Hepatitis E virus infection in haemodialysis patients: a case-control study in Saudi Arabia

Hepatitis E Virus (HEV) in Makkah, Saudi Arabia: A Population-Based Seroprevalence Study

BACKGROUND

The Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Little is known about the seroprevalence of HEV in the general population of Saudi Arabia.

METHODS

A community-based cross-sectional HEV seroprevalence study was conducted in Makkah, Saudi Arabia. Anti-HEV IgG antibodies were detected in sera using an in-house ELISA. The frequency of HEV sageerology and its correlation with demographic, and environmental factors were evaluated.

RESULTS

Enrollment consisted of 1329 individuals, ages ranged from 8 to 88 years, the mean age was 30.17 years, the median age was 28yrs, and the male: female ratio was 1.15. The overall seroprevalence was 23.8% (316/1329). Males had significantly higher seroprevalence than females (66.1 vs. 33.9%; p < 0.001). Seroprevalence had significant correlations with age, occupation, and lack of regular water supply and housing conditions.

CONCLUSIONS

This is the first HEV community-based seroprevalence study from Saudi Arabia. Results show that the HEV is endemic in Makkah and affects all age groups and occupations. HEV affects more males than females and those living in crowded accommodations without a regular supply of water. Further studies are required across all regions of Saudi Arabia to determine the country's seroprevalence of active or past infection using tests for HEV IgG, HEV IgM antibodies and/or HEV RNA and underlying determinants of transmission.

Emerging and Re-emerging Infectious Diseases in the WHO Eastern Mediterranean Region, 2001-2018

BACKGROUND

Countries in the World Health Organization (WHO) Eastern Mediterranean Region (EMR) are predisposed to highly contagious, severe and fatal, emerging infectious diseases (EIDs), and re-emerging infectious diseases (RIDs). This paper reviews the epidemiological situation of EIDs and RIDs of global concern in the EMR between 2001 and 2018.

METHODS

To do a narrative review, a complete list of studies in the field was we prepared following a systematic search approach. Studies that were purposively reviewed were identified to summarize the epidemiological situation of each targeted disease. A comprehensive search of all published studies on EIDs and RIDs between 2001 and 2018 was carried out through search engines including Medline, Web of Science, Scopus, Google Scholar, and ScienceDirect.

RESULTS

Leishmaniasis, hepatitis A virus (HAV) and hepatitis E virus (HEV) are reported from all countries in the region. Chikungunya, Crimean Congo hemorrhagic fever (CCHF), dengue fever, and H5N1 have been increasing in number, frequency, and expanding in their geographic distribution. Middle East respiratory syndrome (MERS), which was reported in this region in 2012 is still a public health concern. There are challenges to control cholera, diphtheria, leishmaniasis, measles, and poliomyelitis in some of the countries. Moreover, Alkhurma hemorrhagic fever (AHF), and Rift Valley fever (RVF) are limited to some countries in the region. Also, there is little information about the real situation of the plague, Q fever, and tularemia.

CONCLUSION

EIDs and RIDs are prevalent in most countries in the region and could further spread within the region. It is crucial to improve regional capacities and capabilities in preventing and responding to disease outbreaks with adequate resources and expertise.

Genetic diversity of hepatitis E virus (HEV) in imported and domestic camels in Saudi Arabia

Camels gained attention since the discovery of MERS-CoV as intermediary hosts for potentially epidemic zoonotic viruses. DcHEV is a novel zoonotic pathogen associated with camel contact. This study aimed to genetically characterize DcHEV in domestic and imported camels in Saudi Arabia. DcHEV was detected by RT-PCR in serum samples, PCR-positive samples were subjected to sequencing and phylogenetic analyses. DcHEV was detected in 1.77% of samples with higher positivity in domestic DCs. All positive imported dromedaries were from Sudan with age declining prevalence. Domestic DcHEV sequences clustered with sequences from Kenya, Somalia, and UAE while imported sequences clustered with one DcHEV isolate from UAE and both sequences clustered away from isolates reported from Pakistan. Full-genome sequences showed 24 amino acid difference with reference sequences. Our results confirm the detection of DcHEV in domestic and imported DCs. Further investigations are needed in human and camel populations to identify DcHEV potential zoonosis threat.

Hepatitis E Virus Infection-Immune Responses to an Underestimated Global Threat

Infection with the hepatitis E virus (HEV) is one of the main ubiquitous causes for developing an acute hepatitis. Moreover, chronification plays a predominant role in immunocompromised patients such as transplant recipients with more frequent severe courses. Unfortunately, besides reduction of immunosuppression and off-label use of ribavirin or pegylated interferon alfa, there is currently no specific anti-viral treatment to prevent disease progression. So far, research on involved immune mechanisms induced by HEV is limited. It is very difficult to collect clinical samples especially from the early phase of infection since this is often asymptomatic. Nevertheless, it is certain that the outcome of HEV-infected patients correlates with the strength of the proceeding immune response. Several lymphoid cells have been identified in contributing either to disease progression or achieving sustained virologic response. In particular, a sufficient immune control by both CD4⁺ and CD8⁺ T cells is necessary to prevent chronic viral replication. Especially the mechanisms underlying fulminant courses are poorly understood. However, liver biopsies indicate the involvement of cytotoxic T cells in liver damage. In this review, we aimed to highlight different parts of the lymphoid immune response against HEV and point out questions that remain unanswered regarding this underestimated global threat.

A tool to measure the economic impact of Hepatitis B elimination: A case study in Saudi Arabia

BACKGROUND

No virologic cure exists for hepatitis B virus (HBV) infection, and existing therapies are designed to control viral replication. We aimed to estimate the national prevalence of HBsAg in 2017 and study the impact of an enhanced diagnosis rate and universal treatment administration on HBV-related outcomes in Saudi Arabia.

MATERIALS AND METHODS

A dynamic transmission and disease burden model was developed to estimate the future economic burden of HBV infection. The infected population was tracked by age and gender-defined cohorts; direct costs (healthcare, screening, diagnostics and treatment) and indirect costs (disability-adjusted life years and the value of a statistical life year) were calculated. The impact of two intervention scenarios (Achieve WHO Targets: diagnose 90% of infections and treat 80% of high viral load patients by 2030; and Diagnose and Treat All: diagnose and treat all infected patients by 2022) were compared against the Base Case scenario (no policy action), with near-universal vaccination coverage rates held constant. A sensitivity analysis of future treatment cost was also conducted.

RESULTS

In 2017, HBsAg prevalence was estimated at 1.7%, corresponding to 574,000 infections. The same year, there was an estimated incidence of 490 cases of decompensated cirrhosis, 1500 cases of hepatocellular carcinoma (HCC) and 1740 liver-related deaths (LRD). HBsAg prevalence was 0.1% among 5-year-olds and <0.1% among infants. Disease burden outcomes by 2030, as compared with 2015, were as follows - Base Case: LRDs and HCC incidence were projected to increase by 70%. WHO Targets: A 30-35% decline in both HCC incidence and LRDs. Diagnose and Treat All: A 50-55% decline in HCC incidence and LRDs. In all scenarios, HBsAg prevalence among infants and 5-year-olds declined to <0.1% with the Diagnose and Treat all scenario resulting in a prevalence approaching zero in this age group. Annual direct costs are projected to increase and peak by 2022 in both intervention scenarios due to expansion of treatment and diagnostics. However, these are offset by the reduction of indirect economic costs, starting immediately in the WHO Targets scenario and by 2023 in the strategy to diagnose and treat all. Achieving WHO Targets is estimated to achieve a positive return on investment (ROI) by 2021 when examining direct costs and indirect economic losses at a treatment price of $2700 USD per patient yearly. Diagnosing and treating all patients, however, would require at least a 50% reduction in the unit cost of treatment to achieve a positive ROI by 2029.

CONCLUSIONS

Increased diagnosis and treatment rates of HBV would lead to substantial declines in HCC and LRD. This effect would be dramatically enhanced by administering treatment to all HBV cases regardless of viral load and estimated to be highly cost-effective if treatment prices can be substantially reduced.

Seroepidemiology of hepatitis E virus infection in patients undergoing maintenance hemodialysis: Systematic review and meta-analysis

Patients undergoing regular hemodialysis (HD) are at an extreme risk of acquiring bloodstream infections compared to the general population. Hepatitis E virus (HEV) infection is an important emerging health issue in these patients. To date, numerous studies have investigated the seroprevalence of HEV among HD patients across the world; however, the data are conflicting. The present study aimed to measure the exposure rate of HD patients to HEV infection by estimating the overall seroprevalence of HEV in this high-risk group. A systematic literature search was carried out using five electronic databases from inception to January 10, 2020, with standard keywords. Pooled seroprevalence estimates with 95% confidence intervals (CIs) were calculated using a random intercept logistic regression model. The seroprevalence of HEV increased from 6.6% between the years of 1994 and 2000 to 11.13% from 2016 to 2020. Blood transfusion was associated with a nearly 2-fold increase in the rate of HEV seropositivity (OR = 1.99; 95% CI: 1.50-2.63, P < .0001, I² = 6.5%). HEV seroprevalence among patients with HD for more than 60 months was significantly higher than those with HD for less than 60 months (27.69%, 95% CI: 20.69%-35.99% vs 15.78%, 95%CI: 8.85%-26.57%, respectively) (P = .06). Our results indicated increased exposure of HD patients with HEV infection over the last decade. We concluded that blood transfusion and duration of HD are considerable risk factors for acquiring HEV infection among HD patients.

Seroprevalence of Dromedary Camel HEV in Domestic and Imported Camels from Saudi Arabia

Hepatitis E Virus (HEV) imposes a major health concern in areas with very poor sanitation in Africa and Asia. The pathogen is transmitted mainly through ingesting contaminated water or food, coming into contact with affected people, and blood transfusions. Very few reports including old reports are available on the prevalence of HEV in Saudi Arabia in humans and no reports exist on HEV prevalence in camels. Dromedary camel trade and farming are increasing in Saudi Arabia with importation occurring unidirectionally from Africa to Saudi Arabia. DcHEV transmission to humans has been reported in one case from the United Arab Emeritus (UAE). This instigated us to perform this investigation of the seroprevalence of HEV in imported and domestic camels in Saudi Arabia. Serum samples were collected from imported and domestic camels. DcHEV-Abs were detected in collected sera using ELISA. The prevalence of DcHEV in the collected samples was 23.1% with slightly lower prevalence in imported camels than domestic camels (22.4% vs. 25.4%, p value = 0.3). Gender was significantly associated with the prevalence of HEV in the collected camels (p value = 0.015) where males (31.6%) were more infected than females (13.4%). This study is the first study to investigate the prevalence of HEV in dromedary camels from Saudi Arabia. The high seroprevalence of DcHEV in dromedaries might indicate their role as a zoonotic reservoir for viral infection to humans. Future HEV seroprevalence studies in humans are needed to investigate the role of DcHEV in the Saudi human population.

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

Background

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

Materials and methods

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

Results

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

Conclusions

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

Prevalence and characteristics of hepatitis E virus infection in kidney transplant recipients: A single-center experience in Japan

BACKGROUND

Hepatitis E virus (HEV) infection can lead to chronic hepatitis in solid organ transplant recipients. To investigate whether HEV infection influences outcomes following kidney transplantation, we examined the prevalence of HEV infection and clinical characteristics of kidney transplant recipients in our hospital.

METHODS

Our cross-sectional study included 184 kidney transplant recipients. Blood samples were obtained from all patients to detect anti-HEV immunoglobulin (Ig)A, IgM, and IgG by enzyme-linked immunosorbent assay and HEV RNA by reverse transcription polymerase chain reaction. Clinical data were collected from medical charts for all patients.

RESULTS

The prevalence of anti-HEV IgG was 8/184 (4.3%). Anti-HEV IgA, anti-HEV IgM, and HEV RNA were not detected in any patients. Compared to their anti-HEV IgG-negative counterparts, anti-HEV IgG-positive patients were significantly older at the time of transplantation, and they were more likely to receive kidneys from deceased donors. No significant differences in other characteristics such as the prevalence of primary cause of end-stage renal disease, blood transfusion, and immunosuppressive therapy use; liver and renal function; and the frequencies of hepatitis B and hepatitis C virus infection were observed according to the patients' anti-HEV IgG status.

CONCLUSION

HEV infection had no significant influence on the outcomes of kidney transplantation at our institution. However, HEV infection should be recognized in kidney transplant recipients similarly as hepatitis B and hepatitis C virus infection in cases of liver dysfunction.

Systematic review with meta-analysis: the association between hepatitis E seroprevalence and haemodialysis

BACKGROUND

Hepatitis E virus (HEV) infection appears to be more common than previously thought. HEV seroprevalence in patients on maintenance haemodialysis (HD) is unclear with a range from 0% to 44%. In addition, risk factors of transmission of HEV in patients on haemodialysis are unknown.

AIM

To perform a systematic review and meta-analysis of HEV seroprevalence in HD patients compared with controls.

METHODS

A systematic search of several databases identified all observational studies with comparative arms. Two reviewers extracted data and assessed the methodological quality. A random-effects model was used for pooled odds ratio (OR) and 95% confidence interval (CI) of positive anti-HEV IgG in both groups. Heterogeneity and publication bias were assessed with appropriate tests.

RESULTS

We identified 31 studies from 17 countries between 1994 and 2016. Sixteen studies were judged to have adequate quality and 15 to have moderate limitations. HEV infection was more prevalent in patients on haemodialysis compared with controls (OR 2.47, 95% CI 1.79-3.40, I² = 75.2%, P < .01). We conducted several subgroup analyses without difference in results. Egger regression test did not suggest publication bias (P = .83). Specific risk factors of HEV transmission in patients on haemodialysis were not clearly identified.

CONCLUSIONS

Hepatitis E virus infection is more prevalent in patients on haemodialysis compared with non-haemodialysis control groups. Further studies are needed to determine risk factors of acquisition, impact on health, and risk for chronic HEV especially among those patients going to receive organ transplantation.

Transmission of Hepatitis E Virus in Developing Countries

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

Anti-Hepatitis E Antibody in Hemodialysis Patients in Isfahan, Iran: Prevalence and Risk Factors

BACKGROUND

Many studies have been performed regarding the prevalence of hepatitis E in the general population, but there is controversial evidence for an increased risk of the infection in patients on maintenance hemodialysis (HD).

OBJECTIVES

The primary end point of the present study was to determine if the prevalence of anti-hepatitis E virus IgG (anti-HEV IgG) is higher in patients on maintenance HD than in the normal population in Isfahan.

PATIENTS AND METHODS

In a case-control study performed in Isfahan in June 2012, we compared the seroprevalence of HEV among 274 patients on maintenance HD and 275 otherwise healthy individuals. The patients were recruited from 3 HD centers in Isfahan. Anti-HEV IgG was detected using a Dia Pro Diagnostic HEV enzyme immunoassay (ELISA) kit. Demographic and clinical data (sex, age, blood transfusion history, HD duration, age at HD initiation, and evidence of hepatitis B and hepatitis C infections) were obtained from the medical records of the HD patients.

RESULTS

Anti-HEV IgG was detected in 27 (9.9%) controls and 78 (28.3%) patients, with the difference being statistically significant (P < 0.05). Furthermore, there was a significant association between positive anti-HEV antibody, HD duration, and blood transfusion history in the HD patients.

CONCLUSIONS

Considering the results, it seems necessary to conduct prospective studies in order to identify factors responsible for the high seroprevalence of HEV in Isfahan HD units.

Hepatitis E virus in the countries of the Middle East and North Africa region: an awareness of an infectious threat to blood safety

PURPOSE

Hepatitis E virus (HEV) is mainly transmitted through contaminated water supplies which make the virus endemic in developing countries including countries of the Middle East and North Africa (MENA) region. Recent reports suggest potential risk of HEV transmission via blood transfusion.

METHODS

Related articles on HEV were collected by searching through the 25 countries of the MENA region using Pubmed and Medline within the past 14 years: January 2000-August 2014.

RESULTS

One hundred articles were extracted, of which 25 were not eligible. The articles discussed the seroprevalence of HEV and HEV markers in 12 countries. Eight articles provided data on HEV in blood donors. The seroprevalence of HEV in the general MENA population ranged from 2.0 to 37.5% and was higher in males than in females. Prevalence increased with age, but exposure seems to be in early life.

CONCLUSIONS

In the MENA region, the role of HEV as an infectious threat to blood safety is under-investigated. More data are needed to quantify the risk of transmission and to assess clinical outcomes. This requires, at least, surveillance screening of donors and recipients for HEV markers using sensitive and specific serological tests. At the present time, serious consideration should be given to selective screening for certain groups of patients (e.g., immunocompromised, pregnant women and others) who commonly require blood transfusion and are at high risk of hepatic failure or chronicity from HEV infection.

Hepatitis E in hemodialysis and kidney transplant patients in south-east Italy

AIM: To investigate the serovirological prevalence and clinical features of hepatitis E virus (HEV) infection in end-stage renal failure patients and in the healthy population.

METHODS: HEV infection is a viral disease that can cause sporadic and epidemic hepatitis. Previous studies unexpectedly showed a high prevalence of HEV antibodies in immunosuppressed subjects, including hemodialysis (HD) patients and patients who had undergone kidney transplant. A cohort/case-control study was carried out from January 2012 to August 2013 in two hospitals in southern Italy (Foggia and S. Giovanni Rotondo, Apulia). The seroprevalence of HEV was determined in 801 subjects; 231 HD patients, 120 renal transplant recipients, and 450 health individuals. All HD patients and the recipients of renal transplants were attending the Departments of Nephrology and Dialysis at two hospitals located in Southern Italy, and were included progressively in this study. Serum samples were tested for HEV antibodies (IgG/IgM); in the case of positivity they were confirmed by a Western blot assay and were also tested for HEV-RNA, and the HEV genotypes were determined.

RESULTS: A total of 30/801 (3.7%) patients were positive for anti-HEV Ig (IgG and/or IgM) and by Western blot. The healthy population presented with a prevalence of 2.7%, HD patients had a prevalence of 6.0%, and transplant recipients had a prevalence of 3.3%. The overall combined HEV-positive prevalence in the two groups with chronic renal failure was 5.1%. The rates of exposure to HEV (positivity of HEV-IgG/M in the early samples) were lower in the healthy controls, but the difference among the three groups was not statistically significant (P > 0.05). Positivity for anti-HEV/IgM was detected in 4/30 (13.33%) anti-HEV Ig positive individuals, in 2/14 HD patients, in 1/4 transplant individuals, and in 1/12 of the healthy population. The relative risk of being HEV-IgM-positive was significantly higher among transplant recipients compared to the other two groups (OR = 65.4, 95%CI: 7.2-592.7, P < 0.001), but the subjects with HEV-IgM positivity were numerically too few to calculate a significant difference. No patient presented with chronic hepatitis from HEV infection alone.

CONCLUSION: This study indicated a higher, but not significant, circulation of HEV in hemodialysis patients vs the healthy population. Chronic hepatitis due to the HEV virus was not observed.

Epidemiology of hepatitis e virus infection in patients on chronic hemodialysis

Background:

Many studies have been done on the epidemiology of Hepatitis E on general population, but the data among patients with end stage renal disease (ESRD) are few and give conflicting results.

Objectives:

The aim of this study was to investigate the prevalence of hepatitis E virus (HEV) infection and its relationship in ESRD patients undergoing maintenance hemodialysis (HD).

Patients and Methods:

This cross-sectional study was carried out on ESRD patients treated with HD in Imam Khomeini Hospital, Ahvaz city, Southwest of Iran. Blood sampling of patients was collected immediately before the dialysis session and the serum were evaluated for anti-HEV IgG titers by enzyme-linked immunosorbent assays. The statistical package for social sciences (SPSS) version 15 software was used for data analysis.

Results:

Out of 47 ESRD patients, 27 were male (57.4%) and 20 were female (42.6%), with mean age of 55.27 ± 8.1 years. The prevalence of anti-HEV antibody was 10.6 % (five patients, four male and one female). The mean age of HEV positive and negative patients were 58 ± 5.52 and 53.82 ± 15.55 years, respectively without any significant difference (P = 0.058). There also was no significant association between HEV and gender (P = 0.28). The mean time of HD in HEV positive and negative patients were 1224.2 and 1168.5 days, respectively with no significant association (P = 0.88). In addition, there also was no association between HEV and HCV (P = 0.61).

Conclusions:

According to the present study, the prevalence of anti-HEV IgG antibody was 10.63 % among chronic HD patients and there was no association between HEV, age, gender, duration of HD and HCV antibody titer.

Epidemiology of Hepatitis E Virus in an Urban Community in Dhaka City

Introduction

Hepatitis E virus (HEV) is endemic in Bangladesh and sporadic and epidemic outbreaks of acute hepatitis E occur in this country almost regularly. Although the real magnitude of HEV prevalence has not been documented in Bangladesh, HEV infections and HEV-related acute hepatitis of Bangladeshi origin have been reported from different parts of the world.

Methods

The study was conducted in Mirpur area of Dhaka city, which is a major residential area of the capital of Bangladesh. Three hundred adults were randomly included in the study. None had any history of jaundice or complains of liver diseases.

Results

The study revealed 30% prevalence of HEV in this population. The prevalence increased with age, but there was no gender difference.

Conclusion

HEV is a highly prevalent disease in Bangladesh as elsewhere in the developing world. Since there is no specific treatment for HEV, improvement of personal hygiene and ensuring supply of safe food and drinking water remain most important approach to sustain the virus.

How to cite this article: Rahman S, Mahtab MA, Jahan M, Tabassum S, Akbar SMF. Epidemiology of Hepatitis E Virus in an Urban Community in Dhaka City. Euroasian J Hepato-Gastroenterol 2014; 4(1):4-6.

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.

Chronic hepatitis e virus infection and treatment

It is now well accepted that hepatitis E virus (HEV) infection can induce chronic hepatitis and cirrhosis in immunosuppressed patients. Chronic genotype-3 HEV infections were first reported in patients with a solid-organ transplant. Thereafter, cases of chronic HEV infection have been reported in patients with hematological disease and in those who are human immunodeficiency virus (HIV)-positive. HEV-associated extra-hepatic manifestations, including neurological symptoms, kidney injuries, and hematological disorders, have been also reported. In transplant patients, reducing the dosage of immunosuppressive drugs allows the virus to be cleared in some patients. In the remaining patients, as well as hematological patients and patients who are HIV-positive, anti-viral therapies, such as pegylated interferon and ribavirin, have been found to be efficient in eradicating HEV infection. This review summarizes our current knowledge of chronic HEV infection, its treatment, and the extra-hepatic manifestations induced by HEV.

Hepatitis E virus infection

PURPOSE OF REVIEW

The spectrum of hepatitis E virus (HEV) infection has changed over the past 2 years, especially in the developed world. Herein, we review the progress made in studying the epidemiology, hepatic, and extrahepatic manifestations, and the treatment of HEV infection, over the past 2 years.

RECENT FINDINGS

HEV infection is an underdiagnosed disease because of the use of low-sensitivity serological assays. In addition to the four known genotypes, other new genotypes have also been recently described. HEV infection is not only a self-limiting disease but it can also evolve to chronic hepatitis and cirrhosis in organ transplant patients, hematological patients receiving chemotherapy, and HIV patients. HEV can also cause extrahepatic manifestations, such as neurological symptoms, kidney injury, and hematological disorders. Pegylated interferon and ribavirin have been found to effectively treat HEV infection.

SUMMARY

HEV is a worldwide disease that can cause hepatic and extrahepatic manifestations.

Hepatitis E seroprevalence in recipients of renal transplants or haemodialysis in southwest England: a case-control study

Locally acquired HEV infection is increasingly recognized in developed countries. Anti-HEV IgG seroprevalence has been shown to be high in haemodialysis patients in a number of previous studies, employing assays of uncertain sensitivity. The aim of this study was to investigate anti-HEV IgG seroprevalence in recipients of haemodialysis and renal transplants compared to a control group using a validated, highly sensitive assay. Eighty-eight patients with functioning renal transplants and 76 receiving chronic haemodialysis were tested for HEV RNA and anti-HEV IgG and IgM. Six hundred seventy controls were tested for anti-HEV IgG. Anti-HEV IgG was positive in 28/76 (36.8%) of haemodialysis and 16/88 (18.2%) of transplant patients. HEV RNA was not found in any patient. 126/670 (18.8%) of control subjects were anti-HEV IgG positive. After adjusting for age and sex, there was a significantly higher anti-HEV IgG seroprevalence amongst haemodialysis patients compared to controls (OR = 1.97, 95% CI = 1.16-3.31, P = 0.01) or transplant recipients (OR = 2.63, 95% CI = 1.18-6.07, P = 0.02). Patients with a functioning transplant showed no difference in anti-HEV IgG seroprevalence compared to controls. The duration of haemodialysis or receipt of blood products were not significant risk factors for HEV IgG positivity. Patients receiving haemodialysis have a higher seroprevalence of anti-HEV IgG than both age- and sex-matched controls and a cohort of renal transplant patients. None of the haemodialysis patients had evidence of chronic infection. The reason haemodialysis patients have a high seroprevalence remains uncertain and merits further study.

Fatal course of an autochthonous hepatitis E virus infection in a patient with leukemia in Germany

An acute infection with hepatitis E virus (HEV) genotype 3 subtype c was diagnosed in a patient with chronic lymphatic B-cell leukemia 6 weeks after the infusion of donor lymphocytes. Despite intensive care the patient died 39 days after admission due to pericardial effusion that was related to acute liver failure. We suggest that diagnostic procedures for detection of HEV infection should be seriously considered for the immunocompromised patient with elevated liver enzymes in the absence of a travel history to HEV endemic countries.

Hepatitis E virus infection in developed countries

Hepatitis E was considered to be endemic infectious disease in developing countries in tropical or subtropical regions with poor sanitary conditions. Large, previously reported outbreaks were mainly due to contaminated water or heavy flooding. Prototype hepatitis E viruses of genotypes I and II were obtained from such endemic cases. In developed countries, in contrast, hepatitis E was rare and diagnosed only in travelers or imported cases. However, the development of accurate diagnostic tests, mainly PCR detection elucidated that autochthonous hepatitis E in developed countries is far more common than previously thought. Although the main route of transmission is food-borne, other routes including blood-borne have been suggested. Recent developments of gene-based diagnostic assays and molecular epidemiology have disclosed the significance of hepatitis E virus infection in developed countries.

Hepatitis E vaccine: current status and future prospects

HEV, a positive ssRNA and nonenveloped virus, is endemic in many developing countries and one of the most frequent causes of acute hepatitis after fecal–oral transmission. Pregnant women are at particular risk for a fatal course of disease, including maternal and fetal mortality. Recent reports indicate that HEV genotype 3, possibly related to zoonotic transmission, may cause chronic hepatitis in some immunosuppressed organ transplant patients. Various approaches have been conducted to develop HEV vaccines, but only one candidate, a recombinant HEV (rHEV) vaccine generated from Spodoptera frugiperda-9 cells by baculoviruses expressing the HEV capsid antigen, has reached clinical Phase I and II trials so far. These trials suggest that the rHEV vaccine is safe and can prevent clinically overt acute hepatitis E in high-risk populations. We herein review the different approaches in HEV-vaccine development and critically discuss the current status and future directions of the rHEV vaccine used in clinical trials.

Prevalence of hepatitis E virus among wild boar in the Ehime area of western Japan

AIMS

Transmission of hepatitis E virus (HEV) from wild boar to humans has been reported, particularly from Japan. We attempted to clarify this issue.

METHODS

We assessed the IgG class antibodies against HEV (anti-HEV) in serum samples taken from 406 boar living in the Ehime area of western Japan from 2001 to 2004, of which 392 were captured in the wild (wild-caught boar) and 14 had been kept in a breeding farm (bred boar).

RESULTS

Anti-HEV positive rate in the bred boar (10/14, 71.4%) was significantly higher than in the wild-caught boar (100/392, 25.5%) (P < 0.001). Of the 392 wild-caught boar, 12 (3.1%) were positive for HEV-RNA, 10 of which were then subjected to phylogenetic analyses by sequencing an 821-nt fragment within ORF1. All the 10 isolates segregated to genotype 3, and eight of them were mutually related to form a cluster. All the eight HEV isolates in this cluster were from the wild-caught boar living in one and the same habitat within the studied area, while the other two independent isolates were from different regions.

CONCLUSION

HEV infection is endemic in wild boar in the Ehime area, and we should regard the wild boar as an important reservoir of HEV.

Prevalence of hepatitis E virus infection in regular hemodialysis patients

The percentage of patients infected with blood-borne diseases, including hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, is high in patients undergoing hemodialysis regularly. Hepatitis E virus (HEV) is transmitted via the fecal-oral route, and blood-borne HEV infection has also been reported recently. On the basis of these findings, we investigated the actual status of HEV infection in regular hemodialysis patients. Out of 1077 patients undergoing hemodialysis at two key hospitals and three outpatient hemodialysis clinics, 300 were randomly selected as the subjects. Among these 300 hemodialysis patients, 19.0% were IgG-type anti-HEV antibody-positive. The percentage of HEV-infected patients increased with patient age and it was particularly high in patients 40 years of age or older. The percent IgG-type anti-HEV antibody positivity was not significantly different (P = 0.14) between anti-HCV antibody-positive patients (27.8%) and anti-HCV antibody-negative patients (17.8%). The percentage of HEV-infected patients among the hemodialysis patients was higher than that previously reported among patients with healthy kidneys. No correlation was observed between the percentage of HEV-infected patients and HCV infection incidence or a history of blood transfusion. The percent IgG-type anti-HEV antibody positivities were significantly different among the facilities. It was impossible to specify the route of infection, and the correlation between the incidence of infection and hemodialysis therapy was not clear. Because more routes of infection are possible for patients undergoing dialysis than for persons with normal kidney function, it seems necessary to analyze the significance of infection incidence, the route of infection and infection prevention measures.

Hepatitis E viruses in humans and animals

Hepatitis E virus (HEV) is an emerging pathogen belonging to a newly recognized family of RNA viruses (Hepeviridae). HEV is an important enterically transmitted human pathogen with a worldwide distribution. It can cause sporadic cases as well as large epidemics of acute hepatitis. Epidemics are primarily waterborne in areas where water supplies are contaminated with HEV of human origin. There is increasing evidence, however, that many animal species are infected with an antigenically similar virus. A recently isolated swine virus is the best candidate for causing a zoonotic form of hepatitis E. The virus is serologically cross-reactive with human HEV and genetically very similar, and the human and swine strains seem to be cross-infective. Very recent evidence has also shown that swine HEV, and possibly a deer strain of HEV, can be transmitted to humans by consumption of contaminated meat. In this review, we discuss the prevalence, pathogenicity, diagnosis and control of human HEV, swine HEV, the related avian HEV and HEV in other hosts and potential reservoirs.

Hepatitis E virus infection in hemodialysis patients: a seroepidemiological survey in Iran

BACKGROUND

The hepatitis E virus (HEV) has a global distribution and is known to have caused large waterborne epidemics of icteric hepatitis. Transmission is generally via the fecal-oral route. Some reports have suggested parenteral transmission of HEV. Anti-HEV prevalence data among chronic hemodialysis (HD) patients are few and give conflicting results.

METHODS

This cross-sectional study was conducted in August of 2004. We tested 324 chronic HD patients attending three different units in the city of Tabriz, northwestern part of Iran, for anti-HEV antibody. A specific solid- phase enzyme-linked immunoassay (Diapro, Italy) was used.

RESULTS

The overall seroprevalence of hepatitis E was 7.4 %(95% CI: 4.6%-10.6%). The prevalence rate of HBV and HCV infection were 4.6% (95% CI: 2.3%-6.9%) and 20.4% (95% CI: 16%-24.8%), respectively. No significant association was found between anti-HEV positivity and age, sex, duration of hemodialysis, positivity for hepatitis B or C virus infection markers and history of transfusion.

CONCLUSION

We observed high anti-HEV antibody prevalence; there was no association between HEV and blood borne infections (HBV, HCV, and HIV) in our HD patients. This is the first report concerning seroepidemiology of HEV infection in a large group of chronic HD individuals in Iran.

Hepatitis E virus antibodies in hemodialysis patients: an epidemiological survey in central Greece

Hepatitis E virus (HEV) is the causative agent for enteric non-A, non-B hepatitis. Transmission is mainly via the fecal-oral route but the possibility of an additional parenteric transmission has been raised. Patients undergoing chronic hemodialysis (HD) have an increased risk of exposure to blood transmitted agents. Previous studies concerning prevalence of antibodies to HEV (anti-HEV) among HD patients gave conflicting results. The aim of the study presented here was to determine the prevalence of anti-HEV among HD patients of a well-defined semi-rural region in central Greece (Thessalia region). All patients (n=351, 234 males, mean age 60+/-14 years) who were being treated in the HD units of central Greece (n=5) during 2001 were tested for anti-HEV antibody. Two commercially available specific solid-phase enzyme-linked immunoassays were applied for anti-HEV detection. Hepatitis B virus markers, antibodies to HCV, HIV and HTLV were also screened in all patients by commercially available assays. Serum aminotransferase (AST, ALT) levels were measured by spectrophotometry. 17 anti-HEV-positive patients were found and prevalence was 4.8%, varying from 1.8 - 9.8% in the various HD units. Prevalence of HBsAg and anti-HCV was 5.7% (2.9 - 15%) and 23.6% (11.5 - 36.2%) respectively. The anti-HEV prevalence was increased compared to healthy blood donors in Greece (0.26%, p < 0.01). The highest prevalence of anti-HEV was seen at the HD unit of the General Hospital of Karditsa (9.8%). Risk factors for anti-HEV antibody were not identified: no association was found between anti-HEV positivity and age or sex, duration of HD, hepatitis B or C virus infection markers, previously elevated aminotransferase levels or history of transfusion. Our investigation of HEV infection in the cohort of HD patients in central Greece showed that the prevalence of anti-HEV was greater than in healthy blood donors. There was no association to blood borne infections (HBV, HCV). The high prevalence of anti-HEV we found in one HD unit was probably related to a local infection in the past. However, long-term prospective studies are needed in an attempt to identify whether intra-unit factors are also responsible for the increased prevalence of serologic markers of HEV infection among HD patients.

Hepatitis E Vaccines

Hepatitis E accounts for the major part of enterally transmitted non-A, non-B hepatitis worldwide. Its agent, the hepatitis E virus (HEV), is a small, single-stranded RNA virus. Only one serotype of HEV is recognised. Infection results in protective immunity with long-lived neutralising antibodies. In developing countries with poor sanitary conditions and high population density, hepatitis E causes water-borne epidemics with substantial mortality rates in pregnant women. In addition, more than 50% of cases of acute hepatic failure and sporadic acute hepatitis are due to hepatitis E. The overall prevalence rates of antibodies to the HEV in populations native to these areas rarely exceed 25%. Hence, many individuals remain susceptible to hepatitis E infection, making hepatitis E an important public health concern. In this context, the development of an HEV vaccine is warranted. Because HEV does not grow adequately in cell cultures the development of a vaccine based on inactivated or attenuated whole-virus particles is not feasible. HEV vaccines currently under study are based on recombinant proteins derived from immunogenic parts of the HEV capsid gene. Other approaches such as DNA-based vaccines or transgenic tomatoes have also been developed. Several recombinant protein-based vaccines elicited neutralising antibodies and protective immunity in vaccinated non-human primates. One such vaccine has passed phase I trial and is currently under further evaluation in field trials. Even so, several questions remain to be answered before vaccination programmes could be implemented.