Hepatitis E: source and route of infection, clinical manifestations and new developments

Acute Viral Hepatitis E Infection Complicating Postliving Liver Donor Hepatectomy Recovery

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

The prevention strategies of swine viruses related to xenotransplantation

Xenotransplantation is considered a solution for the shortage of organs, and pigs play an indispensable role as donors in xenotransplantation. The biosecurity of pigs, especially the zoonotic viruses carried by pigs, has attracted attention. This review introduces several viruses, including porcine endogenous retroviruses that are integrated into the pig genome in a DNA form, herpesviruses that have been proven to clearly affect recipient survival time in previous xenotransplant surgeries, the zoonotic hepatitis E virus, and the widely distributed porcine circoviruses. The detail virus information, such as structure, caused diseases, transmission pathways, and epidemiology was introduced in the current review. Diagnostic and control measures for these viruses, including detection sites and methods, vaccines, RNA interference, antiviral pigs, farm biosecurity, and drugs, are discussed. The challenges faced, including those posed by other viruses and newly emerged viruses, and the challenges brought by the modes of transmission of the viruses are also summarized.

Clinical Manifestations of Hepatitis E

The clinical manifestations of hepatitis E are similar to those of other types of viral hepatitis. While acute hepatitis E is usually self-limited, pregnant women and chronic liver disease patients suffering from acute hepatitis E usually present with severe clinical manifestations that may develop into fulminant hepatic failure. Chronic HEV infection is typically seen in organ transplant patients; most HEV cases are asymptomatic and rarely display jaundice, fatigue, abdominal pain, fever, fatigue, or ascites. The clinical manifestations of HEV infection in neonates are diverse and have varied clinical signs, biochemistry, and virus-biomarkers. Lastly, the extrahepatic manifestations and complications of hepatitis E are in need of further study.

Hepatitis E virus in Saudi Arabia: more surveillance needed

Hepatitis E virus (HEV) is a small quasi-enveloped ssRNA causing acute hepatitis. HEV is the leading cause of intermittent acute hepatitis and fulminant hepatic failure. Risk factors include drinking contaminated water in developing countries and consumption of infected animal products in developed countries. Previous reports on HEV prevalence in Saudi Arabia had small sample sizes. Nationwide systematic seroprevalence studies are needed to investigate risk factors and annual incidence. Camels play a cultural and economic role in the life of Saudi citizens with frequent human contact and potential role in zoonotic transmission. Future research needs to include larger sample-sizes and nationwide studies. Future studies should also focus on raising awareness of HEV infection and the need for wider population testing and screening.

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.

Antigenic Characterization of ORF2 and ORF3 Proteins of Hepatitis E Virus (HEV)

To evaluate the antigenic properties of Hepatitis E Virus (HEV) Open Reading Frame 2 and 3 (ORF2 and ORF3) codified proteins, we expressed different portions of ORF2 and the entire ORF3 in E. coli, a truncated ORF2, was also expressed in baculovirus. A panel of 37 monoclonal antibodies (MAbs) was raised against ORF2 (1-660 amino acids) and MAbs were mapped and characterized using the ORF2 expressed portions. Selected HEV positive and negative swine sera were used to evaluate ORF2 and ORF3 antigens' immunogenicity. The MAbs were clustered in six groups identifying six antigenic regions along the ORF2. Only MAbs binding to the sixth ORF2 antigenic region (394-608 aa) were found to compete with HEV positive sera and efficiently catch the recombinant antigen expressed in baculovirus. The ORF2 portion from 394-608 aa demonstrated to include most immunogenic epitopes with 85% of HEV positive swine sera reacting against the region from 461-544 aa. Only 5% of the selected HEV sera reacted against the ORF3 antigen.

A broadly cross-reactive monoclonal antibody against hepatitis E virus capsid antigen

Abstract

To generate a hepatitis E virus (HEV) genotype 3 (HEV-3)–specific monoclonal antibody (mAb), the Escherichia coli–expressed carboxy-terminal part of its capsid protein was used to immunise BALB/c mice. The immunisation resulted in the induction of HEV-specific antibodies of high titre. The mAb G117-AA4 of IgG1 isotype was obtained showing a strong reactivity with the homologous E. coli, but also yeast-expressed capsid protein of HEV-3. The mAb strongly cross-reacted with ratHEV capsid protein derivatives produced in both expression systems and weaker with an E. coli–expressed batHEV capsid protein fragment. In addition, the mAb reacted with capsid protein derivatives of genotypes HEV-2 and HEV-4 and common vole hepatitis E virus (cvHEV), produced by the cell-free synthesis in Chinese hamster ovary (CHO) and Spodoptera frugiperda (Sf21) cell lysates. Western blot and line blot reactivity of the mAb with capsid protein derivatives of HEV-1 to HEV-4, cvHEV, ratHEV and batHEV suggested a linear epitope. Use of truncated derivatives of ratHEV capsid protein in ELISA, Western blot, and a Pepscan analysis allowed to map the epitope within a partially surface-exposed region with the amino acid sequence LYTSV. The mAb was also shown to bind to human patient–derived HEV-3 from infected cell culture and to hare HEV-3 and camel HEV-7 capsid proteins from transfected cells by immunofluorescence assay. The novel mAb may serve as a useful tool for further investigations on the pathogenesis of HEV infections and might be used for diagnostic purposes.

Key points

• The antibody showed cross-reactivity with capsid proteins of different hepeviruses.

• The linear epitope of the antibody was mapped in a partially surface-exposed region.

• The antibody detected native HEV-3 antigen in infected mammalian cells.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-021-11342-7.

IgG antibody response demonstrates inverse correlation with viral load in Bangladeshi women with acute hepatitis E virus genotype 1 infection

OBJECTIVES

To determine IgG immune responses and hepatitis E virus (HEV) viral load, and to explore the associations with pregnancy.

METHODS

A total of 121 HEV-infected women (57 pregnant, 64 non-pregnant) were analysed. Quantitative reverse transcription PCR (RT-qPCR) was done for 78 HEV IgM-positive patients to determine viral load, and Sanger sequencing was performed for 62 HEV-RNA-positive patients to confirm genotyping. ELISA was conducted to determine HEV antibody and avidity indices.

RESULTS

The HEV genotype was identified as variant 1. Significant negative correlations were observed between log HEV copy number and log hepatitis E virus IgG antibody index in the late acute phase of jaundice for both pregnant women (r = -0.7971, p = 0.0002) and non-pregnant women (r = -0.9117, p = 0.0002). Pregnant women had significantly higher serum log viral copy numbers and lower IgG antibody indices than non-pregnant women in the late acute phase of HEV-induced jaundice (p = 0.0196 and p = 0.0303, respectively). Moreover, pregnant women with acute HEV hepatitis had higher cross-reactive IgG antibodies compared to the non-pregnant women (p = 0.0017). Five patients with HEV hepatitis died, of whom four were pregnant.

CONCLUSIONS

Pregnancy might be associated with higher viral loads and a lower IgG response in the HEV-induced late acute phase of jaundice.

Hepatitis E in Latin America

Hepatitis E virus produces an emerging health problem, knowledge about epidemiology of hepatitis E virus infections in the USA and Latin America is still limited. The wide-ranging clinical manifestations lead to an extensive underestimation of the global seroprevalence. Clinical and diagnostic accuracy are critical to improve patient management.

Viral Hepatitis Other than A, B, and C: Evaluation and Management

Viral hepatitis can cause a wide spectrum of clinical presentations from a benign form with minimal or no symptoms to acute liver failure or death. Hepatitis D coinfection and superinfection have distinct clinical courses, with the latter more likely leading to chronic infection. Management of chronic hepatitis D virus is individualized because of the paucity of treatment options and significant side effect profile of currently available treatments. Sporadic cases of hepatitis E caused by contaminated meats are becoming increasingly prevalent in immunocompromised hosts. Human herpesviruses are an important cause of disease also in immunocompromised individuals.

Implications of Hepatitis E Virus in Blood Transfusions, Hemodialysis, and Solid Organ Transplants

Hepatitis E Virus (HEV) is emerging as the primary cause of acute viral hepatitis in humans. The virus is commonly transmitted by the fecal-oral route via contaminated water in endemic regions or through the consumption of inadequately cooked swine products or game meats in industrialized regions. HEV genotypes 1 and 2 are predominantly associated with waterborne transmission in developing countries, whereas HEV3 and HEV4 are mainly zoonotically transmitted in industrialized countries. Seroprevalence in populations determined by detecting anti-HEV antibodies and serum HEV RNA is commonly used to analyze the presence of HEV. Although HEV RNA-based detection is now standardized, there is a lack of agreement between the assaying methods used for gathering seroprevalence data. Since 2004, HEV has been considered as a transmissible infectious agent through blood transfusion. Recent seroprevalence studies in European countries indicate an underestimated risk for blood transfusion and hence warrant testing the blood supply. HEV infection is usually self-limiting and spontaneously cleared. However, in about 60% of recipients of solid organ transplants, HEV progresses to chronic hepatitis. Immunosuppressive drugs such as tacrolimus are a major cause of chronic hepatitis and reducing its dosage results in viral clearance in about 30% of patients. In hemodialysis patients, the parenteral route is implicated as an important mechanism of transmission. In this review, we explore the clinical and epidemiological characteristics of various HEV genotypes in blood donors, hemodialysis patients, and transplant recipients.

Serum alanine aminotransferase flares in chronic hepatitis B infection: the good and the bad

Chronic hepatitis B virus (HBV) infection follows a dynamic and variable course. At different stages in the disease, hepatitis flares might occur, which can be challenging to predict and manage. Flares are believed to be primarily immune-mediated and might mark transitions to inactive disease or clearance of infection, but in certain scenarios they might also lead to hepatic decompensation or death. As such, understanding of the clinical significance of flares in different patient populations and different scenarios is important for optimal management. In this Review, we summarise what is known about flares in different stages of chronic HBV infection; describe flares in the context of the natural history of chronic infection; summarise the immunological mechanisms underlying flares, and describe flares in different clinical scenarios. Each section reviews existing knowledge and highlights key unanswered questions that need to be addressed to improve the understanding of flares, hopefully providing insights into their pathogenesis that can be used to improve current clinical management and ideally to further develop new curative therapeutic approaches for HBV infection. We also propose a working definition of an ALT flare to facilitate future research.

Clinical presentations of Hepatitis E: A clinical review with representative case histories

Hepatitis E virus (HEV) typically causes an acute, self-limiting hepatitis and is among the commonest cause of such presentations. Hepatitis E viral infection is also increasingly recognized as a cause of chronic hepatitis amongst the immunocompromised, particularly amongst solid organ transplant recipients. Chronic HEV infection remains an underdiagnosed disease and chronic infection can lead to rapidly progressive liver fibrosis and cirrhosis. This review examines current understanding of the HEV. We illustrate typical clinical presentations, management strategies [(based upon guidelines from both the British Transplant Society (BTS) and European Association for the study of liver (EASL)] and outcomes of HEV infection in different cohorts of patients by highlighting select transplant and non-transplant patient cases, from one of the largest tertiary Hepatology centres in Europe.

Hepatitis E during pregnancy: Maternal and foetal case-fatality rates and adverse outcomes-A systematic review

Hepatitis E virus infection during pregnancy can have severe consequences for mother and child, such as vertical transmission, fulminant hepatic failure, even foetal or maternal mortality. The aim of this systematic review is to describe maternal, foetal and neonatal case-fatality rates as well as the prevalence of adverse outcomes in relation to hepatitis E virus infection during pregnancy. A systematic literature search was performed in Pubmed, Embase, Cochrane and CINAHL. Search terms included Pregnant, Women, Maternal, Infant, Foetal, Neonatal and Hepatitis E virus. Data were extracted using predefined data collection forms. All studies were quality assessed, either by the Newcastle-Ottawa Scale or by an adapted assessment scale for cross-sectional studies. We found 23 eligible studies, all observational, which were included in this systematic review with a total of 1338 cases. The median maternal, foetal and neonatal case-fatality rates were 26% (IQR 17%-41%), 33% (IQR 19%-37%) and 8% (IQR 3%-20%), respectively. Adverse outcomes such as fulminant hepatic failure, preterm labour, postpartum haemorrhage, low birth weight and vertical transmission were reported. The two studies that reported the highest prevalence of fulminant hepatic failure also reported the highest case-fatality rates. The median prevalence of fulminant hepatic failure was 45.3%. This systematic review found a high case-fatality rate among pregnant women infected with hepatitis E virus and a high rate of adverse outcomes among these women and their children. The results from this review mainly apply to hospital settings and symptomatic pregnant women from endemic countries.

Outbreak of Hepatitis E Virus Infection in Displaced Persons Camps in Diffa Region, Niger, 2017

Hepatitis E virus (HEV) infection in developing countries is associated with poor hygiene, lack of clean drinking water, and inadequate sanitation. In this study, we report the first case investigation and describe the present situation of HEV outbreak within displaced persons camps in the Diffa region, Republic of Niger. The investigation showed the outbreak to be closely linked to unclean water supply, low hygiene, and sanitation facility standards. Between January and September 2017, a total of 1,917 HEV suspect cases were recorded from which 736 (38.4%) have been confirmed positive for HEV by reverse transcription polymerase chain reaction and enzyme linked immunosorbent assay. Overall, 38 (1.9%) deaths were recorded, including 17 (44.7%) pregnant women. The ongoing outbreak highlights poor drinking water quality and sanitation conditions in displaced persons camps in the Diffa region. Disease containment and patient care activities, particularly for pregnant women, may have resulted in decreased transmission of infection and deaths.

Immunogenicity and safety of an accelerated hepatitis E vaccination schedule in healthy adults: a randomized, controlled, open-label, phase IV trial

OBJECTIVES

This study aimed to evaluate the immunogenicity and safety of a hepatitis E (HE) vaccine using an accelerated vaccination schedule (vaccine doses at 0, 7 and 21 days).

METHODS

A total of 126 participants aged ≥18 years were randomly assigned to receive the hepatitis E virus vaccine in either the accelerated group (0, 7 and 21 days) or the routine group (0, 1 and 6 months). Serology samples were obtained at 0, 21, 28 and 51 days, and 7 months in the accelerated group, or 0, 1, 2 and 7 months in the routine group after the first vaccine injection. Adverse events (AEs) reported during the whole study were analysed.

RESULTS

A total of 126 participants were randomized, 63 for each group. Sixty-two participants in the accelerated group and 63 in the routine group received at least one dose of vaccine; 57 and 63 participants received all three doses and were included in per-protocol set, respectively. In the per-protocol population, at 1 month after the last dose (accelerated group at 51 days versus routine group at 7 months), the seropositive rates were both 100% (57/57 and 63/63, respectively), and the geometric mean concentrations (GMCs) were 8.51 WHO units/mL (95% CI 6.73-10.76) in the accelerated group and 9.67 WHO units/mL (95% CI 7.67-12.20) in the routine group. The ratio of the accelerated group GMC to the routine group GMC was 0.88 (95% CI 0.61-2.17, lower limit of 95% CI > 0.5), indicating that the accelerated vaccination schedule was non-inferior to the routine one. The overall incidence rates of solicited AEs in the accelerated and routine groups were 32.26% (20/62) and 30.16% (19/63), respectively (p 0.800). Most AEs were moderate.

CONCLUSIONS

An accelerated schedule is safe and provides protective antibodies in a shorter time compared with the routine schedule. The accelerated schedule should be recommended to adults who are travelling on short notice to an HE-endemic area or during an HE outbreak (Clinical Trial Registration. NCT03168412).

Hepatitis E virus seroprevalence among blood donors in Pune, India

BACKGROUND

Blood transfusion is a recently reported route of hepatitis E virus (HEV) transmission. It is a bigger concern in regions where large-scale HEV genotype 1 infections occur causing more severe disease. The present study aims to assess the prevalence and rate of HEV infection in the blood donors of Pune, India.

MATERIALS AND METHODS

A total of 2447 healthy blood donors were screened for anti-HEV IgG and IgM antibodies. Anti-HEV IgM antibody positives were further subjected to alanine aminotransferase measurement, HEV RNA detection, viral load quantification and phylogenetic analysis.

RESULTS

Anti-HEV seroprevalence rate was 17.70%, while IgM prevalence rate was 0.20%. An age dependent increase in IgG seropositive rate was observed. Two of five IgM-positives tested positive for HEV RNA. The viral load ranged from 3.5 × 10⁴ to 4.6 × 10⁵ copies/mL and belonged to HEV genotype 1.

CONCLUSIONS

HEV prevalence rate of 17.70% in the blood donors of Pune, India, a developing country, goes at par with the developed countries. Current data of 0.20% (5 of 2447) blood donors positive for anti-HEV IgM and two of them being HEV RNA positive suggest a need for consideration of cost-effective evaluation towards pooled HEV RNA testing in blood banks.

Reactive and pre-emptive vaccination strategies to control hepatitis E infection in emergency and refugee settings: A modelling study

BACKGROUND

Hepatitis E Virus (HEV) is the leading cause of acute viral hepatitis globally. Symptomatic infection is associated with case fatality rates of ~20% in pregnant women and it is estimated to account for ~10,000 annual pregnancy-related deaths in southern Asia alone. Recently, large and well-documented outbreaks with high mortality have occurred in displaced population camps in Sudan, Uganda and South Sudan. However, the epidemiology of HEV is poorly defined, and the value of different immunisation strategies in outbreak settings uncertain. We aimed to estimate the critical epidemiological parameters for HEV and to evaluate the potential impact of both reactive vaccination (initiated in response to an epidemic) and pre-emptive vaccination.

METHODS

We analysed data from one of the world's largest recorded HEV epidemics, which occurred in internally-displaced persons camps in Uganda (2007-2009), using transmission dynamic models to estimate epidemiological parameters and assess the potential impact of reactive and pre-emptive vaccination strategies.

RESULTS

Under baseline assumptions we estimated the basic reproduction number of HEV in three separate camps to range from 3.7 (95% Credible Interval [CrI] 2.8, 5.1) to 8.5 (5.3, 11.4). Mean latent and infectious periods were estimated to be 34 (95% CrI 28, 39) and 40 (95% CrI 23, 71) days respectively. Assuming 90% vaccine coverage, reactive two-dose vaccination of those aged 16-65 years excluding pregnant women (for whom vaccine is not licensed), if initiated after 50 reported cases, led to mean camp-specific reductions in mortality of 10 to 29%. Pre-emptive vaccination with two doses reduced mortality by 35 to 65%. Both strategies were more effective if coverage was extended to groups for whom the vaccine is not currently licensed. For example, two dose pre-emptive vaccination, if extended to include pregnant women, led to mean reductions in mortality of 66 to 82%.

CONCLUSIONS

HEV has a high transmission potential in displaced population settings. Substantial reductions in mortality through vaccination are expected, even if used reactively. There is potential for greater impact if vaccine safety and effectiveness can be established in pregnant women.

Changing Epidemiology of Hepatitis A and Hepatitis E Viruses in China, 1990-2014

We compared the epidemiology of hepatitis A and hepatitis E cases in China from 1990-2014 to better inform policy and prevention efforts. The incidence of hepatitis A cases declined dramatically, while hepatitis E incidence increased. During 2004-2014, hepatitis E mortality rates surpassed those of hepatitis A.

Changing Epidemiology of Hepatitis A and Hepatitis E Viruses in China, 1990-2014

We compared the epidemiology of hepatitis A and hepatitis E cases in China from 1990–2014 to better inform policy and prevention efforts. The incidence of hepatitis A cases declined dramatically, while hepatitis E incidence increased. During 2004–2014, hepatitis E mortality rates surpassed those of hepatitis A.

Hepatitis E virus - key points for the clinical haematologist

In recent years there has been a paradigm shift in our understanding of the epidemiology and clinical features of hepatitis E virus (HEV) infection. Once classically described as an acute hepatitis associated with waterborne outbreaks in areas of poor sanitation, HEV is now recognised to be endemic in Europe and is probably zoonotic in origin. Evidence for transfusion-transmitted HEV has prompted the introduction of blood donor screening in a number of countries, but the risk to the haematology patient from food sources remains. The aim of this review therefore, is to equip the clinical haematologist with the knowledge required to diagnose HEV infection and to aid decision-making in patient management. The article also provides information on addressing patient concerns about their risk of acquiring hepatitis E and how this risk can be mitigated.

Clinical Manifestations of Hepatitis E

The clinical manifestations of hepatitis E are similar to those of other types of viral hepatitis. While acute hepatitis E is usually self-limited, pregnant women and chronic liver disease patients suffering from acute hepatitis E usually present with severe clinical manifestations that may develop into fulminant hepatic failure. Chronic HEV infection is typically only seen in organ transplant patients; most HEV cases are asymptomatic and rarely display jaundice, fatigue, abdominal pain, fever, fatigue, or ascites. The clinical manifestations of HEV infection in neonates are diverse and have varied clinical signs, biochemistry, and virus biomarkers. Lastly, the extrahepatic manifestations and complications of hepatitis E are in need of further study.

Hepatitis E virus RNA in Australian blood donors: prevalence and risk assessment

BACKGROUND AND OBJECTIVES

Hepatitis E virus (HEV) is a known transfusion-transmissible agent. HEV infection has increased in prevalence in many developed nations with RNA detection in donors as high as 1 in 600. A high proportion of HEV infections are asymptomatic and therefore not interdicted by donor exclusion criteria. To manage the HEV transfusion-transmission (TT) risk some developed nations have implemented HEV RNA screening. In Australia, HEV is rarely notified; although locally acquired infections have been reported, and the burden of disease is unknown. The purpose of this study was to determine the frequency of HEV infection in Australian donors and associated TT risk.

MATERIALS AND METHODS

Plasma samples (n = 74 131) were collected from whole blood donors during 2016 and screened for HEV RNA by transcription-mediated amplification (TMA) in pools of six. Individual TMA reactive samples were confirmed by RT-PCR and, if positive, viral load determined. Prevalence data from the study were used to model the HEV-TT risk.

RESULTS

One sample in 74 131 (95% CI: 1 in 1 481 781 to 1 in 15 031) was confirmed positive for HEV RNA, with an estimated viral load of 180 IU/ml, which is below that typically associated with TT. Using a transmission-risk model, we estimated the risk of an adverse outcome associated with TT-HEV of approximately 1 in 3·5 million components transfused.

CONCLUSION

Hepatitis E virus viremia is rare in Australia and lower than the published RNA prevalence estimates of other developed countries. The risk of TT-HEV adverse outcomes is negligible, and HEV RNA donor screening is not currently indicated.

Review article: hepatitis E-a concise review of virology, epidemiology, clinical presentation and therapy

BACKGROUND

Hepatitis E virus (HEV) is a leading cause of acute icteric hepatitis and acute liver failure in the developing world. During the last decade, there has been increasing recognition of autochthonous (locally acquired) HEV infection in developed countries. Chronic HEV infection is now recognised, and in transplant recipients this may lead to cirrhosis and organ failure.

AIM

To detail current understanding of the molecular biology of HEV, diagnostic and therapeutic strategies and propose future directions for basic science and clinical research.

METHODS

PubMed was searched for English language articles using the key words "hepatitis E", "viral hepatitis", "autochthonous infection", "antiviral therapy", "liver transplantation", "acute", "chronic", "HEV", "genotype", "transmission" "food-borne", "transfusion". Additional relevant publications were identified from article reference lists.

RESULTS

There has been increasing recognition of autochthonous HEV infection in Western countries, mainly associated with genotype 3. Chronic HEV infection has been recognised since 2008, and in transplant recipients this may lead to cirrhosis and organ failure. Modes of transmission include food-borne transmission, transfusion of blood products and solid organ transplantation. Ribavirin therapy is used to treat patients with chronic HEV infection, but new therapies are required as there have been reports of treatment failure with ribavirin.

CONCLUSIONS

Autochthonous HEV infection is a clinical issue with increasing burden. Future work should focus on increasing awareness of HEV infection in the developed world, emphasising the need for clinicians to have a low threshold for HEV testing, particularly in immunosuppressed patients. Patients at potential risk of chronic HEV infection must also be educated and given advice regarding prevention of infection.

Hepatitis E virus infections in travellers: assessing the threat to the Australian blood supply

BACKGROUND

In many developed countries hepatitis E virus (HEV) infections have occurred predominantly in travellers to countries endemic for HEV. HEV is a potential threat to blood safety as the virus is transfusion-transmissible. To minimise this risk in Australia, individuals diagnosed with HEV are deferred. Malarialdeferrals, when donors are restricted from donating fresh blood components following travel toanareain which malaria is endemic, probably also decrease the HEV risk, by deferring donors who travel to many countries also endemic for HEV. The aim of this study is to describe overseas-acquired HEV cases in Australia, in order to determine whether infection in travellers poses a risk to Australian blood safety.

MATERIALS AND METHODS

Details of all notified HEV cases in Australia from 2002 to 2014 were accessed, and importation rates estimated. Countries in which HEV was acquired were compared to those for which donations are restricted following travel because of a malaria risk.

RESULTS

Three hundred and thirty-two cases of HEV were acquired overseas. Travel to India accounted for most of these infections, although the importation rate was highest for Nepal and Bangladesh. Countries for which donations are restricted following travel due to malaria risk accounted for 94% of overseas-acquired HEV cases.

DISCUSSION

The vast majority of overseas-acquired HEV infections were in travellers returning from South Asian countries, which are subject to donation-related travel restrictions for malaria. This minimises the risk HEV poses to the Australian blood supply.

Hepatitis E and pregnancy: current state

Hepatitis E virus (HEV) is responsible for more than 50% of acute viral hepatitis cases in endemic countries. Approximately 2 billion individuals live in hepatitis E-endemic areas and, therefore, are at risk of infection. According to World Health Organization, HEV causes about 20.1 million infections and 70 000 deaths every year. In developing countries with poor sanitation, this disease is transmitted through contaminated water and is associated with large outbreaks, affecting hundreds or thousands of people. In developed countries, autochthonous cases of HEV have been increasingly recognized in the past several years. Hepatitis E virus typically causes an acute, self-limiting illness similar to other acute viral hepatitis, such as hepatitis A or B, with about 0.2% to 1% mortality rate in the general population. However, the course of hepatitis E in pregnancy is different than the mild self-constraining infection described in other populations. During pregnancy, HEV infection can take a fulminant course, resulting in fulminant hepatic failure, membrane rupture, spontaneous abortions, and stillbirths. Studies from various developing countries have shown a high incidence of HEV infection in pregnancy with a significant proportion of pregnant women progressing to fulminant hepatitis with a fatality rate of up to 30%. The present review will highlight new aspects of the HEV infection and pregnancy.

Xenotransplantation - A special case of One Health

The chronic shortage of human transplants to treat tissue and organ failure has led to the development of xenotransplantation, the transplantation of cells, tissues and organs from another species to human recipients. For a number of reasons, pigs are best suited as donor animals. Successful, routine xenotransplantation would have an enormous impact on the health of the human population, including the young, who sometimes require a replacement organ or islet cells, but especially the elderly, who more often suffer the consequences of organ failure. The first form of xenotransplantation applied to humans is the use of pig islet cells to treat insulin-dependent diabetes, a procedure that will have a significant economic impact. However, although xenotransplantation using pig cells, tissues and organs may save and prolong the lives of patients, it may also be associated with the transmission of porcine microorganisms to the recipient, eventually resulting in emerging infectious diseases. For this reason, the health of both the donor animals and the human recipients represents a special and sensitive case of the One Health concept. Basic research leading to strategies how to prevent transmission of porcine microorganisms by selection of virus-free animals, treatment of donor pigs by antiviral drugs, vaccines, colostrum deprivation, early weaning, Caesarean delivery, embryo transfer and/or gene editing should be undertaken to supply an increasing number of potential recipients with urgently required transplants. The methods developed for the detection and elimination of porcine microorganisms in the context of xenotransplantation will also contribute to an improvement in the health of pig populations in general and an increase in the quality of meat products. At present, there is evidence for transmission of porcine viruses to humans eating pork and having contact with pigs, however the impact of these viruses on public health is still unknown.

Hepatitis E virus seroepidemiology: a post-earthquake study among blood donors in Nepal

Background

As one of the causative agents of viral hepatitis, hepatitis E virus (HEV) has gained public health attention globally. HEV epidemics occur in developing countries, associated with faecal contamination of water and poor sanitation. In industrialised nations, HEV infections are associated with travel to countries endemic for HEV, however, autochthonous infections, mainly through zoonotic transmission, are increasingly being reported. HEV can also be transmitted by blood transfusion. Nepal has experienced a number of HEV outbreaks, and recent earthquakes resulted in predictions raising the risk of an HEV outbreak to very high. This study aimed to measure HEV exposure in Nepalese blood donors after large earthquakes.

Methods

Samples (n = 1,845) were collected from blood donors from Kathmandu, Chitwan, Bhaktapur and Kavre. Demographic details, including age and sex along with possible risk factors associated with HEV exposure were collected via a study-specific questionnaire. Samples were tested for HEV IgM, IgG and antigen. The proportion of donors positive for HEV IgM or IgG was calculated overall, and for each of the variables studied. Chi square and regression analyses were performed to identify factors associated with HEV exposure.

Results

Of the donors residing in earthquake affected regions (Kathmandu, Bhaktapur and Kavre), 3.2% (54/1,686; 95% CI 2.7–4.0%) were HEV IgM positive and two donors were positive for HEV antigen. Overall, 41.9% (773/1,845; 95% CI 39.7–44.2%) of donors were HEV IgG positive, with regional variation observed. Higher HEV IgG and IgM prevalence was observed in donors who reported eating pork, likely an indicator of zoonotic transmission. Previous exposure to HEV in Nepalese blood donors is relatively high.

Conclusion

Detection of recent markers of HEV infection in healthy donors suggests recent asymptomatic HEV infection and therefore transfusion-transmission in vulnerable patients is a risk in Nepal. Surprisingly, this study did not provide evidence of a large HEV outbreak following the devastating earthquakes in 2015.

Hospitalizations in Immigrants and Nonimmigrants Diagnosed With Chronic Hepatitis C Infection in Québec

BACKGROUND

 Rates of hospitalization due to chronic hepatitis C virus (HCV) are increasing in Canada and the United States. A large proportion of immigrants originate from countries with intermediate to high HCV prevalence but are not screened for HCV post-arrival and may therefore have increased risks of liver-related complications and hospitalization.

METHODS

 We conducted a retrospective cohort study of reported HCV cases in Québec, Canada, from 1998 to 2007 that were linked to administrative health databases. Outcomes included all-cause and liver-related hospitalizations and in-hospital days in immigrants compared with nonimmigrants adjusted for age, sex, and comorbidities.

RESULTS

 We identified 20 139 HCV cases; 9% (N = 1821) were immigrants. At diagnosis, immigrants were older (47.6 vs 43.2 years) and more likely to have hepatocellular carcinoma (HCC; 0.93% vs 0.31%), while nonimmigrants were 2- to 10-fold more likely to have substance use-related comorbidities. Mean time to HCV diagnosis after arrival was 9.8 years. Nonimmigrants had higher rates of all-cause hospitalization (adjusted rate ratio [95% confidence interval], 1.42 [1.35-1.47]), driven by mental illness and injury and/or poisoning. Unadjusted liver-related hospitalization rates were similar between cohorts. After adjustment, immigrant status was associated with lower rates of liver-related hospitalization (0.68 [.53-.88]).

CONCLUSIONS

 Higher burden of all-cause hospitalization in nonimmigrants likely reflects more prevalent behavioral comorbidities. Similar liver-related hospitalization rates appear to be driven by older age in immigrants who were more likely to have HCC at diagnosis possibly reflecting delayed HCV diagnosis. These findings suggest that earlier screening and treatment in immigrants could play an important role in preventing HCV complications in this population.

Thermal Stability of Hepatitis E Virus as Estimated by a Cell Culture Method

Hepatitis E virus (HEV) is an increasingly recognized zoonotic pathogen. Transmission is suspected to occur from infected pigs or wild boars to humans through direct contact, environmental pathways, or contaminated food. However, the physical and chemical stability of HEV is largely unknown, because suitable cell culture methods for infectivity measurement are missing. Here, we developed a titration method using infection of the cell line A549/D3 with HEV genotype 3 strain 47832c and subsequent counting of focus-forming units by immunofluorescence, which allowed HEV infectivity measurements within a 4-log-dilution range. Long-term storage of HEV in cell culture medium at different temperatures indicated a phase of rapid virus inactivation, followed by a slower progression of virus inactivation. Infective HEV was detected up to 21 days at 37°C, up to 28 days at room temperature, and until the end of the experiment (56 days) with a 2.7-log decrease of infectious virus at 4°C. Heat treatment for 1 min resulted in moderate decreases of infectivity up to 60°C, 2- to 3.5-log decreases between 65°C and 75°C, and no remaining virus was detected at temperatures of ≥80°C. Heating for 70°C resulted in a 3.6-log decrease after 1.5 min and the absence of detectable virus (>3.9-log decrease) after 2 min. The data were used to calculate predictive heat inactivation models for HEV. The results may help estimate HEV stability in the environment or food. The established method may be used to study other aspects of HEV stability in the future.

IMPORTANCE

In this study, a cell culture method was developed which allows the measurement of hepatitis E virus (HEV) infectivity. Using this system, the stability of HEV at different time-temperature combinations was assessed, and a predictive model was established. The obtained data may help estimate HEV stability in the environment or food, thus enabling an assessment of the relative risks of HEV infection through distinct routes and by distinct types of food in the future.

Hepatitis E virus is the leading cause of acute viral hepatitis in Lothian, Scotland

Acute viral hepatitis affects all ages worldwide. Hepatitis E virus (HEV) is increasingly recognized as a major cause of acute hepatitis in Europe. Because knowledge of its characteristics is limited, we conducted a retrospective study to outline demographic and clinical features of acute HEV in comparison to hepatitis A, B and C in Lothian over 28 months (January 2012 to April 2014). A total of 3204 blood samples from patients with suspected acute hepatitis were screened for hepatitis A, B and C virus; 913 of these samples were also screened for HEV. Demographic and clinical information on patients with positive samples was gathered from electronic patient records. Confirmed HEV samples were genotyped. Of 82 patients with confirmed viral hepatitis, 48 (59%) had acute HEV. These patients were older than those infected by hepatitis A, B or C viruses, were more often male and typically presented with jaundice, nausea, vomiting and/or malaise. Most HEV cases (70%) had eaten pork or game meat in the few months before infection, and 14 HEV patients (29%) had a recent history of foreign travel. The majority of samples were HEV genotype 3 (27/30, 90%); three were genotype 1. Acute HEV infection is currently the predominant cause of acute viral hepatitis in Lothian and presents clinically in older men. Most of these infections are autochthonous, and further studies confirming the sources of infection (i.e. food or blood transfusion) are required.

Clinical and virological predictors of hepatic flares in pregnant women with chronic hepatitis B

BACKGROUND

Unique immunological changes occur during pregnancy; the impact of which, on virological and biochemical markers of hepatitis B infection is not well established. Rapid changes in the immunological profile post partum and consequent rebound of the inflammatory response may result in hepatic flares.

METHODS

Women with chronic hepatitis B were recruited during pregnancy into this observational study. Demographic and clinical data were collected together with virological and biochemical parameters at two time points during pregnancy (early and late) and two time points post partum (between 6 weeks and 12 weeks and at 12 months). Outcomes analysed included changes in HBV DNA, hepatitis B e antigen (HBeAg) status and flares of hepatitis.

RESULTS

One hundred and twenty-six women were recruited. Twenty-seven women out of 108 with postpartum bloods (25%) met our definition of a postpartum flare (ALT range 38-1654). Using univariate analysis HBeAg status, younger age, gravida and parity were associated with a flare. On multivariate analysis HBeAg positivity at baseline fell just outside of statistical significance in predicting a postpartum flare (p=0.051).

CONCLUSIONS

25% of women with chronic hepatitis B will demonstrate increased liver inflammation in the postpartum period. This is usually asymptomatic and resolves spontaneously. This is more likely if the woman is HBeAg-positive at baseline (2.56 times the risk), although flares also commonly occur in HBeAg-negative women.

Extended Microbiological Characterization of Göttingen Minipigs in the Context of Xenotransplantation: Detection and Vertical Transmission of Hepatitis E Virus

Xenotransplantation has been proposed as a solution to the shortage of suitable human donors. Pigs are currently favoured as donor animals for xenotransplantation of cells, including islet cells, or organs. To reduce the xenotransplantation-associated risk of infection of the recipient the pig donor should be carefully characterised. Göttingen minipigs from Ellegaard are often used for biomedical research and are regularly tested by their vendor for the presence of numerous bacteria, fungi, viruses and parasites. However, screening for some pathogens transmittable to humans had not been performed.The presence of microorganisms was examined in Göttingen Minipigs by PCR methods. Since zoonotic transmission of porcine hepatitis E virus HEV to humans has been demonstrated, extended search for HEV was considered as a priority. RNA from sera, islet and other cells from 40 minipigs were examined for HEV using different real-time reverse transcription (RT)-PCRs, among them two newly established. In addition, sera were examined by Western blot analysis using two recombinant capsid proteins of HEV as antigens. HEV RNA was not detected in pigs older than one year including gilts, but it was detected in the sera of three of ten animals younger than 1 year. Furthermore, HEV was also detected in the sera of three sows six days after delivery and their offspring, indicating vertical transmission of the virus. PCR amplicons were cloned, sequenced and the viruses were found to belong to the HEV genotype (gt) 3/4. Anti-HEV immunoglobulins G were detected in one sow and maternal antibodies in her six day old piglet. Since Göttingen minipigs were negative for many xenotransplantation-relevant microorganisms, they can now be classified as safe. HEV may be eliminated from the Ellegaard herd by selection of negative animals and/or by treatment of the animals.

Hepatitis E virus in patients with decompensated chronic liver disease: a prospective UK/French study

BACKGROUND

In developed countries, hepatitis E is a porcine zoonosis caused by hepatitis E virus (HEV) genotype 3. In developing countries, hepatitis E is mainly caused by genotype 1, and causes increased mortality in patients with pre-existing chronic liver disease (CLD).

AIM

To determine the role of HEV in patients with decompensated CLD.

METHODS

Prospective HEV testing of 343 patients with decompensated CLD at three UK centres and Toulouse France, with follow-up for 6 months or death. IgG seroprevalence was compared with 911 controls.

RESULTS

11/343 patients (3.2%) had acute hepatitis E infection, and three died. There were no differences in mortality (27% vs. 26%, OR 1.1, 95% CI 0.28-4.1), age (P = 0.9), bilirubin (P = 0.5), alanine aminotransferase (P = 0.06) albumin (P = 0.5) or international normalised ratio (P = 0.6) in patients with and without hepatitis E infection. Five cases were polymerase chain reaction (PCR) positive (genotype 3). Hepatitis E was more common in Toulouse (7.9%) compared to the UK cohort (1.2%, P = 0.003). HEV IgG seroprevalence was higher in Toulouse (OR 17, 95% CI 9.2-30) and Truro (OR 2.5, 95% CI 1.4-4.6) than in Glasgow, but lower in cases, compared to controls (OR 0.59, 95% CI 0.41-0.86).

CONCLUSIONS

Hepatitis E occurs in a minority of patients with decompensated chronic liver disease. The mortality is no different to the mortality in patients without hepatitis E infection. The diagnosis can only be established by a combination of serology and PCR, the yield and utility of which vary by geographical location.

Hepatitis E in developed countries: current status and future perspectives

Hepatitis E virus (HEV) was for many years thought to be found almost exclusively in developing countries, where it is a major health issue. Recent studies have shown that HEV causes acute and chronic infection in developed countries. In these geographical settings, HEV is primarily a porcine zoonosis caused by genotypes 3 (HEV3) and 4 (HEV4). The clinical phenotype of hepatitis E continues to emerge, and recent data show that HEV is associated with a range of neurological syndromes including Guillain-Barré syndrome and neuralgic amytrophy.

Hepatitis E Virus of Subtype 3a in a Pig Farm, South-Eastern France

Hepatitis E virus (HEV) has emerged during the past decade as a causative agent of autochthonous hepatitis and is a clinical concern in Western developed countries. It has been increasingly recognized that pigs are a major reservoir of HEV of genotypes 3 and 4 worldwide and pig-derived food items represent a potential source of infections by these viruses in humans. Hepatitis E virus RNA testing was performed here on faeces from rectal swabs sampled in 2012 from 50 3-month-old farm pigs from the same farm located in south-eastern France than in a previous work conducted in 2007. Pig HEV sequences corresponding to genomic fragments of ORF2 and ORF1 genes were obtained after RT-PCR amplification with in-house protocols. Hepatitis E virus genotype was determined by phylogenetic analysis. Prevalence was similar to that determined 5 years earlier (68% versus 62%). Two robust phylogenetic clusters of HEV subtypes 3a and 3f were identified, and these sequences obtained in 2012 largely differ compared with those obtained in 2007. Notably, HEV sequences obtained in 2012 from a majority (62%) of the infected pigs belonged to subtype 3a, which was not previously described in France, including not being found in any of humans, pigs or wild boars. Further studies are needed to assess the circulation of HEV-3a in pigs and humans in this country. In addition, along with previous findings, this study supports the need for increased information to the public on the risk of HEV infection through contacts with pigs or consumption of pig-derived products in France.

Virus safety of islet cell transplantation from transgenic pigs to marmosets

Transplantation of pig islet cells for the treatment of diabetes may be a more effective approach compared with the application of insulin. However, before introduction into the clinic, efficacy and safety of this treatment have to be shown. Non-human primate models may be used for this, despite the fact that they are characterised by several limitations. Here we investigate the prevalence of porcine endogenous retroviruses (PERVs), which are present in the genome of all pigs and which may infect human cells, as well as of porcine herpes viruses in donor pigs and their potential transmission to non-human primate recipients. Despite the fact that all three subtypes of PERV were present in all and porcine cytomegalovirus (PCMV) was found in some of the pigs, neither PERVs nor PCMV were found in the recipient animals under the experimental conditions applied. Porcine lymphotropic herpes viruses (PLHV) were not found in the donor pigs, hepatitis E virus (HEV) was not found in the recipients.

Xenotransplantation and Hepatitis E virus

Xenotransplantation using pig cells, tissues and organs may be associated with the transmission of porcine microorganisms to the human recipient. Some of these microorganisms may induce a zoonosis, that is an infectious disease induced by microorganisms transmitted from another species. With exception of the porcine endogenous retroviruses (PERVs), which are integrated in the genome of all pigs, the transmission of all other microorganisms can be prevented by specified or designated pathogen-free (spf or dpf, respectively) production of the animals. However, it is becoming clear in the last years that the hepatitis E virus (HEV) is one of the viruses which are difficult to eliminate. It is important to note that there are differences between HEV of genotypes (gt) 1 and gt2 on one hand and HEV of gt3 and gt4 on the other. HEV gt1 and gt2 are human viruses, and they induce hepatitis and in the worst case fatal infections in pregnant women. In contrast, HEV gt3 and gt4 are viruses of pigs, and they may infect humans, induce commonly only mild diseases, if any, and are harmless for pregnant women. The goal of this review was to evaluate the risk posed by HEV gt3 and gt4 for xenotransplantation and to indicate ways of their elimination from pigs in order to prevent transmission to the human recipient.

Hepatitis E virus: do locally acquired infections in Australia necessitate laboratory testing in acute hepatitis patients with no overseas travel history?

Hepatitis E virus (HEV) is emerging as a global public health threat. Water-borne HEV outbreaks are common in developing countries and are associated with genotypes 1 and 2. In industrialised countries, sporadic cases of zoonotic transmission associated with genotypes 3 and 4 are increasingly being reported. Transfusion- and transplantation-transmitted HEV have been documented, although ingestion of contaminated food is thought to be the major transmission route. Severe disease is possible and chronic hepatitis infection occurs in solid-organ-transplant recipients and in patients with immunosuppressive disorders. In Australia, HEV cases are mainly travellers returning from disease endemic countries. Indeed, there are few reported cases of locally acquired HEV. Pigs in Australia have been shown to be infected with HEV, which indicates the possibility of zoonotic transmission. The extent of locally acquired infection is not known, however it may be greater than expected and may necessitate laboratory testing in patients reporting no overseas travel.

The impact of hepatitis E in the liver transplant setting

Hepatitis E virus (HEV) infection has been identified as a cause of graft hepatitis in liver transplant recipients. The true frequency and clinical importance of HEV infections after liver transplantations is a matter of debate. It is proposed that consumption of HEV-contaminated undercooked meat is a main source for HEV infections in developed countries--which might also account for some hepatitis E cases after organ transplantation. However, HEV is also transmitted by transfusion of blood products, likely representing a previously underestimated risk particularly for patients in the transplant setting. HEV infection can take chronic courses in immunocompromised individuals, associated in some cases with rapid progression to cirrhosis within 1-2 years of infection. Diagnosis in transplanted patients is based on HEV RNA testing as antibody assays are not sensitive enough. Selection of immunosuppressive drugs is important as different compounds may influence viral replication and the course of liver disease. Ribavirin has antiviral activity against HEV and should be administered for at least three months in chronically infected individuals; however, treatment failure may occur. HEV infections have also been linked to a variety of extrahepatic manifestations both during and after resolution of infection. In this review we summarize the emerging data on hepatitis E with a particular focus on the importance of HEV infections for liver transplant recipients.

Prevalence of hepatitis E virus in slaughter-age pigs in Scotland

The prevalence of anti-HEV isotype-specific antibodies and viraemia were investigated in serum samples collected from slaughter-age pigs (aged 22-24 weeks) from 23 farms in Scotland. Of 176 serum samples tested, 29·0% (n = 51) were anti-HEV IgG positive, 36·9% (n = 65) anti-HEV IgA positive and 29·0% (n = 51) anti-HEV IgM positive. Overall seroprevalence (anti-HEV IgG+ and/or IgA+ and/or IgM+) was 61·4% (n = 108). HEV RNA was detected in 72/162 serum samples (44·4%). Partial sequence of ORF2 (98 nt) was obtained from eight HEV RNA-positive samples and phylogenetic analysis confirmed that they were all of genotype 3. This is the first report on the prevalence of HEV in pigs in Scotland. Given the increasing incidence of locally acquired HEV infection in the UK, evidence that HEV is a foodborne zoonosis emphasizes the need for surveillance in pigs.