Hepatitis E virus and chronic hepatitis in organ-transplant recipients

[Emergent viral threats in blood transfusion]

Au cours des 20 dernières années, la sécurité en transfusion sanguine a fait de très grands progrès vis-à-vis du risque infectieux et notamment de celui représenté par les rétrovirus (HIV et HTLV) et les virus des hépatites B et C. L’objet de cette revue est de répertorier les risques viraux résiduels ou émergents qui seraient susceptibles d’entraîner de nouvelles contaminations chez les receveurs. À côté de nombreux autres virus (HHV-8, erythrovirus B19, virus des hépatites A et E…), une place toute particulière est faite aux arboviroses émergentes (infections à West Nile virus, dengue et chikungunya) qui menacent de toucher le territoire métropolitain suite à l’implantation en Europe du moustique Aedes albopictus, principal vecteur de la dengue et du chikungunya dans les régions tempérées. Un autre risque sanguin émergent, particulièrement au Royaume-Uni et en France, est constitué par le prion à l’origine de la forme variante de la maladie de Creutzfeldt-Jakob. La revue se termine par un rapide panorama des mesures qui sont susceptibles de contrôler ces émergences : exclusion des donneurs à risque, tests diagnostiques spécifiques de tel ou tel agent, déleucocytation des produits sanguins labiles et traitements physiques ou chimiques capables d’inactiver de façon non spécifique les agents infectieux potentiellement contaminants sans trop altérer les propriétés des composants sanguins. La capacité à maîtriser de façon prospective les nouveaux risques viraux au niveau transfusionnel représente un vrai défi pour préserver la confiance retrouvée des prescripteurs et des receveurs vis-à-vis des produits sanguins.

[Prevention of virus hepatitis A to E]

Infection with hepatitis viruses can lead to acute hepatitis with the risk of developing liver failure. Chronic viral hepatitis may evolve into liver cirrhosis and hepatocellular carcinoma. Thus, prevention of viral hepatitis and its sequels is essential. Vaccination against hepatitis A is successful in almost all individuals. Protective antibodies maintain for at least 20 years. Booster vaccinations are not necessary. Since the introduction of hepatitis A vaccines, the incidence of new HAV-infections has declined significantly. Hepatitis B vaccines are safe and highly effective. Special populations such as dialysis patients or immunocompromised patients require special vaccine schedules. New vaccines with improved adjuvants are currently being tested in clinical trials. So far there is no hepatitis C vaccine on the horizon. Prophylaxis of HCV-infections relies primarily on hygiene measures. Early therapy of acute hepatitis C can prevent chronic hepatitis C. HDV-infection can only be established if HBsAg is present. Thus, prevention of hepatitis B or elimination of HBsAg means prevention of hepatitis delta. Hepatitis E vaccines have been evaluated in phase III studies. The development of HEV vaccines becomes more relevant since chronic HEV infections have been reported in immunosuppressed individuals.

Discovery of hepatitis E: the epidemic non-A, non-B hepatitis 30 years down the memory lane

Hepatitis E was first recognised during an epidemic of hepatitis, which occurred in Kashmir Valley in 1978. The epidemic involved an estimated 52,000 cases of icteric hepatitis with 1700 deaths. The disease had unique clinical and epidemiological features. The epidemic was water-borne with highly compressed epidemic curve. Following the epidemic, secondary waves of hepatitis did not occur. Clinical profile was characterized by cholestasis in around 20% of patients. The disease predominantly occurred in young adults. There was increased incidence and severity of the disease in pregnant women. A subset of patients had distinctive liver histology with bile plugs in the canaliculi and formation of pseudo-ductules by hepatocytes around the bile plugs. All surviving patients had self limiting disease. Sera lacked serological markers of acute hepatitis A and hepatitis B. Based on these data, the possibility of another human hepatitis virus distinct from post-transfusion non-A, non-B hepatitis was postulated. Balayan et al. (1983) successfully transmitted the disease into himself by oral administration of pooled stool extracts of 9 patients from a non-A, non-B hepatitis outbreak which had occurred in a Soviet military camp located in Afghanistan. Reyes et al. (1990) cloned and sequenced hepatitis E virus genome. Over the years, hepatitis E was identified as a major health problem in developing countries with unsafe water supplies and poor sanitary disposal. Data from sero-surveys forced re-evaluation of the epidemiology of hepatitis E and gave an indirect indication to vocationally acquired HEV infections in industrialized countries. Soon, autochthonous hepatitis E was recognised as a clinical problem in such countries. Several animal species especially domestic swine, wild boar and wild deer were found to be reservoirs of hepatitis E virus genotype 3 & 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. Chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end stage liver disease was described in organ transplant patients and those with other immunodeficiency states from many European countries. Two recombinant hepatitis E virus vaccines have successfully undergone phase 3 trials.

Standardization of hepatitis E virus (HEV) nucleic acid amplification technique-based assays: an initial study to evaluate a panel of HEV strains and investigate laboratory performance

The performance of hepatitis E virus (HEV) RNA nucleic acid amplification (NAT)-based assays has been investigated using a panel of HEV-containing plasma samples. The panel comprised 22 HEV-positive plasma samples representing 10-fold serial dilutions of HEV genotypes 3a, 3b, 3f, and 4c obtained from blood donors. Two negative-control plasma samples were included. All samples were blinded. The plasma samples were prepared as liquid/frozen materials and distributed to participants on dry ice. Laboratories were requested to test the panel using their routine HEV assays and to score samples as either positive or negative and could optionally return data in copies/ml for HEV RNA. Twenty laboratories from 10 different countries participated in the study. Data were returned by all participating laboratories; 10 laboratories returned quantitative data. All assays except one were developed in-house using conventional or real-time reverse transcriptase PCR (RT-PCR) methodologies. There was a 100- to 1,000-fold difference in sensitivity between the majority of assays, independent of the virus strain. Although the quantitative data were limited, for the samples in the range of ∼6 to 4 log(10) copies/ml, the standard deviations of the geometric means of the samples ranged between 0.38 and 1.09. Except for one equivocal result, HEV RNA was not detected in the negative samples. The variability of assay sensitivity highlights the need for the standardization of HEV RNA NAT assays.

Plasma peptidome profiling of acute hepatitis E patients by MALDI-TOF/TOF

Background

Hepatitis E is endemic to resource-poor regions, where it manifests as sporadic cases and large waterborne outbreaks. The disease severity ranges from acute self-limited hepatitis with low mortality to fulminant hepatic failure with high mortality. It is believed that the host response plays an important role in determining the progression and outcome of this disease. We profiled the plasma peptidome from hepatitis E patients to discover suitable biomarkers and understand disease pathogenesis.

Results

The peptidome (< 10 kDa) fraction of plasma was enriched and analyzed by mass spectrometry. A comparative analysis of the peptide pattern of hepatitis E patients versus healthy controls was performed using ClinPro Tools. We generated a peptide profile that could be used for selective identification of hepatitis E cases. We have identified five potential biomarker peaks with m/z values of 9288.6, 7763.6, 4961.5, 1060.572 and 2365.139 that can be used to reliably differentiate between hepatitis E patients and controls with areas under the receiver operating characteristic curve (AUROC) values of 1.00, 0.954, 0.989, 0.960 and 0.829 respectively. A number of proteins involved in innate immunity were identified to be differentially present in the plasma of patients compared to healthy controls.

Conclusions

Besides the utility of this approach for biomarker discovery, identification of changes in endogenous peptides in hepatitis E patient plasma has increased our understanding of disease pathogenesis. We have identified peptides in plasma that can reliably distinguish hepatitis E patients from healthy controls. Results from this and an earlier proteomics study are discussed.

Adaptive immune responses during acute uncomplicated and fulminant hepatitis E

BACKGROUND AND AIM

Hepatitis E virus (HEV) infection is endemic in several developing countries. Clinical manifestations of this infection vary widely from asymptomatic infection to uncomplicated acute viral hepatitis and fulminant hepatic failure. The pathogenesis of this disease and the reason of varying disease severity remain unknown. In viral infections, tissue injury can be caused either by virus itself or by host immune responses directed against infected cells. We therefore studied adaptive immune responses to HEV antigens in patients with hepatitis E of varying disease severity and healthy controls.

METHODS

Cytokine secreting CD4+ T cells and antibody-producing B cells specific for HEV were enumerated through intracellular cytokine staining and enzyme-linked immunosorbent spot assay, respectively.

RESULTS

Patients with fulminant hepatitis E had a less marked expansion of HEV-specific interferon-γ or tumor necrosis factor-a secreting CD4+ T cells than patients with uncomplicated hepatitis E and healthy controls. These patients also had fewer CD4+ T cells that produce γ-interferon or tumor necrosis factor-a upon in vitro polyclonal stimulation. In addition, patients with fulminant disease had a more marked expansion of B cells that can secrete immunoglobulin G anti-HEV than patients with uncomplicated infection and control patients.

CONCLUSION

These findings suggest that less-marked antiviral cellular immune responses and heightened antiviral humoral responses are associated with a more severe disease during HEV infection.

Clinical characteristics of hepatitis E in a "Non-Endemic" population

Hepatitis E virus (HEV) is a ribonucleic acid (RNA) virus with predominant fecal oral spread. Traditionally in Western Europe it is associated with travel to endemic countries, but an increasing number of locally acquired cases have been reported throughout England. Patients presenting with acute non-travel associated HEV infection in south Wales over a 25-month period were monitored, in an attempt to understand the clinical picture and epidemiology in our patient population. Twenty-four patients were identified with non-travel associated HEV infection and studied prospectively. Patient demographics, symptoms, and serial laboratory results were recorded. There was a male/female ratio of 3:1, with a median patient age of 65.5 years old. Patients developed a significant icteric hepatitis (median peak bilirubin: 139 µmol/L, median peak AST: 1,973 IU/L and ALT: 2,021 IU/L), with liver function remaining abnormal for ∼7 weeks. All patients in whom HEV RNA was isolated were infected with genotype 3. Forty-six percent of patients presented during winter months. The data show a group mortality rate of 4.2%, similar to that reported in endemic countries. HEV results in a severe and occasionally fatal hepatitis. Testing for hepatitis E is now recommended in any patient presenting with acute hepatitis of unknown etiology.

Hepatitis E in Italy: a long-term prospective study

BACKGROUND & AIMS

In developed countries, hepatitis E is usually associated with travelling to endemic areas, but a growing number of sporadic cases are also seen in patients with no travel history. The aim of this study was to assess the impact and the molecular epidemiology of hepatitis E in Italy.

METHODS

Between January 1994 and October 2009, we analyzed 651 patients with acute non-A-C hepatitis. Diagnosis of hepatitis E was based on the presence of IgM anti-HEV and/or the detection of HEV RNA by RT-PCR. Viral isolates were sequenced and phylogenetically characterized.

RESULTS

A total of 134 out of 651 (20.6%) patients tested had acute hepatitis E. All were anti-HEV IgM and IgG positive and 96 (71.6%) were also positive for HEV RNA. Moreover, 39 (6%) patients were anti-HEV IgG positive but negative for both IgM anti-HEV and HEV RNA. A total of 109 (81.3%) patients developed hepatitis E travelling to endemic areas, 3 (2.3%) acquired intra-familial infection from relatives who developed travel-related disease, while 22 (16.4%) patients denied having travelled abroad. In all patients, acute disease had a self-limited course with ALT normalization within 3-6 weeks. Phylogenetic analysis of 39 isolates from patients with a travel-related disease showed that they belonged to genotype 1, while sequences from five patients with autochthonous hepatitis E belonged to genotype 3.

CONCLUSIONS

In Italy, most cases of hepatitis E are travel related, caused by viral genotype 1, while autochthonous cases are caused by genotype 3. The prevalence of genotype 3 among pigs and boars suggests that HEV infection may have zoonotic origins in non-endemic countries.

Hepatitis E: Historical, contemporary and future perspectives

Hepatitis E was suspected for the first time in 1980 during a waterborne epidemic of acute hepatitis in Kashmir, India. In the 30 years since then, a small virus with single-stranded RNA genome has been identified as the cause of this disease and named as hepatitis E virus (HEV). The virus has four genotypes; of these, genotypes 1 and 2 are known to infect only humans, whereas genotypes 3 and 4 primarily infect other mammals, particularly pigs, but occasionally cause human disease. In highly-endemic areas, the disease occurs in epidemic and sporadic forms, caused mainly by infection with genotype 1 or 2 virus, acquired through the fecal-oral route, usually through contaminated water supplies. The disease is characterized by particularly severe course and high mortality among pregnant women. In persons with pre-existing chronic liver disease, HEV superinfection can present as acute-on-chronic liver disease. In low-endemic regions, sporadic cases of locally-acquired HEV infection are reported; these are caused mainly by genotype 3 or 4 HEV acquired possibly through zoonotic transmission from pigs, wild boars or deer. In these areas, chronic infection with genotype 3 HEV, which may progress to liver cirrhosis, has been reported among immunosuppressed persons. Two subunit vaccines containing recombinant truncated capsid proteins of HEV have been shown to be highly effective in preventing the disease; however, these are not yet commercially available. These vaccines should be of particular use in groups that are at high risk of HEV infection and/or of poor outcome.

Hepatitis E in high-income countries

PURPOSE OF REVIEW

To discuss recent advances in characterising viral Hepatitis E (HEV) in nonendemic regions, with a special focus on epidemiology in high-income countries, different clinical aspects of the disease, possible zoonotic origin of these cases and the improvement of Hepatitis E diagnosis.

RECENT FINDINGS

In high-income countries, most cases of Hepatitis E are acquired locally and not imported from endemic regions. Different genotypes are involved in indigenous cases than those in endemic regions. Particular population groups, such as transplant recipients, can be persistently infected by hepatitis E and develop chronic diseases. Viral hepatitis E is frequently observed in people in animal care occupations. Indeed, HEV has a large animal reservoir and this emerging disease in developed countries has probably a zoonotic origin.

SUMMARY

Recent studies on viral Hepatitis E have shown that the epidemiology of the disease differs between endemic and nonendemic regions. Several lines of evidence suggest that Hepatitis E is more frequent than was suspected and that it has a possible animal origin. Particular attention must be paid to the possible chronic evolution of various forms of the disease. Surveillance of human cases and animal reservoirs must be developed further.

[Hepatitis E virus: A new entity]

Hepatitis E virus (HEV) is a RNA enterically transmitted virus that causes large waterborne epidemics of acute hepatitis E in endemic regions (Asia and Africa). Sporadic hepatitis E is an emerging disease in developed countries such as France. The majority of acute hepatitis E in France is indigenous (non travel-associated) and is due to infection with HEV genotype 3. Diagnosis is made on the presence of specific serum antibodies and on viral RNA detection in serum or stools. Characteristic pathological signs of acute hepatitis E are severe intralobular necrosis, polymorph inflammation and acute cholangitis in portal tract with numerous neutrophils. Severe forms of hepatitis are associated with underlying chronic liver disease such alcoholic disease. In immunocompetent patients, HEV causes acute resolutive hepatitis and there is no chronic evolution. Conversely, chronic hepatitis E is frequent in immunocompromised patients with a risk of rapid evolution to cirrhosis. Histologic lesions of chronic hepatitis E are similar to those observed in patients chronically infected with hepatitis C virus with dense lymphocytic portal infiltrate, constant peacemeal necrosis and fibrosis.

Unexpected elevated alanine aminotransferase, aspartate aminotransferase levels and hepatitis E virus infection among persons who work with pigs in accra, Ghana

BACKGROUND

Several studies have suggested that elevated serum alanine aminotransferase (ALT) and asparte aminotransferase (AST) may be markers of hepatitis E virus (HEV) infection. Thus, individuals with elevated ALT and AST may have ongoing subclinical infection of HEV. We estimated the prevalence of anti-HEV antibodies and serum ALT and AST levels among persons who work with pigs in Accra, Ghana.

RESULTS

Three hundred and fifty- persons who work with pigs provided blood samples for unlinked anonymous testing for the presence of antibodies to HEV, ALT and AST levels. The median age of participants was 32.85±11.38 years (range 15-70 years). HEV seroprevelance was 34.84%. Anti-HEV IgG was detected in 19.26% while anti-HEV IgM was detected in 15.58% of the persons who tested positive. On multivariate analysis, the independent determinants of HEV infection were, being employed on the farm for less than six months [odds ratio (OR) 8.96; 95% confidence interval (95% CI) 5.43-14.80], having piped water in the household and/or on the farm (OR 13.33; 95% CI 5.23-33.93) and consumption of alcohol (OR 4.91: 95% CI 2.65-9.10). Levels>3× the expected maximum were found for both ALT and AST among individuals who tested positive for anti-HEV IgG (ALT, 210.17±11.64 U/L; AST, 127.18±11.12 U/L) and anti-HEV IgM (ALT, 200.97±10.76 U/L; AST, 120.00±15.96 U/L).

CONCLUSION

Consistent with similar studies worldwide, the results of our studies revealed a high prevalence of HEV infection, ALT and AST values in pig handlers.

Ribavirin therapy inhibits viral replication on patients with chronic hepatitis e virus infection

BACKGROUND & AIMS

Hepatitis E virus (HEV) infection can evolve to chronic hepatitis in immunocompromised patients. Pegylated α-interferon can effectively treat chronic HEV infection after liver transplantation but is contraindicated for kidney transplantation. We assessed the antiviral effect of ribavirin monotherapy in patients with chronic HEV infection following kidney transplantation.

METHODS

In a pilot study performed at Toulouse University Hospital, 6 patients that received kidney transplants who were positive for HEV RNA (infected with HEV for 36.5 months; [range, 11-46 months]) were given ribavirin monotherapy for 3 months. Ribavirin was given at 600-800 mg/day in 2 separate doses, based on the patient's ability to clear creatinine.

RESULTS

Median serum concentration of HEV RNA at baseline was 5.77 log copies/mL (range, 4.35-7.35 log copies/mL). Three months after ribavirin therapy commenced, HEV RNA was undetectable in serum samples from all patients. A sustained virologic response was observed in 4 patients; the other 2 patients relapsed at 1 and 2 months after ribavirin therapy ended. At the end of the study, all patients had normal levels of alanine and aspartate aminotransferase. Anemia was the main side effect caused by ribavirin therapy.

CONCLUSIONS

Ribavirin monotherapy inhibits the replication of HEV in vivo and might induce a sustained virological response in patients with chronic HEV infections. Further studies are required to determine the optimal duration of ribavirin therapy.

Is there evidence of recent hepatitis E virus infection in English and North Welsh blood donors?

BACKGROUND AND OBJECTIVE

The risk of hepatitis E virus (HEV) to blood safety remains unknown in England. Reports of persistent HEV infection with serious disease sequelae indicate that transfusion transmitted HEV is not a trivial disease in immunosuppressed patients.

MATERIALS AND METHODS

Samples from unselected blood donors and donors with a history of jaundice were tested for HEV antibody and RNA.

RESULTS

Overall, 10% of the donor sera were anti-HEV IgG reactive. Four of the donor samples were anti-HEV IgM reactive but HEV RNA negative.

CONCLUSION

There is evidence of probable recent HEV infections in donors with a predicted attack rate of 2.8%.

A single amino acid substitution changes antigenicity of ORF2-encoded proteins of hepatitis E virus

Extensive genomic diversity has been observed among hepatitis E virus (HEV) strains. However, the implication of the genetic heterogeneity on HEV antigenic properties is uncertain. In this study, monoclonal antibodies (Mabs) against truncated ORF2-encoded proteins (aa452-617, designated p166 proteins) derived from HEV strains of Burma (genotype 1a, p166Bur), Pakistan (1b, p166Pak) and Morocco (1c, p166Mor) were raised and used for identification of HEV antigenic diversity. Six Mabs reacted to these 3 p166 proteins as well as p166 proteins constructed from strains derived from Mexico (genotype 2), US (genotype 3) and China (genotype 4), indicating the existence of pan-genotypic epitopes. Two Mabs, 1B5 and 6C7, reacted with p166Bur and p166Mor, but not p166Pak or p166s derived from genotypes 2, 3, and 4, indicating that these 2 Mabs recognized strain-specific HEV epitopes. Both the common and specific epitopes could not be mapped by 23 synthetic peptides spanning the p166Bur sequence, suggesting that they are confirmation-dependent. Comparative sequence analysis showed that p166Bur and p166Mor shared an identical aa sequence along their entire lengths, whereas for p166Pak the aas occupying positions 606 and 614 are different from aas at corresponding positions of p166Bur and p166Mor. Reactivity between 1B5 and p166Bur was abrogated with mutation of p166Bur/A606V, whereas p166Pak acquired the reactivity to 1B5 with mutation of p166Pak/V606A. However, mutations of p166Bur/L614M and P166Pak/M614L did not affect the immunoreactivity. Therefore, the aa occupying position 606 plays a critical role in maintaining the antigenicity of the HEV p166 proteins.

Hepatitis E virus excretion can be prolonged in patients with hematological malignancies

BACKGROUND

Hepatitis E virus (HEV) is transmitted via the fecal-oral route and locally acquired sporadic hepatitis E can occur in Western countries. Chronic hepatitis E virus infections have been recently described in solid organ transplant recipients. There is little data on the evolution of hepatitis E in patients immunocompromised for other reasons.

OBJECTIVES

The aim of this study was to evaluate the clinical course of hepatitis E in patients immunocompromised because of hematological malignancies.

STUDY DESIGN

Starting on November 2003, all patients in the Toulouse University Hospital Hematology Department with unexplained elevated transaminases were tested for hepatitis E using viral RNA detection in serum or stools and serology.

RESULTS

Acute hepatitis E was diagnosed in six middle-aged hematology patients. All cases were autochthonous. HEV strains were genotype 3. All patients had a significant increase of transaminases (6-95 upper limit normal) and only two had HEV IgG. Five patients were asymptomatic and one had jaundice. Transmission of HEV occurred between two patients who had overlapping stays in the hematology ward. All five evaluable patients ultimately cleared their HEV but viremia was prolonged over 6 months in three patients and specific treatment had to be postponed in two patients.

CONCLUSION

Screening for HEV should be carried out routinely in hematology patients with elevated transaminases, and patient-to-patient transmission is a concern. Further studies are required to determine whether management of malignancy, particularly stem-cell transplantation should be adapted to HEV status.

Acute liver failure

Acute liver failure is a rare disorder with high mortality and resource cost. In the developing world, viral causes predominate, with hepatitis E infection recognised as a common cause in many countries. In the USA and much of western Europe, the incidence of virally induced disease has declined substantially in the past few years, with most cases now arising from drug-induced liver injury, often from paracetamol. However, a large proportion of cases are of unknown origin. Acute liver failure can be associated with rapidly progressive multiorgan failure and devastating complications; however, outcomes have been improved by use of emergency liver transplantation. An evidence base for practice is emerging for supportive care, and a better understanding of the pathophysiology of the disorder, especially in relation to hepatic encephalopathy, will probably soon lead to further improvements in survival rates.

Hepatitis E virus in HIV-infected patients

OBJECTIVES

Many cases of acute autochthonous hepatitic E virus (HEV) hepatitis have been reported in France, mainly from the south. Chronic HEV infection has recently been described in immunosuppressed patients. Although a potential risk of chronicity exists in HIV-infected patients, no survey has been conducted in this population. The aim of this study was to assess the sero-virological prevalence of HEV in French HIV-infected patients.

METHODS

Two hundred and forty-five HIV-infected patients followed at two Infectious Diseases Departments (one in the south, one in the north) were included from January to March 2009. Sera were collected from all patients and tested using anti-HEV IgG and IgM kits. HEV RNA was systematically amplified in the ORF2 region with an in-house method. The IgG avidity index of all IgG-positive samples was determined.

RESULTS

Three of the 133 southern patients showed both anti-HEV IgG and IgM positivities, along with cytolysis and biological cholestasis; HEV RNA was amplified in two of these cases, whereas a low IgG avidity index was observed in all three samples. Twelve of the 130 remaining southern patients (9%) showed anti-HEV IgG positivity. The serological prevalence in the 112 northern patients was 3%, which was significantly lower than in the southern patients (P=0.04). No case of acute hepatitis was reported in the north, whereas the prevalence of patients with biochemical liver abnormalities was similar in both areas (P=0.22).

CONCLUSIONS

In France, HIV-infected patients are at risk of HEV infection with a serological north-to-south gradient. No case of chronic HEV infection was detected in this study.

Hepatitis E virus-induced neurological symptoms in a kidney-transplant patient with chronic hepatitis

It has been shown that hepatitis E virus (HEV) may be responsible for chronic hepatitis in solid-organ transplant patients. It has also been suggested that HEV may be responsible for atypical neurological symptoms during the acute phase. However, the relationship between the neurological symptoms and HEV infection was based on the detection of anti-HEV IgM in the sera. Herein, we report a case where neurological symptoms, that is peripheral nerve involvement with proximal muscular weakness that affected the four limbs joints with central nervous-system involvement and bilateral pyramidal syndrome, occurred in a kidney-transplant patient who was chronically infected by HEV. For the first time, HEV RNA was detected in the serum and cerebrospinal fluid. In addition, clonal HEV sequences were analyzed in both compartments, that is serum and cerebrospinal fluid. The discovery of quasispecies compartmentalization and its temporal association suggests that neurological symptoms could be linked to the emergence of neurotropic variants.

Can human viruses infect porcine xenografts?

Xenotransplantation exposes the recipient to known and unknown pathogens of the donor pig (donor-derived xenosis). A major effort has been undertaken to minimize the risk of transmission from the donor using specialized breeding techniques. With the exception of endogenous retroviruses and porcine lymphotropic herpesvirus, exclusion of known pathogens was successful and has eliminated a majority of donor pathogens. In the recipient, enhanced replication of many pathogens will be stimulated by the immune responses induced by transplantation and by the immune suppression used to prevent graft rejection. Infection of the graft may occur with unpredictable consequences due to the cross-species situation. Infectivity may be decreased as entry or replication is altered by missing receptors or inability to use the cellular machinery. Replication of organisms in the xenograft and the inability of the human host to respond to human pathogens in the context of a xenograft infection due to immune suppression, or the presentation of such pathogens in the context of pig instead of human major histocompatibility complex (MHC) could impair control of such infections. Recent data suggest that some human herpesviruses infections, such as human cytomegalovirus, may infect porcine tissue and are associated with a pro-inflammatory phenotype. This review focuses on human or recipient-derived pathogens and their potential harmful role in xenograft infection.

Zoonotic hepatitis E: animal reservoirs and emerging risks

Hepatitis E virus (HEV) is responsible for enterically-transmitted acute hepatitis in humans with two distinct epidemiological patterns. In endemic regions, large waterborne epidemics with thousands of people affected have been observed, and, in contrast, in non-endemic regions, sporadic cases have been described. Although contaminated water has been well documented as the source of infection in endemic regions, the modes of transmission in non-endemic regions are much less known. HEV is a single-strand, positive-sense RNA virus which is classified in the Hepeviridae family with at least four known main genotypes (1–4) of mammalian HEV and one avian HEV. HEV is unique among the known hepatitis viruses, in which it has an animal reservoir. In contrast to humans, swine and other mammalian animal species infected by HEV generally remain asymptomatic, whereas chickens infected by avian HEV may develop a disease known as Hepatitis-Splenomegaly syndrome. HEV genotypes 1 and 2 are found exclusively in humans while genotypes 3 and 4 are found both in humans and other mammals. Several lines of evidence indicate that, in some cases involving HEV genotypes 3 and 4, animal to human transmissions occur. Furthermore, individuals with direct contact with animals are at higher risk of HEV infection. Cross-species infections with HEV genotypes 3 and 4 have been demonstrated experimentally. However, not all sources of human infections have been identified thus far and in many cases, the origin of HEV infection in humans remains unknown.

[Rare acute hepatitis in a female patient with hemochromatosis: a zoonosis?]

A 58-year-old female patient was transferred by her general practitioner with fatigue, nausea and icterus which had begun 2 weeks prior to admission. Laboratory results revealed acute hepatitis (ALAT [alanine aminotransferase] 3,871 U/l, ASAT [aspartate aminotransferase] 2,004 U/l, bilirubin 6.7 mg/dl, gamma-GT [gamma-glutamyl transferase] 503 U/l). The patient's medical history included genetic hemochromatosis (without cirrhosis). Hepatitis A to C, infection with herpesviruses or Leptospira interrogans were excluded by serologic and molecular biological tests. There was no diagnostic evidence for underlying autoimmune or additional metabolic liver disease. Due to a trip to Africa 5 months earlier, the patient was tested for hepatitis E, leading to positive anti-hepatitis E-IgM and negative anti-hepatitis E-IgG. PCR (polymerase chain reaction) detection of hepatitis E virus (HEV) was positive as well. In conclusion, acute HEV infection was diagnosed. After close reconsideration, the nonfitting incubation period precluded a travel-associated infection. Additionally, there was no evidence for current HEV infections within the patient's social environment, so that a zoonotic origin has to be discussed.

Advances in immunology of hepatitis E virus infection

Hepatitis E virus (HEV) is the cause of human hepatitis E. Hepatitis E is endemic in many developing countries, including China, and represents a major public health problem. In this article, we will review the current knowledge on humoral and cellular immune responses and mechanisms of immunologic injury in HEV infection as well as the development of HEV vaccines.

Hepatitis E virus: a zoonosis adapting to humans

Hepatitis E virus (HEV) infection is gaining global attention, not only because of the increasing burden of the disease in low endemicity countries, in terms of morbidity and mortality rates, but also due to recent advances in the molecular virology and epidemiology of this emerging pathogen. HEV infection spread can be described as the evolution of a zoonosis towards an established human infection. As known from other viruses, such as the human immunodeficiency virus or the influenza viruses, crossing the species barriers from animals to humans is a recurrent phenomenon. Albeit slow at the beginning, once the virus has adapted to humans, the person-to-person spread can proceed very quickly. Although an optimal cell culture system for HEV is not yet available, outstanding progress has been made with the in vitro expression of HEV-like particles. These new tools have fostered new research to understand the molecular, structural and immunological aspects of human HEV infection. Although some promising data from Phase II vaccine trials are available, recent discoveries will certainly open new avenues for HEV-specific prophylaxis and therapy.

Influence of immunosuppressive therapy on the natural history of genotype 3 hepatitis-E virus infection after organ transplantation

BACKGROUND

Hepatitis-E virus (HEV) infection can be responsible for chronic hepatitis in solid-organ transplant patients.

METHODS

We identified 33 cases of autochthonous acute HEV infection in solid-organ transplant patients.

RESULTS

Among 27 HEV-positive patients, who had a follow-up of more than 6 months, 16 (59.25%) evolved to chronic HEV infection, defined by persisting elevated liver-enzyme levels and positive serum HEV RNA 6 months after diagnosis. Serial liver biopsies showed progression in liver activity and liver fibrosis. Three patients developed liver cirrhosis. The proportion of patients receiving tacrolimus compared with cyclosporine A was significantly higher in patients who evolved to chronic disease. Immunosuppressive therapy was reduced in patients with chronic hepatitis; however, those who had a dramatic decrease in tacrolimus trough levels were more likely to clear the virus. Four chronic liver transplant patients were cleared off the virus at 14, 16, 22, and 23 months after diagnosis. At last follow-up, their tacrolimus trough levels and daily steroid doses were significantly lower than those who remained viremic. These four patients had lower liver-enzyme levels and lower activity scores on liver biopsies, and their peripheral blood CD3- and CD4-positive cell counts were also significantly higher.

CONCLUSIONS

The rate of chronic HEV-related hepatitis is approximately 60% in solid-organ transplant patients. When possible, the reduction of immunosuppressive drugs targeting T cells should be considered as a first-line therapeutic option.

Recent advances in Hepatitis E virus

Hepatitis E virus (HEV), the causative agent of hepatitis E, belongs to the family Hepeviridae. At least four major genotypes of HEV have been recognized: genotypes 1 and 2 are restricted to humans and associated with epidemics in developing countries, whereas genotypes 3 and 4 are zoonotic and infect humans and several other animals in both developing and industrialized countries. Besides humans, strains of HEV have been genetically identified from swine, chickens, sika deer, mongeese, and rabbits. The genome of HEV consists of three open reading frames (ORFs): ORF1 codes for nonstructural proteins, ORF2 codes for capsid protein, and ORF3 codes for a small multifunctional protein. The ORF2 and ORF3 proteins are translated from a single bicistronic mRNA and overlap each other but neither overlaps ORF1. The recent determination of the 3D crystal structure of the HEV capsid protein should facilitate the development of vaccines and antivirals. The identification and characterization of animal strains of HEV from pigs and chickens and the demonstrated ability of cross-species infection by swine HEV raise public health concerns for zoonosis. Accumulating evidence indicated that hepatitis E is a zoonotic disease and pigs and more likely other animal species are reservoirs for HEV. This article provides an overview of the recent advances in hepatitis E and its causative agent, including nomenclature and genomic organization, gene expression and functions, 3D structure of the virions, changing perspectives on higher mortality during pregnancy and chronic hepatitis E, animal reservoirs, zoonotic risk, food safety, and novel animal models.

Hepatitis E virus infection as a cause of graft hepatitis in liver transplant recipients

Hepatitis E virus (HEV) infection induces self-limiting liver disease in immunocompetent individuals. Cases of chronic hepatitis E have recently been identified in organ transplant recipients. We questioned if chronic hepatitis E plays a role in graft hepatitis after liver transplantation in a low endemic area. Two hundred twenty-six liver transplant recipients, 129 nontransplanted patients with chronic liver disease, and 108 healthy controls were tested for HEV antibodies. HEV RNA was investigated in all sera from transplanted patients. HEV antibodies were detected in 1 healthy control (1%), 4 patients with chronic liver disease (3%), and 10 liver transplant recipients (4%). Three liver transplant patients also tested positive for HEV RNA. Two of them developed persistent viremia with HEV genotype 3. The patients were anti-HEV immunoglobulin G-negative and HEV RNA-negative before transplantation and had an episode of acute hepatitis 5 or 7 months after transplantation, which led to advanced liver fibrosis after 22 months in 1 patient. Seroconversion to anti-HEV occurred not before 4 months after the first detection of HEV RNA. The possibility of reverse zoonotic transmission was experimentally confirmed by the infection of 5 pigs with a patient's serum. The pigs showed histological inflammation in the liver, and HEV RNA was detectable in different organs, including muscle. In conclusion, the prevalence of HEV infection in Central European liver transplant recipients is low; however, chronic hepatitis E may occur and needs to be considered in the differential diagnosis of graft hepatitis. The diagnosis of HEV infection should be based on HEV RNA determination in immunosuppressed patients. We suggest that immunocompromised individuals should avoid eating uncooked meat and contact with possibly HEV-infected animals.

Fulminant hepatitis E in a woman taking oral contraceptive medication

We describe a fulminant autochthonous hepatic failure caused by hepatitis E (HEV) in a patient admitted in our hospital for liver-transplant evaluation. The only risk factor recorded for this severe course was the use of oral contraceptives that are known to mimic a hormonal status similar to pregnancy. The diagnosis was based on the presence of IgG and IgM anti-HEV in the serum of the patient and confirmed by the isolation of a strain of HEV genotype 3f from a blood sample obtained the fourth day after hospital admission. HEV genotype 3 is present in human and swine populations in Spain. The patient began to recover while waiting for a liver transplant. To our knowledge, this is the first report of fulminant hepatitis E in a non-pregnant European patient on oral contraceptives.

Hepatitis E virus infection in central China reveals no evidence of cross-species transmission between human and swine in this area

Hepatitis E virus (HEV) is a zoonotic pathogen of which several species of animal were reported as reservoirs. Swine stands out as the major reservoir for HEV infection in humans, as suggested by the close genetic relationship of swine and human virus. Since 2000, Genotype 4 HEV has become the dominant cause of hepatitis E disease in China. Recent reports showed that genotype 4 HEV is freely transmitted between humans and swine in eastern and southern China. However, the infection status of HEV in human and swine populations in central China is still unclear. This study was conducted in a rural area of central China, where there are many commercial swine farms. A total of 1476 serum and 554 fecal specimens were collected from the general human and swine populations in this area, respectively. The seroepidemiological study was conducted by enzyme-linked immunosorbent assay. Conserved genomic sequences of open reading frame 2 were detected using reverse transcription-PCR. The results indicated that the overall viral burden of the general human subjects was 0.95% (14/1476), while 7.0% (39/554) of the swine excreted HEV in stool. The positive rate of anti-HEV IgG and IgM in the serum samples was 7.9% (117/1476) and 1.6% (24/1476), respectively. Phylogenetic analysis based on the 150 nt partial sequence of the capsid protein gene showed that the 53 swine and human HEV isolates in the current study all belonged to genotype 4, clustering into three major groups. However, the HEV isolates prevalent in the human and swine populations were classified into known distinct subgenotypes, which suggested that no cross-species transmission between swine and humans had taken place in this area. This result was confirmed by cloning and phylogenetic analysis of the complete capsid protein gene sequence of three representative HEV strains in the three major groups. The cross reactivity between anti-HEV IgG from human sera and the two representative strains from swine in central China was confirmed by Dot-blot assay. In conclusion, although all the HEV strains prevalent in central China belonged to genotype 4, there is no evidence of cross-species transmission between human and swine in this area.

Lack of hepatitis E virus infection in HIV patients with advanced immunodeficiency or idiopathic liver enzyme elevations

Hepatitis E virus (HEV) is an enterically transmissible RNA agent that causes self-limited acute hepatitis. Recent reports have highlighted that organ-transplant recipients may develop chronic hepatitis E and progress to cirrhosis. Similar cases could occur in HIV patients. We have investigated 50 HIV-infected individuals with CD4 counts <200 cells/mm(3) and 43 with cryptogenic hepatitis. None of them showed HEV viremia. Thus, HEV infection does not seem to be prevalent in the HIV population and accordingly universal HEV vaccination is not warranted in these patients.

Acute hepatitis E infection associated with a false-positive serology against Epstein-Barr virus

Hepatitis E virus is a major cause of acute viral hepatitis. The diagnosis of acute viral hepatitis E is based essentially on antibodies and hepatitis E virus RNA. We describe herein a case of acute hepatitis E associated with a false-positive serology for Epstein-Barr virus (EBV). This case report suggests that anti-viral capsid antigen IgM must be interpreted with caution in acute E hepatitis. When positive, EBV RNA polymerase chain reaction can be useful as a false positivity of anti-viral capsid antigen IgM and can be misinterpreted as an acute infection. EBV false positivity was probably related to polyclonal stimulation of the immune system, favoured by hepatitis E.

Sporadic cases of acute autochthonous hepatitis E virus infection in Southwest Germany

Hepatitis E infection is usually a self-limiting disease and an important cause of acute hepatitis in tropical and subtropical regions where the virus is endemic. In industrialized countries, sporadic cases of acute hepatitis E virus (HEV) infections have been described and the number of documented autochthonous infections seems to be increasing. We report three sporadic cases of autochthonous hepatitis E infections in Southwestern Germany which presented at our university hospital within two years. All cases were men who presented with acute hepatitis, icterus and elevated liver. In case 1 and case 2, liver biopsy revealed acute hepatitis, both patients were positive for anti-HEV antibodies, case 1 was also positive for HEV RNA with a viral load of 3.0 x 10(3)copies/ml in serum. In case 3, anti-HEV antibodies were detectable and HEV RNA was detected in serum (4.3 x 10(3)copies/ml) and stool (1.4 x 10(6)copies/ml). None of the patients had a recent travel history outside Germany and close contact to animals has been denied. HEV sequence analysis of two patients revealed genotype 3 with homologies to other European isolates and isolates from swine. Thus the source of infection remains unclear. Hepatitis E should be considered in differential diagnosis in patients with unexplained hepatitis and patients with acute hepatitis, whatever their age or travel history might be, should be tested for HEV.

Imported and autochthonous hepatitis E virus strains in Spain

Hepatitis E virus (HEV) causes hepatitis E, an acute liver disease displaying diverse epidemiological patterns that correlate with the genetic diversity of the virus. Only a few strains have been characterized to date from cases of hepatitis E in Spain. Using three sets of new, HEV-specific primers, viral genome fragments were amplified from serum samples from 13 patients with acute hepatitis in different regions of Spain. Direct sequencing of these fragments and analysis of sequences lead to identify six genotype 1, six genotype 3, and one genotype 4 viral strains. Genotype 1 sequences were found in the clade with subtype 1a strains, and were amplified from travelers from India and Bangladesh, and from an African immigrant. Genotype 3 sequences were found in the clade with subtype 3f strains, were always amplified from patients who did not travel abroad recently, and were closely related to sequences from swine strains isolated in Spain. Patients infected by these strains lived in different regions and were mainly men aged above 50 years. The single genotype 4 sequence detected was amplified from a traveler returning from Vietnam. Hepatitis E is both an imported and an autochthonous disease in Spain, and closely related HEV genotype 3f strains are responsible for infections acquired locally in different regions of the country within a given time. Studies involving a significant number of human, swine, and environmental viral strains collected prospectively are, however, required in order to confirm a swine origin for autochthonous HEV genotype 3 human infections.

Frequent transmission of hepatitis E virus among piglets in farms in Southern France

The present study aimed to assess whether hepatitis E virus (HEV) is present in domestic pigs in Southern France, and to determine the relationship between HEV sequences detected from pigs and from humans. Two hundred fifteen sera, 207 stools, and 107 bile samples were collected from 3- or 6-month-old pigs from different regions of Southern France. Pig IgG anti-HEV antibodies testing was performed using a commercial ELISA kit with minor modifications. Pig HEV RNA was tested by real-time PCR and sequencing assays using "in-house" protocols. Forty percent of pigs were HEV-seropositive. Sixty-five percent of 3-month-old pigs and none of 6-month-old pigs were HEV RNA-positive. HEV RNA was significantly more frequently detected from stools than from sera (65% vs. 22%; P < 0.001). Phylogenetic analysis showed that pig HEV sequences belonged to genotype 3 and formed two clusters of genotype 3f and 3e. Nucleotide homology between pig HEV sequences of each cluster was high (>97%), and clusters were correlated with the geographical origin of pigs and with their repartition into pens and buildings in the pig farm. Based on analysis of 331 nucleotides, pig HEV sequences were close genetically to HEV sequences found from humans or pigs in Europe, and one showed complete nucleotide identity with an HEV sequence obtained in France from a human. The present data indicate that 3-month-old pigs from Southern France might represent a potential source of HEV transmission to humans, and stress the potential of HEV to cause epizootic infections in population of farm pigs.

Transmission routes and risk factors for autochthonous hepatitis E virus infection in Europe: a systematic review

Increasing numbers of non-travel-associated hepatitis E virus (HEV) infections have been reported in Europe in recent years. Our objective was to review the evidence on risk factors and transmission routes of autochthonous HEV infection and hepatitis E in Europe in order to develop recommendations for future research, prevention and control. A systematic literature review was performed to identify all primary reports and studies published during 1998-2008 on hepatitis E in humans and animals in Europe by searching Pubmed, reference lists of major articles and international conference proceedings. Each of the 106 included studies was categorized into one of three evidence levels (EL) based on study design and diagnostic methodology. The evidence was generally weak (73 were assigned to EL1, two to both EL1 and EL2, and 30 to EL2), further compounded by the use of poorly validated serological assays in some studies. Only one case-control study was assigned to EL3. Persons with autochthonous hepatitis E infection were on average older than the general population and predominantly male. There was no evidence for one main transmission route of HEV infection or risk factor for hepatitis E. However, zoonotic transmission seemed likely and person-to-person transmission too inefficient to cause clinical disease. Multiple routes of transmission probably exist and should be further investigated through analytical studies and reliable diagnostic kits. Based on current evidence that points to zoonotic transmission from pigs, thorough cooking of all porcine products, prevention of cross-contamination in the kitchen and improved education for occupationally exposed people (e.g. pig farmers, veterinarians and sewage workers) may help prevent HEV infection. Although evidence for parenteral transmission is limited, it is recommended that a risk assessment is undertaken.

Prevalence of hepatitis E virus infection in liver transplant recipients

Hepatitis E virus (HEV) infection is known to run a self-limited course. Recently, chronic hepatitis E has been described in several immunosuppressed patients after solid organ transplantation. The prevalence of HEV infection after transplantation, however, is unknown. We studied HEV parameters [HEV RNA, HEV immunoglobulin M (IgM), and HEV immunoglobulin G (IgG) by enzyme-linked immunosorbent assay and confirmatory immunoblotting] in a cohort of 285 adult liver transplant recipients. The most recent freeze-stored sera were investigated, and if they were positive, a retrospective analysis was performed. Samples from 274 patients (96.1%) tested negative for all HEV parameters. This included a patient described earlier as having experienced an episode of chronic HEV hepatitis in the past. One patient was found positive for HEV RNA without HEV antibodies. She presently suffers from chronic HEV hepatitis and has also been described before. Sera from 9 patients tested positive for HEV IgG without HEV IgM or HEV RNA. Six of these 9 patients (2.1% of the total) were found to have HEV IgG antibodies in retrospect related to an HEV infection at some time pre-transplant as they also tested positive in a pretransplant serum sample. One of these 9 patients suffered in retrospect from a chronic HEV infection with mild hepatitis between 2 and 5 years after liver transplantation on the basis of the course of HEV RNA, IgM, and IgG, aminotransferases, and liver histology. Overall, the prevalence of acquired HEV hepatitis after liver transplantation was 1% in this cohort. We conclude that liver transplant recipients have a risk for chronic HEV infection, but the prevalence is low.

Detection of hepatitis E virus of genotype 3 in a farm pig in Kinshasa (Democratic Republic of the Congo)

Autochthonous hepatitis E is an emerging disease in industrialized countries where a growing body of data indicates that pigs represent a reservoir for hepatitis E virus (HEV) of genotype 3 or 4. In Africa, only HEV genotypes 1 and 2 have been identified in hepatitis E outbreaks as well as in sporadic cases. We aimed to investigate whether commercial pigs in sub-Saharan Africa might represent an HEV reservoir using molecular assays. Faecal samples from 40 pigs of the Pietrain race housed in a farm in Kinshasa (Democratic Republic of the Congo) were tested using in-house real-time reverse transcription (RT)-PCR and sequencing assays. HEV RNA was detected in faeces of one (2.5%) pig, and the HEV sequence obtained from this pig was classified genotype 3c, and was genetically related to human HEV sequences from France (89-92% nucleotide similarity) and pig HEV sequences from The Netherlands (88-91% nucleotide similarity). Epidemiological investigations revealed that Kinshasa farm pigs tested in the present study are descendants of pigs imported from Belgium in 2002, suggesting that pig HEV genotype 3c recovered in our study may have been imported from Belgium to Democratic Republic of the Congo. Our findings, although needing to be confirmed in further studies, also suggest that pigs in sub-Saharan Africa may be an HEV reservoir.