Hepatitis E virus in blood components: a prevalence and transmission study in southeast England

Evidence of hepatitis E virus transmission by renal graft

Hepatitis E virus (HEV) can cause chronic infection among immunocompromised patients, especially solid organ transplant recipients, and can evolve to cirrhosis. Several modes of transmission are known. Here we describe the first two cases, to our knowledge, of HEV infection transmitted by a kidney graft from the same infected donor that led to chronic hepatitis. Consequently, systematic screening of donors by HEV serology and HEV RNA detection by polymerase chain reaction, particularly in endemic regions, should be considered.

Hepatitis E Virus in Industrialized Countries: The Silent Threat

Hepatitis E virus (HEV) is the main cause of acute viral hepatitis worldwide. Its presence in developing countries has been documented for decades. Developed countries were supposed to be virus-free and initially only imported cases were detected in those areas. However, sporadic and autochthonous cases of HEV infection have been identified and studies reveal that the virus is worldwide spread. Chronic hepatitis and multiple extrahepatic manifestations have also been associated with HEV. We review the data from European countries, where human, animal, and environmental data have been collected since the 90s. In Europe, autochthonous HEV strains were first detected in the late 90s and early 2000s. Since then, serological data have shown that the virus infects quite frequently the European population and that some species, such as pigs, wild boars, and deer, are reservoirs. HEV strains can be isolated from environmental samples and reach the food chain, as shown by the detection of the virus in mussels and in contaminated pork products as sausages or meat. All these data highlight the need of studies directed to control the sources of HEV to protect immunocompromised individuals that seem the weakest link of the HEV epidemiology in industrialized regions.

A Comparative Study of Assay Performance of Commercial Hepatitis E Virus Enzyme-Linked Immunosorbent Assay Kits in Australian Blood Donor Samples

Hepatitis E virus (HEV) is transfusion-transmissible and therefore poses a risk to blood transfusion safety. Seroprevalence studies are useful for estimating disease burden and determining risk factors. Considerable variability in the sensitivity of HEV antibody detection assays exists. This study aimed to compare the performances of commercially available HEV enzyme-linked immunosorbent assays (ELISA) in Australian blood donor samples. Plasma samples that tested positive (n = 194) or negative (n = 200) for HEV IgG (Wantai HEV IgG ELISA) were selected. Of the 194 HEV IgG positive samples, 4 were positive for HEV IgM (Wantai HEV IgM ELISA). All samples were tested with the MP Diagnostics: HEV IgG ELISA, total (IgG, IgM, and IgA) HEV antibody ELISA, and HEV IgM ELISA. Of the 194 Wantai HEV IgG positive samples, 92 (47%) tested positive with the MP Diagnostics HEV IgG ELISA (κ = 0.47) and 126 (65%) with MP Diagnostics total HEV antibody assay (κ = 0.65). There was poor agreement between Wantai and MP Diagnostics HEV IgM assays. This study demonstrated poor agreement between the assays tested. These observations are consistent with previous reports demonstrating significant variability between HEV ELISAs, highlighting that results of HEV serology should be interpreted with caution.

The effect of phylogenetic signal reduction on genotyping of hepatitis E viruses of the species Orthohepevirus A

Commonly, hepatitis E virus (HEV) sequences are genotyped phylogenetically using subgenomic sequences. This paper examines this practice with sequences from members of the species Orthohepevirus A. As the length of sequences becomes progressively shorter, the number of identical sequences in an alignment tends to increase; however, these sequences retain their genotypic identity down to 100 nucleotides in length. The best substitution models tend to become less parameterized, bootstrap support decreases, and trees created from short subgenomic fragments are less likely to be isomorphic with trees from longer subgenomic fragments or complete genome sequences. However, it is still possible to correctly genotype sequences using fragments as small as 200 nucleotides. While it is possible to correctly genotype sequences with short subgenomic sequences, the estimates of evolutionary relationships between genotypes degrade to such an extent that sequences below 1600 nucleotides long cannot be used reliably to study these relationships, and comparisons of trees from different subgenomic regions with little or no sequence overlap can be problematic. Subtyping may be done, but it requires a careful examination of the region to be used to ensure that it correctly resolves the subtypes.

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.

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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.

Acute Hepatitis E: Two Sides of the Same Coin

The relevance of acute hepatitis E virus (HEV) infections has been underestimated for a long time. In the past, HEV infection had been interpreted falsely as a disease limited to the tropics until the relevance of autochthonous HEV infections in the Western world became overt. Due to increased awareness, the incidence of diagnosed autochthonous HEV infections (predominantly genotype 3) in industrialized countries has risen within the last decade. The main source of infections in industrialized countries seems to be infected swine meat, while infections with the tropical HEV genotypes 1 and 2 usually are mainly transmitted fecal-orally by contaminated drinking water. In the vast majority of healthy individuals, acute HEV infection is either clinically silent or takes a benign self-limited course. In patients who develop a symptomatic HEV infection, a short prodromal phase with unspecific symptoms is followed by liver specific symptoms like jaundice, itching, uncoloured stool and darkened urine. Importantly, tropical HEV infections may lead to acute liver failure, especially in pregnant women, while autochthonous HEV infections may lead to acute-on-chronic liver failure in patients with underlying liver diseases. Immunosuppressed individuals, such as transplant recipients or human immunodeficiency virus (HIV)-infected patients, are at risk for developing chronic hepatitis E, which may lead to liver fibrosis and cirrhosis in the long term. Importantly, specific treatment options for hepatitis E are not approved by the regulation authorities, but off-label ribavirin treatment seems to be effective in the treatment of chronic HEV-infection and may reduce the disease severity in patients suffering from acute liver failure.

Hepatitis E virus: Emerging from the shadows in developed countries

Following the discovery of HEV in the 1980s, it became apparent that HEV is endemic in a number of developing countries in Asia, Africa and Mexico. In these geographical settings HEV is spread oral faecally by HEV genotypes (gt) 1 and 2, which are obligate human pathogens. Infection occurs oro-faecally, often as a result in the breakdown of fragile sanitary infrastructure allowing drinking water supplies to become contaminated with human sewage. Hepatitis E usually causes a self-limiting hepatitis in young adults with sporadic cases and occasional dramatic outbreaks involving hundreds or thousands of cases. Clinically the illness is indistinguishable from hepatitis A, except in pregnant women where the mortality is 20-25%. Death occurs in the third trimester from fulminant hepatic failure and obstetric complications such as eclampsia, with very high associated foetal loss. For the best part of 20 years hepatitis E was considered as an imported disease in developed countries, and was only seen in travellers returning from endemic developing countries. We got this very badly wrong: HEV gt3 was 'hiding in the shadows' in humans, pigs, and other animals.

Hepatitis E virus infection in patients with acute non-A, non-B, non-C hepatitis in Central Brazil

Hepatitis E virus (HEV) infection has a worldwide distribution and represents an important cause of acute hepatitis. This study aims to investigate the occurrence of HEV infection and factors associated with this infection in patients with acute non-A, non-B, non-C hepatitis in Central Brazil. From April 2012 to October 2014, a cross-sectional study was conducted among 379 patients with acute non-A, non-B, non-C hepatitis in the City of Goiania, Central Brazil. Serum samples of all patients were tested for serological markers of HEV infection (anti-HEV IgM and IgG) by ELISA. Positive samples were confirmed using immunoblot test. Anti-HEV IgM and IgG positive samples were tested for HEV RNA. Of the 379 serum samples, one (0.3%) and 20 (5.3%) were positive for anti-HEV IgM and IgG, respectively. HEV RNA was not found in any sample positive for IgM and/or IgG anti-HEV. After multivariate analysis, low education level was independently associated with HEV seropositivity (p = 0.005), as well as living in rural area, with a borderline p-value (p = 0.056). In conclusion, HEV may be responsible for sporadic self-limited cases of acute hepatitis in Central Brazil.

Transmission of Hepatitis E Virus in Developing Countries

Hepatitis E virus (HEV), an RNA virus of the Hepeviridae family, has marked heterogeneity. While all five HEV genotypes can cause human infections, genotypes HEV-1 and -2 infect humans alone, genotypes HEV-3 and -4 primarily infect pigs, boars and deer, and genotype HEV-7 primarily infects dromedaries. The global distribution of HEV has distinct epidemiological patterns based on ecology and socioeconomic factors. In resource-poor countries, disease presents as large-scale waterborne epidemics, and few epidemics have spread through person-to-person contact; however, endemic diseases within these countries can potentially spread through person-to-person contact or fecally contaminated water and foods. Vertical transmission of HEV from infected mother to fetus causes high fetal and perinatal mortality. Other means of transmission, such as zoonotic transmission, can fluctuate depending upon the region and strain of the virus. For instance, zoonotic transmission can sometimes play an insignificant role in human infections, such as in India, where human and pig HEV infections are unrelated. However, recently China and Southeast Asia have experienced a zoonotic spread of HEV-4 from pigs to humans and this has become the dominant mode of transmission of hepatitis E in eastern China. Zoonotic HEV infections in humans occur by eating undercooked pig flesh, raw liver, and sausages; through vocational contact; or via pig slurry, which leads to environmental contamination of agricultural products and seafood. Lastly, blood transfusion-associated HEV infections occur in many countries and screening of donors for HEV RNA is currently under serious consideration. To summarize, HEV genotypes 1 and 2 cause epidemic and endemic diseases in resource poor countries, primarily spreading through contaminated drinking water. HEV genotypes 3 and 4 on the other hand, cause autochthonous infections in developed, and many developing countries, by means of a unique zoonotic food-borne transmission.

Immunoadsorption or plasma exchange in the treatment of autoimmune encephalitis: a pilot study

Therapeutic apheresis has emerged as a major treatment option for autoantibody-associated inflammatory diseases of the nervous system. This includes patients with autoimmune encephalitides caused by antibodies against neuronal proteins. Plasma exchange (PE) and immunoadsorption (IA) constitute two possibilities to eliminate pathogenic antibodies from patients' plasma, but their efficacy and safety has not been prospectively assessed in larger patient groups of autoimmune encephalitides. In a prospective observational case control study, we, therefore, investigated the disease courses and treatment effects of 21 patients with autoimmune encephalitis associated with NMDAR, LGI1, CASPR2, GAD, mGluR5 and Hu antibodies. Patients were randomly assigned to receive PE (n = 11) or IA (n = 10). Symptoms were evaluated using the modified Rankin Scale (mRS). Side effects or adverse events were recorded. Both interventions, IA (p = 0.014) and PE (p = 0.01), resulted in significant reduction of the median mRS. With IA, 60 % of the patients improved clinically by at least 1 mRS score, none worsened. PE led to a comparable symptom reduction in 67 % of the cases. During 83 PE sessions, three adverse events were documented, while no side effects occurred under IA. Symptom improvement was significantly associated with younger age (r = -0.58), but not with disease duration. Therapeutic apheresis was most effective for neuronal surface antigens (83.3 %), followed by intracellular-synaptic antigens (66.7 %). Both IA and PE resulted in moderate to marked clinical improvement, with a low rate of adverse events. Apheresis is well tolerated and effective also as first-line therapy in autoimmune encephalitis, particularly in patients with antibodies targeting neuronal surfaces.

Advances in hepatitis E - II: Epidemiology, clinical manifestations, treatment and prevention

INTRODUCTION

Infection with hepatitis E virus (HEV) is the commonest cause of acute hepatitis worldwide. This infection, with fecal-oral transmission, was previously thought to be limited to humans residing in developing countries with poor sanitation, spreading via contaminated drinking water. In recent years, our understanding of epidemiology and clinical spectrum of this infection have changed markedly.

AREAS COVERED

This article reviews the epidemiology, including routes of transmission, and clinical manifestations of HEV infection around the world. In addition, recent findings on transmission-associated HEV infection, extrahepatic manifestations of hepatitis E and chronic infection with HEV, and treatment and prevention of this infection are discussed. Expert commentary: HEV infection has two distinct epidemiologic forms and clinical patterns of disease: (i) acute epidemic or sporadic hepatitis caused by fecal-oral (usually water-borne) transmission of genotype 1 and 2 HEV from a human reservoir in areas with poor hygiene and frequent water contamination, and (ii) infrequent sporadic hepatitis E caused by zoonotic infection, possibly from an animal source through ingestion of undercooked animal meal, of genotype 3 or 4 virus. In disease-endemic areas, pregnant women are at a particular risk of serious disease and high mortality. In less-endemic areas, chronic infection with HEV among immunosuppressed persons is observed. HEV can also be transmitted through Transfusion of blood and blood products. Ribivirin treatment is effective in chronic hepatitis E. Two efficacious vaccines have been tried in humans; one of these has received marketing approval in its country of origin.

Hepatitis E: Discovery, global impact, control and cure

Hepatitis E was identified as an epidemic of non-A, non-B hepatitis from Kashmir, India in 1978. Hepatitis E virus (HEV), the etiological agent is the sole member of family Hepeviridae. The virus has marked heterogeneity and infects many animals like bats, camel, chicken, deer, boar, mongoose, pigs, rats, rabbit and cutthroat trout. Hepatitis E is a disease with a major global impact and has two distinct epidemiological patterns. Hepatitis E is an imperative health issue in developing nations, transmitted through sullied water and happens most every now in young adults. The disease is particularly severe during pregnancy and in people with underlying liver cirrhosis. Autochthonous hepatitis E is increasingly recognized in developed countries. The virus infects domestic pigs, wild boar and Sika deer in these countries. HEV infections in humans occur by eating the undercooked game flesh, raw liver from supermarkets and Figatelli sausages. Blood transfusion-associated HEV infections occur in many countries and screening of donors for HEV RNA is under consideration. Hepatitis E causes a number of extrahepatic diseases, including a wide spectrum of neurological syndromes. HEV genotype 3 causes prolonged viremia, chronic hepatitis, liver fibrosis and cirrhosis in organ transplant patients. The virus is amenable to ribavirin monotherapy and most patients clear the virus in a few weeks. Hepatitis E vaccine -239, marketed in China, has shown high efficacy with sustained protection for over four years.

Role of Envelopment in the HEV Life Cycle

Hepatitis E virus (HEV), an enterically transmitted hepatotropic virus, was thought to be non-enveloped for decades. However, recent studies have revealed that the virus circulating in the patient’s blood is completely cloaked in host membranes and resistant to neutralizing antibodies. The discovery of this novel enveloped form of HEV has raised a series of questions about the fundamental biology of HEV and the way this virus, which has been understudied in the past, interacts with its host. Here, we review recent advances towards understanding this phenomenon and discuss its potential impact on various aspects of the HEV life cycle and immunity.

Viral hepatitis: Indian scenario

Viral hepatitis is a cause for major health care burden in India and is now equated as a threat comparable to the "big three" communicable diseases - HIV/AIDS, malaria and tuberculosis. Hepatitis A virus and Hepatitis E virus are predominantly enterically transmitted pathogens and are responsible to cause both sporadic infections and epidemics of acute viral hepatitis. Hepatitis B virus and Hepatitis C virus are predominantly spread via parenteral route and are notorious to cause chronic hepatitis which can lead to grave complications including cirrhosis of liver and hepatocellular carcinoma. Around 400 million people all over the world suffer from chronic hepatitis and the Asia-Pacific region constitutes the epicentre of this epidemic. The present article would aim to cover the basic virologic aspects of these viruses and highlight the present scenario of viral hepatitis in India.

Hepatitis E Seroprevalence in Europe: A Meta-Analysis

There have been large numbers of studies on anti-HEV IgG seroprevalence in Europe, however, the results of these studies have produced high variability of seroprevalence rates, making interpretation increasingly problematic. Therefore, the aim of this study was to develop a clearer understanding of anti-HEV IgG seroprevalence in Europe and identify risk groups for HEV exposure by a meta-analysis of published studies.

METHODS

All European HEV-seroprevalence studies from 2003 to 2015 were reviewed. Data were stratified by assay, geographical location, and patient cohort (general population, patients with HIV, solid-organ transplant recipients, chronic liver disease patients, and individuals in contact with swine/wild animals). Data were pooled using a mixed-effects model.

RESULTS

Four hundred thirty-two studies were initially identified, of which 73 studies were included in the analysis. Seroprevalence estimates ranged from 0.6% to 52.5%, increased with age, but were unrelated to gender. General population seroprevalence varied depending on assays: Wantai (WT): 17%, Mikrogen (MG): 10%, MP-diagnostics (MP): 7%, DiaPro: 4%, Abbott 2%. The WT assay reported significantly higher seroprevalence rates across all cohorts (p < 0.001). Individuals in contact with swine/wild animals had significantly higher seroprevalence rates than the general population, irrespective of assay (p < 0.0001). There was no difference between any other cohorts. The highest seroprevalence was observed in France (WT: 32%, MP: 16%) the lowest in Italy (WT: 7.5%, MP 0.9%). Seroprevalence varied between and within countries. The observed heterogeneity was attributed to geographical region (23%), assay employed (23%) and study cohort (7%).

CONCLUSION

Seroprevalcence rates primarily depend on the seroassy that is used, followed by the geographical region and study cohort. Seroprevalence is higher in individuals exposed to swine and/or wild animals, and increases with age.

Hepatitis E in Children: A Position Paper by the ESPGHAN Hepatology Committee

BACKGROUND

Hepatitis E virus (HEV) is endemic in large parts of the developing world. Waterborne transmission of genotypes 1 or 2 commonly causes acute hepatitis, which is usually self-limited in healthy individuals. In addition, acute HEV infections also occur outside endemic areas, mostly related to foodborne transmission of HEV genotype 3. A growing number of publications in the last decade have reported chronic infection progressing to cirrhosis in immunosuppressed patients. It has also been suggested that HEV transmission may occur via contaminated blood products. This publication aims to provide recommendations for diagnosis, prevention, and treatment of HEV infection, particularly in children after solid organ transplantation.

METHODS

A systematic PubMed literature search on HEV infection from 1990 to January 2016 was performed focusing on pediatric studies. The existing body of evidence was reviewed and recommendations were agreed upon following discussion and unanimous agreement by all members of the ESPGHAN Hepatology Committee during a consensus meeting in January 2016. In the absence of randomized controlled studies these recommendations were considered to be expert opinions.

KEY RECOMMENDATIONS

Immunocompetent children with increased transaminases and/or extrahepatic manifestations should be considered for testing for evidence of HEV infection. Immunocompromised children with increased aminotransferases should be repeatedly tested for HEV and may require therapeutic intervention.

High prevalence of anti-hepatitis E virus antibodies among blood donors in central Italy, February to March 2014

Prevalence of anti-hepatitis E virus (HEV) antibodies is highly variable in developed countries, which seems partly due to differences in assay sensitivity. Using validated sensitive assays, we tested 313 blood donors attending a hospital transfusion unit in central Italy in January and February 2014 for anti-HEV IgG and IgM and HEV RNA. Data on HEV exposure were collected from all donors. Overall anti-HEV IgG prevalence was 49% (153/313). Eating raw dried pig-liver sausage was the only independent predictor of HEV infection (adjusted prevalence rate ratio = 2.14; 95% confidence interval: 1.23–3.74). Three donors were positive for either anti-HEV IgM (n = 2; 0.6%) or HEV RNA (n = 2; 0.6%); they were completely asymptomatic, without alanine aminotransferase (ALT) abnormalities. Of the two HEV RNA-positive donors (both harbouring genotype 3), one was anti-HEV IgG- and IgM-positive, the other was anti-HEV IgG- and IgM-negative. The third donor was positive for anti-HEV IgG and IgM but HEV RNA-negative. HEV infection is therefore hyperendemic among blood donors (80% men 18–64 years-old) from central Italy and associated with local dietary habits. Nearly 1% of donors have acute or recent infection, implying potential transmission to blood recipients. Neither ALT nor anti-HEV IgM testing seems useful to prevent transfusion-transmitted HEV infection.

Low transfusion transmission of hepatitis E among 25,637 single-donation, nucleic acid-tested blood donors

BACKGROUND

Hepatitis E virus genotype-3 (HEV-gt-3) causes autochthonous infections in western countries, with a primary reservoir in animals, especially pigs. HEV transfusion transmission has been reported, and HEV-gt-3 prevalence is high in some European countries. The prevalence of HEV RNA was investigated among Danish blood donors, and the prevalence of HEV transfusion-transmitted infection (TTI) was investigated among recipients.

STUDY DESIGN AND METHODS

Samples from 25,637 consenting donors collected during 1 month in 2015 were screened retrospectively using an individual-donation HEV RNA nucleic acid test with a 95% detection probability of 7.9 IU/mL. HEV-positive samples were quantified by real-time polymerase chain reaction and genotyped. Transmission was evaluated among recipients of HEV RNA-positive blood components. Phylogenetic analyses compared HEV sequences from blood donors, symptomatic patients, and swine.

RESULTS

Eleven donations (0.04%) were confirmed as positive for HEV RNA (median HEV RNA level, 13 IU/mL). Two donations were successfully genotyped as HEV-gt-3. Only one donor had a travel history outside Europe. Nine of 11 donors were male, but the gender ratio was nonsignificant compared with the total donor population. Seven available recipients tested negative for HEV RNA and anti-HEV immunoglobulin M in follow-up samples. One recipient was HEV RNA-negative but anti-HEV immunoglobulin G-positive. HEV TTI was considered unlikely, but a transfusion-induced secondary immune response could not be excluded. Phylogenetic analysis showed relatively large sequence differences between HEV from donors, symptomatic patients, and swine.

CONCLUSIONS

Despite an HEV RNA prevalence of 0.04% in Danish blood donations, all HEV-positive donations carried low viral loads, and no evidence of TTI was found.

New insights into the natural history of hepatitis E virus infection through a longitudinal study of multitransfused immunocompetent patients in France

Little is known about the natural history of Hepatitis E virus (HEV) infection in immunocompetent individuals. The prevalence, the course of infection and the occurrence of transmission by transfusion were investigated in multitransfused immunocompetent patients/blood donor pairs included in a longitudinal sample repository collection and followed up between 1988 and 2010. Ninety-eight subjects aged 6-89 years and suffering from acquired haemoglobinopathies were tested for HEV markers (IgM, IgG and RNA) in serial samples collected every 2 or 3 years. Eighteen patients (18.4%) were positive for HEV-IgG at baseline with a prevalence increasing from 12.5% below 26 years to 32% above 56 years. Nine patients remained IgG positive along the study and nine lost their antibodies after a mean follow-up of 7.4 years (1-22 years). One seropositive patient showed an increase of IgG level and RNA-HEV reappearance 1 year after inclusion, suggesting a reinfection and one seroconversion, probably acquired through blood transfusion was observed. This first longitudinal study including immunocompetent individuals confirms that HEV infection is common in Western Europe and that transfusion transmission occurs probably less frequently than expected. In addition, seroreversion and reinfection seem to be common. This suggests that the anti-HEV may not persist overtime naturally. However, repeat exposure to the virus related to the high prevalence of HEV infection may result in a sustainable specific IgG response.

Persisting hepatitis E virus infection leading to liver cirrhosis despite recovery of the immune system in an HIV-infected patient

Chronic hepatitis E has been described several times in strongly immunosuppressed HIV-patients. We describe the persistence of HEV-infection in an HIV-patient despite a restored immune response. This case demonstrates that HEV-infection can persist in formerly immunosuppressed individuals irrespective of the current immune status. Persisting HEV-infection can lead to chronic inflammation and liver cirrhosis. Physicians should be aware of the possibility of chronic hepatitis E even in patients that are not any longer immunocompromised. However, ribavirin is an efficient treatment option.

Hepatitis E: latest developments in knowledge

Hepatitis E, caused by Hepatitis E virus (HEV), is a highly prevalent disease in developing countries. In developed nations, autochthonous HEV infections seem to be an emergent disease. Its clinical manifestations and epidemiology are well known for endemic countries. It has been confirmed that hepatitis E is a zoonosis and that parenteral transmission can also occur. The molecular mechanisms of HEV replication are not fully understood, mostly because there are no efficient cell culture systems. HEV can cause chronic hepatitis in organ transplant recipients and immunocompetent patients. Cases with fulminant hepatitis and other extrahepatic manifestations have also been reported. The diagnosis is based on serological studies and detection of HEV RNA in blood and feces. Treatment with ribavirin and/or pegylated-IFN-α have proven to be successful in some cases. The recently approved/marketed vaccine is a good option in order to prevent this infection.

Hepatitis E Virus (HEV) ORF2 Antigen Levels Differentiate Between Acute and Chronic HEV Infection

BACKGROUND

Hepatitis E virus (HEV) genotype 3 infections are frequent in Europe and North America, with acute and chronic courses described in the literature. HEV RNA detection by real-time polymerase chain reaction (PCR) is the gold standard for diagnosis. Recently, an anti-HEV antigen (Ag)-specific enzyme-linked immunosorbent assay (ELISA) directed against the HEV capsid became commercially available. The effectiveness of anti-HEV Ag-specific ELISA at detecting HEV genotype 3 infections remains undefined.

METHODS

The performance of anti-HEV Ag-ELISA was compared with that of real-time PCR, using sera from a cohort of acutely infected individuals, in addition to a cohort of chronically infected patients undergoing ribavirin therapy. Furthermore, virion properties were evaluated by density fractionation.

RESULTS

Anti-HEV Ag-specific ELISA was less sensitive than real-time PCR at detection of HEV infection. Anti-HEV Ag-specific ELISA revealed significantly higher HEV Ag in chronically infected individuals as compared to acutely infected patients, with high sensitivity and specificity to distinguish acute from chronic HEV infection. Of note, HEV Ag remained detectable for >100 days after HEV RNA clearance in ribavirin-treated patients with chronic HEV. Density gradients revealed the presence of membrane-associated virions in the sera, with a different distribution as compared to HEV RNA.

CONCLUSIONS

The anti-HEV Ag-specific ELISA is less sensitive than HEV RNA real-time PCR but represents a useful tool to discriminate chronic from acute infection.

Hepatitis E virus: Current epidemiology and vaccine

Hepatitis E virus infections have been continuously reported in Indian subcontinent, Africa, southeast and central Asia, posing great health threats to the public, especially to pregnant women. Hecolin® is the only licensed HEV vaccine developed by Xiamen Innovax Biotech Co., Ltd. Extensive characterizations on antigenicity, physicochemical properties, efficacy in clinical trials, and manufacturing capability have made Hecolin® a promising vaccine for HEV control. However, there are many obstacles in large scale application of Hecolin®. Efforts are needed to further evaluate safety and efficacy in HEV risk populations, and to complement HEV standards for quality control. Passing World Health Organization prequalification and licensing outside China are priorities as these are also hindering Hecolin® promotion. Multilateral cooperation among Chinese vaccine manufacturers, Chinese National Regulatory Authorization (NRA) and WHO will expedite the entrance of Hecolin® into international market, so that Hecolin® could play its due role in global hepatitis E control.

Human liver chimeric mice as a new model of chronic hepatitis E virus infection and preclinical drug evaluation

BACKGROUND & AIMS

Hepatitis E virus (HEV) is a major cause of acute hepatitis as well as chronic infection in immunocompromised individuals; however, in vivo infection models are limited. The aim of this study was to establish a small animal model to improve our understanding of HEV replication mechanisms and permit the development of effective therapeutics.

METHODS

UPA/SCID/beige mice repopulated with primary human hepatocytes were used for infection experiments with HEV genotype (GT) 1 and 3. Virological parameters were determined at the serological and intrahepatic level by real time PCR, immunohistochemistry and RNA in situ hybridization.

RESULTS

Establishment of HEV infection was achieved after intravenous injection of stool-derived virions and following co-housing with HEV-infected animals but not via inoculation of serum-derived HEV. GT 1 infection resulted in a rapid rise of viremia and high stable titres in serum, liver, bile and faeces of infected mice for more than 25 weeks. In contrast, viremia in GT 3 infected mice developed more slowly and displayed lower titres in all analysed tissues as compared to GT 1. HEV-infected human hepatocytes could be visualized using HEV ORF2 and ORF3 specific antibodies and HEV RNA in situ hybridization probes. Finally, six-week administration of ribavirin led to a strong reduction of viral replication in the serum and liver of GT 1 infected mice.

CONCLUSION

We established an efficient model of HEV infection to test the efficacy of antiviral agents and to exploit mechanisms of HEV replication and interaction with human hepatocytes in vivo.

Management of viral hepatitis in patients with haematological malignancy and in patients undergoing haemopoietic stem cell transplantation: recommendations of the 5th European Conference on Infections in Leukaemia (ECIL-5)

Viral hepatitis affects millions of people worldwide, and host immunity is the key determinant of patient outcome. Viral hepatitis can be life threatening in patients with haematological malignancy, including haemopoietic stem cell transplant recipients, because of the virus itself, or through a need to decrease the dose of chemotherapy. A past or currently infected haemopoietic stem cell donor could also transmit viral hepatitis. The burden of viral hepatitis in patients with haematological malignancies and the weak evidence on which previous guidelines are based has prompted the European Conference on Infection in Leukaemia (ECIL-5) to convene a group of experts in the fields of viral hepatitis and of haematological malignancy to specifically address previously unconsidered issues and grade the available quality of evidence according to the Infectious Diseases Society of America grading system. The group recommends that all patients should be screened for hepatotropic viruses before haematological treatment and that patients or haemopoietic stem cell donors with markers of past or current viral hepatitis should be assessed by an expert. Screening, vaccination, and treatment rules are reported in this Review.

Hepatitis E Virus (HEV) Genotype 3 Infection of Human Liver Chimeric Mice as a Model for Chronic HEV Infection

Genotype 3 (gt3) hepatitis E virus (HEV) infections are emerging in Western countries. Immunosuppressed patients are at risk of chronic HEV infection and progressive liver damage, but no adequate model system currently mimics this disease course. Here we explore the possibilities of in vivo HEV studies in a human liver chimeric mouse model (uPA(+/+)Nod-SCID-IL2Rγ(-/-)) next to the A549 cell culture system, using HEV RNA-positive EDTA-plasma, feces, or liver biopsy specimens from 8 immunocompromised patients with chronic gt3 HEV. HEV from feces- or liver-derived inocula showed clear virus propagation within 2 weeks after inoculation onto A549 cells, compared to slow or no HEV propagation of HEV RNA-positive, EDTA-plasma samples. These in vitro HEV infectivity differences were mirrored in human-liver chimeric mice after intravenous (i.v.) inoculation of selected samples. HEV RNA levels of up to 8 log IU HEV RNA/gram were consistently present in 100% of chimeric mouse livers from week 2 to week 14 after inoculation with human feces- or liver-derived HEV. Feces and bile of infected mice contained moderate to large amounts of HEV RNA, while HEV viremia was low and inconsistently detected. Mouse-passaged HEV could subsequently be propagated for up to 100 days in vitro In contrast, cell culture-derived or seronegative EDTA-plasma-derived HEV was not infectious in inoculated animals. In conclusion, the infectivity of feces-derived human HEV is higher than that of EDTA-plasma-derived HEV both in vitro and in vivo Persistent HEV gt3 infections in chimeric mice show preferential viral shedding toward mouse bile and feces, paralleling the course of infection in humans.

IMPORTANCE

Hepatitis E virus (HEV) genotype 3 infections are emerging in Western countries and are of great concern for immunosuppressed patients at risk for developing chronic HEV infection. Lack of adequate model systems for chronic HEV infection hampers studies on HEV infectivity and transmission and antiviral drugs. We compared the in vivo infectivity of clinical samples from chronic HEV patients in human liver chimeric mice to an in vitro virus culture system. Efficient in vivo HEV infection is observed after inoculation with feces- and liver-derived HEV but not with HEV RNA-containing plasma or cell culture supernatant. HEV in chimeric mice is preferentially shed toward bile and feces, mimicking the HEV infection course in humans. The observed in vivo infectivity differences may be relevant for the epidemiology of HEV in humans. This novel small-animal model therefore offers new avenues to unravel HEV's pathobiology.

Chronic hepatitis E virus infection after living donor liver transplantation via blood transfusion: a case report

Although it occurs worldwide, hepatitis E virus (HEV) infection in developed countries is generally foodborne. HEV infection is subclinical in most individuals. Although fulminant liver failure may occur, progression to chronic hepatitis is rare. This study describes a 41-year-old man with liver cirrhosis caused by non-alcoholic steatohepatitis and hepatocellular carcinoma within the Milan criteria. His liver function was classified as Child-Pugh grade C. Living donor liver transplantation (LDLT) was performed, and he was discharged from the hospital on postoperative day (POD) 22. However, his alanine aminotransferase concentration began to increase on POD 60 and HEV infection was detected on POD 81. Retrospective assessments of stored blood samples showed that this patient became positive for HEV RNA on POD 3. The liver donor was negative for anti-HEV antibodies and HEV RNA. However, the platelet concentrate transfused into the liver recipient the day after LDLT was positive for HEV RNA. The patient remained positive for HEV infection for 10 months. Treatment with 800 mg/day ribavirin for 20 weeks reduced HEV RNA to an undetectable level. In conclusion, this report describes a patient infected with HEV through a blood transfusion after LDLT, who progressed to chronic hepatitis probably due to his immunosuppressed state and was treated well with ribavirin therapy.

Incidence of Hepatitis E Antibodies in Swedish Lung Transplant Recipients

BACKGROUND

Hepatitis E virus (HEV) is an important cause of acute and chronic hepatitis in solid organ transplant recipients, especially liver transplant recipients. However, less is known of the incidence and prevalence of HEV in lung transplant recipients.

METHODS

In a prospective study, 62 patients were observed during the first year after lung transplantation. Sera were analyzed for anti-HEV immunoglobulin G (IgG) and IgM at 12 months after transplantation. Samples positive for anti-HEV were also analyzed for HEV RNA by polymerase chain reaction. Pretransplantation samples were analyzed for patients with detectable anti-HEV 1 year after transplantation.

RESULTS

Eight patients (13%) had anti-HEV IgG at the 12-month follow-up sample. HEV RNA could not be detected in any of these samples. One of these patients seroconverted during the follow-up without developing acute or chronic hepatitis.

CONCLUSIONS

Our results show that the prevalence of HEV antibodies among Swedish lung transplant recipients is similar when compared to the general population. It also suggests that the risk for HEV antibody seroconversion during first year is limited.

Cross-genotype-specific T-cell responses in acute hepatitis E virus (HEV) infection

Hepatitis E is an inflammatory liver disease caused by infection with the hepatitis E virus (HEV). In tropical regions, HEV is highly endemic and predominantly mediated by HEV genotypes 1 and 2 with >3 million symptomatic cases per year and around 70 000 deaths. In Europe and America, the zoonotic HEV genotypes 3 and 4 have been reported with continues increasing new infections per year. So far, little is known about T-cell responses during acute HEV genotype 3 infection. Therefore, we did a comprehensive study investigating HEV-specific T-cell responses using genotypes 3- and 1-specific overlapping peptides. Additional cytokines and chemokines were measured in the plasma. In four patients, longitudinal studies were performed. Broad functional HEV-specific CD4(+) and CD8(+) T-cell responses were detectable in patients acutely infected with HEV genotype 3. Elevated of pro- and anti-inflammatory cytokine levels during acute HEV infection correlated with ALT levels. Memory HEV-specific T-cell responses were detectable up to >1.5 years upon infection. Importantly, cross-genotype HEV-specific T-cell responses (between genotypes 1 and 3) were measurable in all investigated patients. In conclusion, we could show for the first time HEV-specific T-cell responses during and after acute HEV genotype 3 infection. Our data of cross-genotype HEV-specific T-cell responses might suggest a potential role in cross-genotype-specific protection between HEV genotypes 1 and 3.

Foodborne viruses

Among the wide variety of viral agents liable to be found as food contaminants, noroviruses and hepatitis A virus are responsible for most well characterized foodborne virus outbreaks. Additionally, hepatitis E virus has emerged as a potential zoonotic threat. Molecular methods, including an ISO standard, are available for norovirus and hepatitis A virus detection in foodstuffs, although the significance of genome copy detection with regard to the associated health risk is yet to be determined through viability assays. More precise and rapid methods for early foodborne outbreak investigation are being developed and they will need to be validated versus the ISO standard. In addition, protocols for next-generation sequencing characterization of outbreak-related samples must be developed, harmonized and validated as well.

A nationwide survey of hepatitis E viral infection in French blood donors

Most cases of hepatitis E viral (HEV) infection in developed countries are autochthonous. Nevertheless, the reported seroprevalence of HEV varies greatly depending on the geographical area and the performance of the immunoassay used. We used validated assays to determine the prevalence of anti-HEV immunoglobulin G (IgG) and IgM among 10,569 French blood donors living in mainland France and three overseas areas. Epidemiological information was collected using a specific questionnaire. We found an overall IgG seroprevalence of 22.4% (8%-86.4%) depending on the geographical area (P < 0.001). The presence of anti-HEV IgG was associated with increasing age (P < 0.001) and eating pork meat (P = 0.03), pork liver sausages (P < 0.001), game meat (P < 0.01), offal (P < 0.001), and oysters (P = 0.02). Conversely, drinking bottled water was associated with a lower rate of anti-HEV IgG (P = 0.02). Overall IgM seroprevalence was 1% (0%-4.6%). The frequency of anti-HEV IgM was higher in donors living in a high anti-HEV IgG seroprevalence area (1.9% versus 0.7%, P < 0.001) and in those eating pork liver sausage (1.4% versus 0.7%, P < 0.01), pâté (1% versus 0.4, P = 0.04), and wild boar (1.3% versus 0.7%, P < 0.01).

CONCLUSION

HEV is endemic in France and hyperendemic in some areas; eating habits alone cannot totally explain the exposure to HEV, and contaminated water could contribute to the epidemiology of HEV infection in France.

Hepatitis E virus as an emerging zoonotic pathogen

Hepatitis E outbreaks are a serious public health concern in developing countries. The disease causes acute infections, primarily in young adults. The mortality rate is approximately 2%; however, it can exceed 20% in pregnant women in some regions in India. The causative agent, hepatitis E virus (HEV), has been isolated from several animal species, including pigs. HEV genotypes 3 and 4 have been isolated from both humans and animals, and are recognized as zoonotic pathogens. Seroprevalence studies in animals and humans indirectly suggest that HEV infections occur worldwide. The virus is primarily transmitted to humans via undercooked animal meats in developed countries. Moreover, transfusion- and transplantation-mediated HEV infections have recently been reported. This review summarizes the general characteristics of hepatitis E, HEV infection status in animals and humans, the zoonotic transmission modes of HEV, and HEV vaccine development status.

Ribavirin for Chronic Hepatitis Prevention among Patients with Hematologic Malignancies

Findings among a cohort of 26 patients who had hematologic malignancies and hepatitis E virus (HEV) infection support that HEV can induce chronic hepatitis. However, a 3-month course of ribavirin can induce a rapid viral clearance, reducing the risk for chronic hepatitis and enabling continuation of cytotoxic treatments for underlying malignancies.

Blood-Borne Pathogens: A Canadian Blood Services Centre for Innovation Symposium

Testing donations for pathogens and deferring selected blood donors have reduced the risk of transmission of known pathogens by transfusion to extremely low levels in most developed countries. Protecting the blood supply from emerging infectious threats remains a serious concern in the transfusion medicine community. Transfusion services can employ indirect measures such as surveillance, hemovigilance, and donor questioning (defense), protein-, or nucleic acid based direct testing (detection), or pathogen inactivation of blood products (destruction) as strategies to mitigate the risk of transmission-transmitted infection. In the North American context, emerging threats currently include dengue, chikungunya, and hepatitis E viruses, and Babesia protozoan parasites. The 2003 SARS and 2014 Ebola outbreaks illustrate the potential of epidemics unlikely to be transmitted by blood transfusion but disruptive to blood systems. Donor-free blood products such as ex vivo generated red blood cells offer a theoretical way to avoid transmission-transmitted infection risk, although biological, engineering, and manufacturing challenges must be overcome before this approach becomes practical. Similarly, next generation sequencing of all nucleic acid in a blood sample is currently possible but impractical for generalized screening. Pathogen inactivation systems are in use in different jurisdictions around the world, and are starting to gain regulatory approval in North America. Cost concerns make it likely that pathogen inactivation will be contemplated by blood operators through the lens of health economics and risk-based decision making, rather than in zero-risk paradigms previously embraced for transfusable products. Defense of the blood supply from infectious disease risk will continue to require innovative combinations of surveillance, detection, and pathogen avoidance or inactivation.

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A symposium on blood-borne pathogens was held September 26, 2015, in Toronto, Canada.

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Transmission-transmitted infections remain a threat to the blood supply.

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The residual risk from established pathogens is small; emerging agents are a concern.

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Next generation sequencing and donor-free blood are not yet practical approaches.

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Pathogen inactivation technology is being increasingly used around the world.

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Health economic concerns will likely guide future advances in this area.

Prevalence of Hepatitis E Virus Infection in Pigs at the Time of Slaughter, United Kingdom, 2013

Pigs raised in the United Kingdom are unlikely to be the source of UK human infections.

Since 2010, reports of infection with hepatitis E virus (HEV) have increased in England and Wales. Despite mounting evidence regarding the zoonotic potential of porcine HEV, there are limited data on its prevalence in pigs in the United Kingdom. We investigated antibody prevalence, active infection, and virus variation in serum and cecal content samples from 629 pigs at slaughter. Prevalence of antibodies to HEV was 92.8% (584/629), and HEV RNA was detected in 15% of cecal contents (93/629), 3% of plasma samples (22/629), and 2% of both (14/629). However, although HEV is prevalent in pigs in the United Kingdom and viremic pigs are entering the food chain, most (22/23) viral sequences clustered separately from the dominant type seen in humans. Thus, pigs raised in the United Kingdom are unlikely to be the main source of human HEV infections in the United Kingdom. Further research is needed to identify the source of these infections.

Prophylaxis against hepatitis E: at risk populations and human vaccines

Hepatitis E is an emerging global disease caused by hepatitis E virus (HEV) infection. While in developing countries the infection was primarily due to poor sanitary conditions through intake of contaminated water or undercooked meats of infected animals, increasing cases of chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end-stage liver disease have been reported in organ transplant patients or in immune compromised patients in developed countries. Fortunately, hepatitis E is now a vaccine preventable disease with a HEV239 based vaccine licensed for human use. Much work is needed to enable its use outside China. This review recounted the development process of the vaccine, outlined the critical quality attributes of the vaccine antigen and, most importantly, listed the populations at risk for HEV infection and the subsequent disease. These at risk populations could benefit the most from the vaccination if the vaccine is widely adopted.

Virology, serology, and demography of hepatitis E viremic blood donors in South East England

BACKGROUND

Hepatitis E virus (HEV) Genotype 3 (G3) in England comprises two principal phylogenetic groups (Group 1 and Group 2) and can be transmitted by transfusion. Unselected screening identified 79 viremic donors; 76 participated in a follow-up study.

STUDY DESIGN AND METHODS

Viral RNA dynamics, phylogenetics, and seroconversion were characterized in the donors. Detailed demographic, travel, clinical, and lifestyle questionnaires were undertaken.

RESULTS

The majority of viremic individuals (57/79) were seronegative at time of donation but all seroconverted. Viremia was short-lived, with a median of 6.5 weeks to confirmed viral clearance. All infections were acquired in the United Kingdom and were G3, with Group 2 viruses predominating (43/54; 80%). Infection was associated with some clinical symptoms both at and after donation (8/77; 10%). Viral loads and symptoms were more pronounced in Group 1 infections. There was no serologic evidence of reinfection. Donors were more commonly male (p = 0.002); both male and female donors were older than comparator donors. Animal contact was unlikely to be the source of infection. Consumption of chicken and pig meat was common to all infected donors; processed pig meat was most commonly purchased from one particular retail chain.

CONCLUSION

Viremic donors represent primary infection in older members of the community and reflect a widespread zoonotic in the United Kingdom. The two phylogenetic groups of HEV G3 display different pathogenicity and the more common Group 2 appears less adapted to humans. There are no objective demographic criteria that can identify donors at enhanced HEV risk.

Hepatitis E: an emerging global disease - from discovery towards control and cure

Hepatitis E is a systemic disease affecting the liver predominantly and caused by infection with the hepatitis E virus (HEV). HEV has marked genetic heterogeneity and is known to infect several animal species including pigs, boar, deer, mongoose, rabbit, camel, chicken, rats, ferret, bats and cutthroat trout. HEV is the sole member of the family Hepeviridae and has been divided into 2 genera: Orthohepevirus (mammalian and avian HEV) and Piscihepevirus (trout HEV). Human HEVs included within the genus Orthohepevirus are designated Orthohepevirus A (isolates from human, pig, wild boar, deer, mongoose, rabbit and camel). Hepatitis E is an important public health concern, and an estimated one-third of the world population has been infected with HEV. In recent years, autochthonous hepatitis E is recognized as a clinical problem in industrialized countries. Several animal species especially domestic swine, wild boar and wild deer are reservoirs of genotype HEV-3 and HEV-4 in these countries. Human infections occur through intake of uncooked or undercooked meat of the infected animals and pig livers or sausages made from these livers and sold in supermarkets. HEV can be transmitted through blood and blood component transfusions, and donor screening for HEV is under serious consideration. Chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end-stage liver disease has been described in organ transplant patients. Ribavirin monotherapy attains sustained virological response in most patients. HEV 239 vaccine has been marketed in China and its long-term efficacy over four and a half years reported.