Seroprevalence and Incidence of hepatitis E in blood donors in Upper Austria

Emerging Pathogen Threats in Transfusion Medicine: Improving Safety and Confidence with Pathogen Reduction Technologies

Emerging infectious disease threats are becoming more frequent due to various social, political, and geographical pressures, including increased human-animal contact, global trade, transportation, and changing climate conditions. Since blood products for transfusion are derived from donated blood from the general population, emerging agents spread by blood contact or the transfusion of blood products are also a potential risk. Blood transfusions are essential in treating patients with anemia, blood loss, and other medical conditions. However, these lifesaving procedures can contribute to infectious disease transmission, particularly to vulnerable populations. New methods have been implemented on a global basis for the prevention of transfusion transmissions via plasma, platelets, and whole blood products. Implementing proactive pathogen reduction methods may reduce the likelihood of disease transmission via blood transfusions, even for newly emerging agents whose transmissibility and susceptibility are still being evaluated as they emerge. In this review, we consider the Mirasol PRT system for blood safety, which is based on a photochemical method involving riboflavin and UV light. We provide examples of how emerging threats, such as Ebola, SARS-CoV-2, hepatitis E, mpox and other agents, have been evaluated in real time regarding effectiveness of this method in reducing the likelihood of disease transmission via transfusions.

Hepatitis E Virus in Finland: Epidemiology and Risk in Blood Donors and in the General Population

Autochthonous hepatitis E (HEV) cases have been increasingly recognized and reported in Europe, caused predominantly by the zoonotic HEV genotype 3. The clinical picture is highly variable, from asymptomatic to acute severe or prolonged hepatitis in immunocompromised patients. The main route of transmission to humans in Europe is the ingestion of undercooked pork meat. Transfusion-transmitted HEV infections have also been reported. The aim of the study was to determine the HEV epidemiology and risk in the Finnish blood donor population. A total of 23,137 samples from Finnish blood donors were screened for HEV RNA from individual samples and 1012 samples for HEV antibodies. Additionally, laboratory-confirmed hepatitis E cases in 2016-2022 were extracted from national surveillance data. The HEV RNA prevalence data was used to estimate the risk of transfusion transmission of HEV in the Finnish blood transfusion setting. Four HEV RNA-positive were found, resulting in 1:5784 (0.02%) RNA prevalence. All HEV RNA-positive samples were IgM-negative, and genotyped samples represented genotype HEV 3c. HEV IgG seroprevalence was 7.4%. From the HEV RNA rate found in this study and data on blood component usage in Finland in 2020, the risk estimate for a severe transfusion-transmitted HEV infection is 1:1,377,000 components or one in every 6-7 years. In conclusion, the results indicate that the risk of transfusion-transmitted HEV (HEV TTI) in Finland is low. However, continuous follow-up of the HEV epidemiology in relation to the transfusion risk landscape in Finland is necessary, as well as promoting awareness in the medical community of the small risk for HEV TTI, especially for immunocompromised patients.

Higher Risk of HEV Transmission and Exposure among Blood Donors in Europe and Asia in Comparison to North America: A Meta-Analysis

Background and aims: The increasing number of diagnosed hepatitis E virus (HEV) infections in Europe has led to the implementation of the testing of blood products in various countries. Many nations have not yet implemented such screening. To assess the need for HEV screening in blood products worldwide, we conducted a systematic review and meta-analysis assessing HEV RNA positivity and anti-HEV seroprevalence in blood donors. Methods: Studies reporting anti-HEV IgG/IgM or HEV RNA positivity rates among blood donors worldwide were identified via predefined search terms in PubMed and Scopus. Estimates were calculated by pooling study data with multivariable linear mixed-effects metaregression analysis. Results: A total of 157 (14%) of 1144 studies were included in the final analysis. The estimated HEV PCR positivity rate ranged from 0.01 to 0.14% worldwide, with strikingly higher rates in Asia (0.14%) and Europe (0.10%) in comparison to North America (0.01%). In line with this, anti-HEV IgG seroprevalence in North America (13%) was lower than that in Europe (19%). Conclusions: Our data demonstrate large regional differences regarding the risk of HEV exposure and blood-borne HEV transmission. Considering the cost–benefit ratio, this supports blood product screening in high endemic areas, such as Europe and Asia, in contrast to low endemic regions, such as the U.S.

Prevalence of HEV RNA in Croatian blood donors

OBJECTIVES

HEV infection is asymptomatic for immunocompetent blood donors (BD). Transfused HEV-infected blood products may cause potentially hazardous HEV infection in immunocompromised patients. Evaluation of the need for routine BD HEV RNA screening primarily demands the establishment of HEV infection prevalence in Croatian BD.

MATERIALS AND METHODS

We tested BD samples in ID-NAT with the Procleix UltrioPlex E screening test for simultaneous detection of HBV DNA, HCV RNA, HIV-1,2 RNA, and HEV RNA (Grifols, Spain). HEV infection was confirmed with HEV RNA quantitative test (Altona Diagnostics, Germany) and HEV IgM and HEV IgG antibody test (DIA.PRO Diagnostic Bioprobes, Italy). We analysed the HEV RNA sequence and performed a phylogenetic analysis. We recorded BD's anamnestic data and dietary habits. BDs gave follow-up samples after two months and did not donate blood for six months.

RESULTS

Between December 2021 and March 2022, we tested 8,631 donations and found four HEV RNA-positive donations, which equals to one in 2,158 donations (0.046 %, 95 % confidence interval, 0.018 %-0.119 %). Confirmatory HEV RNA testing gave results from negative to 4.73E + 3 IU/ml HEV RNA. Three donations were in the serological window period. We have genotyped HEV RNA of two infected BD as genotype HEV-3c. Blood donors didn't report any health problems and their diet included pork. Testing on follow-up samples presented seroconversion and no HEV RNA could be detected.

CONCLUSION

The incidence of HEV RNA infection in BD in Croatia corresponds with other European data. The decision on implementation of HEV NAT screening in Croatia needs an expert team evaluation of the possible risk of TT-HEV infection.

Low mortality despite temporary liver dysfunction in severe courses of acute hepatitis E

BACKGROUND

Hepatitis E virus (HEV) infection can cause severe viral hepatitis and eventually liver failure. We aim to provide novel data on the epidemiology and the course of HEV infections from Q1/2008 to Q3/2018 at the Vienna General Hospital.

METHODS

Of the 88,945 people tested, we identified HEV-IgM positive (+) or HEV-PCR (+) patients and retrospectively collated information on the course of infection from patient records.

RESULTS

Among 151 HEV-IgM or PCR (+) (median age 51 years, 45.8% female), 7 (4.6%) had non-severe acute HEV infection (ALT ≥ 2-5-fold upper limit of normal, ULN), 11 (7.3%) had severe HEV infection without liver dysfunction (LD) (ALT > 5-fold ULN), and 9 (6.0%) with LD (ikterus or bilirubin > 5 mg/dL, OR coagulopathy or INR > 1.5, OR encephalopathy or ammonia > 100 µmol/L). HEV-RNA-PCR was performed in 58/190 (30.5%) HEV-IgM (+) patients and was positive in 19 (30.6%). Rates of HEV IgM/PCR positivity remained stable over the observation period. The HEV genotype (GT) was GT‑1 in 71.4% (n = 5) and GT‑3 in 28.6% (n = 2). Travel history was recorded for 9/20 (45.0%) of severe HEV and 12/20 (60.0%) patients with severe HEV infection were hospitalized. One patient with pre-existing liver disease and concomitant EBV infection required intensive care. No patient required transplantation and the 30-day mortality was 3/151 (1.9%). Despite the increased testing rates, the absolute number of diagnosed HEV infections at Vienna General Hospital remained constant between 2008 to 2018.

CONCLUSION

Although approximately half of the patients with severe acute HEV infection required hospitalization, admissions to the intensive care unit (ICU) and short-term mortality were low.

Immunobiology and Host Response to HEV

Hepatitis E virus (HEV) usually causes acute self-limiting hepatitis but sometimes leads to chronic infection in immunocompromised persons. HEV is not directly cytopathic. Immunologically mediated events after HEV infection are believed to play important roles in the pathogenesis and clearance of infection. The anti-HEV antibody responses have been largely clarified since the determination of major antigenic determinant of HEV, which is located in the C-terminal portion of ORF2. This major antigenic determinant also forms the conformational neutralization epitopes. Robust anti-HEV immunoglobulin M (IgM) and IgG responses usually develop 3-4 weeks after infection in experimentally infected nonhuman primates. In humans, potent specific IgM and IgG responses occur in the very early phase of the disease and are critical in eliminating the virus, in concert with the innate and adaptive T-cell immune responses. Testing anti-HEV IgM is valuable in the diagnosis of acute hepatitis E. The long-term persistence and protection of anti-HEV IgG provide the basis for estimating the prevalence of HEV infection and for the development of a hepatitis E vaccine. Although human HEV has four genotypes, all the viral strains are considered to belong to a single serotype. It is becoming increasingly clear that the innate and adaptive T-cell immune responses play critical roles in the clearance of the virus. Potent and multispecific CD4+ and CD8+ T cell responses to the ORF2 protein occur in patients with acute hepatitis E, and weaker HEV-specific CD4+ and CD8+ T cell responses appear to be associated with chronic hepatitis E in immunocompromised individuals.

Analysis of seroprevalence and risk factors for hepatitis E virus (HEV) in donation candidates and blood donors in Northeast Brazil

Oral transmission is the main route of hepatitis E virus (HEV) infection; however, genotypes 3 and 4 may also be transmitted by blood transfusion. Individuals who need blood products are often immunosuppressed, which increase the risk of severe disease and death by HEV. Despite this, blood banks in Brazil do not screen for HEV and epidemiological studies in this population are rare; this is an important issue as HEV-3 is frequently identified in the country. Herein, we analyzed the seroprevalence and risk factors for HEV seropositivity in donor candidates/blood donors from Northeast Brazil. Nine hundred and ninety-six donor candidates/blood donors from Foundation of Hematology and Hemotherapy of Pernambuco (HEMOPE) were interviewed regarding socioeconomic, sociodemographic, and behavioral data and analyzed for anti-HEV IgG. Anti-HEV IgG was detected using the HEV IgG (EUROIMMUN) kit. Associations between seropositivity and potential risk factors were analyzed by the χ2 test and Fisher's exact test. Seroprevalence was 0.9% (9/996), 77.77% (7/9) and 22.22% (2/9) in blood donors and donor candidates, respectively. HEV seropositivity was associated with male (OR: 11.65; CI: 0.6755-200.9; p = 0.0163), income higher than BRL 20,000/month (p = 0.0002), and lake bathing (OR: 4.553; CI: 1.391-15.25; p = 0.0258). Importantly, about 43% (3/7) of anti-HEV positive donors made their first donation more than 20 years ago, which must be taken as a warning sign, given the possibility that these individuals may have been infected after registration as donors. Finally, the report of HEV seropositivity, especially in regular blood donors, as well as the identification of potential risk factors, reinforces the need for viral screening in Brazilian blood banks.

Sero-epidemiology and Risk Assessment of Hepatitis E Virus Among Blood Donors in North Lebanon

Background: Hepatitis E virus (HEV) is the causative agent of over 50% of acute viral hepatitis cases. The blood transfusion route has emerged as a possible route of transmission of HEV. Objectives: This study aimed to determine the seroprevalence of IgM and IgG anti-HEV among blood donors in North Lebanon and to assess the risk factors associated with its occurrence. Methods: A cross-sectional study was conducted from November to December 2020. Blood samples were collected from 78 healthy blood donors. A standardized questionnaire containing sociodemographic, food consumption, lifestyle, and health-related characteristics, was filled out to assess the risk factors of HEV exposure. Serum samples were tested for IgM and IgG anti-HEV by an enzyme-linked immunosorbent assay (ELISA). Results: The seroprevalence of IgM and IgG anti-HEV antibodies was reported in our study, and it reached 1.09% (1/78) and 12.82% (10/78), respectively. The use of private wells as a drinking source and the travel history to endemic countries have been identified as risk factors for HEV infections (P

Monitoring Urban Zoonotic Virus Activity: Are City Rats a Promising Surveillance Tool for Emerging Viruses?

Urban environments represent unique ecosystems where dense human populations may come into contact with wildlife species, some of which are established or potential reservoirs for zoonotic pathogens that cause human diseases. Finding practical ways to monitor the presence and/or abundance of zoonotic pathogens is important to estimate the risk of spillover to humans in cities. As brown rats (Rattus norvegicus) are ubiquitous in urban habitats, and are hosts of several zoonotic viruses, we conducted longitudinal sampling of brown rats in Vienna, Austria, a large population center in Central Europe. We investigated rat tissues for the presence of several zoonotic viruses, including flaviviruses, hantaviruses, coronaviruses, poxviruses, hepatitis E virus, encephalomyocarditis virus, and influenza A virus. Although we found no evidence of active infections (all were negative for viral nucleic acids) among 96 rats captured between 2016 and 2018, our study supports the findings of others, suggesting that monitoring urban rats may be an efficient way to estimate the activity of zoonotic viruses in urban environments.

Prevalence and risk factors for hepatitis E virus infection in blood donors: a nationwide survey in Italy, 2017 to 2019

Background

In high-income countries, hepatitis E virus (HEV) infection is mainly a zoonosis. However, it is also transfusion-transmissible and some countries, but not Italy, have introduced HEV screening for blood donations.

Aim

We assessed HEV infection prevalence and risk factors in a nationwide sample of Italian blood donors.

Methods

We selected 107 blood establishments (BE) distributed in the 20 Italian regions by a stratified two-stage design and invited them to participate in the study. Donors were tested for anti-HEV IgG and IgM and HEV RNA. Sociodemographic data and risk factors were collected through a questionnaire.

Results

Overall, 60 BE from 60 provinces in 19 Italian regions joined the study. We assessed HEV markers in 7,172 blood donors, of whom 6,235 completed the questionnaire. Overall crude and adjusted anti-HEV IgG prevalences were 8.3% and 5.5%, respectively. Overall anti-HEV IgM prevalence was 0.5%, while no blood donor was HEV RNA-positive. Anti-HEV IgG prevalence varied widely among regions (range: 1.3%–27.20%) and hyperendemic prevalences (> 40%) were detected in some provinces in two regions. Older age (AOR = 1.81; 95% CI: 1.36–2.41), foreign nationality (AOR = 2.77; 95% CI: 1.06–7.24), eating raw pork liver sausages (AOR = 2.23; 95% CI: 1.55–3.20) and raw homemade sausages (AOR = 3.63; 95% CI: 2.50–5.24) were independent infection predictors.

Conclusion

Italian blood donors showed a low to moderate HEV seroprevalence. High levels in some regions and/or provinces were mainly attributable to eating habits. Prevention should include avoiding consumption of raw or undercooked meat and safe production of commercial pork products.

Hepatitis E in a Portuguese cohort of human immunodeficiency virus positive patients: High seroprevalence but no chronic infections

Introduction

Hepatitis E virus (HEV) infection causes zoonotic hepatitis in Europe, with a higher risk of complications in immunocompromised hosts. HEV natural history in human immunodeficiency virus (HIV) positive patients is not fully understood, and its prevalence is unknown.

Objectives

To study the seroprevalence of HEV and prevalence of chronic HEV in HIV‐positive patients from Porto, Portugal.

Methods

We randomly selected patients from the cohort of HIV‐positive patients followed in our hospital. We performed an enzyme‐linked immunosorbent assay to search for immunoglobulin G for HEV. When the absorbance/cut‐off was inferior to 3.5, the test was repeated, and a confirmatory test executed in that sample. For reactive tests and for immunosuppressed patients (CD4 count < 200/mm³) with nonreactive test, a polymerase chain reaction (PCR) test was also performed.

Results

We included 299 patients. The mean age was 48 and 75.3% were men. Regarding HIV infection, the median follow‐up time was 10 years, the acquisition was mainly heterosexual contact, and 94% were on antiretroviral therapy. Seventy‐six patients (25.4%) had reactive immunoglobulin G (IgG) hepatitis E serology. Patients with a reactive test were older (statistically significant difference). Otherwise, there was no difference between groups concerning birthplace, rural residence, chronic viral hepatitis coinfection, or cirrhosis. Nadir and actual T_CD4+ lymphocyte counts did not differ significantly from patients with HEV reactive and nonreactive serology. Gamma‐glutamyl‐transferase (GGT) was higher in patients with reactive IgG HEV. All serum HEV PCR tests were negative.

Conclusions

Seroprevalence of HEV was 25.4% in HIV‐positive patients. Older age and higher GGT correlated to HEV reactive IgG test. No cases of current hepatitis E were found.

Risk assessment of hepatitis E transmission through tissue allografts

Hepatitis E virus (HEV) is a small non-enveloped single stranded RNA virus whose genotypes 3 and 4 have been associated with zoonotic transmission in industrialized countries. HEV infection is considered the main cause of acute hepatitis worldwide. In some cases, transfusion of blood components or organ transplantation have been reported as the source of infection. We have conducted a literature review on the risk of transmission through cell and tissue allografts. Although no case was found, measures to control this risk should be taken when donor profile (based upon geographical and behavioural data) recommended it. Issues to be considered in donor screening and tissue processing to assess and to reduce the risk of HEV transmission are approached.

Transfusion-transmitted hepatitis E: What we know so far?

Hepatitis E virus (HEV) is a major cause of viral hepatitis globally. There is growing concern about transfusion-transmitted HEV (TT-HEV) as an emerging global health problem. HEV can potentially result in chronic infection in immunocompromised patients, leading to a higher risk of liver cirrhosis and even death. Between 0.0013% and 0.281% of asymptomatic blood donors around the world have HEV viremia, and 0.27% to 60.5% have anti-HEV immunoglobulin G. HEV is infectious even at very low blood concentrations of the virus. Immunosuppressed patients who develop persistent hepatitis E infection should have their immunosuppressant regimen reduced; ribavirin may be considered as treatment. Pegylated interferon can be considered in those who are refractory or intolerant to ribavirin. Sofosbuvir, a nucleotide analog, showed modest antiviral activity in some clinical studies but sustained viral response was not achieved. Therefore, rescue treatment remains an unmet need. The need for HEV screening of all blood donations remains controversial. Universal screening has been adopted in some countries after consideration of risk and resource availability. Various pathogen reduction methods have also been proposed to reduce the risk of TT-HEV. Future studies are needed to define the incidence of transmission through transfusion, their clinical features, outcomes and prognosis.

Prevalence of Hepatitis E Virus Infection Among Blood Donors in the Eastern Province of Saudi Arabia

PURPOSE

Hepatitis E virus (HEV) causes acute hepatitis in humans and constitutes a major problem for immunocompromised patients, patients with hematological diseases, and pregnant women. It is transmitted mainly through fecal oral route; however, transmission through blood and blood products is reported globally and becoming a health concern. We sought to determine the prevalence of HEV among blood donors in the Eastern Province of Saudi Arabia using molecular as well as serological assays to assess the safety of blood transfusion and the need for HEV screening among blood donors.

PATIENTS AND METHODS

A total of 806 whole blood samples were collected from blood donors between May and November 2020 and tested for anti-HEV IgG and IgM antibodies by ELISA and for HEV RNA by RT-PCR.

RESULTS

The overall seroprevalence of HEV IgG antibodies was 3.2% with no statistically significant difference between the non-Saudis (3.28%) and Saudis (3.17%) (p value 0.929) or between males (3.14%) and females (4.88%) (p value 0.527). None of the IgG positive individuals had IgM antibodies. HEV RNA was not detected in any of the blood donors.

CONCLUSION

HEV seroprevalence is low among blood donors in the Eastern Province of Saudi Arabia and may constitute minimal risk for transfusion associated infections.

Unusual high prevalence of antibodies to hepatitis E virus in South Brazil

Hepatitis E virus (HEV) is worldwide distributed and might cause acute or chronic hepatitis mainly in immunocompromised individuals. In previous studies we found a high prevalence of antibodies to HEV within blood donors in south Brazil and also within backyard-raised pigs. Here, we aimed to investigate the prevalence of anti-HEV antibody and HEV RNA within the general population from three major municipalities (Caxias do Sul, Passo Fundo and Santa Maria) in south Brazil. A total of 3000 blood samples were randomly obtained from clinical laboratories at each of the three municipality (n = 1000 each) to determine the presence of anti-HEV antibodies and HEV RNA. Overall, anti-HEV antibodies were detected in 574/1000 (57,4%) samples in Caxias do Sul, 655/1000 (65.5%) samples in Passo Fundo and 554/1000 (55.4%) samples in Santa Maria. The prevalence of HEV-positive samples increased steadily and significantly (P < 0,001) with age and was unusually higher within individual over 40 years. Despite of this, none of the pooled serum samples had detectable levels of HEV RNA. The high anti-HEV antibody prevalence suggests that the virus might be present on the environment and/or foodstuff and poses a permanent threat to immune-compromised individuals.

Comparison of Hepatitis E Virus Sequences from Humans and Swine, the Netherlands, 1998-2015

Pigs are suspected to be a major source of zoonotic hepatitis E virus (HEV) infection in industrialized countries, but the transmission route(s) from pigs to humans are ill-defined. Sequence comparison of HEV isolates from pigs with those from blood donors and patients in 372 samples collected in The Netherlands in 1998 and 1999 and between 2008 and 2015 showed that all sequences were genotype 3 except for six patients (with travel history). Subgenotype 3c (gt3c) was the most common subtype. While the proportion of gt3c increased significantly between 1998 and 2008, it remained constant between 2008 and 2015. Among the few circulating HEV subtypes, there was no difference observed between the human and the pig isolates. Hepatitis E viruses in humans are very likely to originate from pigs, but it is unclear why HEV gt3c has become the predominant subtype in The Netherlands.

Seroprevalence of Hepatitis E Virus Infection among Blood Donors in Bulgaria

Hepatitis E virus (HEV) infection is widespread among domestic pigs, industrial swine, and wild boars in Bulgaria. The aim of the current research was to present the HEV seroprevalence among blood donors in Bulgaria. In the present study, 555 blood donors (479 males and 76 females) were enrolled from five districts in the country (Shumen, Pleven, Stara Zagora, Plovdiv, and Sofia districts). All blood samples were tested for anti-HEV IgG using the recomWell HEV IgG ELISA test (Mikrogen GmbH, Neuried, Germany). Each participating donor completed a short, structured, and specific questionnaire to document data on the current study. Anti-HEV IgG positive results were detected in 144 (25.9%) blood donors, including 129 (26.9%) males and 15 (19.7%) females. The established HEV seropositivity was 28.8% (23/80) in Shumen district, 23.2% (22/95) in Pleven district, 27.1% (38/140) in Stara Zagora district, 27.5% (44/160) in Plovdiv district, and 21.3% (17/80) in Sofia district. A high HEV seroprevalence was found for persons who declared that they were general hunters (48.7%; 19/39; p = 0.001) and hunters of wild boars (51.6%; 16/31; p = 0.001). We present the first seroprevalence rates of HEV infection in blood donors from Bulgaria. The results of our research showed high HEV seropositivity among blood donors.

Hepatitis E virus infection in liver transplant recipients: a descriptive literature review

Hepatitis E virus infection has been recognized as a rising hepatotropic viral infection in the developing countries but overlooked in the developed countries, due to its lower prevalence. However, hepatitis E virus prevalence is on rise in the liver transplant recipients due to immunosuppression, which needs prompt recognition by healthcare practitioners. Hepatitis E virus infection is commonly believed to be transmitted via an animal host; but in the post-liver transplant patients, it can also be acquired via blood and blood products transfusion and autochthonous route. Previous studies have shown the significance of hepatitis E virus infection in post-liver transplant, as the patients at a high risk of progressing to chronic hepatitis and cirrhosis. Pediatric patients are at higher risk of hepatitis E virus infection post-liver transplant. Specific hepatitis E virus genotypes have the potential for greater severity. The clinical manifestation of hepatitis E virus can also present as extrahepatic features which need high level of suspicion for early recognition and treatment. Treatment options of hepatitis E virus range from immunosuppressive drug minimization, ribavirin therapy to novel direct-acting antiviral regimens. Herein, we aim to explore epidemiology, prevalence, risk factor, diagnosis, and management of hepatitis E virus infection giving special attention to liver transplant recipients.

Prevalence and risks of hepatitis E virus infection in blood donors from the Western Cape, South Africa

BACKGROUND

Transfusion-transmitted hepatitis E virus (HEV) infection is a potential risk to recipients of blood transfusions. Infection with HEV poses a high risk to immunocompromised recipients with an increased likelihood of developing chronic infection. The aims of this study were to determine the prevalence of past and active HEV infections in donors from the Western Cape and to identify the risk factors associated with infection.

MATERIALS AND METHODS

We prospectively tested 10 250 blood donors for HEV infection. A risk factor sub-study investigated 250 donors who completed a questionnaire, and plasma samples were tested for HEV IgG antibodies and pooled for HEV RNA detection. The demographic and risk factors associated with HEV infection were assessed. The molecular study tested 10 000 individual donations using a commercial assay to detect viraemia. HEV viral load and genotype were also determined.

RESULTS

The overall anti-HEV IgG seroprevalence was 42·8% (107/250) among donors participating in the risk factor sub-study. The likelihood of past HEV infection was higher with an increase in age. Of the 10 000 donor samples individually tested for HEV RNA, one sample was positive with a viral load of 7·9 x 10⁴ IU/ml and belonged to HEV genotype 3.

CONCLUSION

We found a high seroprevalence of anti-HEV IgG but a low HEV RNA prevalence among donors in the Western Cape, South Africa. The study provides evidence for a potential risk of HEV contamination in the blood supply in South Africa. A cost-benefit analysis is needed before considering the introduction of routine donor screening in our setting.

Hepatitis E virus and blood transfusion safety

While the majority of worldwide hepatitis E viral (HEV) infections that occur in people are from contaminated water or food sources, there has also been a steadily rising number of reported cases of transfusion-transmitted HEV (TT-HEV) in blood donation recipients. For most, HEV infection is acute, self-limiting and asymptomatic. However, patients that are immunocompromised, especially transplant patients, are at much higher risk for developing chronic infections, which can progress to cirrhosis and liver failure, along with overall increased mortality. Because of the rising trend of HEV serological prevalence among the global population, and the fact that TT-HEV infection can cause serious clinical consequences among those patients most at need for blood donation, the need for screening for TT-HEV has been gaining in prominence as an important public health concern for both developing and developed countries. In the review, we summarise evidence for and notable cases of TT-HEV infections, the various aspects of HEV screening protocols and recent trends in the implementation of TT-HEV broad-based blood screening programmes.

Epidemiology of Hepatitis E in England and Wales: A 10-Year Retrospective Surveillance Study, 2008-2017

Indigenous, foodborne transmission of hepatitis E virus genotype 3 (HEV G3) has become recognized as an emerging problem in industrialized countries. Although mostly asymptomatic, HEV G3 infection has a range of outcomes, including mild illness, severe acute hepatitis, and, of particular concern, chronic progressive hepatitis in immunocompromised patients. Public Health England has monitored cases of acute HEV infection in England and Wales since 2003. Between 2010 and 2017, enhanced surveillance using 2 linked laboratory databases and questionnaires on clinical features and risk factors was conducted. There was a year-on-year increase in the number of infections from 2008 (183) through 2016 (1243). Then, in 2017, the number of infections declined (to 912). As reported previously, HEV G3 group 2 (also known as "G3 abcdhij") is the predominant cause of acute infections, and older men are most at risk. Consumption of pork and pork products was significantly higher among patients than in the general population, but other previously reported associations, such as consumption of shellfish, were not observed. Ongoing surveillance is required to monitor future trends and changes in the epidemiology of the virus. The changing methods of animal husbandry and processing and distribution of animal products needs to be further investigated.

Hepatitis E virus infection prevalence among men who have sex with men involved in a hepatitis A virus outbreak in Italy

BACKGROUND

The routes of hepatitis E virus (HEV) transmission have still not been fully clarified. Here, we evaluated the possibility of sexual transmission of HEV, which remains a highly disputed issue.

MATERIALS AND METHODS

Hepatitis E virus sexual transmission risk was assessed by comparing the prevalence of HEV infection in a sample of 196 Italian men who have sex with men (MSM) involved in a multi-country hepatitis A virus (HAV) outbreak, and in 3,912 Italian male blood donors selected from the same regions and provinces as the MSM. Selection of study of participants was motivated by the fact that HEV prevalence among Italian blood donors has been found to vary enormously between different geographical areas.

RESULTS

Anti-HEV IgG prevalence was 14.8% and 5.6% in blood donors and MSM, respectively. Adjusted anti-HEV IgG prevalence was significantly lower in MSM than in blood donors (odds ratio [OR], 0.40; 95% confidence interval [CI]: 0.22-0.75; p<0.01), among residents in northern (OR, 0.45; 95% CI: 0.37-0.55; p<0.01) and southern (OR, 0.45; 95% CI: 0.35-0.58; p <0.01) Italy than among residents in Central Italy, while the prevalence was significantly higher in participants over 50 years of age than in those under 50 years of age (OR, 1.83; 95% CI: 1.48-2.27; p<0.01).

DISCUSSION

Our findings suggest that sexual intercourse does not have a relevant role in HEV transmission. In particular, sexual transmission of HEV is unlikely to influence the prevalence of HEV infection at population level.

Seroprevalence of Hepatitis E virus infection in children after liver transplantation: A single-center experience in France

INTRODUCTION

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide, usually asymptomatic in children. However, a growing number of publications over the last decade have documented cases of chronic hepatitis related to HEV-genotype 3 infection, and progressing to cirrhosis in immuno-compromised patients, particularly in adult kidney transplant recipients. The aim of our study was to evaluate the prevalence and severity of HEV infection among pediatric liver transplant (PLT) recipients managed in our center.

MATERIAL AND METHODS

Between November 1^st 2014 and January 1^st 2016, PLT recipients (less than 18 years-old) were screened for HEV infection [determined by HEV serology, HEV- immunoglobulin M (IgM) and immunoglobulin G (IgG), and HEV-ribonucleic acid (RNA) by reverse transcriptase polymerase chain reaction] at their annual follow-up visit.

RESULTS

Eighty children were tested for HEV infection a mean of 5.4±5.3 years after liver transplantation (LT). The main indication for LT was biliary atresia (n=47, 59%). The prevalence of HEV-IgG was 8% (n=6; age range 1.3 to 14.2 years-old at the time of HEV testing). Prevalence increased to 30% when considering only the 20 children with a past history of an unexplained episode of elevated transaminases since LT. None had HEV IgM, serum HEV-RNA, or increased transaminases at the time of HEV testing. Among the six IgG seropositive children, two had received intravenous immunoglobulins prior to screening and four children had a negative control (seroreversion) 3 to 42 months after the first testing.

CONCLUSION

The prevalence of HEV infection in our cohort is low and similar to other pediatric reports. We saw no cases of chronic hepatitis or fibrosis attributable to HEV. The lower immunosuppressive regimen used in PLT children compared to other solid organ transplant recipients may account for this good outcome.

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.

First evidence of hepatitis E virus infection in a small mammal (yellow-necked mouse) from Croatia

Since the role of wild rodents/small mammals in hepatitis E virus (HEV) epidemiology has been a subject of considerable debate, this study was conducted to investigate the potential presence of HEV RNA in small rodents collected within their natural habitats and to detect if they can be potential reservoirs of the virus. A total of 483 small rodents were captured using snap traps placed at 11 regions in Croatia. Sampling was undertaken in 2008 and repeated from 2010 to 2014. Liver samples were tested for the presence of HEV RNA. HEV RNA was detected in only one liver sample (0.21%) originated from Apodemus flavicollis from the location Medvednica, nearby Zagreb collected in 2014. According to the sequence analysis, the isolate has shown to be a member of Orthohepevirus A species, genotype HEV-3. The genotyping results confirmed grouping into subtype 3a, general cluster 3abchij.The detected HEV strain showed to be genetically highly related to strains found in humans and/or domestic pigs and wild boars from Croatia. Our finding indicates that wild small mammals could play a role in the epidemiology of HEV-3 infection and therefore should be taken under consideration as potential reservoirs or/and transmitters of the disease. However, further investigation is needed to recognize their potential for maintaining the infection in natural conditions.

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 E Virus Infection in Blood Donors and Risk to Patients in the United States and Canada

Hepatitis E virus (HEV) is the most common cause of acute hepatitis worldwide including large water-borne outbreaks, zoonotic infections and transfusion transmissions. Several countries have initiated or are considering blood donor screening in response to high HEV-RNA donation prevalence leading to transfusion-transmission risk. Because HEV transmission is more common through food sources, the efficacy of blood donor screening alone may be limited. HEV-nucleic acids in 101 489 blood donations in the United States and Canada were studied. A risk-based decision-making framework was used to evaluate the quantitative risks and cost-benefit of HEV-blood donation screening in Canada comparing three scenarios: no screening, screening blood for all transfused patients or screening blood for only those at greatest risk. HEV-RNA prevalence in the United States was one per 16 908 (95% confidence interval [CI], 1:5786-1:81987), whereas Canadian HEV-RNA prevalence was one per 4615 (95% CI, 1:2579-1:9244). Although 4-fold greater, Canadian HEV-RNA prevalence was not significantly higher than in the United States. Viral loads ranged from 20 to 3080 international units per mL; all successfully typed infections were genotype 3. No HEV-RNA false-positive donations were identified for 100 percent specificity. Without donation screening, heart and lung transplant recipients had the greatest HEV-infection risk (1:366962) versus kidney transplant recipients with the lowest (1:2.8 million) at costs of $225 546 to $561 810 per quality-adjusted life-year (QALY) gained for partial or universal screening, respectively. Higher cost per QALY would be expected in the United States. Thus, HEV prevalence in North America is lower than in countries performing blood donation screening, and if implemented, is projected to be costly under any scenario.

Systematic review and meta-analysis of the seroprevalence of hepatitis E virus in the general population across non-endemic countries

Background

Hepatitis E virus (HEV) has commonly been associated with large waterborne outbreaks of human jaundice in endemic areas but it has been increasingly recognised as a cause of sporadic human cases of jaundice in non-endemic areas, in individuals with no history of travel. Zoonotic exposure is widely hypothesized to be an important potential transmission route in these sporadic human cases. Serosurveys conducted to determine the frequency of HEV human exposure report wide ranges in prevalence across studies and locations. Our study objective was to compute meta-analysis summary estimates of human seroprevalence of HEV IgG within countries considered HEV non-endemic, where possible, and to determine whether this varied significantly across these countries, as well as investigating the role of potential HEV seroprevalence predictors such as population age structure.

Materials and methods

A broad literature search was conducted in six electronic databases. Citations were appraised, and relevant data extracted using forms designed and pre-tested a priori. Meta-analysis and meta-regression were conducted in R, with HEV IgG seroprevalence in blood donors or the general population being the outcome of interest, and country, assay, population age and sex structure, and chronological time investigated as predictors of the outcome.

Results

From 4163 unique citations initially captured, data were extracted from 135 studies investigating HEV serology in blood donors or the general population, of 31 countries among those categorised as ‘very high human development’ by the United Nations. Country of sampling and assay employed were consistently significant predictors of HEV IgG seroprevalence with chronological time being a non-significant predictor in the dataset of captured studies.

Conclusions

While country of sampling and assay employed were significant predictors of HEV seroprevalence, comparison of HEV seroprevalence across non-endemic countries is hampered by the lack of a gold standard assay and uncertainty regarding residual bias across studies, as well as regional differences within some countries.

Seroprevalence and risk factors for hepatitis E virus infection in the Romanian adult population: a cross-sectional study in a tertiary hospital

Background: The primary goal was to estimate the seroprevalence of autochthonous hepatitis E virus (HEV) infection in adult Romanian population. Additionally, we aimed to identify the risk factors associated with the HEV seropositive status.

Methods: Between January 2015 and December 2016, 201 adult patients were tested for antiHEV-IgG. Multivariate logistic regression was used to examine for factors associated with a positive HEV-IgG test. The level of significance was set at α = 0.05.

Results: The final analysis included 175 patients who followed the study protocol. Forty-sex (26.3%) had positive, 121 (69.1%) had negative, and 8 (4.6%) had indeterminate antiHEV-IgG results. Patients with positive anti-HEV-IgG were older [median age: 54.5 years (IQR 43-65)] compared to patients with negative anti-HEV-IgG [median age: 37.5 years (IQR 28-57.5)], p <0.001. A positive HEV-IgG was more common in patients with history of blood transfusions [n=10 (22.7%) versus (vs) n=11 (9.4%), p=0.025], in those with immunosuppressive conditions [n=18 (40.9%) vs n=27 (23.1%), p=0.025] and in patients with positive hepatitis B surface antigen (HBsAg) [n=14 (31.1%) vs n=10 (10.3%), p=0.002].

Conclusions: In conclusion, we found that autochthonous HEV seropositivity is common in our study population, especially in older patients, previous blood transfusions, presence of immunosuppressive conditions, and positive HBsAg.

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.

High seroprevalence of anti-Hepatitis E antibodies in Austrian patients with autoimmune hepatitis

BACKGROUND & AIMS

Increasing numbers of autochthonous hepatitis E virus infections have been reported in Europe. Chronic infections have been shown in immune-compromised patients after solid organ transplantation. Hepatitis E virus might be a possible trigger for autoimmune hepatitis and might cause disease flares or relapses in the further course of disease. Aim of this study was to investigate the presence of hepatitis E virus antibodies and hepatitis E virus RNA, and to analyse their impact on immunosuppressive treatment in patients with autoimmune hepatitis.

METHODS

Sera from 92 autoimmune hepatitis patients (73/79.3% female, age: 42.2 ± 16.3 years [mean ± SD]) were tested. Patients were scored according to the simplified and revised scoring systems of the International Autoimmune Hepatitis Group. The prevalence of anti- hepatitis E virus antibodies (Beijing Wantai Biological Pharmacy Enterprises Co., Ltd, Beijing, China) and hepatitis E virus RNA was determined.

RESULTS

19/20.7% autoimmune hepatitis patients tested positive for hepatitis E virus-IgG, which was higher than in previous reports of healthy Austrian individuals (12.4%, P = 0.031); hepatitis E virus RNA was not detectable in any patient. Anti-hepatitis E virus positive patients were older (49.5 ± 9.5 vs 40.4 ± 17.2 years [mean ± SD], P = 0.033) but did not differ in laboratory findings at diagnosis (AST: 14.6 [1.3-70.6] vs 9.5 [0.7-62.7] × ULN [median/range]; P = 0.387, alanine aminotransferase: 18.3 [1.6-62.7] vs. 12.9 [0.8-62.6] × ULN; P = 0.511; IgG: 1.4 [1.0-2.5] vs 1.3 [0.6-3.8] g/dL × ULN; P = 0.278) nor in alanine aminotransferase levels after six months (0.7 [0.5-2.4] vs 1.0 U/L × ULN [0.1-22.4]; P = 0.077).

CONCLUSIONS

No chronic hepatitis E virus infection was observed in our cohort of autoimmune hepatitis patients. Anti- hepatitis E virus-IgG positive patients were older and the seroprevalence was nearly twice as high as reported previously in healthy Austrian individuals, suggesting that hepatitis E virus-infection might act as trigger for the development of autoimmune hepatitis.

Meta-Analysis of Human IgG anti-HEV Seroprevalence in Industrialized Countries and a Review of Literature

Although Hepatitis E is increasingly described as a major cause of liver disease in industrialized countries, the epidemiology is far from being fully elucidated. We provide here a comprehensive review of documented clusters of cases, and of serological studies conducted in populations with distinct types of exposure. Seroprevalence rates range from <5% to >50% depending on the countries and the groups of population. Such discrepancies can be attributed to the type of serological assay used, but this solves only a part of the problem. We performed a meta-analysis of studies performed with the broadly used Wantai HEV-IgG ELISA and found striking differences that remain difficult to understand with the current knowledge of transmission pathways.

Hepatitis E virus blood donor NAT screening: as much as possible or as much as needed?

BACKGROUND

The cost-benefit question of general screening of blood products for the hepatitis E virus (HEV) is currently being discussed. One central question is the need for individual nucleic acid amplification techniques (NAT) screening (ID-NAT) versus minipool NAT screening (MP-NAT) approaches to identify all relevant viremias in blood donors. Here, the findings of ID-NAT versus MP-NAT in pools of 96 samples were compared.

STUDY DESIGN AND METHODS

From November 2017 to January 2018, a total of 10,141 allogenic blood donations from 7650 individual German blood donors were screened for the presence of HEV RNA using MP-NAT (96 samples) (RealStar HEV RT-PCR Kit) compared to ID-NAT (cobas HEV assay) on the fully automated cobas 6800 platform.

RESULTS

Parallel screening of MP (n = 122, 96 samples/MP) using both methods detected seven reactive pools. After pool resolution, 8 HEV RNA-positive donations were identified by the in-house detection method, whereas 17 HEV RNA-positive donations were identified by ID-NAT with the cobas HEV assay. This resulted in an incidence of 1:1268 donations (0.079%) for MP-NAT screening and 1:597 donations (0.168%) for ID-NAT screening.

CONCLUSIONS

The detection frequency of HEV RNA was approximately 50% higher if ID-NAT was used compared to MP-NAT. However, viral loads of ID-NAT-only samples were below 25 IU/mL and will often not result in transfusion-transmitted HEV (TT-HEV) infection, taking into account the currently known infectious dose of 5.0E + 04 IU inevitably resulting in TT-HEV infection. The clinical relevance and need for identification of these low-level HEV-positive donors still require further investigation.

Transmission and Epidemiology of Hepatitis E Virus Genotype 3 and 4 Infections

Following the introduction of robust serological and molecular tools, our understanding of the epidemiology of zoonotic hepatitis E virus (HEV) has improved considerably in recent years. Current thinking suggests that consumption of pork meat products is the key route of infection in humans, but it is certainly not the only one. Other routes of infection include environmental spread, contaminated water, and via the human blood supply. The epidemiology of HEV genotype (gt)3 and gt4 is complex, as there are several sources and routes of infection, and it is likely that these vary between and within countries and over time.

Classification and Genomic Diversity of Enterically Transmitted Hepatitis Viruses

Hepatitis A virus (HAV) and hepatitis E virus (HEV) are significant human pathogens and are responsible for a substantial proportion of cases of severe acute hepatitis worldwide. Genetically, both viruses are heterogeneous and are classified into several genotypes that differ in their geographical distribution and risk group association. There is, however, little evidence that variants of HAV or HEV differ antigenically or in their propensity to cause severe disease. Genetically more divergent but primarily hepatotropic variants of both HAV and HEV have been found in several mammalian species, those of HAV being classified into eight species within the genus Hepatovirus in the virus family Picornaviridae. HEV is classified as a member of the species Orthohepevirus A in the virus family Hepeviridae, a species that additionally contains viruses infecting pigs, rabbits, and a variety of other mammalian species. Other species (Orthohepevirus B-D) infect a wide range of other mammalian species including rodents and bats.

Hepatitis E in High-Income Countries: What Do We Know? And What Are the Knowledge Gaps?

Hepatitis E virus (HEV) is a positive-strand RNA virus transmitted by the fecal–oral route. HEV genotypes 1 and 2 infect only humans and cause mainly waterborne outbreaks. HEV genotypes 3 and 4 are widely represented in the animal kingdom, and are mainly transmitted as a zoonosis. For the past 20 years, HEV infection has been considered an imported disease in developed countries, but now there is evidence that HEV is an underrecognized pathogen in high-income countries, and that the incidence of confirmed cases has been steadily increasing over the last decade. In this review, we describe current knowledge about the molecular biology of HEV, its clinical features, its main routes of transmission, and possible therapeutic strategies in developed countries.

A nationwide retrospective study on prevalence of hepatitis E virus infection in Italian blood donors

BACKGROUND

In Europe, hepatitis E virus (HEV) infection is mainly a food-borne zoonosis, but it can also be transmitted by blood transfusion. It is usually a mild and self-limited infection. However, immunocompromised persons, who are also those more likely to undergo blood transfusions, may develop chronic hepatitis and often cirrhosis. Since this is a potential threat to blood safety, we aimed to investigate HEV prevalence in Italian blood donors.

MATERIALS AND METHODS

We used plasma donations collected during 2015-2016 by blood services (BS) scattered throughout the Italian regions and intended for the production of plasma-derived medicines. Plasma samples were tested for IgG and IgM anti-HEV and for HEV RNA using validated assays. Data concerning donor's age and sex, and the location of the BS were collected.

RESULTS

A total of 10,011 plasma samples were tested. Overall IgG and IgM prevalence rates were 8.7 and 0.4%, respectively. No sample was HEV RNA-positive. IgG prevalence was significantly higher in males and in donors aged 44 years and over. IgG prevalence differed greatly according to region. Overall regional rates over 15% were found in Abruzzo and in Sardinia, and rates of 10-15% were found in Lazio, Umbria and the Marche. Considering IgG prevalence according to the province where the BS was located, rates over 30% were found in Sardinia and Abruzzo. Age, sex and donor's region of residence were independently associated with IgG positivity. BS location produced significant heterogeneity on prevalence rates within the regions.

DISCUSSION

The detected IgG rate of 8.7% in this study represents one of the lowest seroprevalence rates reported among blood donors in Europe. Particularly high prevalence rates in some regions and provinces may be explained by local eating habits and/or intensive environmental HEV contamination. Before considering the introduction of HEV RNA screening for blood donations in Italy, further important issues should be addressed and prospective incidence and reliable cost-benefit studies are needed.

Laboratory challenges in the diagnosis of hepatitis E virus

Hepatitis E virus (HEV) is an RNA virus that is an important cause of both acute and chronic hepatitis worldwide. To date, there are eight HEV genotypes that can infect mammals. HEV-1 and HEV-2 infect exclusively humans, while HEV-3 and HEV-4 infect humans and various animals, mainly pigs and deer. Additionally, two new genotypes (HEV-5 and HEV-6) infect mainly wild boar. Recently, newly discovered genotypes HEV-7 and HEV-8 were found to infect camels and possibly humans. Nevertheless, the epidemiological distribution of HEV-7 is not well established. HEV-8 is another newly discovered genotype that was identified in 2016 in Chinese Bactrian camels. Although faecal-oral transmission is the most common route of HEV transmission, HEV can be vertically transmitted from infected mothers to their fetuses. HEV may also spread by zoonotic transmission from infected animals to humans and through person-to-person contact. Nowadays, since the number of reported cases linked to blood donations is increasing annually, HEV is recognized as a transfusion-transmitted virus. Laboratory diagnostic techniques vary in their specificity and sensitivity for HEV detection. Direct techniques allow for detection of the viral proteins, antigens and viral nucleic acid, while HEV-specific IgG and IgM antibodies can help establish a diagnosis in acute and chronic infections. In this review, we will discuss recent technologies in the laboratory diagnosis of HEV, including serological and molecular methods to assess the specificity and sensitivity of currently available HEV commercial assays.

Hepatitis E virus - key points for the clinical haematologist

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

[HEV and transfusion-recipient risk]

HEV infections are mainly food- and water-borne but transfusion-transmission has occurred in both developing and developed countries. The infection is usually asymptomatic but it can lead to fulminant hepatitis in patients with underlying liver disease and pregnant women living in developing countries. It also causes chronic hepatitis E, with progressive fibrosis and cirrhosis, in approximately 60 % of immunocompromised patients infected with HEV genotype 3. Extra-hepatic manifestations such as neurological and renal manifestations have been reported. The risk of a transfusion-transmitted HEV infection is linked to the frequency of viremia in blood donors, the donor virus load and the volume of plasma in the final transfused blood component. Several developed countries have adopted measures to improve blood safety based on the epidemiology of HEV.

Immunobiology and Host Response to HEV

Hepatitis E virus (HEV) causes acute self-limiting hepatitis in most cases and chronic infection in rare circumstances. It is believed to be noncytopathic, so immunologically mediated events should play important roles in its pathogenesis and infection outcomes. The anti-HEV antibody response was clarified when the major antigenic determinants on the ORF2 polypeptide were determined, which are located in its C-terminal portion. This subregion also forms the conformational neutralization epitopes. Robust anti-HEV immunoglobulin M (IgM) and IgG responses usually develop 3-4 weeks after infection in experimentally infected nonhuman primates. In humans, potent specific IgM and IgG responses occur in the very early phase of the disease and are critical in eliminating the virus, in concert with the innate and adaptive T-cell immune responses. They are also very valuable in the diagnosis of acute hepatitis E, when patients are tested for both anti-HEV IgM and IgG. The long-term persistence and protection of anti-HEV IgG provide the basis for estimating the prevalence of HEV infection and for the development of a hepatitis E vaccine. Although HEV has four genotypes, all the viral strains are considered to belong to a single serotype. It is becoming increasingly clear that the innate and adaptive T-cell immune responses play critical roles in the clearance of the virus. Potent and multispecific CD4⁺ and CD8⁺ T-cell responses to the ORF2 protein occur in patients with acute hepatitis E, and weaker HEV-specific CD4⁺ and CD8⁺ T-cell responses appear to be associated with chronic hepatitis E in immunocompromised individuals.

Seroprevalence and incidence of hepatitis E virus among blood donors: A review

Hepatitis E virus (HEV) is an RNA virus with 4 main genotypes. HEV-1 and HEV-2 infect solely humans, while HEV-3 and HEV-4 infect humans and various animals such as pigs, deer, and rabbits. HEV-5 and HEV-6 infect mainly wild boar. Recently, new genotypes, known as HEV-7 and HEV-8, were found to infect camels and humans. HEV is globally distributed into different epidemiological patterns based on socioeconomic factors and ecology. Although HEV is mainly transmitted through the fecal-oral route, it was also recognized as a transfusion-transmitted virus. Transmission through blood donation was documented worldwide with rising annual observations, accounting for more than 2.5% of all transmissions. HEV infection is usually asymptomatic or subclinical in immunocompetent individuals, so it remains questionable whether there is an urgent need to screen for HEV prior to blood transfusion. Moreover, recent studies conducted in the Middle East and North Africa (MENA) region indicate that HEV is highly endemic. Here, we provide a review on HEV epidemiology, transmission, and laboratory diagnosis, giving special emphasis to the newly discovered genotypes, HEV-7 and HEV-8. Furthermore, we underscore the findings of recent HEV seroprevalence and viremia studies among blood donors worldwide. We also shed light on similar studies performed among blood donors in the MENA region.

Hepatitis E: the current state of play

The hepatitis E virus (HEV) is a major cause of acute hepatitis globally. Genotypes 1 and 2 (G1 and G2) are obligate human pathogens transmitted faeco-orally, leading to epidemics in developing countries. In contrast, genotypes 3 and 4 (G3 and G4) have a wider host range, including humans, but are primarily porcine viruses and are transmitted from animals to humans as a food-borne zoonosis when meat from an infected animal is consumed. HEV is increasingly recognised as a problem in developed countries, including countries in Europe. G3 HEV is now the most common cause of acute viral hepatitis in the UK and cases continue to rise. The majority of these infections are acquired within the UK and thought to be from insufficiently cooked meat, predominantly processed pork meat. Previously thought to only cause self-limiting disease, HEV infection can persist in immunosuppressed patients, which may lead to chronic hepatitis and the rapid development of cirrhosis. Of particular interest to the transfusion community has been the possibility of transfusion-transmitted HEV, which has been reported from countries classically considered HEV-endemic but also non-endemic countries in Europe and Japan. This has prompted some countries to introduce screening for HEV in blood donations.

HEV and transfusion-recipient risk

HEV infections are mainly food- and water-borne but transfusion-transmission has occurred in both developing and developed countries. The infection is usually asymptomatic but it can lead to fulminant hepatitis in patients with underlying liver disease and pregnant women living in developing countries. It also causes chronic hepatitis E, with progressive fibrosis and cirrhosis, in approximately 60% of immunocompromised patients infected with HEV genotype 3. The risk of a transfusion-transmitted HEV infection is linked to the frequency of viremia in blood donors, the donor virus load and the volume of plasma in the final transfused blood component. Several developed countries have adopted measures to improve blood safety based on the epidemiology of HEV.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hepatitis E virus and neurological disorders

Hepatitis E is the most common cause of hepatitis worldwide. While originally considered a disease of developing countries, it is increasingly recognised in developed countries, probably related to contaminated pork meat, and where infection is often asymptomatic. However, several non-liver manifestations have become apparent, the most important of which are neurological, including Guillain-Barré syndrome (acute inflammatory demyelinating polyradiculoneuropathy (AIDP)), neuralgic amyotrophy and meningoencephalitis. We recommend testing all patients with AIDP and neuralgic amyotrophy for hepatitis E and consider testing any patient with an unexplained neurological illness and abnormal liver function tests for the virus.