Seroprevalence and incidence of hepatitis E virus infection in German blood donors

Transmission of Hepatitis E Virus in Developing Countries

Hepatitis E virus (HEV), an RNA virus of the Hepeviridae family, has marked heterogeneity. While all five HEV genotypes can cause human infections, genotypes HEV-1 and -2 infect humans alone, genotypes HEV-3 and -4 primarily infect pigs, boars and deer, and genotype HEV-7 primarily infects dromedaries. The global distribution of HEV has distinct epidemiological patterns based on ecology and socioeconomic factors. In resource-poor countries, disease presents as large-scale waterborne epidemics, and few epidemics have spread through person-to-person contact; however, endemic diseases within these countries can potentially spread through person-to-person contact or fecally contaminated water and foods. Vertical transmission of HEV from infected mother to fetus causes high fetal and perinatal mortality. Other means of transmission, such as zoonotic transmission, can fluctuate depending upon the region and strain of the virus. For instance, zoonotic transmission can sometimes play an insignificant role in human infections, such as in India, where human and pig HEV infections are unrelated. However, recently China and Southeast Asia have experienced a zoonotic spread of HEV-4 from pigs to humans and this has become the dominant mode of transmission of hepatitis E in eastern China. Zoonotic HEV infections in humans occur by eating undercooked pig flesh, raw liver, and sausages; through vocational contact; or via pig slurry, which leads to environmental contamination of agricultural products and seafood. Lastly, blood transfusion-associated HEV infections occur in many countries and screening of donors for HEV RNA is currently under serious consideration. To summarize, HEV genotypes 1 and 2 cause epidemic and endemic diseases in resource poor countries, primarily spreading through contaminated drinking water. HEV genotypes 3 and 4 on the other hand, cause autochthonous infections in developed, and many developing countries, by means of a unique zoonotic food-borne transmission.

Hepatitis E: Discovery, global impact, control and cure

Hepatitis E was identified as an epidemic of non-A, non-B hepatitis from Kashmir, India in 1978. Hepatitis E virus (HEV), the etiological agent is the sole member of family Hepeviridae. The virus has marked heterogeneity and infects many animals like bats, camel, chicken, deer, boar, mongoose, pigs, rats, rabbit and cutthroat trout. Hepatitis E is a disease with a major global impact and has two distinct epidemiological patterns. Hepatitis E is an imperative health issue in developing nations, transmitted through sullied water and happens most every now in young adults. The disease is particularly severe during pregnancy and in people with underlying liver cirrhosis. Autochthonous hepatitis E is increasingly recognized in developed countries. The virus infects domestic pigs, wild boar and Sika deer in these countries. HEV infections in humans occur by eating the undercooked game flesh, raw liver from supermarkets and Figatelli sausages. Blood transfusion-associated HEV infections occur in many countries and screening of donors for HEV RNA is under consideration. Hepatitis E causes a number of extrahepatic diseases, including a wide spectrum of neurological syndromes. HEV genotype 3 causes prolonged viremia, chronic hepatitis, liver fibrosis and cirrhosis in organ transplant patients. The virus is amenable to ribavirin monotherapy and most patients clear the virus in a few weeks. Hepatitis E vaccine -239, marketed in China, has shown high efficacy with sustained protection for over four years.

Hepatitis E virus antibody prevalence, RNA frequency, and genotype among blood donors in Cambodia (Southeast Asia)

BACKGROUND

Recent studies conducted in developed countries described hepatitis E virus (HEV) as an emerging infectious threat to blood safety. However, data on HEV among blood donors from southeast Asia are lacking.

STUDY DESIGN AND METHODS

Between July and August 2014, we assessed the presence of HEV immunoglobulin (Ig)G and IgM in 301 Cambodian blood donors. All samples were further tested for the presence of HEV RNA using an in-house reverse transcription-polymerase chain reaction. ORF2/ORF3 phylogenetic analysis was performed on positive HEV RNA specimens.

RESULTS

We found HEV IgG in 28.2% of blood donors from Cambodia. Three blood donors tested positive for HEV IgM with three distinct patterns: IgM(+)/IgG(-)/RNA(-) (n = 1), IgM(+)/IgG(+)/RNA(-) (n = 1), and IgM(+)/IgG(+)/RNA(+) (n = 1). Thus, the prevalence rates of HEV IgM and HEV RNA were 1.0 and 0.3%. Interestingly, the viremic blood donor harbored a HEV strain that belonged to Genotype 3 (HEV-3) and clustered with a Cambodian riverine HEV-3 isolate.

CONCLUSION

Due to the high frequency of Cambodian blood donors with positive HEV IgG, we conclude that HEV is endemic in this country. Large-scale studies must be considered to determine whether Cambodian blood donation screening is warranted to enhance blood safety in regard to HEV. In addition, our findings suggest that river water may be a significant source of exposure to HEV-3.

High prevalence of anti-hepatitis E virus antibodies among blood donors in central Italy, February to March 2014

Prevalence of anti-hepatitis E virus (HEV) antibodies is highly variable in developed countries, which seems partly due to differences in assay sensitivity. Using validated sensitive assays, we tested 313 blood donors attending a hospital transfusion unit in central Italy in January and February 2014 for anti-HEV IgG and IgM and HEV RNA. Data on HEV exposure were collected from all donors. Overall anti-HEV IgG prevalence was 49% (153/313). Eating raw dried pig-liver sausage was the only independent predictor of HEV infection (adjusted prevalence rate ratio = 2.14; 95% confidence interval: 1.23–3.74). Three donors were positive for either anti-HEV IgM (n = 2; 0.6%) or HEV RNA (n = 2; 0.6%); they were completely asymptomatic, without alanine aminotransferase (ALT) abnormalities. Of the two HEV RNA-positive donors (both harbouring genotype 3), one was anti-HEV IgG- and IgM-positive, the other was anti-HEV IgG- and IgM-negative. The third donor was positive for anti-HEV IgG and IgM but HEV RNA-negative. HEV infection is therefore hyperendemic among blood donors (80% men 18–64 years-old) from central Italy and associated with local dietary habits. Nearly 1% of donors have acute or recent infection, implying potential transmission to blood recipients. Neither ALT nor anti-HEV IgM testing seems useful to prevent transfusion-transmitted HEV infection.

Low transfusion transmission of hepatitis E among 25,637 single-donation, nucleic acid-tested blood donors

BACKGROUND

Hepatitis E virus genotype-3 (HEV-gt-3) causes autochthonous infections in western countries, with a primary reservoir in animals, especially pigs. HEV transfusion transmission has been reported, and HEV-gt-3 prevalence is high in some European countries. The prevalence of HEV RNA was investigated among Danish blood donors, and the prevalence of HEV transfusion-transmitted infection (TTI) was investigated among recipients.

STUDY DESIGN AND METHODS

Samples from 25,637 consenting donors collected during 1 month in 2015 were screened retrospectively using an individual-donation HEV RNA nucleic acid test with a 95% detection probability of 7.9 IU/mL. HEV-positive samples were quantified by real-time polymerase chain reaction and genotyped. Transmission was evaluated among recipients of HEV RNA-positive blood components. Phylogenetic analyses compared HEV sequences from blood donors, symptomatic patients, and swine.

RESULTS

Eleven donations (0.04%) were confirmed as positive for HEV RNA (median HEV RNA level, 13 IU/mL). Two donations were successfully genotyped as HEV-gt-3. Only one donor had a travel history outside Europe. Nine of 11 donors were male, but the gender ratio was nonsignificant compared with the total donor population. Seven available recipients tested negative for HEV RNA and anti-HEV immunoglobulin M in follow-up samples. One recipient was HEV RNA-negative but anti-HEV immunoglobulin G-positive. HEV TTI was considered unlikely, but a transfusion-induced secondary immune response could not be excluded. Phylogenetic analysis showed relatively large sequence differences between HEV from donors, symptomatic patients, and swine.

CONCLUSIONS

Despite an HEV RNA prevalence of 0.04% in Danish blood donations, all HEV-positive donations carried low viral loads, and no evidence of TTI was found.

New immunoassays for total, IgA and IgM antibodies against hepatitis E virus: Prevalence in Italian blood donors and patients with chronic liver or kidney diseases

BACKGROUND

Hepatitis E virus (HEV) is a zoonotic agent that causes acute hepatitis in humans with sporadic infections and outbreaks in developing countries worldwide. The global spread of HEV remains underestimated because of subclinical infections and lack of sensitive diagnostic assays.

AIMS

To study the prevalence of HEV antibodies (anti-HEV) in sera of blood-donors and patients with chronic-liver-disease and chronic-renal-disease, using newly developed anti-HEV assays.

METHODS

396 sera from 199 blood-donors, 109 chronic-liver-disease patients and 88 chronic-renal-disease patients and three standard reference serum panels were tested in parallel with a sensitive reference anti-HEV assay and newly developed assays for IgA, IgM and total anti-HEV based on HEV-like-particles produced by recombinant baculo-viruses.

RESULTS

Overall, total anti-HEV was detected in 12.9% (7.0% blood-donors, 9.2% and 30.7% chronic-liver-disease patients and chronic-renal-disease patients, respectively). We observed a higher anti-HEV prevalence in older subjects and in chronic-renal-disease patients in relation with degree on immune-depression (p<0.001). Results from reference serum panels showed an optimal and slightly better performance of the new assay over the commercially available assay.

CONCLUSIONS

Newly developed anti-HEV assays using recombinant HEV-like-particles showed optimal diagnostic performances assessing that HEV-infection is endemic in Italy with seroprevalence ranging from 7% to 30% in blood donors and immune-compromised hosts, respectively.

Hepatitis E virus as an emerging zoonotic pathogen

Hepatitis E outbreaks are a serious public health concern in developing countries. The disease causes acute infections, primarily in young adults. The mortality rate is approximately 2%; however, it can exceed 20% in pregnant women in some regions in India. The causative agent, hepatitis E virus (HEV), has been isolated from several animal species, including pigs. HEV genotypes 3 and 4 have been isolated from both humans and animals, and are recognized as zoonotic pathogens. Seroprevalence studies in animals and humans indirectly suggest that HEV infections occur worldwide. The virus is primarily transmitted to humans via undercooked animal meats in developed countries. Moreover, transfusion- and transplantation-mediated HEV infections have recently been reported. This review summarizes the general characteristics of hepatitis E, HEV infection status in animals and humans, the zoonotic transmission modes of HEV, and HEV vaccine development status.

Hepatitis E: an emerging global disease - from discovery towards control and cure

Hepatitis E is a systemic disease affecting the liver predominantly and caused by infection with the hepatitis E virus (HEV). HEV has marked genetic heterogeneity and is known to infect several animal species including pigs, boar, deer, mongoose, rabbit, camel, chicken, rats, ferret, bats and cutthroat trout. HEV is the sole member of the family Hepeviridae and has been divided into 2 genera: Orthohepevirus (mammalian and avian HEV) and Piscihepevirus (trout HEV). Human HEVs included within the genus Orthohepevirus are designated Orthohepevirus A (isolates from human, pig, wild boar, deer, mongoose, rabbit and camel). Hepatitis E is an important public health concern, and an estimated one-third of the world population has been infected with HEV. In recent years, autochthonous hepatitis E is recognized as a clinical problem in industrialized countries. Several animal species especially domestic swine, wild boar and wild deer are reservoirs of genotype HEV-3 and HEV-4 in these countries. Human infections occur through intake of uncooked or undercooked meat of the infected animals and pig livers or sausages made from these livers and sold in supermarkets. HEV can be transmitted through blood and blood component transfusions, and donor screening for HEV is under serious consideration. Chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end-stage liver disease has been described in organ transplant patients. Ribavirin monotherapy attains sustained virological response in most patients. HEV 239 vaccine has been marketed in China and its long-term efficacy over four and a half years reported.

Hepatitis E Virus Superinfection and Clinical Progression in Hepatitis B Patients

Hepatitis E virus (HEV) infection may cause acute hepatitis and lead to hepatic failure in developing and developed countries. We studied HEV seroprevalences in patients with hepatitis B virus (HBV) infection to understand the consequences of HEV superinfection in a Vietnamese population. This cross-sectional study was conducted from 2012 to 2013 and included 1318 Vietnamese patients with HBV-related liver diseases and 340 healthy controls. The case group included patients with acute (n = 26) and chronic hepatitis B (n = 744), liver cirrhosis (n = 160), hepatocellular carcinoma (n = 166) and patients with both liver cirrhosis and hepatocellular carcinoma (n = 222). Anti-HEV IgG and IgM antibodies were assessed in patients and controls by ELISA. HEV-RNA was identified by PCR assays and sequencing. Seroprevalences of anti-HEV IgG among hepatitis B patients and controls were 45% and 31%, respectively (adjusted P = 0.034). Anti-HEV IgM seroprevalences were 11.6% and 4.7% in patients and controls, respectively (adjusted P = 0.005). Seroprevalences were higher among the elder individuals. When stratifying for patient groups, those with liver cirrhosis had the highest anti-HEV IgG (52%) and anti-HEV IgM (19%) seroprevalences. Hepatitis B patients with current HEV infection had abnormal liver function tests compared to patients with past or without HEV infection. One HEV isolate was retrieved from a patient with both liver cirrhosis and hepatocellular carcinoma and identified as HEV genotype 3. This study indicates high prevalences of HEV infection in Vietnamese HBV patients and among healthy individuals and shows that HEV superinfection may influence the outcome and progression of HBV-related liver disease.

Epidemiology of Hepatitis E Virus in European Countries

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

Hepatitis E virus infection in hematopoietic stem cell transplant recipients

PURPOSE OF REVIEW

Recipients of allogeneic stem cell transplantations are at risk of acquiring acute hepatitis E virus (HEV) infection, leading to chronicity. We review the incidence, sequela, extrahepatic manifestations, and treatment of hepatitis due to HEV infection in allogeneic hematopoietic stem cell transplantation (alloHSCT) recipients.

RECENT FINDINGS

HEV infection and progression to chronic HEV in alloHSCT recipients are recently described. Misdiagnosis of HEV in alloHSCT recipients occurs, with liver enzyme abnormalities often attributed to hepatic graft-versus-host disease or drug-induced liver injury. HEV infection may occur in HSCT donors and emphasizes the need for HEV screening not only after HSCT, but also in donors presenting with liver function disturbances. The discussion about HEV screening of blood products will continue. Extrahepatic manifestations of hepatitis E are described.

SUMMARY

HEV RNA screening in alloHSCT recipients with elevated liver enzymes is advised. Intervention strategies should be considered in cases of acute or chronic HEV infection. The first-line approach includes reduction of immunosuppressive medication. Oral ribavirin is in experienced hands a reasonable well tolerated treatment option, although the optimal dose, duration, and quantitative goals of ribavirin treatment are still unknown. Further studies are needed to improve our understanding of HEV, including extrahepatic manifestations and evaluation of therapeutic options.

Prevalence and clinical consequences of Hepatitis E in patients who underwent liver transplantation for chronic Hepatitis C in the United States

Background

Infection with hepatitis E virus (HEV) in immunocompromised patients can lead to severe liver disease. Treatment options for HEV include peginterferon or ribavirin, routinely also used for the treatment of hepatitis C virus (HCV) infection.

We determined the prevalence and clinical consequences of HEV in United States (US) based patients who underwent liver transplantation (LT) for chronic HCV.

Methods

Seroprevalence of HEV in 145 US LT recipients with a history of chronic HCV was determined pre-LT, 1, 3 and 5 years post-LT. All last available samples and all samples in IgM positive patients and post-LT IgG seroconverters were tested for HEV RNA.

Results

Overall anti-HEV seroprevalence was 42 %. Five patients were HEV IgM positive pre-LT, one patient had IgM seroconversion post-LT and eight patients had IgG seroconversion post-LT. None of the tested samples were positive for HEV RNA. Eight out of nine of the post-LT seroconverters had been treated for HCV recurrence before or at the moment of seroconversion.

Conclusions

LT recipients in the US are at risk of acquiring HEV. Post-LT HCV treatment with interferons and/or ribavirin may have protected patients against chronic HEV. With the arrival of new direct antiviral agents for the treatment of HCV and the elimination of peginterferon and ribavirin from HCV treatment regimens, the prevalence of chronic HEV in this population may rise again.

Variability and pathogenicity of hepatitis E virus genotype 3 variants

Infection with hepatitis E virus (HEV) can be clinically inapparent or produce symptoms and signs of hepatitis of varying severity and occasional fatality. This variability in clinical outcomes may reflect differences in host susceptibility or the presence of virally encoded determinants of pathogenicity. Analysis of complete genome sequences supports the division of HEV genotype 3 (HEV-3) variants into three major clades: 3ra comprising HEV isolates from rabbits, and 3efg and 3abchij comprising the corresponding named subtypes derived from humans and pigs. Using this framework, we investigated associations between viral genetic variability of HEV-3 in symptomatic and asymptomatic infections by comparing HEV-3 subgenomic sequences previously obtained from blood donors with those from patients presenting with hepatitis in the UK (54 blood donors, 148 hepatitis patients), the Netherlands (38 blood donors, 119 hepatitis patients), France (24 blood donors, 55 hepatitis patients) and Germany (14 blood donors, 36 hepatitis patients). In none of these countries was evidence found for a significant association between virus variants and patient group (P>0.05 Fisher's exact test). Furthermore, within a group of 123 patients in Scotland with clinically apparent HEV infections, we found no evidence for an association between variants of HEV-3 and disease severity or alanine aminotransferase level. The lack of detectable virally encoded determinants of disease outcomes in HEV-3 infection implies a more important role for host factors in its clinical phenotype.

Low frequency of acute hepatitis E virus (HEV) infections but high past HEV exposure in subjects from Cambodia with mild liver enzyme elevations, unexplained fever or immunodeficiency due to HIV-1 infection

BACKGROUND

In Cambodia, previous studies conducted on hepatitis E virus (HEV) infection are scant, sometimes old, and showed inconsistent results. Moreover, there is no data about HEV infection in Cambodian HIV-1-infected patients.

OBJECTIVES

To assess the occurrence of acute HEV infections and the level of past HEV exposure in one Mekong country.

STUDY DESIGN

Using anti-HEV IgM and HEV RNA detection, we retrospectively investigated the presence of acute HEV infection in 825 individuals, including 350 subjects with or without fever, 300 subjects with or without liver enzyme elevations (LEE) and 175 antiretroviral treatment (ART)-naïve, severely immunocompromised HIV-1-infected patients. The detection of anti-HEV IgG was also performed to assess ancient HEV exposure.

RESULTS

Nine individuals tested positive for anti-HEV IgM yielding an overall rate of 1.1% (95% confidence interval (CI), 0.5-2.0). We did not find significant differences for anti-HEV IgM rates between subjects with unexplained fevers (1.5%) and those with malaria or dengue-associated fever (1.7%) or non-febrile individuals (0%) (P=0.49), and between subjects with (1.5%) and without (2.0%) LEE (P=0.87). No HIV-infected patient tested positive for anti-HEV IgM. HEV RNA was not detected in all tested plasma specimens (n=578). Overall, the anti-HEV IgG prevalence rate was 30.1% (95% CI, 27.0-33.2).

CONCLUSIONS

The scarcity of recent HEV infection contrasted with the high level of past HEV exposure. The role of HEV in liver disease is likely minor in Cambodia since no HEV RNA was detected in our studied populations, including HIV-positive patients with severe immunodepression.

The emergence of hepatitis E virus in Europe

ABSTRACT 

Hepatitis E virus (HEV) infections appear to be an emerging problem in Europe. Infections are mainly caused by viruses of genotype 3. Pigs and wild boar are the main reservoirs of HEV in Europe and most autochthonous infections are probably caused by the consumption of uncooked or undercooked infected meat. Nevertheless, transfusion-associated transmission has been described in different European countries but the efficiency of this route of transmission need to be further investigated. Most acute infections are asymptomatic or the induced symptoms are rather nonspecific. Although people that are otherwise completely healthy can spontaneously clear an HEV infection, people with underlying liver disease and/or suffering from immune deficiencies may require treatment to avoid chronicity and exacerbation of liver disease. In this review, we give an epidemiological overview of HEV in Europe and the potential complications.

The impact of hepatitis E in the liver transplant setting

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

Seroprevalence of hepatitis E virus (HEV) and detection of HEV RNA with a transcription-mediated amplification assay in blood donors from Catalonia (Spain)

BACKGROUND

Hepatitis E virus (HEV) is an emerging threat to the safety of blood transfusion. The aim of this study was to determine HEV immunoglobulin (Ig)G and RNA prevalence in Catalan blood donors.

STUDY DESIGN AND METHODS

Nearly 10,000 samples were collected from anonymized, unpaid donors at the Banc de Sang i Teixits (Barcelona, Spain) from June to December 2013. For the serology study, a subset of 1082 donations was tested in parallel for HEV IgG using Wantai and Mikrogen enzyme-linked immunosorbent assay tests. Samples were tested individually (individual-donation nucleic acid test [ID-NAT]) for HEV RNA using the Procleix HEV assay (95% limit of detection 7.9 IU/mL). Procleix repeat-reactive donations were confirmed by an in-house real-time polymerase chain reaction (PCR) test.

RESULTS

The prevalences of IgG anti-HEV in Catalan blood donors were 19.96% (Wantai assay) and 10.72% (Mikrogen assay). Screening of 9998 samples with the Procleix HEV assay yielded three real-time PCR-confirmed and IgM and IgG anti-HEV-positive donations with viral loads of 250, 564, and 2755 IU/mL. The donation with highest viral load was genotype 3f. HEV RNA positivity rate was one per 3333 donations (0.03%; 95% confidence interval, 0.01%-0.09%).

CONCLUSION

The Procleix HEV ID-NAT screening system has provided evidence of HEV RNA presence in Catalan blood donors. Further data are needed to assess the impact of HEV infection in at-risk patients to design the best strategy to increase blood safety.

Hepatitis E virus in blood components: a prevalence and transmission study in southeast England

BACKGROUND

The prevalence of hepatitis E virus (HEV) genotype 3 infections in the English population (including blood donors) is unknown, but is probably widespread, and the virus has been detected in pooled plasma products. HEV-infected donors have been retrospectively identified through investigation of reported cases of possible transfusion-transmitted hepatitis E. The frequency of HEV transmission by transfusion and its outcome remains unknown. We report the prevalence of HEV RNA in blood donations, the transmission of the virus through a range of blood components, and describe the resulting morbidity in the recipients.

METHODS

From Oct 8, 2012, to Sept 30, 2013, 225,000 blood donations that were collected in southeast England were screened retrospectively for HEV RNA. Donations containing HEV were characterised by use of serology and genomic phylogeny. Recipients, who received any blood components from these donations, were identified and the outcome of exposure was ascertained.

FINDINGS

79 donors were viraemic with genotype 3 HEV, giving an RNA prevalence of one in 2848. Most viraemic donors were seronegative at the time of donation. The 79 donations had been used to prepare 129 blood components, 62 of which had been transfused before identification of the infected donation. Follow-up of 43 recipients showed 18 (42%) had evidence of infection. Absence of detectable antibody and high viral load in the donation rendered infection more likely. Recipient immunosuppression delayed or prevented seroconversion and extended the duration of viraemia. Three recipients cleared longstanding infection after intervention with ribavirin or alteration in immunosuppressive therapy. Ten recipients developed prolonged or persistent infection. Transaminitis was common, but short-term morbidity was rare; only one recipient developed apparent but clinically mild post-transfusion hepatitis.

INTERPRETATION

Our findings suggest that HEV genotype 3 infections are widespread in the English population and in blood donors. Transfusion-transmitted infections rarely caused acute morbidity, but in some immunosuppressed patients became persistent. Although at present blood donations are not screened, an agreed policy is needed for the identification of patients with persistent HEV infection, irrespective of origin, so that they can be offered antiviral therapy.

FUNDING

Public Health England and National Health Service Blood and Transplant.

Hepatitis E in patients with hepatic disorders and HIV-infected patients in Croatia: is one diagnostic method enough for hepatitis E diagnosis?

We assessed hepatitis E virus (HEV) seroprevalence in patients with hepatic disorders as well as in human immunodeficiency virus (HIV)-infected patients and emphasised the issue of possible non-specific anti-HEV seroresponse and need for combining diagnostic methods for hepatitis E diagnosis. Over a two-year period, from March 2011 to February 2013, we determined anti-HEV immunoglobulin M (IgM) and IgG by enzyme immunoassays (EIA; Mikrogen, Germany) in 504 hepatitis patients negative for acute viral hepatitis A-C. Furthermore, 88 samples from randomly selected consecutive HIV-infected patients were also analysed. All EIA reactive samples were additionally tested by line immunoblot assays (LIA; Mikrogen, Germany). HEV nested reverse transcription polymerase chain reaction (RT-PCR) was carried out in 14 anti-HEV IgM LIA-positive patients. Anti-HEV IgM or IgG were detected in 16.9 % of patients by EIA and confirmed by LIA in 10.7 % [95 % confidence interval (CI) 8.3-13.7 %] of hepatitis patients. HEV RNA was detected in five patients. The agreement between EIA and LIA assessed by Cohen's kappa was 0.47 (95 % CI 0.55-0.75) for IgM and 0.83 (95 % CI 0.78-0.93) for IgG. Anti-HEV IgM and IgG seroprevalence in HIV-infected patients was 1.1 %, respectively. Our findings show a rather high HEV seroprevalence in patients with elevated liver enzymes in comparison to HIV-infected patients. Discordant findings by different methods stress the need to combine complementary methods and use a two-tier approach with prudent interpretation of reactive serological results for hepatitis E diagnosis.

Transfusion-transmitted hepatitis E in Germany, 2013

The reported IgG seroprevalence against hepatitis E virus (HEV) in German blood donations is 6.8%, and HEV RNA detected in 0.08%, but documented evidence for HEV transmission is lacking. We identified two donations from a single donor containing 120 IU HEV RNA/mL plasma and 490 IU/mL. An infectious dose of 7,056 IU HEV RNA was transmitted via apheresis platelets to an immunosuppressed patient who developed chronic HEV. Further, transmission was probable in an immunocompetent child.

Serological and molecular evidence of a plausible transmission of hepatitis E virus through pooled plasma

BACKGROUND AND OBJECTIVES

Recently, hepatitis E virus has been recognized as a new transfusion-associated risk; however, its efficiency of transmission through blood products requires further investigation. Asymptomatic viremia of short duration has been observed in blood donors from several European countries to the rate of <1:10,000 and HEV transmission in recipients of blood products has been documented in Japan and Europe. Although HEV RNA was detected in large plasma fractionation pools used for manufacturing of plasma derived products, HEV transmission has not been demonstrated so far. In this study, we investigated the possibility of HEV transmission in patients with thrombotic thrombocytopenic purpura whose treatment included up to 40 l of plasma exchange.

MATERIALS AND METHODS

Thirty-six TTP patients received either solvent-detergent-treated plasma prepared by pooling of 2500 single-donor or cryosupernatant plasma. Three samples were collected from TTP patients at time 0, 1 and 6 months post-treatment and tested for anti-HEV antibodies. Patients with HEV seroconversion were also tested for viremia by PCR.

RESULTS

Two of seventeen TTP patients treated with SDP showed serological evidence of HEV infection. The 1-month samples from these patients were also positive for HEV RNA. A distinct rise of anti-HEV IgG level was detected in two other TTP patients with weak pre-existing immunity to HEV; this observation is indicative of a possible immune response boost due to a breakthrough infection.

CONCLUSION

This work provides, for the first time, indirect evidence of HEV transmission by pooled plasma and warrants further studies.

Pathogen inactivation and removal methods for plasma-derived clotting factor concentrates

Pathogen safety is crucial for plasma-derived clotting factor concentrates used in the treatment of bleeding disorders. Plasma, the starting material for these products, is collected by plasmapheresis (source plasma) or derived from whole blood donations (recovered plasma). The primary measures regarding pathogen safety are selection of healthy donors donating in centers with appropriate epidemiologic data for the main blood-transmissible viruses, screening donations for the absence of relevant infectious blood-borne viruses, and release of plasma pools for further processing only if they are nonreactive for serologic markers and nucleic acids for these viruses. Despite this testing, pathogen inactivation and/or removal during the manufacturing process of plasma-derived clotting factor concentrates is required to ensure prevention of transmission of infectious agents. Historically, hepatitis viruses and human immunodeficiency virus have posed the greatest threat to patients receiving plasma-derived therapy for treatment of hemophilia or von Willebrand disease. Over the past 30 years, dedicated virus inactivation and removal steps have been integrated into factor concentrate production processes, essentially eliminating transmission of these viruses. Manufacturing steps used in the purification of factor concentrates have also proved to be successful in reducing potential prion infectivity. In this review, current techniques for inactivation and removal of pathogens from factor concentrates are discussed. Ideally, production processes should involve a combination of complementary steps for pathogen inactivation and/or removal to ensure product safety. Finally, potential batch-to-batch contamination is avoided by stringent cleaning and sanitization methods as part of the manufacturing process.

Seroprevalence of hepatitis E virus (HEV) in humans living in high pig density areas of Germany

An increase in acute autochthonous hepatitis E virus (HEV) infections has been recorded in Germany. These are suspected to be zoonotically transmitted from wild boar, deer and domestic pig. The latter may represent a major reservoir for HEV. In this study, 537 sera from humans living in Westphalia and Lower Saxony, representing areas of high pig density in Germany, were tested for the presence of HEV-specific antibodies. Among them were 302 individuals with occupational, direct contact to pigs and 235 individuals without direct contact to pigs. Two commercial tests and one in-house assay were applied for the detection of HEV-specific immunoglobulin G (IgG) antibodies. Sera were also tested in an assay that detects all classes of HEV-specific antibodies. Depending on the test used, the seroprevalence ranged from 4.1 to 27.9 %. Exposition to pigs was found to be associated with a significantly higher seroprevalence in subjects with contact to pigs (13.2-32.8 %) compared with that in non-exposed humans (7.7-21.7 %). In particular, individuals younger than 40 years with occupational exposure exhibited a markedly higher HEV seroprevalence compared with non-exposed individuals of that age group. In general, HEV seroprevalence increased with age resulting in a similar prevalence level in the age group of ≥ 50 years for exposed and non-exposed individuals. Analysis of all sera by a commercial anti-HEV IgM ELISA revealed 35 positive and 25 borderline samples. However, only one positive serum could be confirmed by an IgM line assay. Selected samples from IgM and/or IgG as well as total HEV antibody-positive individuals were also tested for the presence of HEV RNA. In one of the 78 samples, the only IgM ELISA positive and IgM line assay confirmed sample, RNA of HEV genotype 3 was detected. This sequence has high similarity to HEV sequences obtained from wild boars and domestic pigs from Germany and The Netherlands. This study demonstrates that in addition to the consumption of raw or undercooked meat, direct contact to pigs has to be considered as an additional risk factor for HEV infection.

Comparison of real-time PCR and antigen assays for detection of hepatitis E virus in blood donors

Hepatitis E virus (HEV) infection is recognized as an emerging and often undiagnosed disease in industrialized countries, with asymptomatic infections actually occurring in blood donors. Sensitive detection of HEV-RNA is crucial for diagnosis and monitoring of disease progression. We evaluated the analytical sensitivity and performance of three HEV RT-PCR assays (RealStar HEV reverse transcription-PCR [RT-PCR], hepatitis@ceeramTools, and ampliCube HEV RT-PCR) for screening of individuals for HEV infections (ID-nucleic acid amplification technology [ID-NAT]) and for blood donor pool screening (minipool-NAT [MP-NAT]). RNA was extracted using NucliSens easyMAG (ID-NAT) and a high-volume extraction protocol (4.8 ml, chemagic Viral 5K, MP-NAT). Three NAT assays were evaluated for ID-NAT but only two assays for MP-NAT due to inhibition of the ampliCube HEV RT-PCR kit using the corresponding RNA extract. Assays provided good analytical sensitivity, ranging from 37.8 to 180.1 IU/ml (ID-NAT) and from 4.7 to 91.2 IU/ml (MP-NAT). The applicability of HEV antigen (HEV-Ag) screening was compared to that of RT-PCR screening and detection of HEV-IgM antibodies using seroconversion panels of 10 HEV genotype 3-infected individuals. Four individuals revealed a positive HEV-Ag detection result, with corresponding viremias ranging from 1.92 E + 03 to 2.19 E + 05 IU/ml, while the progression of HEV-Ag followed that of HEV viremia. The other six individuals showed no presence of HEV-Ag although the corresponding viremias were also in the range of >1.0 E + 03. Anti-HEV-IgM antibodies were detectable in seven donors; one donor presented parallel positivities of HEV-Ag and anti-HEV IgM. The evaluated NAT methods present powerful tools providing sensitive HEV detection. Application of HEV-Ag or anti-HEV IgM screening is currently inferior for the early detection of HEV infection due to the decreased sensitivity compared to NAT methods.

Prevalence of hepatitis E virus antibodies in children in Germany

BACKGROUND

Since asymptomatic hepatitis E virus (HEV) infections particularly affect children, there is a need for studies to determine the HEV seroprevalence among infants, children and adolescents.

METHODS

The prevalence of anti-HEV IgG antibodies was determined in sera taken in 2008-2010 from 1646 children aged 0-17 years living in Germany. Antibody testing was carried out using the enzyme-linked immunosorbent assay recomWell HEV IgG as well as the recomLine HEV IgG/IgM distributed by Mikrogen. Furthermore, the performance of MP Biomedicals enzyme-linked immunosorbent assay HEV and the HEV-Ab enzyme-linked immunosorbent assay from Axiom was analyzed in comparison with the recomWell/recomLine test system using a defined subset of sera.

RESULTS

In children, the overall prevalence of antibodies was 1.0%. Starting with the 5- to 6-year olds, there was a significant increase of HEV seroprevalence to 1.5% in the group of the 15- to 17-year olds. There was no statistically significant difference between seroprevalences of boys (1.2%) and girls (0.7%). Passively transmitted maternal antibodies persisted for about 3 months. The strength of agreement between the recomWell/recomLine system and the ELISAs from MP Biomedicals or Axiom varied between 0.229 and 0.542 and was calculated at 0.111 when the assays from MP Biomedicals and Axiom were compared.

CONCLUSIONS

In Germany, only a very small number of HEV infections occur in children. Many infections occur in adults with increasing age. Because of considerable variations in assay accordance, there is an urgent need for standardization of HEV serology.

Autochthonous Hepatitis E Virus Infection in Europe: A Matter of Concern for Public Health?

Human hepatitis E virus (HHEV) is the proposed name for a diverse group of RNA viruses from the family Hepeviridae that cause acute hepatitis among humans. Waterborne strains are regularly imported into Europe by international travelers, and virus transmission of zoonotic strains via contaminated aliments is involved in autochthonous cases. Therefore, in Europe, hepatitis E displays a unique dual character, having features of both imported and autochthonous infections. Environmental involvement of waterborne and zoonotic diseases puts alimentary safety at risk. In addition, it may lead to serious health problems derived from persistent infection among patients with immune impairment due to organ transplant, cancer, or human immunodeficiency virus infection. Although the European health authorities know at present that HHEV represents a problem worthy of consideration, the actual incidence of the disease in Europe is unknown, and attempts to ascertain the prevalence of the infection is hampered by unresolved technical issues. In order to determine the burden of hepatitis E in Europe, the World Health Organization Regional Office and the European Centre for Disease Prevention and Control should pay specific attention to hepatitis E, and research efforts in the continent should be transnational and collaborative. Development of a specific European network for hepatitis E would help to achieve these goals.

Light and Darkness: Prevalence of Hepatitis E Virus Infection among the General Population

Human hepatitis E virus (HHEV) spreads early in life among the population in areas endemic for genotype 1 and infects mainly adults in areas endemic for genotype 3, where it would be responsible for about 10% of cases of suspected acute viral hepatitis of unknown etiology and for a number of subclinical, unrecognized infections. The overall prevalence of antibody to HHEV is high in most of the former areas and low in most of the later ones, but wide regional differences have been recorded in both cases. "Hot spots" of HHEV infection would exist for both types of strains in particular regions or among particular populations of the world. Studies on pork derivatives, shellfish bivalves, and vegetables for HHEV contamination at the sale point need to be extended for evaluating the impact of the agent on food safety, and the meaning of the finding of HHEV genotype 1 genomes in urban sewage from developed countries should be established through active surveillance. Consensus about technical issues in regard to anti-HEV testing would improve the knowledge of the HHEV epidemiology. Studies in particular regions and populations, and introduction of molecular diagnosis in the clinical setting as a routine tool, would also be required.

Autochthonous hepatitis e virus infections: a new transfusion-associated risk?

Hepatitis E virus (HEV) has been recognized since 2004 as a transfusion-transmissible infectious agent, and recent epidemiological data suggest that it may pose a safety threat to the blood supply. It has recently become obvious that hepatitis E is endemic in industrialized countries, and that more infections are autochthonous than travel-associated. Epidemiological and phylogenetic analysis suggests that HEV infection has to be considered as a zoonosis and that viral transmission from animals (pigs, wild animals) occurs through food or direct contact. The seroprevalence and incidence of HEV in the general population and blood donors in European countries indicate an underestimated risk for transfusion transmissions. Recently reported cases of transfusion transmission of HEV infection, and detection of viremic, asymptomatic blood donors in nucleic acid amplification technique screening programs give an indication of the importance of this virus. Diagnostic assays for detection of anti-HEV antibodies, HEV antigens and RNA are discussed. Recent studies support the idea that active immunization can prevent hepatitis E, highlighting the need for vaccination programs. Here we review current knowledge of HEV and its epidemiology, blood transmission and prevention of this disease with emphasis on blood supply.

Hepatitis E in liver biopsies from patients with acute hepatitis of clinically unexplained origin

Hepatitis E virus (HEV) is a small RNA virus and the infectious agent of hepatitis E that occurs worldwide either as epidemics in Asia caused by genotype 1 and 2 or as sporadic disease in industrialized countries induced by genotype 3 and 4. The frequency might be underestimated in central Europe as a cause of acute hepatitis. Therefore, we analyzed on liver biopsies, if cases of acute hepatitis with clinically unknown or obscure diagnosis were actually caused by the infection with HEV. We included 221 liver biopsies retrieved from the files of the institute of pathology during the years 2000 till 2010 that were taken from patients with acute hepatitis of obscure or doubtful diagnosis. From all biopsies RNA was extracted, prepared, and subjected to RT-PCR with specific primers. Amplified RNA was detected in 7 patients, sequenced and the genotype 3 could be determined in four of the seven of positive specimens from 221 samples. Histopathology of the biopsies revealed a classic acute hepatitis with cholestatic features and in some cases confluent necrosis in zone 3. Histology in a cohort of matched patients was less severe and showed more eosinophils. The analysis of the immune response by subtyping of liver infiltrating lymphocytes showed circumstantial evidence of adaptive immune reaction with CD 8 positive CTLs being the dominant lymphocyte population. In conclusion, in doubtful cases of acute hepatitis of unknown origin, HEV infection should be considered as etiology in central Europe. We demonstrate for the first time that the diagnosis can be made in paraffin-embedded liver biopsies reliably when no serum is available and also the genotype can be determined. The analysis of the immune response by subtyping of liver infiltrating lymphocytes indicates an adaptive mechanism suggesting in analogy with HAV, HBV and HCV that the virus itself is not cytopathic but liver damage is due to immune reaction.

Describing the silent human virome with an emphasis on giant viruses

Viruses are the most abundant obligate intracellular entities in our body. Until recently, they were only considered to be pathogens that caused a broad array of pathologies, ranging from mild disease to deaths in the most severe cases. However, recent advances in unbiased mass sequencing techniques as well as increasing epidemiological evidence have indicated that the human body is home to diverse viral species under non-pathological conditions. Despite these studies, the description of the presumably healthy viral flora, i.e. the normal human virome, is still in its infancy regarding viral composition and dynamics. This review summarizes our current knowledge of the human virome under non-pathological conditions.