Possible risk factors for the transmission of hepatitis E virus and for the severe form of hepatitis E acquired locally in Hokkaido, Japan

Recent advances in hepatitis E virus research and the Japanese clinical practice guidelines for hepatitis E virus infection

Acute hepatitis E was considered rare until reports emerged affirming the existence of hepatitis E virus (HEV) genotypes 3 and 4 infections in Japan in the early 2000s. Extensive studies by Japanese researchers have highlighted the pivotal role of pigs and wild animals, such as wild boars and deer, as reservoirs for HEV, linking them to zoonotic infections in Japan. Currently, when hepatitis occurs subsequent to the consumption of undercooked or grilled pork, wild boar meat, or offal (including pig liver and intestines), HEV infection should be considered. Following the approval of anti-HEV immunoglobulin A antibody as a diagnostic tool for hepatitis E by Japan's Health Insurance System in 2011, the annual number of diagnosed cases of HEV infection has surged. Notably, the occurrence of post-transfusion hepatitis E promoted nationwide screening of blood products for HEV using nucleic acid amplification tests since 2020. Furthermore, chronic hepatitis E has been observed in immunosuppressed individuals. Considering the significance of hepatitis E, heightened preventive measures are essential. The Japan Agency for Medical Research and Development Hepatitis A and E viruses (HAV and HEV) Study Group, which includes special virologists and hepatologists, held a virtual meeting on February 17, 2024. Discussions encompassed pathogenesis, transmission routes, diagnosis, complications, severity factors, and ongoing and prospective vaccination or treatments for hepatitis E. Rigorous assessment of referenced studies culminated in the formulation of recommendations, which are detailed within this review. This comprehensive review presents recent advancements in HEV research and Japanese clinical practice guidelines for HEV infection.

Global burden of acute hepatitis E between 1990 and 2019 and projections until 2030

BACKGROUND AND AIMS

Acute hepatitis E (AHE) is still a public health issue worldwide. Here, we report the global burden of AHE in 204 countries and territories from 1990 to 2019 by age, sex and socio-demographic index (SDI), and predict the future trends to 2030.

METHODS

Data on AHE were collected from the Global Burden of Diseases, Injuries and Risk Factors Study 2019. The average annual percentage change (AAPC) and joinpoint analysis were used to determine the burden trend.

RESULTS

In 2019, there were 19.47 million (95% UI, 16.04 to 23.37 million) incident cases of AHE globally, with a 19% increase since 1990. Age-standardized rate (ASR) of disability-adjusted life years (DALYs), prevalent and incident cases declined from 1990 to 2019. In 2019, the ASR of incidence, prevalence and DALYs due to HEV infection were highest in the same regions of South Asia for both sexes. Southern Sub-Saharan Africa presented the highest increases in the ASR for incidence of HEV infection in both males (AAPC = .25) and females (AAPC = .24) from 1990 to 2019. Incident cases are higher in males than females before 55-59 years old. The SDI values were negatively correlated with the age-standardized DALYs. Between 2019 and 2030, the ASR for incidence and prevalence of HEV for both sexes showed an increasing trend.

CONCLUSIONS

Although the overall ASR of AHE decreased, the burden of AHE remains an underappreciated problem for society. The findings may provide useful information for policymakers to develop appropriate strategies aimed at reducing the burden of AHE.

The first reported hepatitis E outbreak in a food manufacturing factory: Korea, 2022

OBJECTIVES

On February 16, 2022, 12 cases of hepatitis E virus (HEV) infection were reported in a food manufacturing factory in Korea. The aim of this study was to identify additional cases and to determine the source of this HEV outbreak.

METHODS

This study was an in-depth investigation of 12 HEV immunoglobulin M (IgM)-positive cases and their demographic, clinical, and epidemiological characteristics. On-site specimens were collected from the environment and from humans, and a follow-up investigation was conducted 2 to 3 months after the outbreak.

RESULTS

Among 80 production workers in the factory, 12 (15.0%) had acute HEV infection, all of whom were asymptomatic. The follow-up investigation showed that 3 cases were HEV IgMpositive, while 6 were HEV IgG-positive. HEV genes were not detected in the HEV IgM-positive specimens. HEV genes were not detected in the food products or environmental specimens collected on-site. HEV was presumed to be the causative pathogen. However, it could not be confirmed that the source of infection was common consumption inside the factory.

CONCLUSIONS

This was the first domestic case of an HEV infection outbreak in a food manufacturing factory in Korea. Our results provide information for the future control of outbreaks and for the preparation of measures to prevent domestic outbreaks of HEV infection.

Viral hepatitis in pregnancy

Viral hepatitis is caused by a heterogenous group of viral agents representing a wide range of phylogenetic groups. Many viruses can involve the liver and cause liver injury but only a subset are delineated as 'hepatitis viruses' based upon their primary site of replication and tropism for hepatocytes which make up the bulk of the liver cell population. Since their discovery, beginning with the agent that caused serum hepatitis in the 1960s, the alphabetic designations have been utilized. To date, we have five hepatitis viruses, A through E, though it is postulated that others may exist. This chapter will focus on those viruses. Note that hepatitis D is included as a subset of hepatitis B, as it cannot exist without concurrent hepatitis B infection. Pregnancy has the potential to affect all aspects of these viral agents due to the unique immunologic and physiologic changes that occur during and after the gestational period. In this review, we will discuss the most common viral hepatitis and their effects during pregnancy.

Broadly Reactive Real-Time RT-PCR Assay for the Detection of Hepatitis E Virus and Simultaneous Genotyping by Single Nucleotide Polymorphism Analysis

Hepatitis E virus (HEV) infection is a global public health concern. Although HEV infection is usually asymptomatic and self-limiting, extrahepatic manifestations and chronic infections in immunocompromised patients have been described. HEV strains infecting humans have been classified into four main genotypes. In this study we have developed and validated a novel sensitive real-time RT-PCR assay for the detection of all four HEV genotypes. Simultaneous discrimination of genotypes 1, 2, and 4 from genotype 3 by single nucleotide polymorphism (SNP) analysis was possible. In all, 201 serum samples from cases and carriers previously tested for HEV by nested RT-PCR were analyzed. Twenty-seven HEV-positive samples could not be typed by the nested RT-PCR and nucleotide sequencing, but were newly typed by SNP analysis. As polymorphisms were present at the primer or probe binding site, we adopted a degenerate primer and mixed probes. When a mixed probe was added, the fluorescence intensity increased, facilitating genotype determination.

IMPORTANCE The distribution of HEV-3 and HEV-4 has been changing. HEV-4, which had been predominantly found in Asia, is now being detected in other parts of the world, and there are now reports of chronic infections. Additionally, neurological disorders have frequently been reported in patients with acute or chronic HEV infections. HEV-4 has also been shown to lead to a higher severity in terms of acute hepatitis than does HEV-3. Early typing can provide useful information regarding the route of infection and for tailoring treatment to the expected course of the disease. The present method afforded a good detection rate even when polymorphisms were present within the target region for viral gene detection. We believe that this method can be applied to the analysis of mutation-prone viral genes in the future.

Hepatitis E Virus: An emerging enigmatic and underestimated pathogen

Hepatitis E virus (HEV) is an RNA virus causing hepatitis E disease. The virus is of one serotype but has diverse genotypes infecting both humans and animals. Based on evidence from seroprevalence studies, about 2 billion people are estimated to have been infected with HEV globally. HEV, therefore, poses a significant public health and economic challenge worldwide. HEV was discovered in the 1980s and was traced back to the 1955 - 1956 outbreak of hepatitis that occurred in India. Subsequently, several HEV epidemics involving thousands of individuals have occurred nearly annually in different countries in Asia and Africa. Initially, the virus was thought to be only enterically transmitted, and endemic in developing countries. Due to the environmental hygiene and sanitation challenges in those parts of the world. However, recent studies have suggested otherwise with the report of autochthonous cases in industrialised countries with no history of travel to the so-called endemic countries. Thus, suggesting that HEV has a global distribution with endemicity in both developing and industrialised nations. Studies have also revealed that HEV has multiple risk factors, and modes of transmission as well as zoonotic potentials. Additionally, recent findings have shown that HEV leads to severe disease, particularly among pregnant women. In contrast to the previous narration of a strictly mild and self-limiting infection. Studies have likewise demonstrated chronic HEV infection among immunocompromised persons. Consequent to these recent discoveries, this pathogen is considered a re - emerging virus, particularly in the developed nations. However, despite the growing public health challenges of this pathogen, the burden is still underestimated. The underestimation is often attributed to poor awareness among clinicians and a lack of routine checks for the disease in the hospitals. Thus, leading to misdiagnosis and underdiagnosis. Hence, this review provides a concise overview of epidemiology, diagnosis, and prevention of hepatitis E.

A systematic review and meta-analysis of hepatitis E virus (HEV) in wild boars

This systematic review and meta-analysis summarize the available information on Hepatitis E virus (HEV) -specific antibody seroprevalence and HEV RNA prevalence in wild boar, one of the most abundant game species worldwide. A literature search (CAB Abstracts, Web of Science, Embase and Scopus) was performed to find relevant peer-reviewed works published during the period 1990-2020. A random-effect model was carried out to calculate the pooled HEV-specific antibody seroprevalence and HEV RNA prevalence estimates with 95% confidence intervals, and I2 statistic was used to assess the heterogeneity of the data. Values by subgroups were compared according to the geographical area, age class (≤ 12 months old and > 12 months old), and sample type (bile, faeces, liver, meat/muscle, serum). Sixty-nine publications were selected, with the majority of the studies from Southern Europe (n = 27). The pooled HEV-specific antibody seroprevalence in wild boar was 28% (CI95% 23-34) and the HEV RNA prevalence 8% (CI95% 6-10). The analysis highlighted a significant heterogeneity among the estimates from the included studies (I2 = 98% and I2 = 95% for HEV-specific antibody seroprevalence and viral prevalence respectively). The moderator analysis indicated a statistically significant difference (p-value = 0.03) for the HEV RNA prevalence according to the sample type, with the highest value in bile (17%, CI95% 9-27), followed by liver (10%, CI95% 7-14), serum (7%, CI95% 4-10), faeces (5%, CI95% 2-9), and meat/muscle (3%, CI95% 0.04-10). Finally, the HEV RNA prevalence in Europe (8.7, CI95% 6.7-11) was significantly (p-value = 0.04) higher than in Asia (4, CI95% 0.6-8). The analysis highlights the important role of wild boar in the epidemiology of HEV.

An Autopsy Case of Primary Biliary Cholangitis with Histological Submassive Hepatic Necrosis Caused by Acute Hepatitis E Virus Infection

A 59-year-old woman who had been diagnosed with cirrhotic primary biliary cholangitis (PBC) 5 years earlier was admitted for severe jaundice (total bilirubin: 30.1 mg/dL). We suspected that her cirrhotic PBC had deteriorated acutely for some reason. Her general condition deteriorated quickly, and she passed away on day 18 of admission. Hepatitis E virus (HEV)-IgA antibodies were positive, and Genotype 3b HEV involvement was confirmed from a blood sample taken on admission. Histopathological findings revealed cirrhosis and submassive loss and necrosis of hepatocytes. Clinicians should consider the possibility of acute HEV infection as a trigger for acute PBC exacerbation.

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.

Analyses of Clinical and Biological Data for French and Belgian Immunocompetent Patients Infected With Hepatitis E Virus Genotypes 4 and 3

Hepatitis E virus (HEV) genotypes 3 and 4 are the major causes of acute hepatitis in industrialized countries. Genotype 3 is mainly found in Europe and America, while genotype 4 is predominant in Asia. Several Japanese studies have suggested that genotype 4 is more virulent than genotype 3. We investigated this aspect by analyzing the clinical and biological data for 27 French and Belgian immunocompetent patients infected with HEV genotype 4. Their infections were probably acquired locally, since none of these patients reported traveling outside France or Belgium during the 2–8 weeks before symptoms onset. Each patient was matched for age (±5 years) and gender with two patients infected with HEV genotype 3. Bivariate analysis indicated that the HEV genotype 4-infected patients had significantly higher alanine aminotransferase (ALT) (2067 IU/L) and aspartate aminotransferase (AST) (1581 IU/L) activities and total bilirubin concentrations (92.4 μmol/L) than did those infected with HEV genotype 3 (1566 IU/L, p = 0.016; 657 IU/L, p = 0.003 and 47 μmol/L, p = 0.046) at diagnosis. In contrast, more patients infected with HEV genotype 3 reported dark urine (71% vs. 39%, p = 0.02) and experienced asthenia (89% vs. 58%, p < 0.01) than did those infected with HEV genotype 4. Two HEV genotype 4-infected patients died of multi-organ failure, while none of the genotype 3-infected patients died (p = 0.035). Finally, stepwise regression analysis retained only a greater increase in ALT (odds-ratio: 1.0005, 95% confidence interval: 1.00012–1.00084) and less frequent fever (odds-ratio = 0.1244; 95% confidence interval: 0.01887–0.82020) for patients infected with HEV genotype 4. We conclude that HEV-4 infections are likely to be associated with higher ALT activity than HEV-3 infections. Additional immunological and virological studies are required to confirm these findings and better understand the influence, if any, of genotype on HEV pathophysiology.

A review of food poisoning caused by local food in Japan

Increasingly popular worldwide, Japanese cuisine includes several raw preparations such as sashimi and sushi; however, limited information on food poisoning from Japanese local food is available in English literature. Without appropriate knowledge, physicians may underdiagnose traveler's diarrhea among people returning from Japan. To provide accurate information to primary care physicians worldwide, we conducted a narrative review on food poisoning research published in Japanese and English over the past four years, considering the frequency and clinical importance of various presentations.

Hepatitis E in Sub Saharan Africa - A significant emerging disease

Hepatitis E is an emerging endemic disease found across the African continent, but there are clear differences in epidemiology between North Africa and countries south of the Sahara. In this systematic review, Google scholar and PubMed databases were searched for peer-reviewed articles on HEV epidemiology. Publications meeting our inclusion criteria were critically reviewed to extract consistent findings and identify knowledge gaps. Hepatitis E has been reported in 25 of the 49 countries in Sub Saharan Africa.

Mortality rates of 1–2% in the general population and ~ 20% in pregnant women. Outbreaks were closely linked to refugees and Internally Displaced Persons in camps which accounted for 50% of reported outbreaks. There was very little research and concrete evidence for sources of contamination and transmission routes. There are indications of zoonotic transmission of Hepatitis E Virus infection but further research in these fields is required.

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No data from 50% of African countries

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Outbreaks closely linked to refugee and IDP camps

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Little data on sources of HEV contamination

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Indications but little evidence of zoonotic transmission

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Low awareness amongst health professionals and general public

The First Case Report of Acute Symptomatic HEV Genotype 4 Infection in an HIV-positive Patient in Japan

Hepatitis E virus (HEV) is a common cause of acute hepatitis. Four major genotypes of HEV have been studied, with genotype 4 being the predominant genotype across Asia. We herein describe the case of a 50-year-old man with a history of human immunodeficiency virus (HIV) infection who was admitted with acute transaminitis. Serum anti-HEV-IgA and HEV-RNA were detected at the time of presentation and further testing revealed HEV genotype 4. To the best of our knowledge, this represents the first clinical case report of acute symptomatic HEV genotype 4 infection in an HIV-positive patient in Japan.

Hepatitis E: an expanding epidemic with a range of complications

BACKGROUND

Hepatitis E virus (HEV) is a common cause of viral hepatitis worldwide. Previously considered a disease of the developing world, it is increasingly recognized that locally acquired HEV infection is common in industrialized countries.

OBJECTIVES

The aim was to highlight the changing epidemiology of HEV infection, particularly in the developed world, and inform clinicians of the diverse clinical presentations and extra-hepatic complications associated with the virus.

SOURCES

References for this review were identified through searches of MEDLINE/PubMed, and Google Scholar, up to January 2020. Searches were restricted to articles published in English.

CONTENT

Hepatitis E virus is an under-recognized, emerging pathogen with important implications for public health in both the developing and developed world. The number of cases reported in resource-rich settings is increasing, in part due to improved case ascertainment but also as a result of increased incidence in some countries. The reasons behind these epidemiological shifts are not currently known. Chronic HEV infection has been reported in immunocompromised patients. A range of extra-hepatic manifestations have also been reported, most notably neurological and renal complications. There is evidence to suggest a causal link with Guillain-Barré syndrome, neuralgic amyotrophy and encephalitis/myelitis. Glomerular disease has been reported in the context of both acute and chronic infection.

IMPLICATIONS

HEV should be included in non-invasive liver screens and considered in the differentials for patients presenting with alanine aminotransferase elevation, suspected drug-induced liver injury or decompensated liver disease. Any patients with acute neurological injury and deranged liver function should be tested for hepatitis E, and all patients presenting with Guillain-Barré syndrome or neuralgic amyotrophy should be tested regardless of liver enzymes. Immunocompromised patients with persistently raised liver enzymes should be tested with molecular techniques and offered annual routine screening.

Occurrence of Hepatitis E Virus in Pigs and Pork Cuts and Organs at the Time of Slaughter, Spain, 2017

Zoonotic hepatitis E, mainly caused by hepatitis E virus (HEV) genotype (gt) 3, is a foodborne disease that has emerged in Europe in recent decades. The main animal reservoir for genotype 3 is domestic pigs. Pig liver and liver derivates are considered the major risk products, and studies focused on the presence of HEV in pig muscles are scarce. The objective of the present study was to evaluate the presence of HEV in different organs and tissues of 45 apparently healthy pigs from nine Spanish slaughterhouses (50% national production) that could enter into the food supply chain. Anti-HEV antibodies were evaluated in serum by an ELISA test. Ten samples from each animal were analyzed for the presence of HEV RNA by reverse transcription real-time PCR (RT-qPCR). The overall seroprevalence obtained was 73.3% (33/45). From the 450 samples analyzed, a total of 26 RT-qPCR positive samples were identified in the liver (7/45), feces (6/45), kidney (5/45), heart (4/45), serum (3/45), and diaphragm (1/45). This is the first report on detection of HEV RNA in kidney and heart samples of naturally infected pigs. HEV RNA detection was negative for rib, bacon, lean ham, and loin samples. These findings indicate that pig meat could be considered as a low risk material for foodborne HEV infection.

Incidence, predictors and prognosis of genotype 4 hepatitis E related liver failure: A tertiary nested case-control study

BACKGROUND/AIMS

Hepatitis E virus (HEV) infection has been recognized an important insult of acute or acute-on-chronic liver failure (A(C)LF). This study aimed to identify the incidence, predictors and outcomes of A(C)LF in patients with hepatitis E.

METHODS

All patients diagnosed of hepatitis E between 2012 and 2018 in the tertiary hospital were retrospectively and consecutively analysed. Patients with hepatitis E who developed A(C)LF were enrolled as cases (HEV-LF) and controls were randomly selected from those who did not develop liver failure with 1:3 ratio in the same cohort.

RESULTS

Eight hundred and nine patients were diagnosed with hepatitis E, among which 80 were identified with HEV-related liver failure (HEV-LF) with HEV as the solely acute aetiology of A(C)LF. Sequencing of HEV genome showed genotype (GT) 4 strains in all available serum samples. Hepatitis E patients with cirrhosis underwent higher risk to develop liver failure, compared to non-cirrhotic patients. Hydrothorax, respiratory infections, lower γ-glutamyl transferase, higher lactate dehydrogenase and alpha-foetoprotein were found to be independent predictors of A(C)LF in patients with hepatitis E. The 28-day and 90-day mortality for HEV-LF was 12.86% and 30.36% respectively. Renal injury and lower triglyceride were independent factors associated with 28-day mortality. Lower alanine aminotransferase and higher International normalized ratio were independent predictors of 90-day mortality.

CONCLUSIONS

Patients with GT4 hepatitis E are at high risk to develop A(C)LF. Different CLD status impacted the incidence of HEV-LF distinctively. The identified variables shall help to identify HEV patients with high risk for developing liver failure and the risk for death.

[Hepatitis E Virus: Epidemiology, Diagnosis, and Management]

The HEV is a known cause of water-borne outbreaks of acute non-A non-B hepatitis in developing countries, which affects young people and may result in high mortality in pregnant women. In recent decades, however, HEV genotypes 3 and 4 have been known as a cause of sporadic zoonotic infections in older males from swine HEV worldwide. Most acute HEV infections are self-limited. On the other hand, in immunosuppressed patients, including solid organ transplant recipients, chronic HEV infections may exist and progress to liver cirrhosis or decompensation. Therefore, physicians need to recognize HEV as a major pathogen for acute and chronic hepatitis of unknown causes and investigate this disease.

Donor-Derived Genotype 4 Hepatitis E Virus Infection, Hong Kong, China, 2018

Hepatitis E virus (HEV) genotype 4 (HEV-4) is an emerging cause of acute hepatitis in China. Less is known about the clinical characteristics and natural history of HEV-4 than HEV genotype 3 infections in immunocompromised patients. We report transmission of HEV-4 from a deceased organ donor to 5 transplant recipients. The donor had been viremic but HEV IgM and IgG seronegative, and liver function test results were within reference ranges. After a mean of 52 days after transplantation, hepatitis developed in all 5 recipients; in the liver graft recipient, disease was severe and with progressive portal hypertension. Despite reduced immunosuppression, all HEV-4 infections progressed to persistent hepatitis. Four patients received ribavirin and showed evidence of response after 2 months. This study highlights the role of organ donation in HEV transmission, provides additional data on the natural history of HEV-4 infection, and points out differences between genotype 3 and 4 infections in immunocompromised patients.

Hepatitis E Virus Infection in Blood Donors and Risk to Patients in the United States and Canada

Hepatitis E virus (HEV) is the most common cause of acute hepatitis worldwide including large water-borne outbreaks, zoonotic infections and transfusion transmissions. Several countries have initiated or are considering blood donor screening in response to high HEV-RNA donation prevalence leading to transfusion-transmission risk. Because HEV transmission is more common through food sources, the efficacy of blood donor screening alone may be limited. HEV-nucleic acids in 101 489 blood donations in the United States and Canada were studied. A risk-based decision-making framework was used to evaluate the quantitative risks and cost-benefit of HEV-blood donation screening in Canada comparing three scenarios: no screening, screening blood for all transfused patients or screening blood for only those at greatest risk. HEV-RNA prevalence in the United States was one per 16 908 (95% confidence interval [CI], 1:5786-1:81987), whereas Canadian HEV-RNA prevalence was one per 4615 (95% CI, 1:2579-1:9244). Although 4-fold greater, Canadian HEV-RNA prevalence was not significantly higher than in the United States. Viral loads ranged from 20 to 3080 international units per mL; all successfully typed infections were genotype 3. No HEV-RNA false-positive donations were identified for 100 percent specificity. Without donation screening, heart and lung transplant recipients had the greatest HEV-infection risk (1:366962) versus kidney transplant recipients with the lowest (1:2.8 million) at costs of $225 546 to $561 810 per quality-adjusted life-year (QALY) gained for partial or universal screening, respectively. Higher cost per QALY would be expected in the United States. Thus, HEV prevalence in North America is lower than in countries performing blood donation screening, and if implemented, is projected to be costly under any scenario.

Genetic Variability and Evolution of Hepatitis E Virus

Hepatitis E virus (HEV) is a single-stranded positive-sense RNA virus. HEV can cause both acute and chronic hepatitis, with the latter usually occurring in immunocompromised patients. Modes of transmission range from the classic fecal–oral route or zoonotic route, to relatively recently recognized but increasingly common routes, such as via the transfusion of blood products or organ transplantation. Extrahepatic manifestations, such as neurological, kidney and hematological abnormalities, have been documented in some limited cases, typically in patients with immune suppression. HEV has demonstrated extensive genomic diversity and a variety of HEV strains have been identified worldwide from human populations as well as growing numbers of animal species. The genetic variability and constant evolution of HEV contribute to its physiopathogenesis and adaptation to new hosts. This review describes the recent classification of the Hepeviridae family, global genotype distribution, clinical significance of HEV genotype and genomic variability and evolution of HEV.

Hepatitis E: an underestimated emerging threat

Hepatitis E virus (HEV) is the most common cause of viral hepatitis in the world. It is estimated that millions of people are infected every year, resulting in tens of thousands of deaths. However, these estimates do not include industrialized regions and are based on studies which employ assays now known to have inferior sensitivity. As such, this is likely to represent a massive underestimate of the true global burden of disease. In the developing world, HEV causes large outbreaks and presents a significant public-health problem. Until recently HEV was thought to be uncommon in industrialized countries, and of little relevance to clinicians in these settings. We now know that this is incorrect, and that HEV is actually very common in developed regions. HEV has proved difficult to study in vitro, with reliable models only recently becoming available. Our understanding of the lifecycle of HEV is therefore incomplete. Routes of transmission vary by genotype and location: endemic regions experience large waterborne epidemics, while sporadic cases in industrialized regions are zoonotic infections likely spread via the food chain. Both acute and chronic infection has been observed, and a wide range of extrahepatic manifestations have been reported. This includes neurological, haematological and renal conditions. As the complete clinical phenotype of HEV infection is yet to be characterized, a large proportion of cases go unrecognized or misdiagnosed. In many cases HEV infection does not feature in the differential diagnosis due to a lack of knowledge and awareness of the disease amongst clinicians. In combination, these factors have contributed to an underestimation of the threat posed by HEV. Improvements are required in terms of recognition and diagnosis of HEV infection if we are to understand the natural history of the disease, improve management and reduce the burden of disease around the world.

Acute liver failure caused by hepatitis E virus genotype 3 and 4: A systematic review and pooled analysis

BACKGROUND & AIMS

Acute liver failure caused by hepatitis E virus genotype 3 and 4 has been rarely described. Because of the presence of a short golden therapeutic window in patients with viral acute liver failure from other causes, it is possible that early recognition and treatment might reduce the morbidity and mortality. We performed a systematic review and pooled analysis of acute liver failure caused by hepatitis E virus genotype 3 and 4.

METHODS

Two reviewers appraised studies after searching multiple databases on June 12th, 2017. Appropriate tests were used to compare hepatitis E virus genotype 3 vs 4, suspected vs confirmed genotypes, hepatitis E virus-RNA positive vs negative, and to discern important mortality risk factors.

RESULTS

We identified 65 patients, with median age 58 years (range: 3-79), and a male to female ratio of 1.2:1. The median bilirubin, ALT, AST and alkaline phosphatase (expressed by multiplication of the upper limit of normal) levels were 14.8, 45.3, 34.8 and 1.63 respectively. Antihepatitis E virus IgG, antihepatitis E virus IgM and hepatitis E virus-RNA were positive in 84%, 91% and 86% of patients respectively. The median interval from symptoms onset to acute liver failure was 23 days, and 16 patients underwent liver transplantation. Final outcome was reported in 58 patients and mortality was 46%. Age was a predictor of poor prognosis in multivariate analysis. No important differences were found between patients infected with genotype 3 vs 4, patients with confirmed vs suspected genotypes, or patients with positive vs negative RNA.

CONCLUSION

Acute liver failure caused by hepatitis E virus genotype 3 and 4 is rare, similar between genotypes, occurs commonly in middle-aged/elderly patients and has a very high mortality. Age is predictive of poor prognosis in multivariate analysis.

Hepatitis E Virus infection seroprevalence and the associated risk factors in animals raised in Ibadan, Nigeria

Hepatitis E (HE) is an important viral hepatitis of global public and livestock health, and food security significance due to the ubiquitous distribution, multiple transmission route and zoonotic potentials. HE is also endemic in most developing countries including Nigeria. This study therefore investigates the seroprevalence and associated risk factors of HEV infection in pigs raised in Ibadan, Nigeria. Taking an analytical cross-sectional study design, 176 animals (comprising 120 pigs, 26 goats, and 30 cattle) were randomly sampled at the Bodija Municipal abattoir, Ibadan. Serum samples and demographic information were collected for HEV antibody detection (using a commercial recombinant genotype-3 antigen ELISA kit) and risk factors, respectively. A 57.5% (69/120) HEV seroprevalence was reported in the pigs while 0% prevalence was reported in the goats and cattle. In the pigs, a significant age-based HEV seropositivity difference (χ² = 5.30; OR = 0.20-0.89; p = 0.02) with a higher seroprevalence in the < 6 months (68.42%; 39/57) compared to the > 6 months age group (47.62%; 20/63) was reported. No significant sex, breed and husbandry system effect on HEV seroprevalence was detected in the pigs. This study therefore underscores the high HEV seroprevalence and age-based odds of HEV-exposure in pigs in Ibadan, Nigeria.

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

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

Hepatitis E virus: zoonotic and foodborne transmission in developed countries

Hepatitis E virus (HEV), together with hepatitis A virus, transmits via the fecal–oral route. The number of domestic hepatitis E cases among Europeans has grown alarmingly during the past 5 years. Surveillance studies suggest that the number of foodborne HEV infections is increasing most rapidly. Zoonotic HEV genotype HEV-3 is prevalent among pigs and wild boars in Europe and many developed countries, whereas zoonotic genotype HEV-4 is more common in pigs in some Asian countries. This review presents the most recent data about possible foodborne transmission of HEV via pigs and other production animals and about the presence of HEV in high-risk foods, such as ready-to-eat meat products. Possible solutions about how to tackle this problem are discussed here.

Detection of hepatitis E virus genotypes 3 and 4 in pig farms in Korea

Zoonotic transmission of hepatitis E virus (HEV) is mostly mediated by HEV-3 and HEV-4 genotypes, and domestic pigs are an important reservoir of these genotypes. A survey of 14 pig farms in Korea revealed HEV RNA in 30 of 148 (20.3%) fecal samples. HEV-3a and HEV-4c subtypes were identified in five pig farms (35.7%) and two pig farms (14.3%), respectively. Phylogenetic analysis indicated that the isolated HEV strains were closely related to previously reported zoonotic strains in Korea. The results of the genetic analysis partially explain the possible source of the zoonotic transmission of HEV to humans in Korea.

Characterization of Three Novel Linear Neutralizing B-Cell Epitopes in the Capsid Protein of Swine Hepatitis E Virus

Hepatitis E virus (HEV) causes liver disease in humans and is thought to be a zoonotic infection, with domestic animals, including swine and rabbits, being a reservoir. One of the proteins encoded by the virus is the capsid protein. This is likely the major immune-dominant protein and a target for vaccination. Four monoclonal antibodies (MAbs), three novel, 1E4, 2C7, and 2G9, and one previously characterized, 1B5, were evaluated for binding to the capsid protein from genotype 4 swine HEV. The results indicated that ⁶²⁵DFCP⁶²⁸, ⁴⁵⁸PSRPF⁴⁶², and ⁴⁰⁷EPTV⁴¹⁰ peptides on the capsid protein comprised minimal amino acid sequence motifs recognized by 1E4, 2C7, and 2G9, respectively. The data suggested that 2C7 and 2G9 epitopes were partially exposed on the surface of the capsid protein. Truncated genotype 4 swine HEV capsid protein (sp239, amino acids 368 to 606) can exist in multimeric forms. Preincubation of swine HEV with 2C7, 2G9, or 1B5 before addition to HepG2 cells partially blocked sp239 cell binding and inhibited swine HEV infection. The study indicated that 2C7, 2G9, and 1B5 partially blocked swine HEV infection of rabbits better than 1E4 or normal mouse IgG. The cross-reactivity of antibodies suggested that capsid epitopes recognized by 2C7 and 2G9 are common to HEV strains infecting most host species. Collectively, MAbs 2C7, 2G9, and 1B5 were shown to recognize three novel linear neutralizing B-cell epitopes of genotype 4 HEV capsid protein. These results enhance understanding of HEV capsid protein structure to guide vaccine and antiviral design.IMPORTANCE Genotype 3 and 4 HEVs are zoonotic viruses. Here, genotype 4 HEV was studied due to its prevalence in human populations and pig herds in China. To improve HEV disease diagnosis and prevention, a better understanding of the antigenic structure and neutralizing epitopes of HEV capsid protein are needed. In this study, the locations of three novel linear B-cell recognition epitopes within genotype 4 swine HEV capsid protein were characterized. Moreover, the neutralizing abilities of three MAbs specific for this protein, 2C7, 2G9, and 1B5, were studied in vitro and in vivo Collectively, these findings reveal structural details of genotype 4 HEV capsid protein and should facilitate development of applications for the design of vaccines and antiviral drugs for broader prevention, detection, and treatment of HEV infection of diverse human and animal hosts.

Disparities in detection of antibodies against hepatitis E virus in US blood donor samples using commercial assays

BACKGROUND

Reported hepatitis E virus (HEV) antibody assay performance characteristics are variable. Using a subset of surplus US blood donation samples, we compared assays for detecting anti-HEV immunoglobulin M (Ig)M and IgG or total anti-HEV antibodies.

STUDY DESIGN AND METHODS

Samples from 5040 random blood donations, all HEV-RNA negative, collected primarily in the midwestern United States in 2015 were tested for anti-HEV IgM and IgG or total anti-HEV using assays manufactured by Diagnostic Systems, Wantai, and MP Biomedicals.

RESULTS

Overall, the percentage of detection for anti-HEV IgG and total anti-HEV was 11.4%, and for anti-HEV IgM was 1.8%. Nine samples were reactive for anti-HEV IgM by all assays, giving a recent infection rate of 0.18%. Anti-HEV IgG/total anti-HEV detection rates increased with age. Interassay agreement was higher among the IgG anti-HEV/total anti-HEV assays (84%) than the IgM assays (22%). Regression analyses of signal-to-cutoff ratios from IgG/total antibody assay were heteroskedastic, indicating no constant variance among these assays, suggesting they may detect different epitopes or were affected by waning or less avid antibodies in the US donor population.

CONCLUSIONS

Although similar percentages of IgG anti-HEV/total anti-HEV detection were observed across the three commercial assays, each assay detected a unique sample subpopulation and was heteroskedastic when compared pairwise. Discordance was higher among anti-HEV IgM assays, but a recent HEV infection rate of at least 0.18% was estimated based on assay concordance.

Detection of Serum Antibodies to Hepatitis E Virus Based on HEV Genotype 3 ORF2 Capsid Protein Expressed in Nicotiana benthamiana

BACKGROUND

Hepatitis E virus (HEV) causes epidemics in developing countries and is primarily transmitted through the fecal-oral route. There have been recent reports on the zoonotic spread of the virus, and several animal species, primarily pigs, have been recognized as reservoirs of HEV. Because of its possible spread, there is an urgent need of a method for the cost-effective production of HEV proteins that can be used as diagnostic antigens for the serological detection of anti-HEV antibodies.

METHODS

The HEV open reading frame (ORF)2 protein was purified from plant tissue by using immobilized metal-anion chromatography (IMAC). The recombinant protein was used to develop an in-house ELISA for testing anti-HEV antibodies in both human and swine sera. Thirty-six serum samples collected from patients with serologically proven HEV infection with commercial kits were tested for anti-HEV IgG antibodies by using the plant-expressed protein. Forty-five serum samples collected from apparently healthy pigs in Bulgarian farms were also tested.

RESULTS

We confirmed the transient expression and purification of a truncated version of the HEV genotype 3 capsid protein in Nicotiana benthamiana and its usefulness as a diagnostic antigen. ELISA showed the presence of anti-HEV IgG antibodies in 29 of the 36 human samples. The in-house ELISA showed anti-HEV IgG antibodies in 34 of the 45 pigs.

CONCLUSIONS

We describe a method for the production of HEV ORF2 protein in N. benthamiana and the usefulness of this protein for the serological detection of anti-HEV antibodies in both humans and swine.

Seroepidemiology and molecular characterization of hepatitis E virus infection in swine and occupationally exposed workers in Punjab, India

Hepatitis E virus (HEV) has two discrete epidemiological patterns: waterborne epidemics in developing countries only, caused by HEV genotype I, and sporadic zoonotic outbreaks in developing and developed countries caused by genotypes III and IV. This study was designed to investigate seroprevalence, molecular detection and the characterization of HEV by nested RT-PCR in swine as well as the occupational risk to exposed human population in Punjab state of north-western India. The occupational risk-exposed group comprised of swine farmers (organized - mixed feed feeders and unorganized - swill feeders), slaughterhouse workers, sewage workers and veterinary internes. During the study period, blood and faecal samples were collected from 320 swine and 360 humans with both high and low occupational exposure risks. The overall seroprevalence of swine HEV was 65.00%, with a significantly higher seropositivity in growing pigs (2-8 months of age). The prevalence of HEV RNA in swine faecal samples by nRT-PCR was 8.75% with a significantly higher detection in swill-fed pigs. With humans in the high occupational exposure risk population, significantly higher anti-HEV IgG seropositivity was observed (60.48%) as compared to control population (10.71%). Strong evidence of association between human anti-HEV IgG seropositivity and certain occupational exposure risk groups was observed (p < 0.05). This indicates that unorganized swine farmers, slaughterhouse workers and sewage workers have higher odds of HEV infection in this study region. Percentage of nucleotide similarity between swine and human HEV isolates was less than that found in countries with zoonotic HEV outbreaks. Molecular characterization revealed the circulation of G IV and G I genotypes among swine and human population in Punjab state, respectively.

Investigation of underlying comorbidities as risk factors for symptomatic human hepatitis E virus infection

BACKGROUND

Symptomatic Hepatitis E virus (HEV) infection occurs in few infected subjects, and the risk factors are not completely known.

AIM

To explore the risk factors for adverse clinical outcomes in acute HEV infections.

METHODS

A large retrospective study was conducted. The baseline characteristics, clinical outcomes, and laboratory data of 512 acute HEV infection cases were analysed using logistic regression models.

RESULTS

All patients exhibited autochthonous sporadic HEV infections, and most were elderly. Their symptoms varied from asymptomatic to severe liver diseases. In all, 215 patients (42.0%) had liver failure and/or decompensation, and 45 (8.2%) patients died within 3 months. Nearly 60% of patients had underlying chronic liver diseases (CLDs), 20% were cirrhotic, and various extrahepatic underlying comorbidities were common. The logistic regression analysis revealed that underlying CLDs, especially cirrhosis, were closely associated with disease severity (OR = 8.78, P < 0.001) but not with mortality in patients with severe liver diseases. In addition to the known factors, including an old age, the male gender and CLDs, we identified pre-existing extrahepatic tumours, diabetes, and chronic respiratory and renal diseases as novel independent predictors for adverse clinical outcomes. Importantly, patients without these four extrahepatic comorbidities showed a much lower mortality rate (4.2%, P < 0.001) than patients with one (18.5%) or more comorbidities (34.5%).

CONCLUSIONS

Previous comorbidities, including tumours, diabetes, and chronic liver, lung and kidney diseases, were independent risk factors for adverse outcomes, especially mortality, in acute HEV infections. This study provides valuable data for improving the prevention and control of HEV infection.

Molecular Epidemiology and Strain Comparison between Hepatitis E Viruses in Human Sera and Pig Livers during 2014 to 2016 in Hong Kong

Hepatitis E virus (HEV) causes substantial morbidity and mortality in developing countries and is considered an emerging foodborne pathogen in developed countries in which it was previously not endemic. To investigate genetic association between human HEV infection and HEV-contaminated high-risk food in Hong Kong, we compared local virus strains obtained from hepatitis E patient sera with those surveyed from high-risk food items during 2014 to 2016. Twenty-four cases of laboratory-confirmed human HEV infections were identified from January 2014 to March 2016 in our hospitals. Five types of food items at risk of HEV contamination were purchased on a biweekly basis from April 2014 to March 2016 in two local market settings: supermarkets (lamb, oyster, and pig liver) and wet markets (oyster, pig blood curd, pig large intestine, and pig liver). HEV RNA detection was performed by a real-time reverse transcription-PCR assay. HEV RNA was detected in pig liver, pig intestine, and oyster samples with prevalences of 1.5%, 0.4%, and 0.2%, respectively. Neighbor-joining phylogenetic inference showed that all human and swine HEV strains belonged to genotype 4. HEV subtype distributions in humans and swine were highly comparable: subtype 4b predominated, while subtype 4d was the minority. Local human and swine HEV genotype 4 strains shared over 95% nucleotide identity and were genetically very similar, implicating swine as an important foodborne source of autochthonous human HEV infections in Hong Kong. Action should be taken to raise the awareness among public and health care professionals of hepatitis E as an emerging foodborne disease.

Isolation of hepatitis E virus genotype 4 from patients with acute cryptogenic hepatitis in Korea

BACKGROUND

Autochthonous hepatitis E occurs sporadically in developed countries. The consumption of undercooked pork containing hepatitis E virus genotype 3 (HEV-3) or 4 (HEV-4) is the major risk factor for infection. The serological diagnostic kits currently used in hospitals sometimes produce false-negative or -positive results. Therefore, detection of both HEV RNA and antibodies to the virus is required for confirmative diagnosis of hepatitis E.

OBJECTIVES

We aimed to detect HEV in serum samples from patients with cryptogenic hepatitis and to determine the origin of HEV.

STUDY DESIGN

A nested polymerase chain reaction (PCR) method was developed for detection of HEV-3 and HEV-4 in patients with hepatitis. A total of 23 serum samples, deposited in 2006-2012, from patients with acute cryptogenic hepatitis who were serologically negative for hepatitis A, B, C, and E were examined using this method. The amplified PCR products were genetically analyzed.

RESULTS

Four HEV-4 isolates were detected from the 23 serum samples. Phylogenetic analysis indicated that three of the four isolates were closely related to HEV-4 isolates found in pigs in Korea and in patients with hepatitis E in Japan.

CONCLUSIONS

The newly developed nested PCR method was useful for detection of HEV in patients with cryptogenic hepatitis. The close relationship between the human HEV-4 isolates identified in this study and swine isolates implied that zoonotic transmission of HEV might be a source of infection in patients with hepatitis.

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.

Incidence and characteristics of hepatitis E virus infection in children in Assiut, Upper Egypt

Objective To describe the characteristics of hepatitis E virus (HEV) infection in a cohort of children from Upper Egypt using data from a large multicentre prospective study of acute viral hepatitis (AVH). Methods Data from subjects aged 2-18 years with AVH or close contacts of those with AVH found to have asymptomatic AVH were included in the analysis. Information concerning medical history, clinical examination, liver function tests and screening for hepatotropic viruses was recorded and analysed. Results A total of 123 patients (73 boys, 50 girls) were included in the analysis. Of these, 33 (26.8%) had HEV infection, 17 (13.8%) had hepatitis A virus infection, 10 (8.1%) had hepatitis B virus infection, 14 (11.4%) had cytomegalovirus hepatitis, five (4.1%) had autoimmune hepatitis, 11 (8.9%) had hepatitis due to mixed viral infections and 33 (26.8%) had non A-E hepatitis. Overall, 38 (30.9%) had infection with HEV. HEV infection was significantly higher among those using underground wells as a water source compared with tap water. Liver enzymes were significantly raised in patients with non-HEV infection compared with those with HEV infection. Conclusions HEV is a significant cause of AVH among children in Upper Egypt. Contamination of drinking water appears to be a major source of infection. Screening for HEV should be considered in all Egyptian children with AVH.

Hepatitis E Virus in Surface Water, Sediments, and Pork Products Marketed in Southern Brazil

Hepatitis E virus (HEV) is an emerging causative agent of food and waterborne hepatitis in human beings. HEV circulates among human populations and swine herds, and may be found in water contaminated by swine feces, as well as in pork. In the present study, 68 sediment samples and 250 water samples collected from the Sinos River tributaries, as well as 50 samples of pork products (pâté and blood sausage) marketed in the Sinos River watershed region, Brazil, were tested for the presence of HEV genome. Reverse-transcriptase polymerase chain reaction followed by nucleotide sequencing was used for detection and characterization of HEV genomes. Overall, 36 % of food samples tested positive for HEV (genotype 3). No sediment or water samples were positive. These results suggest that contaminated pork products may be a source of HEV infection within this region and indicate a need for better monitoring of food safety and swine herds.

Hepatitis E Virus Mutations: Functional and Clinical Relevance

Hepatitis E virus (HEV) infection is a major cause of acute hepatitis and affects more than 20 million individuals, with three million symptomatic cases and 56,000 recognized HEV-related deaths worldwide. HEV is endemic in developing countries and is gaining importance in developed countries, due to increased number of autochthone cases. Although HEV replication is controlled by the host immune system, viral factors (especially specific viral genotypes and mutants) can modulate HEV replication, infection and pathogenesis. Limited knowledge exists on the contribution of HEV genome variants towards pathogenesis, susceptibility and to therapeutic response. Nonsynonymous substitutions can modulate viral proteins structurally and thus dysregulate virus-host interactions. This review aims to compile knowledge and discuss recent advances on the casual role of HEV heterogeneity and its variants on viral morphogenesis, pathogenesis, clinical outcome and antiviral resistance.

•

HEV causes acute hepatitis and recently comes into focus because of persistent infection in immunocompromised patients.

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HEV variability can be associated with clinical pathogenesis and transmission dynamics.

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Mutations in the HEV genome can influence HEV physiology and virus-host interaction.

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HEV mutations and variability are likely associated with fulminant hepatic failure and chronic hepatitis E.

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The Y1320H and G1634R/K mutations in the RdRp domain contribute to antiviral resistance through enhancing HEV replication.

We searched MEDLINE database and PubMed for articles from 1980 through June 30, 2016. Search terms used in various combinations were “hepatitis E”, “hepatitis E virus”, “hepatitis E virus infection”, “hepatitis E virus mutation”, “HEV variability”, “HEV genotype”, “HEV drug resistance”, “HEV replication” and “ribavirin”. Articles resulting from these searches and relevant references cited in those articles were selected based on their related topics and were reviewed. Abstracts and reports from meetings were also included. Articles published in English were included.

Excretion of infectious hepatitis E virus into milk in cows imposes high risks of zoonosis

Hepatitis E virus (HEV) represents the main cause of acute hepatitis worldwide. HEV infection in immunocompromised patients involves a high risk for the development of chronic hepatitis. Because HEV is recognized as a zoonotic pathogen, it is currently believed that swine is the primary reservoir. However, this is not sufficient to justify the strikingly high seroprevalence of HEV in both developing and Western countries. Thus, this study aimed to identify new zoonotic sources that bear a high risk of transmission to humans. We collected fecal, blood, and milk samples of cows in a typical rural region of Yunnan Province in southwest China, where mixed farming of domestic animals is a common practice. HEV RNA was quantified by quantitative real-time polymerase chain reaction, and the whole genome was sequenced. HEV infectivity was assessed in rhesus macaques. We found a high prevalence of active HEV infection in cows as determined by viral RNA positivity in fecal samples. Surprisingly, we discovered that HEV is excreted into milk that is produced by infected cows. Phylogenetic analysis revealed that all HEV isolates from cow/milk belong to genotype 4 and subtype 4h. Gavage with HEV-contaminated raw and even pasteurized milk resulted in active infection in rhesus macaques. Importantly, a short period of boiling, but not pasteurization, could completely inactivate HEV.

CONCLUSION

Infectious HEV-contaminated cow milk is recognized as a new zoonotic source that bears a high risk of transmission to humans; these results call attention to understanding and establishing proper measurement and control of HEV zoonotic transmission, particularly in the setting of mixed farming of domestic animals. (Hepatology 2016;64:350-359).

Detection of Hepatitis E Virus Genotype 1 Among Blood Donors From Southwest of Iran

BACKGROUND

Infection with hepatitis E virus (HEV) is endemic in developing countries and reveals significant regional differences. Several studies have reported virus transmission via blood transfusion. To date, however, no cases of HEV RNA detection in blood donors have been reported from Iran.

OBJECTIVES

The aim of this study was to determine the presence of HEV RNA in plasma samples of blood donors referred to a blood transfusion center in Shiraz in the southwest of Iran. The HEV genotypes were also investigated using nucleotide sequencing.

PATIENTS AND METHODS

Blood samples were collected from 700 blood donors who were referred to Fars blood transfusion organization from January to March 2014. Plasma samples were screened for the presence of HEV IgG and IgM antibodies by standard enzyme immunoassay. Samples seroreactive to anti-HEV were further tested for the presence of HEV RNA using nested polymerase chain reaction (PCR) with universal primers for detection of all four HEV genotypes. Positive PCR samples were then subjected to DNA sequencing for further analysis.

RESULTS

Fifty (50, 7.1%) out of 700 plasma samples tested positive for anti-HEV antibodies. HEV RNA was detected in 7/50 (12%) of the antibody-positive samples, the majority of which were IgM positive. Sequence analysis of seven isolates of the HEV RNA ORF 2 gene region revealed > 80% similarity with genotype 1.

CONCLUSIONS

The analysis indicates that the HEV isolated from blood donors in the southwest of Iran belongs to genotype 1. However, more samples from other geographic regions of Iran are needed to confirm these findings. Because transmission of HEV by administration of blood or blood components is likely to occur, it may be sensible to screen donor blood for HEV to eliminate transfusion-transmitted HEV infection when the recipient is immunocompromised.

Characteristics of 20 Patients with Autochthonous Acute Hepatitis E in Hokkaido, Japan: First Report of Bilateral Facial Palsy Following the Infection with Genotype 4 Hepatitis E Virus

Autochthonous hepatitis E is increasingly being recognized in industrialized countries, including Japan. Although neurological abnormalities have been sporadically reported as an extrahepatic manifestation of hepatitis E virus (HEV) infection, it is rare and has not been reported in Japan. The present study aimed to characterize a total of 20 patients consecutively diagnosed with sporadic acute hepatitis E at a city hospital in Hokkaido, Japan, during 2001-2014, focusing on a patient complicated with neuropathy. Seventeen patients were infected with genotype 4 HEV, while the remaining three patients were with genotype 3 HEV. Although a 67-year-old male with severe hepatitis did not have predisposing factors associated with the development of neurological disorders, such as diabetes mellitus and the use of immunosuppressive agents, he developed bilateral peripheral facial palsy six days after admission. A neurological examination revealed the inability to smile, frown, close his eyes completely or puff out his cheeks. MRI brain scans were considered to be normal. Although it took 83 days after admission for the total bilirubin levels to normalize, his neurological symptoms resolved gradually within three weeks without any sequelae following conservative therapy. A full-length genomic analysis of the HEV strain (HE-JA30) isolated from the patient belonged to genotype 4 and was closest to that currently circulating in Hokkaido, Japan. This is the first report of HEV-associated neuropathy in Japan. While all of previous reports on HEV-related neuropathy involve genotype 3 HEV, the present report is unique in that genotype 4 HEV is responsible for the neuropathy.

Hepatitis E virus infection: Epidemiology and treatment implications

Hepatitis E virus (HEV) infection is now established as an emerging enteric viral hepatitis. Standard treatments in acute and chronic hepatitis E remain to be established. This study undertakes a review of the epidemiology, treatment implication and vaccine prevention from published literature. HEV infection is a worldwide public health problem and can cause acute and chronic hepatitis E. HEV genotypes 1 and 2 are primarily found in developing countries due to waterborne transmission, while the zoonotic potential of genotypes 3 and 4 affects mostly industrialized countries. An awareness of HEV transmission through blood donation, especially in the immunocompromised and solid organ transplant patients, merits an effective anti-viral therapy. There are currently no clear indications for the treatment of acute hepatitis E. Despite concerns for side effects, ribavirin monotherapy or in combination with pegylated interferon alpha for at least 3 mo appeared to show significant efficacy in the treatment of chronic hepatitis E. However, there are no available treatment options for specific patient population groups, such as women who are pregnant. Vaccination and screening of HEV in blood donors are currently a global priority in managing infection. New strategies for the treatment and control of hepatitis E are required for both acute and chronic infections, such as prophylactic use of medications, controlling large outbreaks, and finding acceptable antiviral therapy for pregnant women and other patient groups for whom the current options of treatment are not viable.

Hepatitis E Virus in Cambodia: Prevalence among the General Population and Complete Genome Sequence of Genotype 4

Hepatitis E virus (HEV) is a growing public health problem in many countries. In this study, we investigated HEV seroprevalence among the general population in the Siem Reap province, Cambodia, and performed HEV genetic analysis with the aim to develop an HEV prevention strategy. This seroepidemiological cross-sectional study conducted from 2010 to 2014 included 868 participants from four different locations in Siem Reap province, Cambodia. They answered questionnaires and provided blood samples for the analysis of hepatitis virus infections. Among the participants (360 men and 508 women; age range, 7-90 years), the prevalence of anti-HEV IgG was 18.4% (95% confidence interval: 15.9-21.0); HEV RNA was detected in two participants (0.23%) and was classified as genotype 3 and 4. Full-length genome of the genotype 4 isolate, CVS-Sie10, was sequenced; it contained 7,222 nucleotides and three ORFs and demonstrated high sequence identity with the swine China isolates swGX40 (95.57%), SS19 (94.37%), and swDQ (91.94%). Multivariate logistic regression analysis revealed that men, elderly people, and house workers were risk groups significantly associated with the positivity for anti-HEV IgG. This is the first report on the detection of HEV genotype 4 in humans in Cambodia and on the complete genome sequence of HEV genotype 4 from this country. Our study demonstrates that new HEV infection cases occur frequently among the general population in Cambodia, and effective preventive measures are required.

Variability and pathogenicity of hepatitis E virus genotype 3 variants

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

Acute infection by hepatitis E virus with a slight immunoglobulin M antibody response

The anti-hepatitis E virus (HEV) immunoglobulin (Ig) M antibody response is generally regarded as a useful marker for diagnosing primary infection. However, in some cases, this antibody is not detected during the acute phase of infection. An 81-year-old man with stable membranous nephropathy who presented with asymptomatic acute liver dysfunction came to our hospital. HEV RNA of genotype 3 was detected in his serum, and he was diagnosed with acute hepatitis E. According to an enzyme-linked immunosorbent assay, high-level positivity for anti-HEV IgG and IgA antibodies was observed, but the assay was negative for IgM antibody throughout the clinical course of infection. The patient was not immunosuppressed. We further investigated the presence of IgM antibody using two other polyclonal antibodies against human IgM as secondary antibodies and another recombinant ORF2 protein of genotype 3 as an immobilized antigen. IgM was weakly detected in the serum during the acute phase only by the test with the antigen of genotype 3. Multi-genotype antigens can detect a slight IgM antibody response; however, anti-HEV IgA is more useful in diagnosing primary HEV infection, particularly in cases with a low IgM antibody response.

Temporal evolution of the distribution of hepatitis E virus genotypes in Southwestern France

Southwest France is a highly endemic region for hepatitis E virus (HEV). This study examined the circulation of HEV strains between 2003 and 2014 in the Midi-Pyrénées, and compared these data with those from the rest of France. The polyproline region (PPR) of the ORF1 region of the HEV genome was also analyzed. HEV genotype was determined by sequencing a 348-nt fragment within the ORF2 gene for 333 strains in the Midi-Pyrénées and for 571 strains from the rest of France. PPR region was characterized for 56 strains. The frequency of subgenotype 3f decreased over time, whereas subgenotype 3c increased in the Midi-Pyrénées. Repartition of strains did not differ in the Midi-Pyrénées compared to the rest of France. HEV3i and HEV4 have been recently detected throughout France. PPR lengths showed that two major groups of HEV3f exist. Our study shows that HEV3 distribution in the Midi-Pyrénées was similar to the whole of France. Local dietary habits could explain the higher seroprevalence in the Midi-Pyrénées rather the circulation of a particular variant in this region.

Clinical and molecular analyses of sporadic acute hepatitis A and E and the specific viral genotypes isolated in Iwate and three neighboring prefectures in the northern part of Honshu, Japan, between 2004 and 2013

AIM

To examine the prevalence and characteristics of hepatitis A virus (HAV) and hepatitis E virus (HEV) infections in the northern part of Honshu, Japan, during the last decade.

METHODS

Using the registration system of a prospective cohort study for acute liver injury (ALI) in Iwate and three neighboring prefectures, we examined the prevalence of sporadic acute hepatitis (AH) with HAV (AH-A) and HEV (AH-E) and the distribution of viral genotypes in 487 patients diagnosed with ALI between 2004 and 2013.

RESULTS

Among all 487 patients, 135 (28%) had ALI with viral infection. In the cases with viral ALI, the prevalence of hepatitis B virus-related AH was highest (55.6%). AH-E was seen in 23 patients (17.0%) and its prevalence was higher than that of AH-A (10 patients, 7.4%). There were no appreciable differences in the prevalence of AH-A and AH-E between 2004-2008 and 2009-2013. However, subgenotype IIIA HAV homologous to Korean strains has recently emerged, and the number of AH-E cases seems to be increasing. HEV genotype 3 was predominant throughout the observation period, but HEV genotype 4 was found in three patients after 2010. The transmission routes of HAV and HEV infections were unknown in approximately 60% of the patients.

CONCLUSION

In the northern part of Honshu, Japan, HEV has been more frequently implicated in the development of AH than HAV, and HEV genotype 4 has been recently increasing. To provide an effective prophylactic management for HAV and HEV infections, further clarification of the transmission routes is needed.

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.