitis A and E spread via the fecal-oral route, which corresponds mainly to the ingestion of food or water contaminated with infected stools. However, in developed countries hepatitis E is predominantly a zoonosis. Although hepatitis A virus and hepatitis E virus are usually responsible for a self-limiting hepatitis, a serious, rarely fatal illness is also possible, and in immunosuppressed patients, such as organ transplant recipients, hepatitis E virus infection can become chronic. The description of goals achieved, unresolved issues, and the latest research on this topic may make it possible to speculate on future scenarios in the world of viral hepatitis.

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

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

Extrahepatic manifestations related to hepatitis E virus infection and their triggering mechanisms

Hepatitis E virus (HEV) infection has many extrahepatic manifestations as well as liver symptoms. Multiple studies have shown that HEV infection has symptoms related to the nervous system, kidneys, cryoglobulinemia, hematological system, reproductive system, autoimmunity and pancreas. Hence, HEV infection should be considered as a systemic disease, rather than solely a liver disease. The extrahepatic manifestations induced by different genotypes of HEV vary. The severity of these diseases does not necessarily correlate with the severity of HEV infection, and even asymptomatic HEV infection may trigger and cause systemic diseases. Patients with systemic manifestations of HEV infection should have priority for antiviral therapy, which could alleviate or improve the extrahepatic manifestations related to HEV infection. However, the extrahepatic manifestations caused by different genotypes of HEV and their corresponding mechanisms have not been clearly identified. This review discusses the extrahepatic manifestations related to HEV infection and their triggering mechanisms.

Safety of treating acute liver injury and failure

INTRODUCTION

Acute liver injury and progression to acute liver failure can be life-threatening conditions that require prompt careful clinical assessment and therapeutic management.

AREAS COVERED

The aim of this article is to review the safety and side effect profile of pharmacological therapies used in the treatment of acute liver injury with specific focus on hepatic toxicity. We performed an extensive literature search with the terms 'acute liver injury,' 'acute liver failure,' 'therapy,' 'safety,' 'adverse reactions' and 'drug induced liver injury.' A thorough discussion of the main drugs and devices used in patients with acute liver injury and acute liver failure, its safety profile and the management of complications associated to therapy of these conditions is presented.

EXPERT OPINION

Several pharmacological approaches are used in acute liver injury and acute liver failure in an empirical basis. Whilst steroids are frequently tried in serious drug-induced liver injury there is concern on a potential harmful effect of these agents because of the higher mortality in patients receiving the drug; hence, statistical approaches such as propensity score matching might help resolve this clinical dilemma. Likewise, properly designed clinical trials using old and new drugs for subjects with serious drug-induced liver injury are clearly needed.