Laboratory challenges in the diagnosis of hepatitis E virus

Clinical utility of two-step hepatitis E virus IgM antibody testing in a low-prevalence setting: A 10-year retrospective multicenter study

BACKGROUND

Diagnostic uncertainty caused by the low positive predictive value of HEV-specific IgM antibody (Ab) testing in a low-prevalence setting. We investigated the utility of a two-step HEV IgM Ab testing approach for diagnosing HEV infection.

METHODS

We retrospectively reviewed all adults who underwent HEV IgM Ab and/or HEV RNA testing from July 2013 through June 2023 at Mayo Clinic. Two-step HEV IgM testing involved initial testing using recomWell HEV IgM ELISA (Mikrogen, Neuried, Germany), with reflex to recomLine HEV IgM Strip (Mikrogen, Neuried, Germany) on all recomWell HEV IgM-reactive or IgM-equivocal specimens, as recomLine HEV IgM has higher specificity than recomWell HEV IgM but is more labor-intensive.

RESULTS

A total of 1640 patients had HEV IgM Ab or HEV RNA testing, including 1293 (79%) with only HEV IgM Ab testing, 213 (13%) with only HEV RNA testing, and 134 (8%) with both HEV IgM Ab and HEV RNA testing. Eighteen HEV infections were diagnosed with acute (N=16) and chronic (N=2) infections. Two-step IgM Ab testing did not identify 2 solid organ transplant recipients with chronic HEV infection. In acute HEV infection with HEV viremia, 3 out of 4 patients (2 solid organ transplant recipients and 1 patient with Guillain-Barre syndrome) were treated with ribavirin.

CONCLUSIONS

A two-step HEV IgM Ab test may accurately diagnose acute HEV infection in immunocompetent persons. However, this approach fails to identify chronic HEV infection in immunocompromised individuals who need HEV RNA testing to establish the diagnosis.

Current knowledge on the epidemiology and detection methods of hepatitis E virus in China

Hepatitis E is recognized as a significant zoonotic disease burden in China, with the hepatitis E virus (HEV) identified as the etiological agent responsible for this disease. HEV exhibits no specific host tropism, which facilitates its transmission among various mammalian species, including humans, pigs, cattle, goats, and others. Currently, the availability of effective therapeutic agents and vaccines for HEV infection is limited. Therefore, a comprehensive understanding of the epidemiological characteristics of HEV, and the existing detection methods, is crucial for disease prevention and control. In this review, we provide an overview of the current knowledge on HEV in China, mainly focusing on detection strategies, molecular characteristics, and the prevalence of this pathogen in the human population and other susceptible species. This review will be useful to enhance public awareness of HEV and to accelerate disease control efforts in the future.

Acute Hepatitis Related to Hepatitis E Virus Genotype 3f Infection in Brazil

The hepatitis E virus (HEV) is an important causative agent of acute hepatitis (AH). Despite reports of human infection in Brazil, the investigation is not routinely conducted, even in cases of elevated liver enzymes. This study evaluated two groups: group 1-patients with acute hepatitis A (n = 44); group 2-patients with nonA-C AH (n = 47). They were tested by enzyme immunoassay for anti-HEV IgM/IgG and real-time PCR for HEV RNA detection. The positive sample for HEV RNA was submitted for sequencing. The seroprevalence of anti-HEV IgM and IgG in group 1 was 4% (2/44) and 14.5% (7/44), respectively. Viral RNA was not detected in any sample. In group 2, the anti-HEV IgM positivity was 4.3% (2/47), and IgG 14.9% (7/47). RNA was detectable in one case, which presented a viral load of 222.4 IU/μL and positive anti-HEV IgM/IgG. In the phylogenetic analysis, the genotype identified was HEV-3f. These results indicate that HEV infection should be considered a possible diagnosis in cases of non-A-C AH. The patient identified with acute hepatitis E had recently traveled to the Northeast region of Brazil (Garanhuns city in Pernambuco state), where there are reports of high HEV seroprevalence among pigs. The close phylogenetic relationship observed between the sequence characterized in this study and strains isolated from pigs in nearby cities where the patient went suggested a possible zoonotic transmission in this region. This study highlights the importance of expanding studies and improving surveillance to understand better and manage HEV infections nationwide.

Performance Comparison of Four Hepatitis E Antibodies Detection Methods

HEV antibody detection constitutes the main screening test for HEV infection. The aim of this study is to compare the sensitivity and specificity of four techniques: LIAISON® MUREX DiaSorin anti-HEV IgG and anti-HEV IgM assays, Hepatitis E VIRCLIA® IgM and IgG monotests, WANTAI HEV-IgM and IgG ELISA and VIDAS® anti-HEV IgM and IgG tests in five panels of samples configurated according to the immunoblot (RecomLine, Mikrogen, Neuss, Germany). Anti-HEV IgM sensitivity in the acute phase was 100% in all techniques, while sensitivity, including the immediate convalescence phase, was 96.74% for LIAISON®, 83.14% for VIRCLIA®, 84.78% for WANTAI and 88.04% for VIDAS®. Anti-HEV IgM specificity was 100% for both LIAISON® and VIRCLIA®. Anti-HEV IgM WANTAI agreed with VIRCLIA® with a good Kappa coefficient (κ = 0.71). Anti-HEV IgG post-infection sensitivity was 100% for LIAISON®, VIDAS® and VIRCLIA® and 99% for WANTAI. Anti-HEV IgG specificity reached 97.17% for LIAISON and 88.68% for VIRCLIA®. Our results demonstrated a better capacity of LIAISON® MUREX anti-HEV IgM than that of competitors for detecting acute infections as well as accurate anti-HEV IgG results and in how to resolve them.

Assessment of the Diagnostic Performance of Fully Automated Hepatitis E Virus (HEV) Antibody Tests

The detection of anti-hepatitis E virus (HEV) antibodies contributes to the diagnosis of hepatitis E. The diagnostic suitability of two automated chemiluminescence immunoassays (CLIAs, LIAISON® MUREX Anti-HEV IgG/Anti-HEV IgM test, DiaSorin) was assessed by comparison with the results of a combination of enzyme immunoassays and immunoblots (recomWell HEV IgG/IgM ELISA, recomLine HEV IgG/IgM, MIKROGEN). Samples with a deviating result were analyzed with the WANTAI ELISAs. Compared to the recomWell ELISAs, the Anti-HEV IgG CLIA had a percentage overall agreement (POA) of 100% (149/149; 95% CI: 97.5-100%) and the Anti-HEV IgM CLIA had a POA of 83.3% (85/102; 95% CI: 74.9-89.3%); considering the recomLine HEV IgM results, the POA was 71.7% (38/53; 95% CI: 58.4-82%). The WANTAI test confirmed 52.9% (9/17) of negative CLIA IgMs; HEV RNA was not detectable. Since acute infection with the Epstein-Barr virus (EBV) or human cytomegalovirus (CMV) may influence the results of other serological assays, HEV antibodies were examined in 17 EBV and 2 CMV patients: One had an isolated and probably unspecific HEV IgM in the CLIA, as HEV RNA was not detectable. Both CLIAs are well suited for HEV diagnostics, but isolated IgM should be confirmed. An acute EBV/CMV infection can influence HEV serodiagnostics.

Profile of clinical characteristics and serologic markers of sporadic hepatitis E in a community cohort study

Hepatitis E virus (HEV) is a pathogen of global significance, but the value of HEV-related markers in the diagnosis of hepatitis E remains controversial. Previous studies on hepatitis E profiles have been mainly cross-sectional and conducted among inpatients in large hospitals, and hepatitis E cases have been primarily defined by limited partial markers. In this community-based study, 4,110 active hepatitis cases from a population of nearly 600,000 were followed over 48 months and serial serum samples were collected. Both HEV pathogen (HEV RNA and antigen) and anti-HEV antibody markers were used to determine HEV infection status and the relationship between hepatitis and HEV infection. In total, 98 hepatitis E patients were identified and all available isolates from 58 patients belonged to HEV genotype 4. The mean age of the patients was 58.14 years, with an overwhelming proportion of males (70.4%). Hepatitis E accounted for 22.86% of active hepatitis cases with alanine aminotransferase levels ≥15.0-fold the upper limit of normal, suggesting the need to include HEV in routine testing for these patients. Ninety-two hepatitis E patients were positive for at least 2 of HEV antigen, anti-HEV IgM, and HEV RNA markers at presentation, and 90.22% of them were positive for HEV antigen and anti-HEV IgM. HEV antigen, HEV RNA, and anti-HEV IgM positivity were observed in 89.80%, 82.65%, and 93.88% of hepatitis E patients at presentation, respectively. However, only 57.14% of anti-HEV IgM positivity occurred in hepatitis E patients. These findings will advance our understanding of hepatitis E and improve diagnosis.

Seroprevalence of hepatitis E virus (HEV) among male craft and manual workers in Qatar (2020-2021)

Background

The rapid growth of Qatar in the last two decades has attracted a large influx of immigrant craft and manual workers (CMWs) seeking employment in jobs associated with food handling, domestic service, and construction. Nearly 60 % of Qatar's population are expatriates CMWs, including many from hyperendemic countries for HEV. Thus, estimating the seroprevalence of HEV in Qatar and understanding its epidemiology is essential for public health efforts to control HEV transmission in Qatar.

Methods

Blood samples from 2670 CMWs were collected between 2020 and 2021. All samples were tested for HEV-IgG antibodies. Positive HEV-IgG samples were tested for HEV-IgM antibodies, and those positives were also tested for viral antigens using an HEV-Ag ELISA kit and HEV-RNA by RT-PCR to confirm current HEV infections.

Results

The seroprevalence of HEV-IgG was 27.3 % (729/2670; 95 % CI: 25.6-29.0). Of those HEV-IgG positive, 8.23 % (60/729; 95 % CI: 6.30-10.5) were HEV-IgM positive. Of the IgM-positive samples, 2 were HEV-RNA positive (3.39 %; 95 % CI: 0.40-11.7), and 1 was HEV-Ag positive (1.69 %; 95 % CI: 0.04-9.09). In addition, HEV-IgG seroprevalence was associated with age and nationality, with the highest seroprevalence in participants from Egypt (IgG 60.0 %; IgM 5.56 %), Pakistan (IgG 59.0 %; IgM 2.24 %), Nepal (IgG 29.3 %; IgM 2.70 %), Bangladesh (IgG 27.8 %; IgM 2.45 %), and India (IgG 23.9 %; IgM 2.43 %).

Conclusion

In this study, we showed that the seroprevalence of HEV among CMWs was slightly higher than what was previously reported among the urban population in Qatar (2013-2016).

A multispecies competitive nanobody-based ELISA for the detection of antibodies against hepatitis E virus

The hepatitis E virus (HEV) is an emergent zoonotic virus causing viral hepatitis worldwide. Clinically, hepatitis E is not easily distinguished from other types of acute viral hepatitis. There is a need for HEV diagnostic assays to detect and prevent interspecies transmission among susceptible populations. Nanobodies (Nbs) are expressed recombinantly in different systems, produced with high yields, and have superior physicochemical properties compared with conventional antibodies (Ab). Several Nbs against ORF2, the capsid protein and main antigen, were selected and produced in E. coli. Nb39 and Nb74 specifically recognized HEV ORF2 (genotypes 3 and 4). A competitive ELISA (cELISA) was developed and validated using a reference panel of human (n = 86) and swine sera (n = 116) tested in comparison with a commercial kit. The optimal cutoff values determined by ROC analysis were 69.16% (human) and 58.76% (swine); the sensitivity and specificity were high: 97.4% (95% CI 86.5-99.5%) and 95.8% (95% CI 86.0-98.8%) for human vs. 100% (95% CI 93.5-100%) and 98.3% (95% CI 91.0-99.7%) for swine. Further, the cELISA detected total anti-HEV antibodies in wild boar, deer, and mice. To our knowledge, this is the first report of production of Nbs against HEV-3 ORF2 for diagnostic purposes.

A Comparison of Clinical Manifestations and Outcomes between Acute Sporadic Hepatitis A and Hepatitis E Infections in Thailand

Hepatitis A virus (HAV) and hepatitis E virus (HEV) infections often present as acute hepatitis with prodromal symptoms. These infections, transmitted via the oral-enteral route, constitute significant public health challenges, particularly in developing countries with subpar sanitary systems. The aim of the study was to describe the clinical manifestations, laboratory findings, and outcomes of hepatitis A and hepatitis E infections in Thailand. We conducted a retrospective chart review and analysis of 152 patients diagnosed with acute hepatitis A or hepatitis E from January 2007 to August 2018 at Siriraj Hospital. The hepatitis E cohort was older with a greater prevalence of comorbidities (hypertension, diabetes mellitus, chronic kidney disease, chronic hepatitis B, and post-kidney transplantation status) than the hepatitis A cohort. While the majority of hepatitis A patients presented with fever (98%) and jaundice (96%), these symptoms were less pronounced in hepatitis E patients. Furthermore, hepatitis A patients exhibited significantly higher aminotransferase and total bilirubin levels. However, clinical outcomes, such as hospitalization rates, progression to acute liver failure, and mortality, were comparable across both groups. In conclusion, although the clinical manifestations of hepatitis A and hepatitis E were similar, fever and jaundice were more prevalent and aminotransferase and bilirubin levels were higher in the HAV-infected group.

Epidemiology of Suspected and Confirmed Acute Hepatitis E Cases Reported Among Los Angeles County Residents, 2017-2019

In a 3-year period, 38 of 48 persons testing positive for hepatitis E virus (HEV) immunoglobulin M in Los Angeles County did not meet the acute HEV case definition. Healthcare providers should restrict HEV serologic testing for persons with clinically compatible symptoms or epidemiologic risk factors.

Transfusion-Transmitted Disorders 2023 with Special Attention to Bone Marrow Transplant Patients

Transfusion medicine is traditionally a strong/fundamental part of clinical practice, saving hundreds of millions of lives. However, blood-borne or transmitted infections are a well-known and feared possibility, a risk we relentlessly mitigate. Pathogens are continuously and rather quickly changing, so during the last decade, many, sometimes exotic, new pathogens and diseases were recorded and analyzed, and some of them were proved to be transmitted with transfusions. Blood or blood component transfusions are carried out after cautious preparative screening and inactivation maneuvers, but in some instances, newly recognized agents might escape from standard screening and inactivation procedures. Here, we try to focus on some of these proven or potentially pathogenic transfusion-transmitted agents, especially in immunocompromised patients or bone marrow transplantation settings. These pathogens are sometimes new challenges for preparative procedures, and there is a need for more recent, occasionally advanced, screening and inactivation methods to recognize and eliminate the threat a new or well-known pathogen can pose. Pathogen transmission is probably even more critical in hemophiliacs or bone marrow transplant recipients, who receive plasma-derived factor preparations or blood component transfusions regularly and in large quantities, sometimes in severely immunosuppressed conditions. Moreover, it may not be emphasized enough that transfusions and plasma-derived product administrations are essential to medical care. Therefore, blood-borne transmission needs continued alertness and efforts to attain optimal benefits with minimized hazards.

Calibrating Hepatitis E Virus Serological Assays Using Asymptomatic Specimens Obtained in Japan

This study aimed to calibrate hepatitis E virus (HEV) serological assays. We optimized the previously developed in-house HEV antibody enzyme-linked immunosorbent assay (ELISA) by setting the cutoff with an in-house serological performance panel consisting of broad HEV antibody titers and subtracting nonspecific background values for anti-HEV IgM, IgA, and IgG. We also compared the assay's performance with that of commercial serological assay kits (four kits for IgM, one for IgA, and two for IgG). Although all serological assays readily detected HEV antibodies at high titers in the symptomatic hepatitis E population, considerable variations between assays were observed in the asymptomatic population. The in-house ELISA showed a higher sensitivity for HEV IgM, IgA, and IgG than the commercial kits and detected the seroconversion of HEV IgM and IgG earlier when testing a commercially available HEV seroconversion panel. The low sensitivity of the commercial kits was due to the high setting of the original cutoff, which was demonstrated by receiver operating characteristic analysis. However, the corrected cutoff value reduced assay specificity. Background subtraction is essential to achieve high specificity because the in-house ELISA without background subtraction reduced its specificity. These results indicate that asymptomatic specimens and background subtraction contribute to the optimization of HEV serological assays. IMPORTANCE Accurate diagnosis of hepatitis E virus (HEV) infection is essential for public health surveillance and for preventing HEV-contaminated blood transfusion. Anti-HEV IgM or IgA is used as a reliable marker of recent HEV infection. However, considerable variability in the sensitivity and specificity of HEV antibody detection is observed among several commercially available assay kits. In addition, none of the HEV antibody detection methods have been approved by the U.S. Food and Drug Administration (FDA). Here, we show that the in-house enzyme-linked immunosorbent assay (ELISA) could detect HEV IgM and IgA more sensitively than commercial kits in the asymptomatic population. We also suggest that the assay performance of commercial kits might be improved by optimizing the cutoff and reducing nonspecific background noise. A sensitive serological (IgM or IgA) assay in addition to HEV RNA testing will contribute to accurate diagnosis of acute HEV infection because HEV RNA-positive duration is relatively short.

Hepatitis E in immunocompromised individuals

Hepatitis E virus (HEV) originally identified as a cause of acute icteric hepatitis in developing countries has grown to be a cause of zoonotic viral hepatitis in developed countries such as the United States. While there are eight identified genotypes to date, genotype 1 (HEV1), HEV2, HEV3, HEV4 are the most common to infect humans. HEV1 and HEV2 are most common in developing countries including Latina America, Africa and Asia, and are commonly transmitted through contaminated water supplies leading to regional outbreaks. In contrast HEV3 and HEV4 circulate freely in many mammalian animals and can lead to occasional transmission to humans through fecal contamination or consumption of undercooked meat. The incidence and prevalence of HEV in the United States is undetermined given the absence of FDA approved serological assays and the lack of commercially available testing. In majority of cases, HEV infection is a self-limiting hepatitis requiring only symptomatic treatment. However, this is not the case in immunocompromised individuals, including those that have undergone solid organ or stem cell transplantation. In this subset of patients, chronic infection can be life threatening as hepatic insult can lead to inflammation and fibrosis with subsequent cirrhosis and death. The need for re-transplantation as a result of post-transplant hepatitis is of great concern. In addition, there have been many reported incidents of extrahepatic manifestations, for which the exact mechanisms remain to be elucidated. The cornerstone of treatment in immunocompromised solid organ transplant recipients is reduction of immunosuppressive therapies, while attempting to minimize the risk of organ rejection. Subsequent treatment options include ribavirin, and pegylated interferon alpha in those who have demonstrated ribavirin resistance. Further investigation assessing safety and efficacy of anti-viral therapy is imperative given the rising global health burden. Given this concern, vaccination has been approved in China with other investigations underway throughout the world. In this review we introduce the epidemiology, diagnosis, clinical manifestations, and treatment of HEV, with emphasis on immunocompromised individuals in the United States.

Low Prevalence of HEV Infection and No Associated Risk of HEV Transmission from Mother to Child among Pregnant Women in Vietnam

Infections with HEV in low- and middle-income countries (LMICs) are associated with increased rates of preterm birth, miscarriage, and stillbirth. The aim of the present study was to investigate HEV infections in pregnant women and the possibility of mother-to-child transmission, and associated outcomes. A total of 183 pregnant women in their third trimester were recruited and followed until delivery. Anti-HEV IgG and IgM were determined via enzyme-linked immunosorbent assay (ELISA), and HEV nucleic acids were detected in stool and cord blood samples. HEV genotypes were identified by Sanger sequencing, and phylogenetic analyses were performed. Mother-to-child transmission and associated adverse outcomes were not observed. Only 2% of patients (n = 4/183) tested positive for anti-HEV IgM, and 8% (n = 14/183) tested positive for anti-HEV IgG antibodies. Cord blood (n = 150) analysis showed that there was no IgM detected, while 4% (n = 6/150) tested positive for anti-HEV IgG, which was consistent with mothers testing positive for anti-HEV IgG. Nucleic acid tests for HEV RNA yielded 2% (n = 4/183) from the serum and stool of pregnant women, and none from cord blood. The HEV isolates belonged to the genotype HEV-3a, with 99% homology with humans and 96% with pigs. No association was found between the risk of HEV infection and pregnancy outcomes or HEV transmission from mother to child. HEV-3 infections of zoonotic origin in pregnancy might have eventually resolved without complications.

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

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

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

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

Viral hepatitis update: Progress and perspectives

Viral hepatitis, secondary to infection with hepatitis A, B, C, D, and E viruses, are a major public health problem and an important cause of morbidity and mortality. Despite the huge medical advances achieved in recent years, there are still points of conflict concerning the pathogenesis, immune response, development of new and more effective vaccines, therapies, and treatment. This review focuses on the most important research topics that deal with issues that are currently being solved, those that remain to be solved, and future research directions. For hepatitis A virus we will address epidemiology, molecular surveillance, new susceptible populations as well as environmental and food detections. In the case of hepatitis B virus, we will discuss host factors related to disease, diagnosis, therapy, and vaccine improvement. On hepatitis C virus, we will focus on pathogenesis, immune response, direct action antivirals treatment in the context of solid organ transplantation, issues related to hepatocellular carcinoma development, direct action antivirals resistance due to selection of resistance-associated variants, and vaccination. Regarding hepatitis D virus, we describe diagnostic methodology, pathogenesis, and therapy. Finally, for hepatitis E virus, we will address epidemiology (including new emerging species), diagnosis, clinical aspects, treatment, the development of a vaccine, and environmental surveillance.

Hepatitis E: An update on One Health and clinical medicine

The hepatitis E virus (HEV) is one of the main causes of acute hepatitis and the de facto global burden is underestimated. HEV-related clinical complications are often undetected and are not considered in the differential diagnosis. Convincing findings from studies suggest that HEV is clinically relevant not only in developing countries but also in industrialized countries. Eight HEV genotypes (HEV-1 to HEV-8) with different human and animal hosts and other HEV-related viruses are in circulation. Transmission routes vary by genotype and location, with large waterborne outbreaks in developing countries and zoonotic food-borne infections in developed countries. An acute infection can be aggravated in pregnant women, organ transplant recipients, patients with pre-existing liver disease and immunosuppressed patients. HEV during pregnancy affects the fetus and newborn with an increased risk of vertical transmission, preterm and stillbirth, neonatal jaundice and miscarriage. Hepatitis E is associated with extrahepatic manifestations that include neurological disorders such as neuralgic amyotrophy, Guillain-Barré syndrome and encephalitis, renal injury and haematological disorders. The risk of transfusion-transmitted HEV is increasingly recognized in Western countries where the risk may be because of a zoonosis. RNA testing of blood components is essential to determine the risk of transfusion-transmitted HEV. There are currently no approved drugs or vaccines for HEV infections. This review focuses on updating the latest developments in zoonoses, screening and diagnostics, drugs in use and under development, and vaccines.

Hepatitis E Infection in a Longitudinal Cohort of Hepatitis C Virus and HCV/HIV Coinfected Persons

Hepatitis E virus (HEV) is thought to be common in the United States with increased prevalence in those with concomitant hepatitis C virus (HCV) or HCV/HIV coinfection. Little is known regarding true prevalence, incidence, and antibody seroreversion in these populations. We sought to define these rates among HCV and HCV/HIV coinfected persons in the Washington, DC area. Two longitudinal cohorts of HCV and HCV/HIV coinfected subjects from the Washington, DC area were evaluated. Multiple HEV test modalities were deployed including immunoglobulin G (IgG) and immunoglobulin M (IgM) antibody testing, evaluation of antibody avidity, HEV RNA testing, and HEV enzyme-linked immune absorbent spot (ELISPOT) analysis. A total of 379 individuals were evaluated including 196 who were HCV monoinfected and 183 HCV/HIV coinfected. Anti-HEV IgG was detected and confirmed in 18.7% of the cohort at baseline. None demonstrated anti-HEV IgM positive or HEV RNA positive results. Proportions of HEV antibody prevalence did not significantly differ between groups. Longitudinal follow-up samples were available for 226 individuals with a mean follow-up time of 24 months. Seroreversion was noted in 1.8%. One HCV/HIV infected person seroconverted to HEV IgG positivity in the followed cohort. About 40% of the positive population demonstrated high avidity suggestive of more remote exposure. Interferon gamma ELISPOT was performed in 70 subjects and false negative and false positive HEV enzyme-linked immunosorbent assay antibodies were identified. In HIV-infected persons in the United States HEV exposure and seroconversion is frequent enough that HEV should be considered in the differential diagnosis of acute hepatitis. Seroreversion may lead to underestimation of true infection risk.

The prevalence of HEV among non-A-C hepatitis in Qatar and efficiency of serological markers for the diagnosis of hepatitis E

BACKGROUND

The rapid growth of Qatar in the last two decades has attracted a large influx of immigrant workers who mostly come from HEV-hyperendemic countries. Thus, we aim to investigate the prevalence of HEV among acute non-A-C hepatitis patients in Qatar; and to evaluate the performance of four dominant commercial serological assays for HEV diagnosis.

METHODS

259 patients with non-A-C hepatitis were tested using the Wantai HEV-IgM, HEV-IgG, HEV-Ag ELISA kits, and the MP Biomedical HEV-Total Ab ELISA kit. ALT levels were tested and HEV RNA (viral loads) was performed using Taqman AmpliCube HEV RT-PCR kit (Mikrogen, Neuried, Germany). The performance of each kit was assessed according to the RT-PCR results.

RESULTS

HEV-RNA was detected in 23.1% of the samples. Most of these HEV-RNA-positive cases belonged to non-Qatari residents from the Indian subcontinent; India, Pakistan, etc. HEV-Ag, HEV-IgM, HEV-IgG, HEV-Total Ab were detected in 5.56%, 8.65%, 32.1%, and 34.2% of all tested samples, respectively. Elevated ALT levels were highly correlated with the HEV-Ag, HEV-IgM, HEV-RNA but not with the HEV-IgG and HEV-Total Ab. Although HEV-Ag was very specific (100%), yet its sensitivity was poor (36.7%). HEV-IgM demonstrated the best second marker for diagnosis of acute HEV after RT-PCR as jugged by the overall performance parameters: specificity (96.2%), sensitivity (71.4%), PPV (83.3%), NPP (92.7%), agreement with RT-PCR (91.0%), and Kappa-value (0.71).

CONCLUSION

Our study demonstrated a high prevalence of HEV virus in Qatar, mostly among immigrants from the Indian subcontinent. The HEV-IgM represents the best marker for detecting the acute HEV infection, where RT-PCR cannot be performed.

Seroprevalence of the hepatitis E virus antibodies among blood donors in the Qassim region, Saudi Arabia

Aim: Hepatitis E virus (HEV) transmission through blood transfusion is a major public health issue worldwide. We aimed to determine the seroprevalence of HEV in blood donors in the Qassim region of Saudi Arabia. Materials & methods: Serum samples (n = 1078) were collected from volunteer blood donors and tested for the presence of anti-HEV IgG and IgM by indirect ELISA. Results: The seroprevalence of anti-HEV IgG among the blood donors was 5.7% overall. Anti-HEV IgG and IgM seropositivity were significantly higher in non-Saudi donors than in Saudi donors (22.1 vs 3 and 7.8 vs 0.2% for anti-HEV IgG and IgM, respectively). Conclusion: The seroprevalence of HEV among blood donors in the Qassim region was lower than previous estimates for other regions of the country and neighboring countries.

Evaluation of a Novel CLIA Monotest Assay for the Detection of Anti-Hepatitis E Virus-IgG and IgM: A Retrospective Comparison with a Line Blot and an ELISA

Despite the increasing relevance of Hepatitis E, an emerging disease endemic in developing and with increasing numbers of sporadic cases in industrialized countries, commercial tests are mainly based on batch oriented serological assays. In this retrospective study, we compared a line immunoassay (LIA; recomLine HEV, Mikrogen) and an ELISA (EIA; Anti-Hepatitis E Virus ELISA, Euroimmun) with a novel chemoluminescence immunoassay in a monotest format (CLIA; Hepatitis E VirClia, Vircell). Twenty sera of PCR proven cases of hepatitis E and 68 blood samples serologically pre-characterized were included. Applying the WHO reference standard, the CLIA demonstrated the highest analytical sensitivity for IgG and IgM. The combinations of CLIA/EIA (IgG and IgM) and CLIA/LIA (IgG) measurements showed substantial correlation. Compared to overall antibody detection (seropositivity in ≥2 assays), CLIA correlation was excellent, outperforming LIA (IgM) and EIA (IgG and IgM). Minor IgM cross reactivity in samples of patients with acute EBV infection was observed in all three assays. The CLIA showed good performance in diagnostic samples compared to established LIA and EIA assays. Due to its ready-to-use monotest format, the CLIA allows simple, time- and cost-effective handling of single samples. These qualities make the assay suitable for diagnostics, especially in the emergency setting and for low-throughput laboratories.

Risk of hepatitis-E virus infections among blood donors in a regional blood transfusion centre in western India

BACKGROUND

Hepatitis-E virus (HEV) is an emerging infectious threat to blood safety. The enormity of the transmission of HEV and its clinical consequence are issues currently under debate. This study aimed to evaluate the prevalence of HEV-RNA in blood donors in western India.

MATERIALS AND METHODS

We screened 13 050 blood donors for HEV using HEV-RNA screening of 10 mini-pools using RealStar HEV RT-PCR Kit (95% limit of detection (LOD): 4.7 IU/ml). Furthermore, all HEV-RNA-positive donors were investigated for the presence of IgM/IgG antibody along with liver function tests.

RESULTS

Of the 13 050 blood donations, 7 (0.53%) were found to be HEV-RNA positive, and the prevalence of HEV nucleic acid testing yield cases among blood donors was 1 in 1864. All seven HEV-RNA-positive samples were tested with anti-HEV IgM and anti-HEV IgG antibodies; this resulted in two (28.5%) positive anti-HEV IgM and two (28.5%) positive anti-HEV IgG antibodies. Hepatic activity was measured, with two of seven HEV-RNA-positive donors demonstrating abnormal serum glutamic oxaloacetic transaminase (SGOT) andserum glutamic pyruvic transaminase (SGPT). Two HEV-RNA-positive blood donors who had abnormal SGOT and SGPT were found to have a high HEV viral load. Furthermore, we were able to follow up two HEV-RNA donors, and both were HEV-RNA positive and had anti-HEV IgM and anti-HEV IgG antibodies; moreover, their liver function tests were also abnormal. One of the HEV-RNA donors with high viral load did show hepatitis-E-like virus on electron microscopy.

CONCLUSION

Our studies indicate that there is a significant risk of blood-borne transmission of HEV. This finding may help to provide a direction towards the safety of blood transfusions in clinical settings in countries like India, which fall under the endemic category for HEV infection.

Epidemiology, diagnosis, vaccines, and bibliometric analysis of the 100 top-cited studies on Hepatitis E virus

INTRODUCTION

In low-income countries, Hepatitis E infection is a common cause of acute hepatitis. So far, only two recombinant vaccines (rHEV and HEV 239) have been developed against Hepatitis E virus (HEV). Of which HEV 239 is licensed in China, but is not yet available in any other country.

OBJECTIVE

This study aims to discuss epidemiology, diagnosis, available vaccines for HEV, and provides an overview of 100 top-cited studies on HEV.

METHODS

A bibliometric analysis was conducted on the topic "HEV" through a systematic search of the Web of Science. The keywords used were "Hepatitis E" and retrieved articles were assessed for number of attributes.

RESULTS

The search returned a total of 3,235 publications, cited 95,858 times with h-index 129. The main finding for the 100 top-cited articles on HEV showed: number of authors ranging from 1 to 23, cited references range from 4 to 304, global citations score per year range from 6.61 to 175, and global citations score range from 148 to 791. Of the 100 top-cited studies, the authors who published most articles are Purcell (n = 18), Meng (n = 17), and Emerson (n = 15). Most The largest share of articles on HEV was contributed by United States of America (n = 49) with 12,795 citations. The National Institute of Allergy andInfectious Diseases was leading institute with greatest number of publications (n = 16), cited 3,950 times.

CONCLUSIONS

The studies conducted on HEV have increased over time. The information presented would be very useful in decision making for policy makers providing health care, and for academicians in providing a reference point for future research.

Occurrence of Human Enteric Viruses in Water Sources and Shellfish: A Focus on Africa

Enteric viruses are a diverse group of human pathogens which are primarily transmitted by the faecal-oral route and are a major cause of non-bacterial diarrhoeal disease in both developed and developing countries. Because they are shed in high numbers by infected individuals and can persist for a long time in the environment, they pose a serious threat to human health globally. Enteric viruses end up in the environment mainly through discharge or leakage of raw or inadequately treated sewage into water sources such as springs, rivers, dams, or marine estuaries. Human exposure then follows when contaminated water is used for drinking, cooking, or recreation and, importantly, when filter-feeding bivalve shellfish are consumed. The human health hazard posed by enteric viruses is particularly serious in Africa where rapid urbanisation in a relatively short period of time has led to the expansion of informal settlements with poor sanitation and failing or non-existent wastewater treatment infrastructure, and where rural communities with limited or no access to municipal water are dependent on nearby open water sources for their subsistence. The role of sewage-contaminated water and bivalve shellfish as vehicles for transmission of enteric viruses is well documented but, to our knowledge, has not been comprehensively reviewed in the African context. Here we provide an overview of enteric viruses and then review the growing body of research where these viruses have been detected in association with sewage-contaminated water or food in several African countries. These studies highlight the need for more research into the prevalence, molecular epidemiology and circulation of these viruses in Africa, as well as for development and application of innovative wastewater treatment approaches to reduce environmental pollution and its impact on human health on the continent.

Towards the Improved Accuracy of Hepatitis E Diagnosis in Vulnerable and Target Groups: A Global Perspective on the Current State of Knowledge and the Implications for Practice

The hepatitis E virus (HEV) is a positive single-stranded, icosahedral, quasi-enveloped RNA virus in the genus Orthohepevirus of the family Hepeviridae. Orthohepevirus A is the most numerous species of the genus Orthohepevirus and consists of eight different HEV genotypes that can cause infection in humans. HEV is a pathogen transmitted via the fecal-oral route, most commonly by consuming fecally contaminated water. A particular danger is the HEV-1 genotype, which poses a very high risk of vertical transmission from the mother to the fetus. Several outbreaks caused by this genotype have been reported, resulting in many premature births, abortions, and also neonatal and maternal deaths. Genotype 3 is more prevalent in Europe; however, due to the openness of the market, i.e., trade-in animals which represent a natural reservoir of HEV (such as pigs), there is a possibility of spreading HEV infections outside endemic areas. This problem is indeed global and requires increased hygiene measures in endemic areas, which entails special care for pregnant women in both endemic and non-endemic regions. As already highlighted, pregnant women could have significant health consequences due to the untimely diagnosis of HEV infection; hence, this is a population that should be targeted with a specific combination of testing approaches to ensure optimal specificity and sensitivity. Until we advance from predominantly supportive treatment in pregnancy and appraise the safety and efficacy of a HEV vaccine in this population, such screening approaches represent the mainstay of our public health endeavors.

Hepatitis E should be a global public health priority: recommendations for improving surveillance and prevention

INTRODUCTION

Hepatitis E virus (HEV) is an important cause of enterically transmitted viral hepatitis and a significant contributor to maternal mortality in endemic regions around the world, yet the global response has been limited. HEV is a disease of poverty, and the populations experiencing the greatest burden of HEV-associated illness are not benefitting from existing interventions, including WASH strategies and immunization.

AREAS COVERED

Though a vaccine exists (HEV 239, Hecolin®, Xiamen Innovax Biotech, China), it is only licensed and available in the private market in China and has yet to be prequalified by the WHO for use in endemic settings and outbreaks. This review of the current state of HEV disease and subsequent recommendations for a coordinated public health response are intended to guide the global health community towards breaking the current 'vicious cycle,' in which a lack of data prevents actions that would improve health outcomes.

EXPERT OPINION

Vaccine implementation in future outbreaks, targeted studies assessing vaccine effectiveness and immunogenicity in endemic regions and populations, improved understanding of the global burden, and improvements in diagnostic and epidemiologic tools are urgently needed. Strategies for implementing routine vaccination programs, improving water, sanitation, and hygiene in endemic regions.

Clinical Outcomes and Prevalence of Hepatitis E Virus (HEV) Among Non-A-C Hepatitis Patients in Egypt

Background

Hepatitis E virus (HEV) is an emerging infectious agent that causes acute hepatitis in developing and developed countries. Diagnosis of HEV infection has not been routinely done in Egyptian hospitals, and clinicians do not prescribe ribavirin (RBV) for acute hepatitis cases of unknown etiology (AHUE). We aimed to screen patients with AHUE for the presence of HEV markers and to determine the complications associated with HEV infection.

Patients and Methods

HEV markers (anti-HEV IgM, anti-HEV IgG, and HEV RNA) were assessed in patients with AHUE (n=300) admitted to Assiut University Hospitals. RT-qPCR was used to detect the viral load and sequencing analysis was carried out to determine the genotype of the detected viruses. Phylogenetic tree was constructed to evaluate the genetic relatedness between the isolates. Laboratory parameters and the outcomes of infection were determined.

Results

Acute HEV infection (AHE) was detected in 30 out of 300 (10%) of AHUE patients. Anti-HEV IgM, HEV RNA, and anti-HEV IgG were reported in 83%, 50%, and 43% of the samples, respectively. HEV RNA load ranged from 5×10² IU/mL to 1.1×10⁴ IU/mL. Sequencing of the isolated viruses revealed that five viruses belong to HEV-1 and one isolate belongs to HEV-3 with high homology to the virus recently isolated from the cow and goat milk in the Egyptian villages. Although previous reports showed that attenuated HEV isolates were circulating in Egypt, four out of 30 patients (13%) developed coagulopathy and hepatic encephalopathy and died due to fulminant hepatic failure (FHF) within 3–6 weeks of hospitalization. Age, malignancy, and a history of pre-existing liver diseases were a risky factor for FHF development.

Conclusion

AHE is common in Upper Egypt. Older patients with malignancy and/or a history of liver diseases are risky. HEV diagnosis and treatment become pivotal in Egyptian hospitals to reduce the fatality rate and they should start urgently and promptly.

Prevalence of hepatitis E virus among swine in China from 2010 to 2019: A systematic review and meta-analysis

Hepatitis E virus (HEV) is a zoonotic pathogen that has spread worldwide. The HEV reservoir associated with livestock hepatitis E poses a huge threat to public health. Awareness of the prevalence and spatial distribution of livestock hepatitis E is valuable to prevent and control diseases caused by HEV, especially human hepatitis E infection. Currently, swine, including pigs (Sus scrofa), are recognized as the major reservoir of HEV. Therefore, we conducted a systematic review and meta-analysis to evaluate the pooled prevalence of HEV among swine in China. A total of 71 published papers on HEV infection in swine in China (including data from 49,523 animals) from January 1, 2010 to December 31, 2019 met the standard after searching five databases including the Technology Periodical Database, the Wan Fang Database, the China National Knowledge Infrastructure, PubMed, and ScienceDirect. A random effects model was used to calculate the pooled prevalence of HEV in swine. The results showed that the seroprevalence was 48.0% (95% confidence interval (CI) 39.6-56.9) and the prevalence of HEV RNA was 14.4% (95% CI 10.7-18.5). The estimated overall prevalence was 34.1% (95% CI 27.2-41.4). Central China (68.0%, 95% CI 42.2-89.1) had a significantly higher prevalence than other regions. In the publication year subgroup, the prevalence in 2016 or later (27.2%, 95% CI 19.3-36.0) was significantly lower than that in 2011 or earlier (49.0%, 95% CI 36.2-61.8). The prevalence of IgG (42.9%, 95% CI 31.7-54.6) was significantly higher than that of IgM (4.9%, 95% CI 1.6-9.7). Suckling piglets (15.6%, 95% CI 6.6-27.1) had a lower prevalence compared with that in other age groups. In all sample types, body fluids showed the highest prevalence (50.5%, 95% CI 41.7-59.3). Moreover, the pooled prevalence of HEV in boars was higher than that in sows (35.4% > 17.3%). The analysis suggested that HEV infection is common among swine in China. Further strengthening HEV testing in boars, controlling environmental pollution, and reducing the mixed feeding of different stages could contribute to reducing HEV infection in pigs in China and the risk of porcine HEV infection in humans.

Travel-related hepatitis E: a two-decade GeoSentinel analysis

BACKGROUND

Hepatitis E virus (HEV) is widely distributed worldwide and is endemic in developing countries. Travel-related HEV infection has been reported at national levels, but global data are missing. Moreover, the global availability of HEV diagnostic testing has not been explored so far. The aim of this study is to describe the epidemiology of HEV infections in returning travellers and availability of HEV diagnostic testing in the GeoSentinel surveillance network.

METHODS

This was a multicentre retrospective cross-sectional study. All confirmed and probable HEV travel-related infections reported in the GeoSentinel Network between 1999 and 2018 were evaluated. GeoSentinel sites were asked to complete a survey in 2018 to assess the availability and accessibility of HEV diagnostic procedures (i.e. serology and molecular tests) throughout the study period.

RESULTS

Overall, 165 travel-related HEV infections were reported, mainly since 2010 (60%) and in tourists (50%). Travellers were exposed to hepatitis E in 27 countries; most travellers (62%) were exposed to HEV in South Asia. One patient was pregnant at the time of HEV infection and 14 had a concomitant gastrointestinal infection. No deaths were reported. In the 51% of patients with information available, there was no pre-travel consultation. Among 44 GeoSentinel sites that responded to the survey, 73% have access to HEV serology at a local level, while 55% could perform (at a local or central level) molecular diagnostics.

CONCLUSION

Reported access to HEV diagnostic testing is suboptimal among sites that responded to the survey; this could negatively affect diagnosing HEV. Pre-travel consultations before travel to South Asia and other low-income and high-prevalence areas with a focus on food and water precautions could be helpful in preventing hepatitis E infection. Improved HEV diagnostic capacity should be implemented to prevent and correctly diagnose travel-related HEV infection.

Stable HEV IgG seroprevalence in Belgium between 2006 and 2014

Recent European studies suggest an emergence of hepatitis E virus (HEV) infection. We evaluated trends in birth cohort-specific HEV seroprevalence and regional differences in Belgium. HEV IgG seroprevalence was analysed on national serum banks (1579 and 2087 samples for 2006 and 2014, respectively. Hepatitis E virus antigen was tested on positive samples. Observed data were modelled using a generalized additive model with a complementary log-log link. No significant differences between birth cohorts or sexes were found. Modelling identified the individual's age and province as relevant factors. The probability of HEV seropositivity increases significantly with age. An estimated total of 434 819 (yearly rate of 54,352) (sero-)infections were found between 2006 and 2014. Overall, HEV IgG seroprevalences were 4.1% (64/1579, 95% CI 3.1-5.1) and 5.8% (121/2087, CI 4.8-6.9) in 2006 and 2014, respectively. Observed HEV antigen seroprevalence was 0.027% (1/3666) for the entire cohort. These results show stable HEV IgG seroprevalence in Belgium.

Phylogenetic analysis of two new complete genomes of the hepatitis E virus (HEV) genotype 3 from Thailand

Hepatitis E virus (HEV) is a causative agent of acute viral hepatitis globally. Evolutionary phylogeny classifies the HEV into eight genotypes that correlate with the viral transmission. Only four genotypes have been proven to be responsible for transmission in humans. However, there has been no report on the genomics and genotyping of HEV in Thailand during the past ten years. Here, we identified the genotype distributions of the Thai isolates of HEV and we sequenced two HEV genomes. We screened for 18 Thai isolates of HEV from Siriraj Hospital in Bangkok, from 2014–2016. The HEV genomes were sequenced from the serum and feces of a patient. The results showed that all Thai isolates of HEV were identified as genotype 3 (HEV-3). The ORF2 and genome phylogenies suggested two subgenotypes, called 3.1 and 3.2. The Thai isolates of HEV were frequently found in the subgenotype 3.1. The genome sequences of the two Thai isolates of HEV from the serum and fecal samples of the same patient showed 91% nucleotide similarity with the HEV genotype 3. Comparisons between the HEV genome and the ORF2 phylogenies illustrated that the ORF2 tree can be used to identify HEV genotypes, but it has less phylogenetic power for the HEV evolution. The two new genome sequences of HEV-3 from Thailand could contribute valuable information to the HEV genome study. (226 words)

Proposed Algorithm for Hepatitis E Virus Diagnosis in the Early Phase of Illness

Hepatitis E virus (HEV), a major etiologic agent of enterically transmitted hepatitis worldwide, is known to cause outbreaks. Diagnosis of the causative agent is important for patient management, understanding epidemiology and outbreak mitigation. We attempted to develop an algorithm for molecular diagnosis and compared the diagnostic accuracy of 2 of HEV IgM ELISA tests during an outbreak. Eighty-four blood samples collected during an outbreak in central India were referred to a nodal laboratory for confirmation of diagnosis. The samples were tested by serological and molecular testes. The results were analyzed by statistical tests. Both the IgM ELISAs were equally competent to diagnose HEV infection when samples were collected after 7.95 ± 3.2 days of onset of illness, whereas nRT-PCR proved a better test when samples were collected between 0 and 6.17 ± 1.97 days of illness. During HEV outbreaks, it is not possible to test all suspected cases by both serological and molecular tests; we suggest testing all ELISA-negative and samples collected in early phase (<7 days) of illness by molecular tests to rule out false-negative results. More studies with large sample size will aid in designing national guidelines for molecular diagnosis of HEV.

Cryptogenic liver cirrhosis and hepatitis E virus (HEV): Are they related?

INTRODUCTION AND OBJECTIVES

Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis. In recent years, its role in the development of chronic hepatitis and cirrhosis especially in immunosuppressed patients and its wide range of extrahepatic involvement have increased the amount of research on HEV. In this study we aimed to investigate the presence of HEV infection in individuals with cryptogenic cirrhosis.

MATERIALS AND METHODS

HEV antibodies were analysed using the Anti HEV enzyme-linked immunosorbent assay (ELISA) kit (anti-HEV ELISA; Diapro Prodiagnostic Bioprobes, Milan, Italy). HEV RNA was isolated with using QIAMP Viral RNA mini kit (QIAGEN, Hilden, Germany). The HEV RNA titre was detected with the Rotor Gene 3000 real time polymerase chain reaction (PCR) system using GenoSen's HEV (Rotor Gene) Quantitative Real Time PCR Kit (Genome Diagnostics Private Limited, the Netherlands).

RESULTS

Our study included 21 healthy volunteers (12 males) and 35 cryptogenic cirrhosis patients (19 males). The ages of the patients and the controls were similar (46±12.1 vs. 37.5±9.7years). The mean Child-Pugh score was 8±2.5. The anti HEV immunoglobulin G(IgG) positivity rate was 9.5% and 25.7% in the control and patient groups respectively (p>0.05). HEV RNA positivity was not detected in the control group, but 3 cases (8.6%) in the patient group were positive (p>0.05). The HEV RNA, aspartate aminotransferase (AST) and alanine aminotransferase(ALT) levels for these 3 cases were 326.461copies/mL, 91IU/L and 67IU/L; 480copies/mL, 68IU/L and 36IU/L and 72copies/mL, 42IU/L and 24IU/L respectively. There were positive correlations between HEV RNA levels and AST and ALT levels (p<0.05).

CONCLUSIONS

Anti HEVIgG and HEV RNA positivity rates are high in cryptogenic cirrhosis although it is not statistically significant and there is a positive correlation between HEV RNA and aminotransferases.

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

INTRODUCTION AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

[Line immunoassay for detection of IgG antibodies to hepatitis E virus (Hepeviridae, Orthohepevirus, Orthohepevirus A)]

INTRODUCTION

The diagnostic efficacy of methods for hepatitis E serodiagnostic varies over a wide range; therefore, the combined use of tests of various formats is recommended. The aim of the research was to develop a test system for the detection of IgG antibodies to hepatitis E virus (HEV) in human serum by linear immunoassay (LIA).

MATERIAL AND METHODS

Serum samples from patients with hepatitis and healthy individuals were tested using commercial enzyme-linked immunosorbent assay systems for the presence of IgG antibodies to viral agents causing hepatitis and other infections associated with liver pathology. Recombinant antigens ORF2 and ORF3 of HEV genotypes 1 and 3 were used. The "RecomLine HEV IgG/IgM" reagent kit (Mikrogen GmbH, Germany) was used as a comparison test system.

RESULTS

The first Russian diagnostic kit "Blot-HEV", designed to detect IgG antibodies to individual HEV proteins in human serum using LIA, was developed. The antigenic base is represented by strips of a nitrocellulose membrane with immobilized recombinant antigens ORF2 (aa 406-660) and ORF3 (aa 1-113) of HEV genotypes 1 and 3, and control antigens in the form of discrete lines. The conjugate was mouse monoclonal antibodies to human class G immunoglobulins labeled with horseradish peroxidase. The chromogen solution contained the 3,3',5,5'-tetramethylbenzidine. A visual and digital recording of results was provided. The analytical sensitivity of the test kit was 0.625 IU/ml for ORF2 antigens and 2.5 IU/ml for ORF3 antigens. The absence of the influence of endogenous interfering substances on the results of the analysis and the absence of cross-reactions with antibodies to hepatitis pathogens of the other etiologies had been shown. The sensitivity of the test system compared to the "RecomLine HEV IgG/IgM" kit was 92%, specificity 97%. Shelf life in condition of storage was determined to be 12 months.

CONCLUSIONS

The developed test can be used to confirm the results of ELISA in laboratory diagnosis of hepatitis E.

Performance of Roche qualitative HEV assay on the cobas 6800 platform for quantitative measurement of HEV RNA

BACKGROUND

Hepatitis E virus (HEV) infection is an increasingly recognized cause of acute and chronic hepatitis in high-income countries and is the most frequent cause of acute viral hepatitis in many European countries. Appropriate tools to detect and quantify HEV RNA are needed. This study aimed to evaluate the performance of the Roche cobas® HEV assay and compare it with the Fast Track Diagnostics (FTD) Hepatitis E RNA assay.

METHODS

HEV viral load determination and lower limit of detection (LOD, defined as the lowest amount of viral copies that could be detected in 95 % of repeats) were assessed using a WHO standard dilution panel, testing 240 samples of various concentrations. Reproducibility was tested at three different concentration levels, for different genotypes, and with different sample types (serum, plasma) in 30 samples. Sample stability was analyzed after three freeze/thaw cycles in 25 samples.

RESULTS

Cobas HEV assay showed a strong linear relationship between log of HEV WHO dilution series and Ct values over the reportable range from 200-5000 IU/mL HEV RNA copies. The amplification efficiency was higher than 92 %. LOD was 22 IU/mL (95 % CI: 17.4-31.8) and reproducibility tests showed a 100 % nucleic acid test (NAT) reactivity of cobas HEV for WHO dilution series (range 200-5000 IU/mL, n = 90). Cobas HEV assay detected all different HEV genotypes from biobank samples irrespective of the sample type. NAT reactivity of cobas HEV was not affected by three freeze/thaw cycles.

CONCLUSIONS

Roche cobas HEV assay is a powerful NAT tool in terms of robustness, reproducibility and linearity. It is a feasible alternative for high-volume testing.

Hepatitis E virus infection during pregnancy

BACKGROUND

Hepatitis E virus (HEV) generally causes self-limiting viral hepatitis. However, in pregnant women, HEV infection can be severe and has been associated with up to 30% mortality in the third trimester. Additionally, HEV infection in pregnancy is also associated with high rates of preterm labor and vertical transmission.

MAIN BODY

HEV is now recognized as a global health problem in both developing and industrialized countries. HEV can be transmitted via the fecal-oral route, zoonotic route, and blood transfusion route. An altered immune status, hormonal levels, and viral factors may be related to the severity of the disease. Currently, no established treatment is available for HEV in pregnant women. A Chinese vaccine has been demonstrated to be protective against HEV in the general population and seems to be safe in pregnancy; however, its safety and efficacy in a large population of pregnant women remain to be determined.

CONCLUSION

This review summarizes the current knowledge about HEV infection during pregnancy and focuses on the epidemiology, clinical manifestations, mechanisms underlying severe liver injury, and management and prevention of HEV infection during pregnancy. Considering that HEV infection during pregnancy may result in poor outcomes, screening for and monitoring HEV infection early in pregnancy should be taken into account. In addition, a better understanding of the pathogenesis will help to develop potential treatment strategies targeting HEV infection in pregnancy.

Prevalence of hepatitis E viraemia among blood donors: a systematic review

BACKGROUND

Hepatitis E virus (HEV) is usually transmitted by faecal-oral route. Recent reports have documented HEV viraemia in donated blood units and HEV transmission through blood transfusion. This systematic review summarizes the available data on prevalence of HEV viraemia in blood donors.

METHODS

Electronic databases were searched on 17 December 2018 to identify full-text English papers reporting original data on prevalence of HEV RNA in donated blood units. Two authors independently extracted the relevant data, which were pooled using simple aggregation as well as a random-effects meta-analysis; heterogeneity was assessed using the I2 method.

RESULTS

In all, 59 data sets from 28 countries were identified. The available data showed marked heterogeneity. Of a total of 2 127 832 units studied, 561 (263·6 [95% confidence intervals = 242·7-286·4] per million units) tested positive for HEV RNA. On random-effects meta-analysis, the pooled prevalence was 60·9 [6·7-155·4] per million units. In the viraemic units, HEV RNA titre varied by nearly one million-fold, and most had genotype 3 HEV. The prevalence was higher in blood units with anti-HEV antibodies or elevated alanine aminotransferase. Only nearly one-fourth of viraemic units had anti-HEV antibodies.

CONCLUSIONS

The prevalence of HEV viraemia among healthy blood donors is low, though the available data had limited geographical representation and marked heterogeneity. There is a need for further data on HEV viraemia in blood donors from areas with non-3 HEV genotype preponderance.

Seroprevalence of hepatitis E virus in dromedary camels, Bedouins, Muslim Arabs and Jews in Israel, 2009-2017

Hepatitis E virus (HEV) is an emerging cause of viral hepatitis worldwide. Recently, HEV-7 has been shown to infect camels and humans. We studied HEV seroprevalence in dromedary camels and among Bedouins, Arabs (Muslims, none-Bedouins) and Jews and assessed factors associated with anti-HEV seropositivity. Serum samples from dromedary camels (n = 86) were used to determine camel anti-HEV IgG and HEV RNA positivity. Human samples collected between 2009 and 2016 from &gt;20 years old Bedouins (n = 305), non-Bedouin Arabs (n = 320) and Jews (n = 195), were randomly selected using an age-stratified sampling design. Human HEV IgG levels were determined using Wantai IgG ELISA assay. Of the samples obtained from camels, 68.6% were anti-HEV positive. Among the human populations, Bedouins and non-Bedouin Arabs had a significantly higher prevalence of HEV antibodies (21.6% and 15.0%, respectively) compared with the Jewish population (3.1%). Seropositivity increased significantly with age in all human populations, reaching 47.6% and 34.8% among ⩾40 years old, in Bedouins and non-Bedouin Arabs, respectively. The high seropositivity in camels and in ⩾40 years old Bedouins and non-Bedouin Arabs suggests that HEV is endemic in Israel. The low HEV seroprevalence in Jews could be attributed to higher socio-economic status.

Hepatitis E Virus Infection in an Italian Cohort of Hematopoietic Stem Cell Transplantation Recipients: Seroprevalence and Infection

Chronic hepatitis E virus (HEV) infection in hematopoietic stem cell transplantation (HSCT) recipients is an emerging threat. The aim of this study was to provide data on the HEV burden in an Italian cohort of HSCT recipients and analyze risk factors for HEV seropositivity. This retrospective study reports data from 596 HSCT recipients compiled between 2010 and 2019. It included patients who underwent transplantation between 2010 and 2015 for whom pretransplantation (n = 419) and post-transplantation (n = 161) serum samples were available and tested retrospectively, as well as patients in whom prospective HEV testing was performed during the standard care: pre-HSCT IgG screening in 144, pre-HSCT HEV-RNA screening in addition to IgG screening in 60, and HEV-RNA testing in case of clinical suspicion of HEV infection in 59 (26 of whom were also included in the IgG screening cohorts). The rate of pre-HSCT HEV-IgG positivity was 6.0% (34 of 563). Older age was an independent risk factor for seropositivity (P = .039). None of the 34 HEV-IgG-positive patients had detectable HEV-RNA. One case of transient HEV-RNA positivity pre-HSCT was identified through screening. Two patients were diagnosed with chronic HEV hepatitis, and 1 patient was successfully treated with ribavirin. The burden of HEV infection in HSCT recipients in Italy is limited, and pre-HSCT screening appears to be of no benefit. Timely diagnosis of HEV infection with HEV-RNA is mandatory in cases of clinical suspicion.

Establishment of a Highly Sensitive Assay for Detection of Hepatitis E Virus-Specific Immunoglobulins

Hepatitis E, a liver disease caused by infection with the hepatitis E virus (HEV), is a worldwide emerging disease. The diagnosis is based on the detection of viral RNA and of HEV-specific immunoglobulins (Ig). For the latter, various assays are commercially available but still lack harmonization. In this study, a Luminex-based multiplex serological assay was established that measures the presence of total IgG, IgA, and IgM antibodies, targeting a short peptide derived from the viral E2 protein. For the validation, 160 serum samples with a known HEV serostatus were used to determine the assay cutoff and accuracy. Thereby, HEV IgG- and RNA-positive sera were identified with a sensitivity of 100% and a specificity of 98% (95% confidence interval [CI], 94% to 100%). Application of the assay by retesting 514 serum samples previously characterized with different HEV-IgG or total antibody tests revealed a high level of agreement between the assays (Cohen's kappa, 0.58 to 0.99). The established method is highly sensitive and specific and can be easily implemented in a multiplex format to facilitate rapid differential diagnostics with a few microliters of sample input.

Low Serologic Prevalences Suggest Sporadic Infections of Hepatitis E Virus in Chamois (Rupicapra rupicapra) and Red Deer (Cervus elaphus) in the Italian Alps

Hepatitis E virus (HEV) is a worldwide public health concern, with an increase in human autochthonous cases in Europe. Although domestic pigs and wild boar (Sus scrofa) are the main reservoirs of HEV, the constant expansion of wild ruminants increases the potential for HEV transmission. We investigated HEV infection in chamois (Rupicapra rupicapra) and red deer (Cervus elaphus) in the Italian Alps using an enzyme-linked immunosorbent assay (ELISA). We detected HEV antibodies from 2013 to 2015 in both host species, with seroprevalences of 1.2% and 0.8% in chamois and red deer, respectively. All serum samples that were positive to HEV antibodies by ELISA were negative when tested by real-time reverse-transcriptase PCR to detect HEV RNA. The observed low seroprevalence of HEV suggested a sporadic circulation of HEV in the alpine environment, and it was consistent with the low seroprevalence observed in wild boar in the Alps. Our observations supported the role of chamois and red deer as spillover hosts of HEV infections in the Italian Alps.

[Hepatitis E Virus: Epidemiology, Diagnosis, and Management]

The HEV is a known cause of water-borne outbreaks of acute non-A non-B hepatitis in developing countries, which affects young people and may result in high mortality in pregnant women. In recent decades, however, HEV genotypes 3 and 4 have been known as a cause of sporadic zoonotic infections in older males from swine HEV worldwide. Most acute HEV infections are self-limited. On the other hand, in immunosuppressed patients, including solid organ transplant recipients, chronic HEV infections may exist and progress to liver cirrhosis or decompensation. Therefore, physicians need to recognize HEV as a major pathogen for acute and chronic hepatitis of unknown causes and investigate this disease.

Hepatitis E virus in Tibetan pigs on the Qinghai-Tibetan Plateau: detection, molecular characterization and infection of BALB/c mice

This study was performed to investigate the prevalence and genetic variation of hepatitis E virus (HEV) in Tibetan pigs and to determine its ability to infect mice. A total of 38 out of 229 (16.59%; 95% CI = 12.00%-22.10%) fecal samples from Tibetan pigs from the Qinghai-Tibetan Plateau in 2018 were positive for HEV RNA, which was detected by RT-nPCR. Significantly different detection rates were observed between samples from diarrheic and clinically healthy animals (OR = 9.56; 95% CI, 2.84-32.14; p < 0.001), suggesting a potential association between HEV infection and diarrhea in Tibetan pigs. Phylogenetic analysis showed that the HEV isolates were clustered into subtypes 4a (31 samples), 4b (1), 4d (2), and 4j (4). HEV-4a was the predominant subtype, indicating that it might be circulating in Tibetan pigs. Nine complete HEV genome sequences obtained from Tibetan pigs were found by phylogenetic analysis to be closely related to those of genotype 4 HEV isolates from humans. Two recombinant events were identified in both HEV-4a strains; a novel recombination breakpoint was first identified at the 3' end of the ORF2 region in the SWU/L9/2018 strain, and a common recombination region was found at the junction of the ORF1 and ORF2 regions in the SWU/31-12/2018 strain. Furthermore, HEV-4a could be detected in all BALB/c mice that were experimentally infected by gavage and contact exposure. The information presented here about the prevalence and genotype diversity of HEV from Tibetan pigs provides important insights into the epidemic features of HEV on the Qinghai-Tibetan Plateau.

Occupational swine exposure and Hepatitis E virus, Leptospira, Ascaris suum seropositivity and MRSA colonization in Austrian veterinarians, 2017-2018-A cross-sectional study

We investigated the prevalence of Hepatitis E Virus (HEV), Leptospira and Ascaris suum (A. suum) seropositivity, and of nasal methicillin-resistant Staphylococcus aureus (MRSA) colonization among Austrian practising veterinarians, and assessed the association with occupational swine livestock exposure. The 261 participants completed a questionnaire on demographics, intensity of occupational swine livestock contact and glove use during handling animals and their secretions. Participants' blood samples were tested for HEV, Leptospira and A. suum seropositivity and nasal swabs cultured for MRSA. We compared swine veterinarians (defined as >3 swine livestock visits/week) to non-swine veterinarians (≤3 swine livestock visits/week) with regard to the outcomes through calculating prevalence ratio (PR) and 95% confidence interval (CI). Furthermore, the relationship between occupational swine livestock contact and the study outcomes was examined by age (</≥55 years) and glove usage. The prevalence of nasal MRSA colonization was 13.4% (95% CI: 9.3-17.6), of HEV seropositivity 20.8% (95% CI: 15.8-25.7) and A. suum seropositivity 44% (95% CI: 37.7-50.2). The highest anti-leptospiral antibodies titres were 1:200 (L. hebdomadis) and 1:100 (L. autumnalis, L. caicola) found in three non-swine veterinarians. Compared to non-swine veterinarians, swine veterinarians were 1.9 (95% CI: 1.0-3.4) and 1.5 (95%CI: 1.0-2.3) times more likely HEV seropositive and A. suum seropositive, respectively, and 4.8 (95%CI: 2.5; 9.3) times more likely nasally colonized with MRSA. Among glove-using veterinarians, occupational swine contact was no longer a determinant for HEV seropositivity (PR 1.6; 95% CI: 0.8-2.9). Similar was found for A. suum seropositivity, which was no longer associated with occupational swine livestock contact in the subgroup of glove using, ≥55-year-old veterinarians (PR: 1.07; 95% CI: 0.4-3.3). Our findings indicate that >3 occupational swine livestock visits per week is associated with HEV and A. suum seropositivity and nasal MRSA colonization and that glove use may play a putative preventive role in acquiring HEV and A. suum. Further analytical epidemiological studies have to prove the causality of these associations.

Hepatitis B Virus Molecular Epidemiology, Host-Virus Interaction, Coinfection, and Laboratory Diagnosis in the MENA Region: An Update

Hepatitis B virus (HBV) is an enveloped partial double-stranded DNA virus that can cause acute and chronic hepatitis. According to the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), 257 million people are living with HBV. Moreover, 20,900 acute hepatitis B cases were reported in 2016. Hepatitis B is highly prevalent in the African, Western Pacific, Eastern Mediterranean, South-East Asia, and European regions, respectively. Due to the high mutational rate of HBV and lack of reverse transcriptase proofreading activity, ten different genotypes with different geographical distributions have been identified. HBV pathogenesis and severity of infection depend on several host and viral factors, particularly, the genetic variability of both the host and virus. Although HBV infection is a global health concern, there is a lack of adequate studies and reports in the Middle East and North Africa (MENA) region. Here, we provide a review on HBV epidemiology, pathogenesis, host-pathogen interactions, coinfection with selected viruses, and laboratory diagnosis, focusing on studies conducted in the MENA region to determine the current situation of the HBV infection and outline the future study areas.