High hepatitis E virus seroprevalence with absence of chronic infection in HIV-infected patients

Hepatitis E Virus (HEV) Infection Among Immunocompromised Individuals: A Brief Narrative Review

Hepatitis E virus (HEV) is a single-stranded positive-sense RNA virus that belongs to Hepeviridae family. HEV is the most common cause of acute viral hepatitis worldwide. According to the World Health Organization (WHO), there are estimated 20 million HEV infections worldwide every year, leading to estimated 3.3 million symptomatic cases of HEV infection. The WHO estimates that HEV infection caused approximately 44,000 deaths in 2015, which represents 3.3% of mortality rates due to viral hepatitis. In low-income (LI) countries and lower-middle-income (LMI) countries, HEV is a waterborne infection induced by HEV genotype (gt) 1 and HEV gt 2 that cause large outbreaks and affect young individuals with a high mortality rate in pregnant women from South Asian countries and patients with liver diseases. HEV gt 3, HEV gt 4, and HEV gt 7 are responsible for sporadic infections with zoonotic transmission mainly through the consumption of raw or undercooked meat from different animals. Acute HEV infection is relatively asymptomatic or mild clinical form, in rare cases the disease can be moderate/severe clinical forms and result in fulminant hepatitis or acute liver failure (ALF). Furthermore, HEV infection is associated with extrahepatic manifestations, including renal and neurological clinical signs and symptoms. Pregnant women, infants, older people, immunocompromised individuals, patients with comorbidities, and workers who come into close contact with HEV-infected animals are recognized as major risk groups for severe clinical form of HEV infection and fatal outcome. Chronic HEV infection can occur in immunocompromised individuals with the possibility of progression to cirrhosis.

Hepatitis E Virus in the Iberian Peninsula: A Systematic Review

One of the most frequent causes of acute viral hepatitis is hepatitis E virus (HEV) causing 20 million infections worldwide each year and 44,000 deaths. Studies on HEV in the Iberian Peninsula have been increasing through time with HEV infection being identified in humans and animals. The aim of the present systematic review was to compile and evaluate all the published data on HEV from studies performed in humans, animals and environmental samples in the Iberian Peninsula. The electronic databases Mendeley, PubMed, Scopus, and Web of Science were thoroughly searched, and research published up until February 01, 2023 were included. Resulting in a total of 151 eligible papers by full reading and application of PRISMA exclusion/inclusion criteria. Overall, the present review shows that several HEV genotypes, namely HEV-1, 3, 4, and 6 as well as Rocahepevirus, are circulating in humans, animals, and in the environment in the Iberian Peninsula. HEV-3 was the most common genotype circulating in humans in Portugal and Spain, as expected for developed countries, with HEV-1 only being detected in travelers and emigrants from HEV endemic regions. Spain is the biggest pork producer in Europe and given the high circulation of HEV in pigs, with HEV-3 being primarily associated to zoonotic transmission through consumption of swine meat and meat products, in our opinion, the introduction of an HEV surveillance system in swine and inclusion of HEV in diagnostic routines for acute and chronic human hepatitis would be important. Additionally, we propose that establishing a monitoring mechanism for HEV is crucial in order to gain a comprehensive understanding of the prevalence of this illness and the various strains present in the Iberian Peninsula, as well as their potential impact on public health.

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

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

Serological and molecular survey of hepatitis E virus in cats and dogs in Spain

Hepatitis E virus (HEV) is an emerging zoonotic pathogen that is currently recognized as one of the major causes of acute human hepatitis worldwide. In Europe, the increasing number of hepatitis E cases is mainly associated with the consumption of animal food products or contact with infected animals. Dogs and cats have been suggested as a zoonotic source of HEV infection. The aim of this study was to assess Orthohepevirus circulation, including HEV-A, HEV-B and HEV-C species, in sympatric urban cats and dogs in southern Spain. Between 2017 and 2020, blood samples were collected from 144 stray cats and 152 dogs, both strays and pets. The presence of antibodies against HEV were tested using a double-antigen sandwich ELISA and seropositive samples were further analyzed by western blot. A RT-PCR was performed to detect RNA of Orthohepevirus species (HEV-A, HEV-B and HEV-C). A total of 19 (6.4%; 95%CI: 3.6-9.2) of the 296 animals tested showed anti-HEV antibodies by ELISA. Seropositivity was significantly higher in dogs (9.9%; 15/152; 95%CI: 5.1-14.6) than in cats (2.8%; 4/144; 95%CI: 0.1-5.5). Ten out of the 18 ELISA-positive animals that could be further analyzed by western blot, reacted against HEV-3 and/or HEV-C1 antigens, which suggest circulation of both genotypes in urban cats and dogs in the study area. However, HEV-A, HEV-B and HEV-C RNA was not detected in any of the tested sera. This is the first study to assess HEV circulation in both stray cats and dogs in Europe. Our results provide evidence of HEV exposure in sympatric urban cat and dog populations in southern Spain. Further studies are needed to determine the role of these species in the epidemiology of HEV. This article is protected by copyright. All rights reserved.

Hepatitis E 3ra Genotype Infection in People Living With HIV in Spain

Background

The objective of our study was to assess the prevalence and incidence of HEV in people living with HIV (PLWH) in a Spanish national cohort.

Methods

Retrospective longitudinal study including PLWH recruited in the cohort of adult HIV-infected patients of the AIDS Research Network in follow-up at 28 Spanish hospitals with available serum samples in 2014 and 2015. All samples were tested for HEV IgG, IgM, and RNA. Samples with detectable HEV viral loads were genotyped. Prevalence and incidence of HEV infection were calculated.

Results

The study sample comprised 845 PLWH. At baseline, 101 patients were positive for HEV IgG antibodies (11.9%), none had HEV IgM antibodies, and 2 presented detectable HEV RNA (0.23%). Forty-two seroconverted for IgG, supposing a cumulative incidence of 5.7%. One subject was positive for IgM (0.13%), and 2 showed detectable HEV RNA (0.27%). One case was infected by the emergent HEV genotype 3ra.

Conclusion

Our study identifies one case of HEV 3ra genotype infection, the main host of which is rabbit, showing a potential zoonotic role of this emerging genotype in Spain.

Evaluation of a non-invasive screening approach to determine hepatitis E virus status of pig farms

BACKGROUND

Identifying pig farms infected with hepatitis E virus (HEV) is a key aspect to implement surveillance programmes for this emerging zoonotic agent. Detection of HEV in blood has several drawbacks, including animal handling, economic costs and animal stress. The objective of this study was to evaluate the effectiveness of a non-invasive screening approach for determining the HEV status of pig farms under different management systems.

METHODS

Forty stool samples randomly collected from the pen floor of 17 intensive pig farms and the yard of nine extensive ones were tested for HEV RNA. The invasive method used to confirm the HEV status of the farm was HEV RNA analysis of serum samples randomly collected from 40 animals on each farm.

RESULTS

Twenty-one HEV-positive farms were detected by invasive and non-invasive methods. No positive serum or stool samples were detected on five intensive farms. A high intertest agreement (K=1; P<0.00001) was observed between both methodologies, showing the stool screening approach a 100 per cent of sensitivity and specificity with respect to the invasive method. Likewise, a significant negative relationship was observed between the HEV within-farm prevalence and the number of the first HEV-positive stool sample found (Spearman's rho=-0.64; P=0.0004). This negative relationship was higher in intensively managed farms.

CONCLUSION

This non-invasive screening approach could be reliably applied in a large-scale surveillance programme for determining the HEV status of pig farms under different management systems.

Human Immunodeficiency Virus Infected Patients are Not at Higher Risk for Hepatitis E Virus Infection: A Systematic Review and Meta-Analysis

Hepatitis E virus (HEV) infection is the most common cause of acute hepatitis in the world. It is not well established whether people infected with the human immunodeficiency virus (HIV) are more susceptible to infection with HEV than people not infected with HIV. Many studies have evaluated this relationship, although none are conclusive. The aim of this systematic review and meta-analysis was to assess whether patients with HIV infection constitute a risk group for HEV infection. A systematic review and meta-analysis was performed in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), to find publications comparing HEV seroprevalences among HIV infected and uninfected populations. The analysis was matched by sex, age and geographical area, and compared patients who live with HIV and HIV-negative individuals. The odds ratio (OR) for patients with HIV was 0.87 (95% CI: 0.74-1.03) in the fixed effects meta-analysis and 0.88 (95% CI: 0.70-1.11) in random effects, with I² = 47%. This study did not show that HIV infection was a risk factor for HEV infection when compared with those who are HIV-negative.

Mutations in the Progesterone Receptor (PROGINS) May Reduce the Symptoms of Acute Hepatitis E and Protect Against Infection

BACKGROUND

Mutations in the progesterone receptor (PR) gene, PROGINS, have been studied in relation to hepatitis E virus (HEV) infection. Patients with the PROGINS gene may develop a worse clinical course of hepatitis E. The aim of our study was to evaluate the influence of PROGINS on the susceptibility to and the clinical course of HEV infection in HIV patients.

METHODS

This study included patients with HIV who were evaluated in previous prospective studies for the prevalence and incidence of HEV. The following three groups of patients were studied: (i) never infected, (ii) past infections, and (iii) recently infected. We determined the PR genotype to evaluate the proportion of patients who were homozygous for PROGINS according to HEV infection. We also compared the proportion of PROGINS carriers with a recent HEV infection according to their symptomatology.

RESULTS

In this study, 311 patients infected with HIV were included. Of those patients, 198 were homozygous wild type (63.7%), 91 were heterozygous (29.3%), and 22 were homozygous PROGINS (7.1%). We found that the homozygous PROGINS genotype in women was associated with a lower HEV seroprevalence. In addition, in patients with a recent HEV infection, none of those homozygous for PROGINS presented symptoms.

CONCLUSION

The PROGINS mutation plays a protective role against HEV infection and is associated with subclinical infection in HIV-infected patients, particularly women.

Hepatitis E Infection in HIV-Infected Patients

BACKGROUND

The hepatitis E virus (HEV) represents a major cause of acute hepatitis worldwide. The majority of HEV cases occur in low-income countries, mainly Asia and Africa, where HEV causes large outbreaks associated with the consumption of contaminated water and high mortality in specific populations. In high-income countries, HEV infection is considered a zoonotic disease that is linked to the consumption of contaminated food. Although a high proportion of cases have self-limiting asymptomatic or subclinical infections, immunosuppression may modify the pathogenesis and clinical impact of this emerging disease.

RESULTS AND DISCUSSION

Here, we review the current knowledge about the epidemiology, diagnosis, clinical manifestations, management and prevention of HEV infection in HIV-infected subjects.

CONCLUSIONS

Despite the increasing knowledge about the pathogenesis, epidemiology and clinical impact of HEV infection, several major factors are faced by HIV-infected patients, including treatment recommendations, immunization and risk practices.

Prevalence of anti-hepatitis E virus immunoglobulin G in HIV-infected individuals over three decades

BACKGROUND

Hepatitis E virus (HEV) genotype 3 is endemic in Europe, and the infection is mostly subclinical or acute and self-limiting. However, persistent infection is described among HIV-infected individuals. The prevalence of antibodies against HEV (anti-HEV) among HIV-infected persons varies geographically and is unknown in Denmark. Rates of co-infection with HEV among HIV-infected individuals in Denmark over three decades, from the early 1980s to 2013, were investigated.

METHODS

A total of 2506 HIV-infected persons were investigated from two cohorts followed at Hvidovre Hospital, Denmark. Blood samples were tested retrospectively for anti-HEV, including samples from 2216 persons who were enrolled in a prospective clinical cohort and followed between 1995 and 2013, as well as samples from 290 persons from a historical cohort followed between 1980 and 1994. For anti-HEV seroconverting individuals, serial samples were tested for HEV RNA. Factors associated with anti-HEV status were explored using multivariable logistic regression analysis.

RESULTS

The overall HEV seroprevalence rates were stable during the 1980s, 1990s, and 2000-2013 (23.1%, 22.9%, and 23.7%, respectively). In all decades, rates of anti-HEV increased with older age, and anti-HEV seropositivity was associated with older generations, HIV risk group, and geographic origin. Persistent HEV infection was not detected in any of 57 individuals with anti-HEV seroconversion.

CONCLUSIONS

HEV seroprevalence rates were stable in HIV-infected individuals from the early 1980s to 2013. Rates increased with age. No evidence of persistent HEV infection was detected. Infection with HEV is frequent, but persistent HEV infection is rare among HIV-infected individuals.

Hepatitis E virus in Spanish donors and the necessity for screening

Hepatitis E virus (HEV) represents a major health problem worldwide. As the course of HEV cases is often subclinical, asymptomatic infections could represent an important source of viral spread and infection via routes such as blood donations. Before universal screening for HEV in blood donations can be implemented, studies evaluating the incidence of infection are needed to establish the potential risk of viral transmission. This is a prospective longitudinal study that included blood donors recruited at the Hospital de Ciudad Real Transfusion Service between October 2017 and January 2018. Pools of eight donations were tested for HEV viremia by PCR. Positive pools were individually evaluated following the same procedure. Positive samples were tested for anti-HEV IgG and IgM. Recipients of blood transfusions obtained from HEV-positive donors were retrospectively evaluated. The prevalence of HEV was calculated. A total of 11 313 healthy donors were analysed during the study period. Four blood donations from four different donors were HEV RNA-reactive. The prevalence of HEV infection was 0.035% (95% CI: 0.01%-0.09%), which meant a ratio of one positive donation per 2828 donations. All donors were negative for anti-HEV IgM at the time of the donation. Five patients received transfusions from HEV-positive blood donations, none of them showed an increase in alanine aminotransferase levels after transfusion. In conclusion, our study found a high prevalence of HEV infection in blood donors from south-central Spain. In view of the prevalence, Spanish blood banks should carefully consider including screening for HEV.

Prevalence of hepatitis E infection in HIV/HCV-coinfected patients in Spain (2012-2014)

Hepatitis E virus (HEV) has emerged as a relevant pathogen for HIV-infected patients. However, there is scarce data on HEV infection in HIV/HCV-coinfected individuals with advanced fibrosis, which seems to increase the risk of HEV infection and worsen the prognosis of liver disease. We aimed to determine the prevalence of anti-HEV antibodies, acute hepatitis E, resolved hepatitis E, and exposure to HEV in HIV/HCV-coinfected patients and to evaluate associations with clinical and epidemiological characteristics. We performed a cross-sectional study on 198 HIV/HCV-coinfected patients, 30 healthy controls and 36 HIV-monoinfected patients. We found a low concordance between techniques used for detection of anti-HEV antibodies (ELISA versus Immunoblot), particularly in HIV/HCV-coinfected patients. HIV/HCV-coinfected patients showed the highest prevalence of IgG against HEV, resolved hepatitis E, and exposure to HEV (19.2%, 17.2%, and 22.2% respectively). However, we did not find any samples positive for HEV-RNA nor significant differences between groups. Moreover, HIV/HCV-coinfected patients with CD4 T-cells <350 cells/mm³ had higher prevalence for anti-HEV IgG antibodies, resolved hepatitis E, and exposure to HEV than healthy controls or those with CD4 T-cells ≥ 350 cells/mm³ (p = 0.034, p = 0.035, and p = 0.053; respectively). In conclusion, HIV/HCV-coinfected patients in Spain have a high prevalence for IgG anti-HEV antibodies, resolved hepatitis E, and exposure to HEV; particularly patients with CD4+T-cells <350 cells/mm³.

Seroprevalence of Hepatitis E Virus Infection Among People Living With HIV in the Central African Republic

Background

Hepatitis E virus (HEV) is a waterborne virus that causes acute hepatitis in immunocompromised patients and those who are immunocompetent. Few cases of chronic HEV have been described in industrialized countries. The Central African Republic is 1 of the few countries in the world that is endemic for both HIV and HEV. The prevalence of HIV infection is estimated to be 4.9% among adults aged 15-49 years, and hepatitis E is epidemo-endemic. The aim of this study was to characterize the epidemiology of HEV infection in people living with HIV (PLHIV) in Bangui.

Methods

A cross-sectional study was conducted between April and September 2015 based on answers to a questionnaire, and blood samples were collected for determination of immunological markers by enzyme-linked immunosorbent assay and molecular tests.

Results

Of the 200 PLHIV included, 15 (7.5%) had the IgM that characterizes acute HEV infection; 8.9% were women, and 2.2% were men. The overall seroprevalence of IgG was 68% (48% women and 70.4% men), indicating that men are statistically significantly more exposed to HEV than women. HEV infection had no effect on transaminase or T-CD4+ lymphocyte cell levels. The origin of infection could not be identified.

Conclusions

The seroprevalence of HEV is very high among PLHIV and in the general population of Bangui. This must be taken into account in studies of the risk factors of PLHIV infected with HEV.

Detection and quantification of hepatitis E virus in the absence of IgG and IgM anti-HEV in HIV-positive patients

AIMS

To improve RT-qPCR with an internal control and a synthetic standard curve to detect HEV in HIV co-infected patients.

METHODS AND RESULTS

A single-stranded RNA (ssRNA) and a double-stranded DNA (dsDNA) synthetic curve were designed, compared to the international reference panel for HEV genotypes, and tested to quantify and detect a reference panel for HEV genotypes. The detection limit of the RNA synthetic curve (50 copies per ml) was better than the DNA synthetic curve (100 copies per ml) and the WHO standard curve (250 copies per ml). Then, 280 serum samples from HIV-positive patients were tested for HEV RNA, which was detected in 3·6% of serum samples. The viral load ranged from 2 × 10² copies per ml to 4·78 × 10⁸ copies per ml. HEV IgM/IgG antibodies were not detected in the RNA-positive patients. Sequencing analysis of HEV showed that the virus belongs to genotype 3 (HEV GT3).

CONCLUSIONS

Real-time PCR was a useful tool to estimate co-infection with HEV/HIV, even in patients with low viral loads and undetectable anti-HEV IgG and IgM antibodies.

SIGNIFICANCE AND IMPACT OF THE STUDY

Hepatitis E virus genotype 3 (HEV GT3) has been associated with silent chronic hepatitis and cirrhosis in HIV-positive subjects worldwide, but there is a lack of data on this co-infection in Brazil.

Role of Hepatitis E Virus Infection in Acute-on-Chronic Liver Failure

Chronic liver disease (CLD) with a variety of causes is currently reported to be one of the main causes of death worldwide. Patients with CLD experience deteriorating liver function and fibrosis, progressing to cirrhosis, chronic hepatic decompensation (CHD), end-stage liver disease (ESLD), and death. Patients may develop acute-on-chronic liver failure (ACLF), typically related to a precipitating event and associated with increased mortality. The objective of this review was to analyze the role of acute hepatitis E virus (HEV) infection in patients with CLD, focusing on the impact of this infection on patient survival and prognosis in several world regions.

Hepatitis E virus infection in HIV-infected patients: A large cohort study in Yunnan province, China

Hepatitis E virus (HEV) infection in immunocompromised patients often results in distinct outcome, compared to the infection in general population. This study aimed to investigate the prevalence, potential risk factors, and clinical features of HEV infection among HIV patients treated with antiretroviral therapy (ART) in Yunnan province, China. A total of 770 HIV-infected patients between May 2015 and February 2016 were enrolled in Yunnan, China. All patients received ART. All plasma samples were tested for anti-HEV IgG, anti-HEV IgM antibodies using ELISA kits, and HEV RNA by real-time qRT-PCR. Association between anti-HEV antibody positivity and demographic, clinical and laboratory measures was assessed in univariate and multivariate logistic regression models. Of the 770 HIV-infected patients, 342 patients (44.42%) were anti-HEV IgG antibody positive, and six patients (0.78%) were anti-HEV IgM antibody positive. None of the patients was HEV RNA positive, as tested in our assays. We found that age, gender, CD4 cell count, WHO stage, marital status, and total cholesterol levels were associated with HEV infection. We report a high seroprevalence rate and several potential risk factors of HEV infection in a large HIV cohort from Yunnan province in China. Further research on identification of the circulating HEV strains and the clinical outcome of this patient population is required.

Prevalence of hepatitis E virus infection in wild boars from Spain: a possible seasonal pattern?

BACKGROUND

It has been shown that wildlife can serve as natural reservoirs of hepatitis E virus (HEV). The wild boar (Sus scrofa) is probably the main natural reservoir of HEV and could therefore represent an important route of transmission in Europe, especially in regions where game meat is widely consumed. We evaluated the prevalence of HEV infection in wild boar in the south of Spain, with the aim of identifying associated risk factors. A cross-sectional study that included hunted wild boar was carried out during the 2015/2016 hunting season (October 15 to February 15) in Andalusia (southern Spain). The outcome variable was HEV infection, defined as amplification of HEV RNA in serum by RT-PCR.

RESULTS

A total of 142 animals, selected from 12 hunting areas, were included and formed the study population. Thirty-three wild boars (23.2%; 95% CI: 16.8%-30.7%) were positive for HEV infection. Prevalence peaked in October and November, then gradually declined until the end of December. After multivariate analysis, only hunting date was independently associated with HEV infection across sex and age.

CONCLUSIONS

Our study found a relatively high prevalence of HEV infection in wild boar in the south of Spain, suggesting that prevalence may depend on the season when the animal is hunted. In consequence, the potential risk of zoonotic transmission could fluctuate.

Familial Hepatitis E Outbreak Linked to Wild Boar Meat Consumption

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

Rural habitat as risk factor for hepatitis E virus seroconversion in HIV-infected patients: A prospective longitudinal study

Our objective was to determine the incidence and clinical manifestations of acute hepatitis E virus (HEV) in HIV-infected patients. A prospective longitudinal study including HIV-infected HEV-seronegative patients was conducted; HEV seroconversion (to IgG and/or IgM) was the main outcome variable. All patients were tested for HEV antibodies every 3-6 months. For patients who developed HEV seroconversion, a data collection protocol was followed to identify associated clinical manifestations and analytical alterations. A total of 627 patients (89.9%) were followed during a median of 11.96 months (IQR: 8.52-14.52 months) and formed the study population. Forty-one patients developed detectable anti-HEV antibodies (7.2 cases per 100 patients/year). Our study found a high incidence of HEV in HIV-infected patients in southern Spain strongly associated with a rural habitat.

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.

Hepatitis E Virus Mutations: Functional and Clinical Relevance

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

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

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

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

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

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

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

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 virus infection in the HIV-positive patient

Hepatitis E virus (HEV) is a RNA virus that can cause hepatitis. In immunocompetent individuals, infection with HEV usually leads to asymptomatic seroconversion. However, in immunosuppressed patients, such as transplant recipients, HEV can develop into a chronic infection. Studies regarding the seroprevalence and clinical implications of HEV in patients infected with the human immunodeficiency virus (HIV) are conflicting. Levels of CD4 count in blood seem to be the most widely associated risk factor, while other factors such as meat consumption or proximity to animals are less clearly associated with HEV infection. Progression to chronicity, as well as extrahepatic manifestations of HEV seem rare in HIV, and the implications of HEV in liver disease progression are poorly understood in the HIV-infected. In this review we describe the epidemiology, risk factors, and clinical implications of HEV infection in individuals infected with HIV.

Epidemiology of Hepatitis E Virus in European Countries

Over the last decade the seroprevalence of immunoglobulin (IgG) anti hepatitis E virus (HEV) has been increasing in European countries and shows significant variability among different geographical areas. In this review, we describe the serological data concerning the general population and risk groups in different European countries. Anti-HEV antibody prevalence ranged from 1.3% (blood donors in Italy) to 52% (blood donors in France). Various studies performed on risk groups in Denmark, Moldova and Sweden revealed that swine farmers have a high seroprevalence of HEV IgG (range 13%-51.1%), confirming that pigs represent an important risk factor in HEV infection in humans. Subtypes 3e,f are the main genotypes detected in the European population. Sporadic cases of autochthonous genotype 4 have been described in Spain, France, and Italy. Although most HEV infections are subclinical, in immune-suppressed and transplant patients they could provoke chronic infection. Fulminant hepatitis has rarely been observed and it was related to genotype 3. Interferon and ribavirin treatment was seen to represent the most promising therapy.