Autochthonous hepatitis E in southwest England

Hepatitis E virus infection in the United States: Seroprevalence, risk factors and the influence of immunological assays

In the United States (U.S.), a hepatitis E virus (HEV) seroprevalence between 6 and 21% has been described, with a decreasing trend. We aimed to investigate HEV infection in the U.S. population from 2009 to 2016, and examine the differences in seroprevalence using different assays. We used data from the National Health and Nutrition Examination Survey (NHANES-CDC) to estimate HEV seroprevalence and analyze demographic variables related to the infection. Additionally, we compared 4 serological tests used. The estimated HEV seroprevalence between 2009–2016 was 6.1% (95% CI: 5.6%-7.0%) for IgG and 1.02% (0.8%-1.2%) for IgM. Higher HEV IgG prevalences were found in older people, females, non-Hispanic Asians and those born outside of the U.S. The in-house immunoassay and the Wantai HEV-IgG ELISA presented the highest sensitivity values in the tested population. The highest specificity values corresponded to the DSI-EIA-ANTI-HEV-IgG assay. The kappa statistical values showed concordances no greater than 0.64 between the assays. HEV prevalence in our study was similar to previously reported, and a decline in the prevalence was observed through the NHANES assessments (from 1988 to 2016). The sensitivity and specificity of the assays varied widely, making comparisons difficult and highlighting the need to develop a gold standard assay.

Assessment of subclinical effects of Hepatitis E virus infection in the United States

Some studies have exposed an increase in liver cirrhosis in hepatitis E seropositive individuals living with human immunodeficiency virus. The interrelation between HEV seroprevalence and risk of liver disease in immune-competent individuals remains under- investigated. Using the National Health and Nutrition Examination Survey (NHANES) data containing >30,000 subjects, we addressed if HEV exposure leads to subclinical effects that can influence liver health. We determined the association between HEV IgM and ALT and that of HEV IgG and Fib-4-a composite score reflecting potential liver fibrosis. These analyses were repeated in populations at risk for liver disease as well as among different races and ethnicities. The prevalence of HEV IgG was significantly associated with age as IgG positive individuals were, on average, 20 years older than IgG negative patients. We found a statistically significant increase in the likelihood of having a Fib-4 score >1.45 (significant fibrosis) in those positive for HEV IgG (RR: 1.03; 95% CI: 1.01-1.05). However, due to the small effect, it is unlikely that this association has clinical significance. Moreover, the effect was not present in those with pre-existing liver disease. We found no association between ALT levels and the presence of HEV IgM or IgG. This is the first study examining subclinical effects of HEV infection in the United States. Our study found that in the general US population, predominantly asymptomatic HEV infections do not contribute to the overall burden of liver disease.

The Foodborne Transmission of Hepatitis E Virus to Humans

Globally, Hepatitis E virus (HEV) causes over 20 million cases worldwide. HEV is an emerging and endemic pathogen within economically developed countries, chiefly resulting from infections with genotype 3 (G3) HEV. G3 HEV is known to be a zoonotic pathogen, with a broad host range. The primary source of HEV within more economically developed countries is considered to be pigs, and consumption of pork products is a significant risk factor and known transmission route for the virus to humans. However, other foods have also been implicated in the transmission of HEV to humans. This review consolidates the information available regarding transmission of HEV and looks to identify gaps where further research is required to better understand how HEV is transmitted to humans through food.

Effector memory CD8 T cell response elicits Hepatitis E Virus genotype 3 pathogenesis in the elderly

Genotype 3 Hepatitis E virus (HEV-3) is an emerging threat for aging population. More than one third of older infected patients develops clinical symptoms with severe liver damage, while others remain asymptomatic. The origin of this discrepancy is still elusive although HEV-3 pathogenesis appears to be immune-mediated. Therefore, we investigated the role of CD8 T cells in the outcome of the infection in immunocompetent elderly subjects. We enrolled twenty two HEV-3-infected patients displaying similar viral determinants and fifteen healthy donors. Among the infected group, sixteen patients experienced clinical symptoms related to liver disease while six remained asymptomatic. Here we report that symptomatic infection is characterized by an expansion of highly activated effector memory CD8 T (EM) cells, regardless of antigen specificity. This robust activation is associated with key features of early T cell exhaustion including a loss in polyfunctional type-1 cytokine production and partial commitment to type-2 cells. In addition, we show that bystander activation of EM cells seems to be dependent on the inflammatory cytokines IL-15 and IL-18, and is supported by an upregulation of the activating receptor NKG2D and an exuberant expression of T-Bet and T-Bet-regulated genes including granzyme B and CXCR3. We also show that the inflammatory chemokines CXCL9-10 are increased in symptomatic patients thereby fostering the recruitment of highly cytotoxic EM cells into the liver in a CXCR3-dependent manner. Finally, we find that the EM-biased immune response returns to homeostasis following viral clearance and disease resolution, further linking the EM cells response to viral burden. Conversely, asymptomatic patients are endowed with low-to-moderate EM cell response. In summary, our findings define immune correlates that contribute to HEV-3 pathogenesis and emphasize the central role of EM cells in governing the outcome of the infection.

The outcome of Genotype 3 Hepatitis E virus (HEV-3) infection differs among the elderly. Some patients develop severe forms of Hepatitis E while others remain asymptomatic. Nonetheless, parameters which can lead to severe versus silent infection are largely unknown. Therefore, we investigated immunological features of CD8 T cells in infected patients (aged ≥55) with similar viral determinants but distinct clinical outcomes. We show that drastic phenotypic changes were specifically observed within the effector memory (EM) compartment. Compared to asymptomatic patients, symptomatic ones display a strong activation of both HEV-3-specific and -nonspecific EM CD8 T cells associated with qualitative and quantitative alterations in cytokine production. In addition, EM cells are endowed with high cytotoxic capacity and have the ability to rapidly migrate to the liver. Finally, we report that the inflammatory response to HEV-3 infection shape EM cell activation and function in symptomatic elderly patients. In summary, our results present the first report demonstrating that the nature and the magnitude of EM CD8 T cell response play an important role in the outcome of HEV-3 infection in the elderly.

Hepatitis E virus and blood transfusion safety

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

The Prevalence of Hepatitis E in a Patient Cohort Presenting With Addictive Injection Behavior

Introduction: Hepatitis E is the most common cause of acute viral hepatitis worldwide. Seroprevalence is approximately 15% in developed countries, and 22% in France. hepatitis E virus (HEV) can be transmitted via transfusions and therefore possibly intravenous (IV) drug use. Hepatitis E serology is routinely tested in patients who seek medical advice for addictive injection behavior at the addiction treatment, support and prevention unit of Toulouse University Hospital. We assume that hepatitis E is more prevalent in patients presenting with addictive injection behavior than in the general French population. Methods: Hepatitis E serological assays [immunoglobulin M (IgM) and IgG] were carried out for all patients presenting with addictive injection behavior during an initial evaluation. The controls were taken from a cohort of 3,353 blood donors living in southern France and who donated blood during the first 2 weeks of October 2011. Results: We included 52 patients presenting with addictive injection behavior and 103 healthy controls matched for age, sex, and area of residence. We found no difference between patients and controls for the prevalence of hepatitis E: patients vs. healthy controls: positive IgGs: 42.31%, 95% confidence interval (CI) (28.73-56.80%) vs. 43.43%, 95% CI (33.50-53.77%) (p = 0.89) and positive IgMs: 3.85%, 95% CI (0.47-13.22%) vs. 4.85%, 95% CI (0.16-10.97%) (p = 0.57). Conclusion: There was no difference in HEV seroprevalence between IV drug users and the general population, suggesting that the IV route of HEV infection is not significant in this population.

[HEV and transfusion-recipient risk]

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

HEV and transfusion-recipient risk

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

Investigation of liver dysfunction: who should we test for hepatitis E?

AIM

Hepatitis E virus (HEV) is endemic in developed countries, but unrecognized infection is common. Many national guidelines now recommend HEV testing in patients with acute hepatitis irrespective of travel history. The biochemical definition of 'hepatitis' that best predicts HEV infection has not been established. This study aimed to determine parameters of liver biochemistry that should prompt testing for acute HEV.

METHODS

This was a retrospective study of serial liver function tests (LFTs) in cases of acute HEV (n=74) and three comparator groups: common bile duct stones (CBD, n=87), drug-induced liver injury (DILI, n=69) and patients testing negative for HEV (n=530). To identify the most discriminating parameters, LFTs from HEV cases, CBD and DILI were compared. Optimal LFT cutoffs for HEV testing were determined from HEV true positives and HEV true negatives using receiver operating characteristic curve analysis.

RESULTS

Compared with CBD and DILI, HEV cases had a significantly higher maximum alanine aminotransferase (ALT) (P<0.001) and ALT/alkaline phosphatase (ALKP) ratio (P<0.001). For HEV cases/patients testing negative for HEV, area under receiver operating characteristic curve was 0.805 for ALT (P<0.001) and 0.749 for the ALT/ALKP ratio (P<0.001). Using an ALT of at least 300 IU/l to prompt HEV testing has a sensitivity of 98.6% and a specificity of 30.3% compared with an ALT/ALKP ratio higher than or equal to 2 (sensitivity 100%, specificity 9.4%).

CONCLUSION

Patients with ALT higher than or equal to 300 IU/l should be tested for HEV. This is simple, detects nearly all cases and requires fewer samples to be tested than an ALT/ALKP ratio higher than or equal to 2. Where clinically indicated, patients with an ALT less than 300 IU/l should also be tested, particularly if HEV-associated neurological injury is suspected.

A Case of Acute Hepatitis E Infection in a Patient with Non-Hodgkin Lymphoma Treated Successfully with Ribavirin

We present the case of a man who, following immunosuppressive treatment for non-Hodgkin lymphoma, became infected with viral hepatitis E. Acute hepatitis E virus infection should be considered in patients with deranged liver function on a background of haematological malignancies or immunosuppression, even without travel to endemic regions. Whilst clearance is usually spontaneous in immune-competent individuals, these at-risk groups may develop a more complicated and protracted disease course. Thus awareness is important as additional treatment with ribavirin or pegylated interferon may be required, as in this case, in order to help achieve eradication.

Acute Hepatitis E: Two Sides of the Same Coin

The relevance of acute hepatitis E virus (HEV) infections has been underestimated for a long time. In the past, HEV infection had been interpreted falsely as a disease limited to the tropics until the relevance of autochthonous HEV infections in the Western world became overt. Due to increased awareness, the incidence of diagnosed autochthonous HEV infections (predominantly genotype 3) in industrialized countries has risen within the last decade. The main source of infections in industrialized countries seems to be infected swine meat, while infections with the tropical HEV genotypes 1 and 2 usually are mainly transmitted fecal-orally by contaminated drinking water. In the vast majority of healthy individuals, acute HEV infection is either clinically silent or takes a benign self-limited course. In patients who develop a symptomatic HEV infection, a short prodromal phase with unspecific symptoms is followed by liver specific symptoms like jaundice, itching, uncoloured stool and darkened urine. Importantly, tropical HEV infections may lead to acute liver failure, especially in pregnant women, while autochthonous HEV infections may lead to acute-on-chronic liver failure in patients with underlying liver diseases. Immunosuppressed individuals, such as transplant recipients or human immunodeficiency virus (HIV)-infected patients, are at risk for developing chronic hepatitis E, which may lead to liver fibrosis and cirrhosis in the long term. Importantly, specific treatment options for hepatitis E are not approved by the regulation authorities, but off-label ribavirin treatment seems to be effective in the treatment of chronic HEV-infection and may reduce the disease severity in patients suffering from acute liver failure.

Hepatitis E in a region of Italy: An emerging autochthonous infection?

BACKGROUND

Recent data showed an increasing number of "autochthonous" cases of hepatitis E in Italy.

AIMS

Analysing cases of acute hepatitis E to define frequency, clinical features, prognosis and risk factors.

METHODS

We considered all the patients admitted to our Regional Hospital between August 2011 and September 2014, with a diagnosis of acute hepatitis; serological screening for hepatitis B, C and A viruses was performed; in the event of negative results, sera were tested for cytomegalovirus, Epstein-Barr and hepatitis E viruses.

RESULTS

Among 200 patients, 66 were affected by viral infection. IgM anti-HEV was detected in 14 patients with a predominance of males (79%) with a mean age of 55. Genotype 3 of HEV was found in 8 patients. Only one patient died of acute on chronic liver failure; all others evolved favourably towards clinical remission within two months from clinical onset. Thirteen patients had had local exposure to infection and 9 reported the consumption of raw or undercooked locally produced pork.

CONCLUSION

The incidence of HEV in our cohort of patients with acute viral hepatitis is high (about 20% per year). In over 85% an autochthonous exposure to infection could be recognised, with a clear link with food habits.

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 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.

Evaluation of rapid tests for diagnosis of acute hepatitis E

BACKGROUND

Hepatitis E virus diagnosis still presents difficulties due to discordant results among diagnostic tests.

OBJECTIVES

The aim of this study was to evaluate the performance of two rapid tests for detection of anti-HEV IgM antibodies.

STUDY DESIGN

The rapid tests were compared with three commercial anti-HEV ELISA assays and one Real-Time PCR assay on 59 sera from patients with acute viral non-AC hepatitis.

RESULTS

The presence of anti-HEV IgM antibodies was evaluated by two rapid tests (Wantai and Assure) on 25 HEV RNA positive samples. Anti-HEV IgM antibodies were detected in 24/25 and 23/25 samples respectively. The sensitivity and specificity of Wantai and Assure Rapid tests were evaluated using the 25 HEV RNA positive samples and 50 HEV RNA negative samples (including sera from acute-phase HAV and HBV infections and blood donors). Overall, the sensitivity of Wantai Rapid and Assure Rapid tests was 96.1% and 92.6% respectively; the specificity of the 2 tests was 100%.

CONCLUSION

Our data suggest the potential use of anti-HEV IgM rapid assays as a first line test in primary health care settings, particularly useful for patients with chronic liver disease or pregnant women who urgently need an antiviral treatment.

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

BACKGROUND

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Hepatitis E virus and neurological injury

Hepatitis E is hyperendemic in many developing countries in Asia and Africa, and is caused by hepatitis E virus (HEV) genotypes 1 and 2, which are spread via the faecal-oral route by contaminated water. Recent data show that HEV infection is also endemic in developed countries. In such geographical settings, hepatitis E is caused by HEV genotypes 3 and 4, and is mainly a porcine zoonosis. In a minority of cases, HEV causes acute and chronic hepatitis, but infection is commonly asymptomatic or unrecognized. HEV infection is associated with a number of extrahepatic manifestations, including a range of neurological injuries. To date, 91 cases of HEV-associated neurological injury--most commonly, Guillain-Barré syndrome, neuralgic amyotrophy, and encephalitis/myelitis--have been reported. Here, we review the reported cases, discuss possible pathogenic mechanisms, and present our perspectives on future directions and research questions.

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.

Prevalence of hepatitis viruses in patients with acute hepatitis and characterization of the detected genotype 4 hepatitis E virus sequences in Mongolia

Hepatitis E is considered to be a worldwide public health problem. Although the prevalence of hepatitis E virus (HEV) antibodies in healthy individuals is noted to be 11%, no patients with acute hepatitis E have previously been identified in Mongolia. Three hundred two consecutive patients (183 males and 119 females; median age of 22.0 [Interquartile range: 18.3-25.0] years) who were clinically diagnosed with sporadic acute hepatitis during 2012-2013 in Ulaanbaatar, Mongolia, were studied. By serological and/or molecular approaches, 77 (25.5%), 93 (30.8%), 19 (6.3%), 48 (15.9%), and 12 (4.0%) of the patients were diagnosed with acute hepatitis of types A, B, C, D (superinfection of hepatitis delta virus on a background of chronic hepatitis B virus infection) and E, respectively, while the cause of hepatitis was unknown in the remaining 53 patients (17.5%). The 12 hepatitis E patients had no history of travel abroad in the 3 months before the onset of disease, and lived separately in fixed or movable houses with water supplied via pipe, tank or well, denying transmission from a common water supply. The 12 HEV isolates obtained from the patients showed high nucleotide identities of 99.7-100%, and a representative HEV isolate, MNE13-227, was closest to the Chinese isolates of genotype 4, with the highest identity of 97.3% in the 304-nt ORF2 sequence and 92.1% over the entire genome. The present study revealed the occurrence of autochthonous acute hepatitis E in Mongolia, caused by a monophyletic genotype 4 HEV strain.

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.

Seasonality of hepatitis: a review update

Background:

Viral hepatitis is an infection that has been reported to be present throughout the year, but some particular months are associated with higher incidences. The primary objective was to review and report on the current knowledge and evidence that existed on seasonality of different type of acute viral hepatitis worldwide in order to develop recommendations for future research, prevention and control.

Materials and Methods:

A systematic literature review was performed to identify all the primary reports and studies published during 1970-2013 on acute hepatitis A, B, C and E (AHA, AHB, AHC and AHE) in human subjects by searching PubMed, reference lists of major articles and correspondence with scientific experts. For each report or study included, the following information was extracted (as applicable to study): Location (country and setting), study population (number of cases, patients), seasonal or monthly rate and study duration.

Results:

There is no definite and consistent seasonal pattern has been observed on AHA; AHB; AHE and AHC, although evidence points towards spring and summer peak for hepatitis A, B, C and E. Multiple source of transmission such as; summer travel to an endemic area, swimming habits of the population in hot months, increase sexual contact, tattoo, poor hygiene and environmental sanitation and food habits (feco-oral transmission of viral hepatitis) probably exists and should be further investigated through analytical and epidemiological.

Hepatitis E Virus (HEV) seroprevalence in the general population of the Republic of Korea in 2007-2009: a nationwide cross-sectional study

Background

Hepatitis E virus (HEV) is an emerging pathogen associated with endemic and acute viral hepatitis. In this study, we investigate the HEV seroprevalence and putative risk factors by a nationwide cross-sectional study in the Republic of Korea.

Methods

The prevalence of anti-HEV antibody was investigated in 2,450 serum samples collected in fourth Korea National Health and Nutrition Examination Survey. In addition, epidemiological information on possible risk factors including gender, age, education, occupation, and residence location for exposure to HEV was obtained.

Results

The frequency of anti-EIA reactive sample was 5.9% (144/2450). The individuals in groups with male, older age, low education level and living in rural or coastal regions had high seroprevalence estimates (P ≤ 0.001). In addition, seroprevalence was significantly higher among individuals with self-identified skilled agricultural, forestry, and fishery workers (31.3%, P < 0.001).

Conclusions

This study provides valuable data that could be used to investigate associations of HEV seroprevalence and putative risk factors by a nationwide cross-sectional study. The high HEV seroprevalence of skilled agricultural, forestry, and fishery workers and individuals lived in coastal and rural area indicated that zoonotic transmission is an important risk factor for HEV infection in the republic of Korea. Further studies that include detailed and continuous nationwide surveys are required to identify unrecognized risk factors and to monitor the HEV infection prevalence.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-517) contains supplementary material, which is available to authorized users.

Hepatitis E virus infection

Hepatitis E virus (HEV) infection is a worldwide disease. An improved understanding of the natural history of HEV infection has been achieved within the last decade. Several reservoirs and transmission modes have been identified. Hepatitis E is an underdiagnosed disease, in part due to the use of serological assays with low sensitivity. However, diagnostic tools, including nucleic acid-based tests, have been improved. The epidemiology and clinical features of hepatitis E differ between developing and developed countries. HEV infection is usually an acute self-limiting disease, but in developed countries it causes chronic infection with rapidly progressive cirrhosis in organ transplant recipients, patients with hematological malignancy requiring chemotherapy, and individuals with HIV. HEV also causes extrahepatic manifestations, including a number of neurological syndromes and renal injury. Acute infection usually requires no treatment, but chronic infection should be treated by reducing immunosuppression in transplant patients and/or the use of antiviral therapy. In this comprehensive review, we summarize the current knowledge about the virus itself, as well as the epidemiology, diagnostics, natural history, and management of HEV infection in developing and developed countries.

Epidemiology and associated risk factors of hepatitis e virus infection in plateau state, Nigeria

A cross-sectional study in Nigeria was undertaken to determine the epidemiology, seroprevalence, and associated risk factors, of hepatitis E virus (HEV). A total of 462 subjects were used for the study, categorized into four groups: apparently healthy persons, pregnant women, HIV positive subjects, and animal handlers. Information was obtained from subjects using interviewer-administered questionnaire. Blood samples were collected and analyzed for HEV antibodies (IgG and IgM) using enzyme-linked immunosorbent assay (ELISA) technique. Results obtained were analyzed using Statistical Package for Social Sciences (SPSS) version 17.0 statistical software. The overall seroprevalence of IgG and IgM was 42.7 and 0.9%, respectively. Animal handlers had the highest seroprevalence (66.7%). The associated risk factors for IgM seroprevalence were rural dwelling (P = 0.039, odds ratio (OR) 3.3, 95% confidence interval (CI) 0.7–15.4), blood transfusion (P < 0.001, OR 9.6, 95% CI 2.6–35.6), attending to animals (P = 0.032, OR 4.9, 95% CI 0.9–26.6), and waste disposal (P < 0.001). Factors associated with IgG were age (P = 0.044), location (P < 0.001), marital status (P < 0.001), formal education (P < 0.001), farming as occupation (P < 0.001), rural dwelling (P = 0.001), waste disposal (P < 0.001), alcohol consumption (P = 0.001, OR 2.4, 95% CI 1.4–4.0), open defecation (P < 0.001, OR 2.9, 95% CI 1.4–5.7), attending to animals (P < 0.001, OR 2.3, 95% CI 1.6–3.4), consuming unwashed fruits/vegetables (P < 0.001, OR 4.2, 95% CI 0.3–54.1), and stream/river as a source of drinking water (P < 0.001, OR 3.6, 95% CI 1.6–7.8). Preventive public health measures should be reinforced among all communities, particularly domestic animal handlers and pregnant women. Potable water should be provided for all communities. Data suggest that HEV remains an under-recognized and significant public health problem, warranting further attention and research.

Hepatitis E: an emerging disease

Currently, the infection with the hepatitis E virus represents the most frequent cause for acute hepatitis and jaundice in the world. According to WHO estimations, around two billion people, representing one third of the world's population, live in endemic areas for HEV and, therefore, are at risk of infection. In developed countries, the circulation of the virus in both human and animal (swine, boar, deer) sewage has been confirmed; however, the incidence rate is low compared to that of developing countries where outbreaks of acute hepatitis transmitted via the fecal-oral route are originated, more frequently in the flooding season or after natural disasters, combined with deficient sanitary conditions. There are currently 4 known genotypes of HEV. Genotypes 1 and 2 are isolated in all human epidemic outbreaks in developing countries, while genotypes 3 and 4 are isolated not only in humans but also in animals, in both developing and industrialized countries. These data support genotypes 3 and 4 having zoonotic nature. The diagnosis of this disease is based in the detection of anti-HEV IgG and IgM in blood serum using enzyme-linked immunosorbent methods. However, the method that best confirms the diagnosis is the RT-PCR, which detects HEV RNA in blood serum and also provides the genotype. The clinical course is generally that of an acute hepatitis which in some cases may require hospitalization and that, in transplant patients or HIV infected individuals can become a chronic hepatitis. Furthermore, the virus constitutes an important risk for pregnant women. The hepatitis E can present a wide range of symptoms, from a subclinical case to chronic liver disease with extrahepatic manifestations. For this reason, the diagnostic is challenging if no differential diagnosis is included. There is no specific antiviral drug for hepatitis E, but satisfactory results have been observed in some patients treated with pegylated interferon alfa2a and/or ribavirin. This revision is an update of all the molecular, epidemiological, clinic and preventive knowledge on this emergent disease up to date.

Features of hepatitis E virus infection in humans and animals in Japan

In Japan, hepatitis E had long been considered to be a rare liver disease which can be accidentally imported from endemic countries in Asia and Africa, where the sanitation conditions are suboptimal. However, since the identification of the first autochthonous hepatitis E case and hepatitis E viremic domestic pigs in Japan in 2001, our understanding of hepatitis E virus (HEV) infection in this country has been changing markedly. This has largely been due to the development of serological and gene-based diagnostic assays, the accumulation of molecular epidemiological findings on HEV infection in humans and animals (as potential reservoirs for HEV in humans) and the recognition of the importance of zoonotic food-borne and other routes of transmission of HEV, including blood-borne transmission. Although it is now evident that autochthonous hepatitis E in Japan is far more common than was previously thought, clinical and subclinical HEV infections indigenous to Japan remain underdiagnosed and their prevalence is still underestimated due to the presence of unknown transmission routes and a low awareness of the infection status by many physicians in Japan. This review focuses on the features of HEV infection in humans and animals, as definitive or potential reservoirs for HEV, in Japan, and updates the current knowledge on the routes of transmission, including zoonotic routes, which are important for the maintenance and spread of HEV in Japan.

Host immune status and response to hepatitis E virus infection

Hepatitis E virus (HEV), identified over 30 years ago, remains a serious threat to life, health, and productivity in developing countries where access to clean water is limited. Recognition that HEV also circulates as a zoonotic and food-borne pathogen in developed countries is more recent. Even without treatment, most cases of HEV-related acute viral hepatitis (with or without jaundice) resolve within 1 to 2 months. However, HEV sometimes leads to acute liver failure, chronic infection, or extrahepatic symptoms. The mechanisms of pathogenesis appear to be substantially immune mediated. This review covers the epidemiology of HEV infection worldwide, the humoral and cellular immune responses to HEV, and the persistence and protection of antibodies produced in response to both natural infection and vaccines. We focus on the contributions of altered immune states (associated with pregnancy, human immunodeficiency virus [HIV], and immunosuppressive agents used in cancer and transplant medicine) to the elevated risks of chronic infection (in immunosuppressed/immunocompromised patients) and acute liver failure and mortality (among pregnant women). We conclude by discussing outstanding questions about the immune response to HEV and interactions with hormones and comorbid conditions. These questions take on heightened importance now that a vaccine is available.

Novel hepatitis E like virus found in Swedish moose

A novel virus was detected in a sample collected from a Swedish moose (Alces alces). The virus was suggested as a member of the Hepeviridae family, although it was found to be highly divergent from the known four genotypes (gt1–4) of hepatitis E virus (HEV). Moose are regularly hunted for consumption in the whole of Scandinavia. Thus, the finding of this virus may be important from several aspects: (a) as a new diverged HEV in a new animal species, and (b) potential unexplored HEV transmission pathways for human infections. Considering these aspects, we have started the molecular characterization of this virus. A 5.1 kb amplicon was sequenced, and corresponded to the partial ORF1, followed by complete ORF2, ORF3 and poly(A) sequence. In comparison with existing HEVs, the moose HEV genome showed a general nucleotide sequence similarity of 37–63 % and an extensively divergent putative ORF3 sequence. The junction region between the ORFs was also highly divergent; however, two putative secondary stem–loop structures were retained when compared to gt1–4, but with altered structural appearance. In the phylogenetic analysis, the moose HEV deviated and formed its own branch between the gt1–4 and other divergent animal HEVs. The characterization of this highly divergent genome provides important information regarding the diversity of HEV infecting various mammalian species. However, further studies are needed to investigate its prevalence in the moose populations and possibly in other host species, including the risk for human infection.

Idiosyncratic drug-induced liver injury: an update on the 2007 overview

INTRODUCTION

Idiosyncratic drug induced liver injury (DILI) is rare, with an incidence of approximately 19 per 100,000 treated individuals.

AREAS COVERED

An update on the epidemiology, pathogenic mechanisms, diagnosis, outcome, risk factors for idiosyncratic drug-induced hepatotoxicity, specific classes of drug hepatotoxicity and biomarkers to predict DILI are covered. Cumulative drug exposure and HLA phenotypes play an important role in the pathogenesis of DILI. Patients who present with suspected DILI and jaundice should have biliary obstruction and acute viral hepatitis, including hepatitis E excluded. Immune-mediated DILI will respond to steroid therapy. Patients with an elevated bilirubin and a hepatocellular pattern of liver function tests have severe liver injury with a mortality of greater than 10% and a risk of acute liver failure. Women have an increased risk of hepatocellular DILI. Antibiotics, anticonvulsants, and antidepressant therapy remain the commonest causes of DILI in the Western Hemisphere. Statin therapy rarely causes severe liver injury.

EXPERT OPINION

The establishment of prospective registries for DILI has provided valuable data on the pathogenesis and outcome of DILI. Drug-specific computerised causality assessment tools should improve the diagnosis of DILI. The clinical utility of genetic polymorphisms associated with drug-specific DILI is limited.

Validation of an internally controlled multiplex real time RT-PCR for detection and typing of HEV genotype 3 and 4

Hepatitis E virus (HEV) genotypes 1 and 2 are restricted to humans, whereas genotypes 3 (HEV 3) and genotype 4 (HEV 4) infect humans and a variety of animal species. Cross-species infections by animal strains raise potential public health concerns for zoonotic HEV transmission. Therefore, a real-time reverse transcription polymerase chain reaction (RT-qPCR) combining the HEV 3-tpye specific RT-qPCR assay with the HEV 4-tpye specific assay was developed. Furthermore, a heterologous RNA, an in vitro transcript of the enhanced green fluorescent protein (EGFP) gene, was introduced as an internal control. The data showed that EGFP gene provided a very reliable and simple way of monitoring both the sample manipulation and amplification procedures. The final multiplex RT-qPCR assay showed a high analytical sensitivity of less than 50 copies RNA per reaction for both HEV genotypes. The specificity and amplification efficiency of the multiplex assay for the respective HEV were confirmed by co-amplification of the other target. By comparing with the results of mono-specific assay and nested PCR as well as sequencing, HEV infection in a panel of clinical samples was reliably detected and typed, which indicated that the novel multiplex RT-qPCR assay could be used for sensitive detection and rapid differentiation of zoonotic HEV genotype 3 and 4.

Hepatitis E: source and route of infection, clinical manifestations and new developments

Hepatitis E was previously thought to be a disease of developing countries causing significant morbidity and mortality in young adults, particularly among pregnant women and patients with pre-existing chronic liver disease. Recent studies have shown that hepatitis E is also an issue in developed countries. In this setting, hepatitis E is a zoonotic infection and causes acute infection mainly in middle-aged and elderly men; and chronic infection in the immunosuppressed. The scope and burden of disease are still emerging. The diagnosis of hepatitis E should be considered in any patient with hepatitis, irrespective of their age or travel history.

Hepatitis E infection is an under recognized cause of acute decompensation in patients with chronic liver disease

BACKGROUND/AIMS

We aimed to assess characteristics of patients with a positive hepatitis E virus serology with emphasis on acute on chronic liver disease.

METHODS

This was a retrospective audit performed at a large teaching hospital.

RESULTS

Of the 164 patients tested, 15(9.1%) had a positive serology (hepatitis E virus IgG and or IgM) of whom two also had a positive hepatitis E virus RNA. Six (42.8%) had underlying chronic liver disease and presented with deteriorating liver tests±decompensation. In one patient (16%) acute hepatitis E virus infection was the aetiology for the decompensation and in three the positive hepatitis E virus IgG was a reflection of prior subclinical infection. However, in two of the six patients with unexplained decompensation there was delay (150-270 days) in obtaining a hepatitis E virus serology, which may have resulted in a negative hepatitis E virus IgM at time of testing.

CONCLUSIONS

9.1% of patients presenting with abnormal liver tests at a large teaching hospital in south east England have a positive hepatitis E virus serology of whom 42.8% have acute on chronic liver disease. In 16% hepatitis E virus infection is the aetiology for the acute decompensation. This may be an under representation as in >30% of patients with unexplained decompensation there is considerable delay in requesting a hepatitis E virus serology.

Serological evidence for a hepatitis e virus-related agent in goats in the United States

Hepatitis E virus (HEV) causes an important public health disease in many developing countries and is also endemic in some industrialized countries. In addition to humans, strains of HEV have been genetically identified from pig, chicken, rat, mongoose, deer, rabbit and fish. While the genotypes 1 and 2 HEV are restricted to humans, the genotypes 3 and 4 HEV are zoonotic and infect humans and other animal species. As a part of our ongoing efforts to search for potential animal reservoirs for HEV, we tested goats from Virginia for evidence of HEV infection and showed that 16% (13/80) of goat sera from Virginia herds were positive for IgG anti-HEV. Importantly, we demonstrated that neutralizing antibodies to HEV were present in selected IgG anti-HEV positive goat sera. Subsequently, in an attempt to genetically identify the HEV-related agent from goats, we conducted a prospective study in a closed goat herd with known anti-HEV seropositivity and monitored a total of 11 kids from the time of birth until 14 weeks of age for evidence of HEV infection. Seroconversion to IgG anti-HEV was detected in seven of the 11 kids, although repeated attempts to detect HEV RNA by a broad-spectrum nested RT-PCR from the faecal and serum samples of the goats that had seroconverted were unsuccessful. In addition, we also attempted to experimentally infect laboratory goats with three well-characterized mammalian strains of HEV but with no success. The results indicate that a HEV-related agent is circulating and maintained in the goat population in Virginia and that the goat HEV is likely genetically very divergent from the known HEV strains.

Diagnosis of HEV infection by serological and real-time PCR assays: a study on acute non-A-C hepatitis collected from 2004 to 2010 in Italy

Background

The impact of hepatitis E in developed countries, like Italy, still requires a clear definition. In the present study, we evaluated HEV infection in patients with acute non-A-C hepatitis by an approach comparing data from Real-time PCR and serological assays.

Methods

In a first analysis, sera from 52 patients hospitalized with a diagnosis of acute viral non-A-C hepatitis in Italy were tested by in-house Real-Time PCR assay for identification of Hepatitis E Virus (HEV) RNA and by anti-HEV IgM and IgG assays. In a subsequent analysis, selected samples were evaluated by additional IgM tests to confirm diagnosis.

Results

Among the 52 samples, 21 showed positive results for all three markers (IgM, IgG and HEV RNA). One patient showed HEV RNA as single marker. Uncertain results were found in 8 samples while the remaining 22 were negative for all markers. Further analysis of the 8 undefined samples by additional IgM tests confirmed HEV infection in 1 patient. Overall, acute HEV infections were reliably identified in 23 (44.2%) out of 52 patients.

Conclusions

In the present paper, we performed a study evaluating HEV infection in 52 sporadic non-A-C acute hepatitis cases. All samples were collected from 2004 to 2010 in Italy. By a diagnostic strategy based on genomic and serological assays we identified HEV infections in 23 out of 52 patients (44.2%), a percentage higher than previous estimates. Thus, the actual impact of HEV infections in Italy needs to be further evaluated on a national scale by a diagnostic strategy based on multiple and last generation assays.

Molecular epidemiology and genetic history of European-type genotype 3 hepatitis E virus indigenized in the central region of Japan

In Mie prefecture in Japan, 12 cases of sporadic hepatitis E occurred from 2004 to 2011. Mie prefecture is located in the central region of Japan, far from the most prevalent regions of hepatitis E virus (HEV) infection in Japan, the north and northeastern part. These 12 cases did not have any common risk factors of HEV infection. We analyzed the molecular epidemiology of the cases in Mie prefecture. We obtained the nucleotide sequences of the HEV strains and analyzed them with the sequences of other HEV strains by phylogenetic and coalescent analyses. Japan-indigenous genotype 3 HEV strains were divided into two major subtypes, namely, 3a and 3b; one minor subtype, 3e; and a few other unassigned lineages. The Japan-indigenous subtype 3e strains were closely related to European subtype 3e HEV strains and were comparatively rare in Japan; however, eight strains of the 12 cases we examined belonged to subtype 3e, indicating a close phylogenetic relationship, despite the lack of common risk factors. Coalescent analyses indicated that the Mie 3e strains seemed to have intruded into Mie prefecture about 10 years ago. Sporadic acute hepatitis E cases caused by the 3e strains occurred consistently from 2004 to 2011 in Mie prefecture. This is the first report of unexpected persistent occurrence of hepatitis by the European-type genotype 3 HEV, subtype 3e, in a country outside of Europe. Phylogenetic and coalescent analyses traced the history of the indigenization of the Mie 3e strains from Europe. Because hepatitis E cases caused by 3e strains are relatively rare in Japan, molecular evolutionary analyses of HEV infection in Mie prefecture is important for preventing a future hepatitis endemic or epidemic by 3e strains in Japan.

HEV infection in swine from Eastern Brazilian Amazon: evidence of co-infection by different subtypes

Hepatitis E virus (HEV) is a fecal-orally transmitted member of the genus Hepevirus that causes acute hepatitis in humans and is widely distributed throughout the world. Pigs have been reported as the main source of genotypes 3 and 4 infection to humans in non-endemic areas. To investigate HEV infection in pigs from different regions of Pará state (Eastern Brazilian Amazon), we performed serological and molecular analyses of serum, fecal and liver samples from 151 adult pigs slaughtered between April and October 2010 in slaughterhouses in the metropolitan region of Belém, Pará. Among the animals tested, 8.6% (13/151) were positive for anti-HEV IgG but not for anti-HEV IgM. HEV RNA was detected in 4.8% (22/453) of the samples analyzed and 9.9% (15/151) of the animals had at least one positive sample. Phylogenetic analysis showed that all sequences belonged to genotype 3 that were related to human isolates from other non-endemic regions, suggesting that the isolates had zoonotic potential. Subtypes 3c and 3f were simultaneously detected in some pigs, suggesting co-infection by more than one strain and/or the presence of a recombinant virus. These results constitute the first molecular and serologic evidence of swine HEV circulation in the Eastern Brazilian Amazon.

The epidemiology of hepatitis E virus infections in developed countries and among immunocompromised patients

Hepatitis E virus (HEV) is an important cause of acute hepatitis in humans worldwide, both as epidemic and sporadic disease. Since the virus was identified in 1983, epidemics have occurred regularly in many countries across South and Southeast Asia when seasonal floods have contaminated drinking water supplies and in Africa during humanitarian crises among refugee populations without access to clean water. In addition, sporadic cases and small clusters of HEV infections have been recognized throughout the world in developed countries over the past couple of decades. This review will focus on emerging evidence of HEV infection as an under-recognized pathogen in Europe, the USA and other industrialized countries. We will discuss some of the issues associated with the recognition, diagnosis and treatment of these sporadic cases. We will also summarize the recent literature on autochthonous HEV infection among populations in developed countries in industrialized Europe, the USA, Japan and other industrialized Asian countries. We will review recent reports of acute and chronic HEV infections among transplant recipients and other immunocompromised individuals including HIV/AIDS patients.

Liver transplant from a donor with occult HEV infection induced chronic hepatitis and cirrhosis in the recipient

Acute hepatitis E virus (HEV) infection is a self-limiting symptomatic or asymptomatic disease. However, as recently observed, it can manifest itself as chronic hepatitis in patients receiving solid organ transplants as well as in patients with HIV infection or severe hematologic disorders. Here, we describe the clinical course of a 73-year-old male patient in whom HEV transmission occurred after receiving a HEV-infected liver from a donor with occult HEV infection, whereby the patient had tested negative for HEV RNA and anti-HEV antibodies shortly before explantation. Anti-HEV IgG, IgM, and HEV RNA were detected in the first tested serum sample of the liver recipient obtained 150 days after liver transplantation and remained positive (earlier samples after OLT were not available). Liver cirrhosis developed within 15 months and the patient died of septic shock. Based on phylogenetic analyses of the donor and recipient's HEV strains, we were able to prove that the occult HEV infection was transmitted via the graft.

Progress in research of chronic hepatitis E

Hepatitis E caused by hepatitis E virus (HEV) has long been considered as an acute self-limiting disease. But in recent years, cases which progress to chronic liver disease mainly in immunocompromised patients have been detected, such as organ transplant recipients and patients with human immunodeficiency virus infection. Studies indicate that chronic HEV hepatitis may result in cirrhosis and end-stage liver disease. Since clearance of the virus depends on the development of specific immunity, lowering the immunosuppressive medication is generally recommended. Ribavirin, interferon-alpha-2a and interferon-alpha-2b were found to be effective in patients with chronic HEV infection.

Hepatitis E virus infection as a cause of acute hepatitis in Southern Italy

BACKGROUND

Hepatitis E virus (HEV) is a major cause of acute hepatitis in developing countries, whereas it is not considered a major health problem in Western World.

AIMS

To investigate the spread of HEV and its possible role in causing acute hepatitis in Southern Italy.

METHODS

Four hundred and thirty patients observed from April to December 2009 were studied and grouped as follows: 55 individuals with acute hepatitis (AH), 33 of whom cryptogenic; 321 individuals with chronic liver diseases (CLD), (278 Italians and 43 immigrants); 54 individuals without liver disease (control-group). Serum samples from all cases were tested for IgG anti-HEV antibodies and those positive to this test as well as all AH cases were also tested both for IgM anti-HEV and HEV RNA.

RESULTS

Two of 33 (6%) cryptogenic AH cases were associated with HEV infection as shown by positive IgM anti-HEV test. Both these patients had not travelled to areas at high HEV endemicity. HEV RNA was not found in any sample tested. IgG anti-HEV antibodies were detected in 5.7% of Italians with CLD and 3.7% of the control-group. No immigrant was found positive for any HEV marker.

CONCLUSION

Autochthonous HEV infection is present in Southern Italy where it may cause AH.

Epidemiology of liver failure

The etiology of fulminant hepatitis varies in different countries and at different times. The main causes of fulminant hepatitis are viruses, paracetamol, drugs (other than paracetamol), poisons and 15-30% remained of undetermined origin. The prevalence of these etiologies varies according to the geographic region and has changed over the past 10 years. Paracetamol has now overtaken viruses (particularly hepatitis B virus) as the leading cause of fulminant hepatitis. Establishing the cause of fulminant hepatitis is an important step in the management of acute liver failure, so that specific therapy can be initiated and any contraindications to liver transplantation be eliminated.