Hepatitis E

From discovery to treatment: tracing the path of hepatitis E virus

The hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide. HEV is classified into eight genotypes, labeled HEV-1 through HEV-8. Genotypes 1 and 2 exclusively infect humans, while genotypes 3, 4, and 7 can infect both humans and animals. In contrast, genotypes 5, 6, and 8 are restricted to infecting animals. While most individuals with a strong immune system experience a self-limiting infection, those who are immunosuppressed may develop chronic hepatitis. Pregnant women are particularly vulnerable to severe illness and mortality due to HEV infection. In addition to liver-related complications, HEV can also cause extrahepatic manifestations, including neurological disorders. The immune response is vital in determining the outcome of HEV infection. Deficiencies in T cells, NK cells, and antibody responses are linked to poor prognosis. Interestingly, HEV itself contains microRNAs that regulate its replication and modify the host's antiviral response. Diagnosis of HEV infection involves the detection of HEV RNA and anti-HEV IgM/IgG antibodies. Supportive care is the mainstay of treatment for acute infection, while chronic HEV infection may be cleared with the use of ribavirin and pegylated interferon. Prevention remains the best approach against HEV, focusing on sanitation infrastructure improvements and vaccination, with one vaccine already licensed in China. This comprehensive review provides insights into the spread, genotypes, prevalence, and clinical effects of HEV. Furthermore, it emphasizes the need for further research and attention to HEV, particularly in cases of acute hepatitis, especially among solid-organ transplant recipients.

Hepatitis E infection: A review

Hepatitis E virus (HEV) is a small non-enveloped virus that is transmitted via the fecal-oral route. It is a highly common cause of acute hepatitis, particularly in low to middle income regions of Asia, Africa, and Central America. Most cases are self-limited, and symptomatic patients usually present with acute icteric hepatitis. A subset of patients including pregnant women, older men, those with pre-existing liver disease and immunocompromised patients however, may develop severe disease and hepatic failure. Immunocompromised patients are also at risk for chronic infection, and their immunosuppression should be decreased in order to facilitate viral clearance. HEV can also present with a variety of extra-intestinal manifestations including neurological, renal, hematological, and pancreatic derangements. The gold standard of diagnosis is HEV ribonucleic acid detection via nucleic acid amplification testing. Currently, there are no approved treatments for Hepatitis E, though ribavirin is the most commonly used agent to reduce viral load. Studies assessing the safety and efficacy of other antiviral agents for HEV are currently underway. HEV vaccination has been approved in China, and is currently being investigated in other regions as well. This review article aims to discuss the epidemiology, pathogenesis, presentation, diagnosis, complications, and treatment of Hepatitis E infection.

Serological Evidence of Hepatitis E Virus (HEV) Infection Among Ruminant Farmworkers: A Retrospective Study from Malaysia

Background

As scant data are available about Hepatitis E virus (HEV) infection in Malaysia, this study aimed to determine the seroprevalence of HEV amongst ruminant farmworkers in Malaysia.

Methods

A total of 87 farmworkers provided serum samples, which were collected from eight farms. All serum samples were tested for anti-HEV IgG and anti-HEV IgM by an enzyme-linked immunosorbent assay (ELISA) using the Wantai HEV-IgG and HEV-IgM ELISA kits from Beijing Wantai Biological Pharmacy Enterprise Co., Ltd, Beijing, China.

Results

Farmworkers from six cattle farms, one sheep farm and one goat farm were investigated in this study. Only one farm practices zero-grazing, with the rest using rotational grazing. Of the 87 farmworkers, males comprised 83.9%, and almost half (47.1%) were aged 20-35 years old. By ethnic group, the vast majority were Malay. Most of the farmworkers have good hygiene practices; washing or changing their clothes and showering after dealing with farm animals were common. None of the farmworker serum samples had anti-HEV IgM and IgG detected (95% confidence interval (CI): 0, 0.0415).

Conclusion

The finding suggests that the farmworkers had no previous exposure to Hepatitis E, and were not at risk of occupational exposure to HEV infection. Our findings suggest that a zero seroprevalence of HEV infection among ruminant farmworkers in the Muslim majority country. Good farm management, hygiene practices and the absence of contact with swine-related contamination might have contributed to the no or minimal zoonotic risks of HEV amongst farmworkers surveyed in this study.

Seroprevalence of Hepatitis E Virus Antibodies (IgG) in the Community of Rawalpindi

Knowledge regarding the prevalence of the hepatitis E virus (HEV) in the general population can indicate public health and personal hygiene practices in a community. HEV spreads through the fecal-oral route and contaminates drinking water through sewage. Moreover, poverty also contributes to its prevalence in developing countries, including Pakistan. A cross-sectional study was conducted on 650 blood samples taken from suspected patients of HEV in the Rawalpindi cantonment area (Pakistan) from April to November 2019 at the Department of Virology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan. Out of them, 444 (68.15%) were male and 206 (31.85%) were female; the detection of anti-HEV IgG antibodies was carried out using a commercial Anti-Hepatitis E virus antibody (IgG) ELISA Kit. The overall anti-HEV IgG prevalence percentages were 19.23% and 4.77% in males and females, respectively. Patients were categorized into eight groups with ages ranging between 1 and 90 years. HEV IgG seroprevalence was the highest in ages 31–40 (6.46%). The study concluded that males aged 40 or above were susceptible and infected with hepatitis E.

Hepatitis E virus: Whole genome sequencing as a new tool for understanding HEV epidemiology and phenotypes

Hepatitis E Virus (HEV) is emerging as a public health concern across Europe and tools for complete genome data to aid epidemiological and virulence analysis are needed. The high sequence heterogeneity observed amongst HEV genotypes has restricted most analyses to subgenomic regions using PCR-based methods, which can be unreliable due to poor primer homology. We designed a panel of custom-designed RNA probes complementary to all published HEV full genome NCBI sequences. A target enrichment protocol was performed according to the NimbleGen® standard protocol for Illumina® library preparation. Optimisation of this protocol was performed using 40 HEV RNA-positive serum samples and the World Health Organization International Reference Panel for Hepatitis E Virus RNA Genotypes for Nucleic Acid Amplification Technique (NAT)-Based Assays and related reference materials. Deep sequencing using this target enrichment protocol resulted in whole genome consensus sequences from samples with a viral load range of 1.25 × 10⁴-1.17 × 10⁷ IU/mL. Phylogenetic analysis of these sequences recapitulated and extended the partial genome results obtained from genotyping by Sanger sequencing (genotype 1, ten samples and genotype 3, 30 samples). The protocol is highly adaptable to automation and could be used to sequence full genomes of large sample numbers. A more comprehensive understanding of hepatitis E virus transmission, epidemiology and viral phenotype prediction supported by an efficient method of sequencing the whole viral genome will facilitate public health initiatives to reduce the prevalence and mitigate the harm of HEV infection in Europe.

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.

A systematic review and meta-analysis of predictors of human hepatitis E virus exposure in non-endemic countries

The reported incidence of clinical hepatitis E cases is rising in some non-endemic countries, with concurrent concerns regarding potential hepatitis E virus (HEV) contamination of the blood supply. Therefore, the characterization of major potential sources of human HEV exposure is important to inform risk assessment and public health policy. A systematic review was conducted, including a comprehensive search in six electronic bibliographic databases, verified by hand-searching reference lists of HEV reviews, and a grey literature search, of the broad research question 'what is the evidence of the association between predictors of human HEV exposure, and HEV IgG seropositivity, in non-endemic countries?' Using forms designed a priori, captured studies were appraised at first-level screening, second-level characterization, and third-level data extraction and risk of bias assessment. Meta-analysis yielded summary estimates of association between potential predictors and odds of HEV seropositivity. Meta-analysis and meta-regression of the odds of HEV seroprevalence in specific groups characterized potential sources of HEV exposure. From 4,163 captured citations, 245 relevant studies underwent data extraction, investigating HEV seroprevalence or predictors in both healthy subjects and targeted patient groups. Across these groups, increasing age was a predictor of HEV IgG seropositivity. Both human immunodeficiency virus patients and haemodialysis patients had significantly increased odds of HEV seropositivity relative to the general population. Working with pigs, in forestry, or in hospitals, was significantly associated with increased odds of HEV seropositivity, as were consumption of meat, pork or game meat, or hunting. Chronological time was not associated with HEV seropositivity within our data sets. Further study of the distribution of potential dietary or behavioural predictors between high and lower prevalence areas within non-endemic countries could improve our understanding of the relative importance of specific HEV transmission pathways.

Inactivation of a broad spectrum of viruses and parasites by photochemical treatment of plasma and platelets using amotosalen and ultraviolet A light

BACKGROUND

The INTERCEPT Blood System pathogen reduction technology (PRT), which uses amotosalen and ultraviolet A light treatment (amotosalen/UV-PRT), inactivates pathogens in plasma and platelet components (PCs). This review summarizes data describing the inactivation efficacy of amotosalen/UVA-PRT for a broad spectrum of viruses and parasites.

METHODS

Twenty-five enveloped viruses, six nonenveloped viruses (NEVs), and four parasites species were evaluated for sensitivity to amotosalen/UVA-PRT. Pathogens were spiked into plasma and PC at high titers. Samples were collected before and after PRT and assessed for infectivity with cell cultures or animal models. Log reduction factors (LRFs) were defined as the difference in infectious titers before and after amotosalen/UV-PRT.

RESULTS

LRFs of ≥4.0 log were reported for 19 pathogens in plasma (range, ≥4.0 to ≥7.6), 28 pathogens in PC in platelet additive solution (PC-PAS; ≥4.1-≥7.8), and 14 pathogens in PC in 100% plasma (PC-100%; (≥4.3->8.4). Twenty-five enveloped viruses and two NEVs were sensitive to amotosalen/UV-PRT; LRF ranged from >2.9 to ≥7.6 in plasma, 2.4 or greater to greater than 6.9 in PC-PAS and >3.5 to >6.5 in PC-100%. Infectious titers for four parasites were reduced by >4.0 log in all PC and plasma (≥4.9 to >8.4).

CONCLUSION

Amotosalen/UVA-PRT demonstrated effective infectious titer reduction for a broad spectrum of viruses and parasites. This confirms the capacity of this system to reduce the risk of viral and parasitic transfusion-transmitted infections by plasma and PCs in various geographies.

Blood transfusion is unlikely to be a source for hepatitis E virus transmission in India

INTRODUCTION

Transmission of hepatitis E virus (HEV) through transfusion has been reported from countries where genotype 3 virus is predominant. Data from countries with predominantly genotype 1 HEV, such as India, are limited. We studied the risk of HEV transmission following transfusion of blood or blood components in India.

METHODS

Adult patients undergoing cardiac surgery who received transfusion of blood or blood products in the peri-operative period and who lacked history of any transfusion or surgery in the preceding 1 year were studied. A pre-transfusion blood specimen was collected for IgG anti-HEV antibody test. For the participants who were seronegative for anti-HEV, follow up specimens were collected at every 2-3-month intervals for up to 6 months after surgery and were tested for IgM and IgG anti-HEV antibodies.

RESULTS

Of the 335 participants originally enrolled, 191 (57%) could be followed up. Of them, 103 (53.9%) were seropositive for HEV IgG at baseline and were excluded. Of the remaining 88 participants (age 42 ± 14.1 years; 55 [63%] male), none reported hepatitis-like illness during the follow up period of 81 ± 23 days. Also, none of these 88 participants was found to have seroconversion to anti-HEV IgM or IgG positivity in the follow up specimens.

CONCLUSION

Transfusion-mediated transmission of HEV was not observed in our cohort and may be infrequent in the Indian population, where genotype 1 is the predominant HEV type.

Hepatitis E as a cause of adult hospitalization in Bangladesh: Results from an acute jaundice surveillance study in six tertiary hospitals, 2014-2017

In the absence of reliable data on the burden of hepatitis E virus (HEV) in high endemic countries, we established a hospital-based acute jaundice surveillance program in six tertiary hospitals in Bangladesh to estimate the burden of HEV infection among hospitalized acute jaundice patients aged ≥14 years, identify seasonal and geographic patterns in the prevalence of hepatitis E, and examine factors associated with death.

We collected blood specimens from enrolled acute jaundice patients, defined as new onset of either yellow eyes or skin during the past three months of hospital admission, and tested for immunoglobulin M (IgM) antibodies against HEV, HBV and HAV. The enrolled patients were followed up three months after hospital discharge to assess their survival status; pregnant women were followed up three months after their delivery to assess pregnancy outcomes. From December’2014 to September’2017, 1925 patients with acute jaundice were enrolled; 661 (34%) had acute hepatitis E, 48 (8%) had hepatitis A, and 293 (15%) had acute hepatitis B infection. Case fatality among hepatitis E patients was 5% (28/589). Most of the hepatitis E cases were males (74%; 486/661), but case fatality was higher among females—12% (8/68) among pregnant and 8% (7/91) among non-pregnant women. Half of the patients who died with acute hepatitis E had co-infection with HAV or HBV. Of the 62 HEV infected mothers who were alive until the delivery, 9 (15%) had miscarriage/stillbirth, and of those children who were born alive, 19% (10/53) died, all within one week of birth. This study confirms that hepatitis E is the leading cause of acute jaundice, leads to hospitalizations in all regions in Bangladesh, occurs throughout the year, and is associated with considerable morbidity and mortality. Effective control measures should be taken to reduce the risk of HEV infections including improvements in water quality, sanitation and hygiene practices and the introduction of HEV vaccine to high-risk groups.

In the absence of reliable surveillance data on the burden of hepatitis E in endemic countries, we conducted a hospital-based acute jaundice surveillance study over a two and a half year period in six tertiary hospitals in Bangladesh. The study confirms that HEV infections occur throughout the year, and is a major (34%) cause of acute jaundice in tertiary hospitals in Bangladesh. Three-quarters of the acute hepatitis E cases were male, and HEV infection was higher among patients residing in urban areas than patients in rural areas (41% vs 32%). The overall case fatality rate of acute HEV infections in hospitals was 5%, but was higher among pregnant women (12%). Hepatitis E patients who died were more likely to have co-infection with HAV or HBV than the HEV infected patients who did not die. Fifteen percent of HEV infected mothers had miscarriage/stillbirth. Of the children who were born alive, 19% died, all within one week of birth. Considering the high burden of hepatitis E among hospitalized acute jaundice patients, Bangladesh could take control measures to reduce this risk including improvements in water quality, sanitation and hygiene practices and the introduction of hepatitis E vaccine in high-risk areas.

Hepatitis E virus (HEV) in Scotland: evidence of recent increase in viral circulation in humans

BackgroundPrevious studies showed low levels of circulating hepatitis E virus (HEV) in Scotland. We aimed to reassess current Scottish HEV epidemiology. Methods: Blood donor samples from five Scottish blood centres, the minipools for routine HEV screening and liver transplant recipients were tested for HEV antibodies and RNA to determine seroprevalence and viraemia. Blood donor data were compared with results from previous studies covering 2004-08. Notified laboratory-confirmed hepatitis E cases (2009-16) were extracted from national surveillance data. Viraemic samples from blood donors (2016) and chronic hepatitis E transplant patients (2014-16) were sequenced. Results: Anti-HEV IgG seroprevalence varied geographically and was highest in Edinburgh where it increased from 4.5% in 2004-08) to 9.3% in 2014-15 (p = 0.001). It was most marked in donors < 35 years. HEV RNA was found in 1:2,481 donors, compared with 1:14,520 in 2011. Notified laboratory-confirmed cases increased by a factor of 15 between 2011 and 2016, from 13 to 206. In 2011-13, 1 of 329 transplant recipients tested positive for acute HEV, compared with six cases of chronic infection during 2014-16. Of 10 sequenced viraemic donors eight and all six patients were infected with genotype 3 clade 1 virus, common in European pigs. Conclusions: The seroprevalence, number of viraemic donors and numbers of notified laboratory-confirmed cases of HEV in Scotland have all recently increased. The causes of this change are unknown, but need further investigation. Clinicians in Scotland, particularly those caring for immunocompromised patients, should have a low threshold for testing for HEV.

Estimation of the hepatitis E assay-dependent seroprevalence among Croatian blood donors

BACKGROUND

Seroprevalence of hepatitis E virus (HEV) in blood donors presenting to the Croatian Institute of Transfusion Medicine was assessed with 4 available tests (3 ELISA tests and 1 immunoblot (IB) test).

MATERIALS AND METHODS

In October and November 2014, a total of 1,036 serum samples of blood donors were collected for the study. Samples were primarily tested for total HEV antibodies by Dia.Pro HEV Ab test (a). All reactive samples were tested by ELISA tests: Dia.Pro HEV IgG (b) and IgM (c), Mikrogen recomWell HEV IgG_old (d) and IgM_old (e), recomWell HEV IgG_new (f) and IgM_new (g), and IB Mikrogen recomLine HEV IgG (h) and IgM (i). HEV IgM reactive samples also positive by the IB were further tested for HEV RNA.

RESULTS

There were 21.5% of samples reactive for total HEV antibodies (a). Seroprevalence of HEV IgG according to the b, d, f and h tests was 20.2%, 9.6%, 18.1% and 17.8%, respectively. Seroprevalence of HEV IgM according to the c, e, g and i tests was 4.4%, 1.5%, 2.0% and 1.7%, respectively. Out of 46 HEV IgM (Dia.Pro HEV IgM) positive samples, 18 (39.1%) were also positive by IB. HEV RNA was not detected in any of those samples. There was a significant association between age and HEV seroprevalence (P<0.001).

CONCLUSION

Different HEV antibody detection assays showed a high HEV IgG seroprevalence in Croatian blood donors. Among HEV IgG and HEV IgM positive samples HEV RNA was not detected.

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.

Blood Donor Screening for Hepatitis E Virus in the European Union

This review article summarises hepatitis E virus (HEV) blood donation screening strategies in effect in the European Union (EU). Since 2012, eight EU countries have implemented HEV screening. Local rates of seroprevalence, RNA incidence, and molecular epidemiology are variable and not usually directly comparable. We report a range of HEV-RNA reactivity rates from 1 in 744 donations (France) to 1 in 8,636 donations (Wales) with an overall EU rate of 1 in 3,109 donations (3.2 million donations screened). HEV genotypes 3c, 3e, and 3f are the most frequently reported subtypes. In these 8 countries, both universal (n = 5) and selective (n = 3) screening policies have been introduced utilising either individual donation (ID; n = 1) or mini-pool (MP; n = 7; MP-6, -16, -24, and -96) testing. We also describe the Irish experience of HEV screening utilising an ID-NAT-based donor screening algorithm which intercepts donations even from those with low-level viraemia; 21 of 56 donors (37.5%) had a viral load (VL) < 100 IU/mL. We performed a MP-24 experiment which may prove useful to colleagues in relation to donor screening and associated blood component transmissibility. Irish results indicate that 59% of donors with a HEV-VL < 450 IU/mL may have screened negative in a MP-24.

Prevention of transfusion-transmitted infections

Since the 1970s, introduction of serological assays targeting virus-specific antibodies and antigens has been effective in identifying blood donations infected with the classic transfusion-transmitted infectious agents (TTIs; hepatitis B virus [HBV], HIV, human T-cell lymphotropic virus types I and II, hepatitis C virus [HCV]). Subsequently, progressive implementation of nucleic acid-amplification technology (NAT) screening for HIV, HCV, and HBV has reduced the residual risk of infectious-window-period donations, such that per unit risks are <1 in 1 000 000 in the United States, other high-income countries, and in high-incidence regions performing NAT. NAT screening has emerged as the preferred option for detection of newer TTIs including West Nile virus, Zika virus (ZIKV), and Babesia microti Although there is continual need to monitor current risks due to established TTI, ongoing challenges in blood safety relate primarily to surveillance for emerging agents coupled with development of rapid response mechanisms when such agents are identified. Recent progress in development and implementation of pathogen-reduction technologies (PRTs) provide the opportunity for proactive rather than reactive response to blood-safety threats. Risk-based decision-making tools and cost-effectiveness models have proved useful to quantify infectious risks and place new interventions in context. However, as evidenced by the 2015 to 2017 ZIKV pandemic, a level of tolerable risk has yet to be defined in such a way that conflicting factors (eg, theoretical recipient risk, blood availability, cost, and commercial interests) can be reconciled. A unified approach to TTIs is needed, whereby novel tests and PRTs replace, rather than add to, existing interventions, thereby ameliorating cost and logistical burden to blood centers and hospitals.

Evaluation of an antigen assay for diagnosing acute and chronic hepatitis E genotype 4 infection

BACKGROUND AND AIM

Results obtained from different hepatitis E virus (HEV) tests are usually inconsistent. The detection of serum HEV antigen (Ag) has been suggested to be more sensitive for the diagnosis of genotypes 1 and 3 HEV.

METHODS

We compared the diagnostic accuracies of serum HEV Ag and HEV RNA by using 202 serum samples from patients suspected acute viral hepatitis.

RESULTS

The HEV Ag assay was 100% specific. The lower detected levels of viremia ranged from 10² to 10³  copies/mL. The sensitivity of the HEV Ag test was 90.5%. One of the 42 cases was negative for anti-HEV IgM, but HEV Ag was still detectable. The detectable period of HEV Ag was in concordance with the detectable period of HEV RNA. Serum HEV Ag was persistently detected in two cases of chronic hepatitis E, confirmed by the persistent presence of HEV RNA despite being negative for anti-HEV IgM. HEV Ag demonstrated good consistency with positive HEV RNA (k = 0.938, P < 0.001). Receiver operating characteristic analysis of HEV Ag suggested a second cut-off value of >0.095 to predict HEV patients with 95.24% sensitivity and 98.75% specificity, and the area under the curve was 0.9887, which was higher than that of three commercial anti-HEV IgM ELISA tests.

CONCLUSIONS

The presence of HEV Ag has good consistency with HEV RNA in both acute and chronic genotype 4 hepatitis E. HEV Ag is a more promising serum marker to identify active genotype 4 HEV infection than anti-HEV IgM and HEV RNA.

Probable transmission of hepatitis E virus (HEV) via transfusion in the United States

BACKGROUND

Hepatitis E virus (HEV) can inapparently infect blood donors. To assess transfusion transmission of HEV in the United States, which has not been documented, a donor-recipient repository was evaluated.

STUDY DESIGN AND METHODS

To identify donations that contained HEV RNA and were linked to patient-recipients with antibody evidence of HEV exposure, we assayed samples from the Retrovirus Epidemiology Donor Study (REDS) Allogeneic Donor and Recipient repository that represents 13,201 linked donations and 3384 transfused patients. Posttransfusion samples, determined to contain IgG anti-HEV by enzyme-linked immunosorbent assay, were reassayed along with corresponding pretransfusion samples for seroconversion (incident exposure) or at least fourfold IgG anti-HEV increase (reexposure). HEV-exposed patients were linked to donations in which HEV RNA was then detected by reverse-transcription quantitative polymerase chain reaction, confirmed by transcription-mediated amplification, and phylogenetically analyzed as subgenomic cDNA sequences.

RESULTS

Among all patients, 19 of 1036 (1.8%) who had IgG anti-HEV before transfusion were reexposed; 40 of 2348 (1.7%) without pretransfusion IgG anti-HEV seroconverted. These 59 patients were linked to 257 donations, 1 of which was positive by reverse-transcription quantitative polymerase chain reaction and transcription-mediated amplification. Plasma from this donation contained 5.5 log IU/mL of HEV RNA that grouped with HEV genotype 3, clade 3abchij. The patient-recipient of RBCs from this donation had a greater than eightfold IgG increase; however, clinical data are unavailable.

CONCLUSIONS

This is the first report of probable HEV transmission via transfusion in the United States, although it has been frequently observed in Europe and Japan. Additional data on the magnitude of the risk in the United States are needed.

[Belgorod region - the territory endemic for hepatitis E.]

INTRODUCTION

Belgorod region is the territory with the highest incidence of hepatitis E in the Russian Federation.

OBJECTIVES

The aim of the study was to comprehensively characterize the circulation of hepatitis E virus (HEV) in the Belgorod region, including the study of population immunity to the virus, determining the prevalence of infection among the pig population and analysis of the genetic diversity of HEV from patients and animals.

MATERIAL AND METHODS

Serum samples of a conditionally healthy population (n = 2027) of all age groups were tested for anti-HEV IgG and IgM by ELISA with commercial assays. HEV RNA was determined in fecal samples from pigs aged 2-4 months (n = 526), in sewage samples from pig farms (n = 10), as well as in stool samples from patients with hepatitis E (n = 6) using reverse transcription polymerase chain reaction (RT-PCR). Phylogenetic analysis was performed for an amplified 300 nt fragment corresponding to HEV open reading frame 2.

RESULTS AND DISCUSSION

The prevalence of anti-HEV IgG in general population averaged 16.4% (95% CI: 14.8-18.1; 332/2027). The proportion of individuals who had both anti-HEV IgM and IgG averaged 2.8% (95% CI: 2.2-3.6; 57/2027). The incidence rate of anti-HEV IgG increased with age, from 2.8% (95% CI: 1.3-5.8) in children aged 1-14 years to 40.1% (95% CI: 34.9-45.6) in people 70 years or older. The detection rate of HEV RNA in pigs was 20% (95% CI: 16.8-23.6; 105/526). HEV RNA was detected in 2 out of 10 sewage samples. The HEV sequences isolated from patients with hepatitis E, pigs, and sewage samples in Belgorod region belonged to the HEV genotype 3, had a 95-100% homology, and formed common clusters on a phylogenetic tree.

CONCLUSIONS

The high prevalence of HEV in pigs population has led to the formation of an endemic territory in the Belgorod region, which is the center of pig breeding. Measures aimed at reducing the circulation of HEV among pig population and decontamination of sewage from pig farms are necessary to control HEV infection.

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.

Hiding in Plain Sight? It's Time to Investigate Other Possible Transmission Routes for Hepatitis E Virus (HEV) in Developed Countries

Historically in developed countries, reported hepatitis E cases were typically travellers returning from countries where hepatitis E virus (HEV) is endemic, but now there are increasing numbers of non-travel-related ("autochthonous") cases being reported. Data for HEV in New Zealand remain limited and the transmission routes unproven. We critically reviewed the scientific evidence supporting HEV transmission routes in other developed countries to inform how people in New Zealand may be exposed to this virus. A substantial body of indirect evidence shows domesticated pigs are a source of zoonotic human HEV infection, but there is an information bias towards this established reservoir. The increasing range of animals in which HEV has been detected makes it important to consider other possible animal reservoirs of HEV genotypes that can or could infect humans. Foodborne transmission of HEV from swine and deer products has been proven, and a large body of indirect evidence (e.g. food surveys, epidemiological studies and phylogenetic analyses) support pig products as vehicles of HEV infection. Scarce data from other foods suggest we are neglecting other potential sources of foodborne HEV infection. Moreover, other transmission routes are scarcely investigated in developed countries; the role of infected food handlers, person-to-person transmission via the faecal-oral route, and waterborne transmission from recreational contact or drinking untreated or inadequately treated water. People have become symptomatic after receiving transfusions of HEV-contaminated blood, but it is unclear how important this is in the overall hepatitis E disease burden. There is need for broader research efforts to support establishing risk-based controls.

Prevalence of hepatitis E virus viremia and antibodies among healthy blood donors in India

BACKGROUND

Hepatitis E virus (HEV) is transmitted primarily through contaminated water and food. Recently, HEV viremia in blood donors and transfusion-related transmission of HEV have been reported, leading to calls to screen donated blood for this virus. However, these data are from regions where genotype 3 HEV is predominant. In India, where human infections are caused only by genotype 1 HEV, the frequency of subclinical HEV viremia is unknown.

METHODS

Minipools of sera prepared from three donor units each from our institution's  blood bank in Lucknow, India, were tested for HEV RNA using a sensitive amplification-based assay. A randomly selected subset was also tested for IgG anti-HEV antibodies using a commercial (Wantai) immunoassay.

RESULTS

Sera from 1799 donors (median [range] age 30 [18-63] years; 1746 [97.0%] men) were collected (June-July 2016, 900; November-December 2016, 899). Of these, 17 (0.95%), 16 (0.90%), and 3 (0.17%) tested positive for HBsAg, anti-HCV, and anti-HIV antibodies, respectively. None of the donors tested positive for HEV RNA. Of 633 randomly selected donors (age 30 [18-63] years, 613 [96.8%] male) tested for IgG anti-HEV, 383 (60.5%) tested positive. Seropositivity rate increased with age, being 70/136 (52%), 177/299 (59%), 100/154 (65%), 30/34 (88%), and 6/10 (60%) in the 18-24, 25-34, 35-44, 45-54, and 55 years or older age groups, respectively.

CONCLUSIONS

In healthy blood donors from northern India, HEV viremia is infrequent though anti-HEV antibody prevalence is high. This suggests that asymptomatic HEV viremia may be less frequent in areas with genotype 1 predominance than those with genotype 3 predominance.

Molecular and serological infection marker screening in blood donors indicates high endemicity of hepatitis E virus in Poland

BACKGROUND

Until now, markers of hepatitis E virus (HEV) infection have not been studied in blood donors throughout Poland, and no acute case of HEV infection has been closely documented or confirmed by HEV RNA detection. The prevalence of HEV infection markers, including HEV RNA in Polish blood donors and virus genotypes was investigated.

STUDY DESIGN AND METHODS

In total, 12,664 individual donations from 22 Polish blood transfusion centers were tested for HEV RNA by transcription-mediated amplification. In addition, 3079 first-time donors sampled throughout Poland also were screened for antibodies to HEV. HEV RNA and immunoglobulin M-positive donations were confirmed using real-time reverse transcription-polymerase chain reaction and Western blotting, respectively.

RESULTS

Ten donors were identified as RNA initial reactive (one of 1266 donors), and six (one of 2109) were identified as repeat reactive and confirmed by real-time reverse transcription-polymerase chain reaction or seroconversion. Sequence analysis identified HEV Genotype 3c in one donor and Genotype 3i in two others. On average, 43.5% of donors were immunoglobulin G-positive. Immunoglobulin G seroprevalence ranged from 22.7% to 60.8% in group ages 18 to 27 years and 48 to 57 years, respectively and differed between administrative regions from 28.9% in Podlasie to 61.3% in Wielkopolska. Thirty-nine of the donors were immunoglobulin M-positive, and seven donors were IgM positive only (0.2%). Of 37 immunoglobulin M-reactive samples tested by Western blot, 24 (64.9%) were confirmed.

CONCLUSIONS

The current results indicate a high level of HEV endemicity throughout Poland compared with other countries. There is an urgent need to consider the protection of recipients of blood components against transfusion-transmitted HEV infection.

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.

[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.

Hepatitis E: prevention and treatment

PURPOSE OF REVIEW

Infection with the hepatitis E virus (HEV) is very common worldwide. The epidemiology, viral genotypes, and transmission routes differ between low-resource countries and economically developed countries. These differences have resulted in the design of diverse prevention and treatment strategies to combat HEV.

RECENT FINDINGS

The population seroprevalence of HEV immunoglobulin G varies between 5 and 50%. However, the diagnosis of acute hepatitis from HEV has not been common in the United States or Western Europe. Chronic progressive HEV infections have been reported among patients who are immunocompromised. Successful treatment of patients with chronic hepatitis from HEV infection with antiviral agents, such as ribavirin or interferon-α, has been reported. Extrahepatic manifestations of HEV infection are common. Large epidemics of hundreds or thousands of cases continue to be reported among populations in Asia and Africa. A subunit peptide HEV vaccine has been found to be highly efficacious in a large clinical trial. However, the vaccine has not been evaluated in populations of pregnant women or other risk groups and is only available in China.

SUMMARY

Although HEV infections are increasingly recognized as a global public health problem, there are few methods for prevention and treatment that are widely available.

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.

[Risk of transmission of blood-derived pathogens by transfusion in Poland]

Blood transfusion in Poland is the safest in history. High virological level of safety has been achieved mainly by improving not only the qualification of donors and methods used for donor screening, but also applying leukoreduction, pathogen reduction technology and grace period for serum.In this article, we discuss the improvement of the epidemic situation among blood donors for hepatitis B virus (HBV) and hepatitis C virus (HCV) and the increasing trend for HIV. Preliminary results of residual risk calculation for these pathogens are presented.Hepatitis E virus (HEV) and Babesia microti were considered as new factors potentially relevant for the safety of blood transfusion in our country. Due to evidence of West Nile virus (WNV) circulation in the ecosystem in Poland, it is also necessary to monitor the infections with this pathogen.In this article, it was emphasized that the reporting of all possible complications associated with transfusion and meticulous implementation of the look-back procedure play a key role for monitoring the risk of transmission of infectious agents by blood. It is especially important in view of the increasing epidemiological problems associated with emerging infectious agents.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

DISCUSSION

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

Phage-displayed peptides that mimic epitopes of hepatitis E virus capsid

Hepatitis E is an emerging zoonotic infection of increasing public health threat for the UK, especially for immunosuppressed individuals. A human recombinant vaccine has been licensed only in China and is not clear whether it protects against hepatitis E virus (HEV) genotype 3, the most prevalent in Europe. The aim of this study was to use phage display technology as a tool to identify peptides that mimic epitopes of HEV capsid (mimotopes). We identified putative linear and conformational mimotopes using sera from Scottish blood donors that have the immunological imprint of past HEV infection. Four mimotopes did not have homology with the primary sequence of HEV ORF2 capsid but competed effectively with a commercial HEV antigen for binding to anti-HEV reference serum. When the reactivity profile of each mimotope was compared with Wantai HEV-IgG ELISA, the most sensitive HEV immunoassay, mimotopes showed 95.2-100% sensitivity while the specificity ranged from 81.5 to 95.8%. PepSurf algorithm was used to map affinity-selected peptides onto the ORF2 crystal structure of HEV genotype 3, which predicted that these four mimototopes are clustered in the P domain of ORF2 capsid, near conformational epitopes of anti-HEV neutralising monoclonal antibodies. These HEV mimotopes may have potential applications in the design of structural vaccines and the development of new diagnostic tests.

Hepatitis E in Canadian blood donors

BACKGROUND

Hepatitis E virus (HEV) is a virus of emerging importance to transfusion medicine as studies on blood donors and other populations demonstrate that the prevalence of endemic cases is higher than previously recognized and the risk to vulnerable transfusion recipients is not insignificant.

STUDY DESIGN AND METHODS

We carried out an HEV prevalence study on 13,993 Canadian blood donors with polymerase chain reaction (PCR) testing on all donors and antibody testing on a subset of 4102 donors. HEV antibody-positive and age- and sex-matched antibody-negative donors were invited to participate in a scripted telephone interview about risk factors.

RESULTS

There were no PCR-positive samples found (95% confidence interval [CI], 0%-0.026%). The seroprevalence of HEV in our tested population was 5.9% (95% CI, 5.16%-6.59%). HEV antibody positivity was associated with male sex and increasing age. In case-control analysis history of living outside Canada (odds ratio [OR], 2.9; 95% CI, 1.56-5.32) and contact with farm animals (OR, 1.5; 95% CI, 1.01-2.28) were associated with HEV seropositivity.

CONCLUSION

This is the largest data set to date on HEV infection in Canada. Results suggest low lifetime exposure to HEV and that infectious donations are rare.

Hepatitis E Virus in Industrialized Countries: The Silent Threat

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

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

Background

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

Methods

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

Results

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

Conclusion

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

Risk Profile of Hepatitis E Virus from Pigs or Pork in Canada

The role and importance of pigs and pork as sources of zoonotic hepatitis E virus (HEV) has been debated in Canada and abroad for over 20 years. To further investigate this question, we compiled data to populate a risk profile for HEV in pigs or pork in Canada. We organized the risk profile (RP) using the headings prescribed for a foodborne microbial risk assessment and used research synthesis methods and inputs wherever possible in populating the fields of this RP. A scoping review of potential public health risks of HEV, and two Canadian field surveys sampling finisher pigs, and retail pork chops and pork livers, provided inputs to inform this RP. We calculated summary estimates of prevalence using the Comprehensive Meta-analysis 3 software, employing the method of moments. Overall, we found the incidence of sporadic locally acquired hepatitis E in Canada, compiled from peer-reviewed literature or from diagnosis at the National Microbiology Laboratory to be low relative to other non-endemic countries. In contrast, we found the prevalence of detection of HEV RNA in pigs and retail pork livers, to be comparable to that reported in the USA and Europe. We drafted risk categories (high/medium/low) for acquiring clinical hepatitis E from exposure to pigs or pork in Canada and hypothesize that the proportion of the Canadian population at high risk from either exposure is relatively small.

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

INTRODUCTION

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

AREAS COVERED

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

Foodborne viruses

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

Fulminant hepatic failure from hepatitis E in a non-pregnant female traveller

A non-pregnant Canadian woman returning from India presented with a 1-week history of jaundice and malaise. Subsequently, she developed fulminant hepatic failure caused by hepatitis E virus (HEV). HEV can cause fulminant hepatic failure, most commonly in pregnant women and those with chronic liver disease; however, all travellers are at risk.

Hepatitis E virus as a Cause of Acute Hepatitis in The Netherlands

BACKGROUND

Recent studies indicate that 27% of Dutch blood donors have evidence of past infection with HEV. However, the low number of diagnosed HEV infections indicates either an asymptomatic course or under diagnosis.

OBJECTIVES

We investigated whether HEV is a cause of acute hepatitis in Dutch patients and which diagnostic modality (serology or PCR) should be used for optimal detection.

STUDY DESIGN

Serum samples were retrospectively selected from non-severely immuno-compromised patients from a university hospital population, suspected of having an infectious hepatitis. Criteria were: elevated alanine aminotransferase (ALT> 34 U/l) and request for antibody testing for CMV, EBV or Hepatitis A (HAV).

RESULTS

All samples were tested for HEV using ELISA and PCR. Ninety patients/sera were tested, of which 22% were HEV IgG positive. Only one serum was IgM positive. HEV PCR was positive in two patients: one patient was both HEV IgM and IgG positive, the other patient was only IgG positive. Both HEV RNA positive samples belonged to genotype 3. Evidence of recent infection with CMV, EBV and HAV was found in 13%, 10% and 3% respectively.

CONCLUSIONS

Although our study is limited by small numbers, we conclude that HEV is a cause of acute hepatitis in hospital associated patients in The Netherlands. Moreover, in our study population the prevalence of acute HAV (3%) was almost similar to acute HEV (2%). We propose to incorporate HEV testing in panels for acute infectious hepatitis. Negative results obtained for HEV IgM in a HEV PCR positive patient, indicates that antibody testing alone may not be sufficient and argues for PCR as a primary diagnostic tool in hospital associated patients. The high percentage of HEV IgG seropositivity confirms earlier epidemiological studies.