Autochthonous Hepatitis E during Pregnancy, France

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.

Prevalence of Hepatitis E Virus and Its Associated Outcomes among Pregnant Women in China

Hepatitis E virus (HEV) is a significant public health concern worldwide. Pregnant women are at high risk of severe HEV infection. Various adverse outcomes in pregnant women related to HEV infection have been well documented in low-income and middle-income countries with poor sanitation. However, previous studies have provided inconsistent conclusions regarding the effects of HEV infection on the health of pregnant women and their infants in developed countries and contemporary China. In China, previous studies on HEV in pregnant women mainly focused on anti-HEV IgM and/or anti-HEV IgG. In this study, 4244 pregnant women were retrospectively analyzed for HEV-related markers. The positive rates of HEV antigen, HEV RNA, anti-HEV IgM, and anti-HEV IgG were 0.28%, 0.54%, 0.35%, and 10.49%, respectively. Among the 467 pregnant women who tested positive for at least one HEV-related marker, 92.93% (434) were positive for anti-HEV IgG only and 0.21% (1) were positive for HEV antigen, anti-HEV IgM, and anti-HEV IgG. Although the prevalence of anti-HEV IgG significantly increased with age, the prevalence of anti-HEV IgM, HEV RNA, and HEV antigen did not differ among pregnant women of different ages. Thirty-three pregnant women were positive for at least one of anti-HEV IgM, HEV antigen, and HEV RNA, and these individuals were recently or currently infected with HEV. None of the 33 pregnant women exhibited obvious clinical symptoms. Of the 33 pregnant women, 39.39% (13) experienced adverse fetal outcomes, including preterm birth, fetal distress, and low birth weight, the incidence of which was significantly higher than in pregnant women who were not recently or currently infected with HEV. These findings suggest that maternal HEV infection may impact the health of fetuses; thus, these results may contribute to the development of appropriate public health interventions for this population.

Efficacy of an accelerated vaccination schedule against hepatitis E virus infection in pregnant rabbits

An important goal of the Hepatitis E virus (HEV) vaccine is to prevent adverse pregnancy outcomes caused by different HEV genotypes during pregnancy, but studies directly evaluating maternal vaccination for HEV are lacking. Here we report maternal vaccination using HEV 239 vaccine in a pregnant rabbit model. Two dose of accelerated vaccination schedule (0, 7 days) induced high titers of anti-HEV protective antibodies in a short period of time in pregnant rabbits, which could protect the pregnant rabbits from HEV infection and adverse pregnancy outcomes. In addition, the immunized rabbits transfer maternal antibodies to pups through the placenta and breast milk, which protect neonates against HEV infection. Our results suggest that, besides vaccinating nonpregnant individuals, HEV 239 vaccine may also be discreetly considered for maternal vaccination.

Transfusion-transmitted hepatitis E: What we know so far?

Hepatitis E virus (HEV) is a major cause of viral hepatitis globally. There is growing concern about transfusion-transmitted HEV (TT-HEV) as an emerging global health problem. HEV can potentially result in chronic infection in immunocompromised patients, leading to a higher risk of liver cirrhosis and even death. Between 0.0013% and 0.281% of asymptomatic blood donors around the world have HEV viremia, and 0.27% to 60.5% have anti-HEV immunoglobulin G. HEV is infectious even at very low blood concentrations of the virus. Immunosuppressed patients who develop persistent hepatitis E infection should have their immunosuppressant regimen reduced; ribavirin may be considered as treatment. Pegylated interferon can be considered in those who are refractory or intolerant to ribavirin. Sofosbuvir, a nucleotide analog, showed modest antiviral activity in some clinical studies but sustained viral response was not achieved. Therefore, rescue treatment remains an unmet need. The need for HEV screening of all blood donations remains controversial. Universal screening has been adopted in some countries after consideration of risk and resource availability. Various pathogen reduction methods have also been proposed to reduce the risk of TT-HEV. Future studies are needed to define the incidence of transmission through transfusion, their clinical features, outcomes and prognosis.

Clinical features of sporadic hepatitis E virus infection in pregnant women in Shanghai, China

OBJECTIVES

Hepatitis E virus (HEV) infection causes high mortality in pregnant women of developing regions during large outbreaks. The aim of this study was to investigate the clinical features of HEV-infected pregnant women in Shanghai, China where the epidemiology of HEV has shifted from large outbreaks to the sporadic form.

METHODS

Clinical data of 516 pregnant and nonpregnant child-bearing age women diagnosed with HEV infection during 2009-2020 was collected at the Shanghai Public Health Clinical center. Patients' data were analysed for clinical features and laboratory parameters accordingly.

RESULTS

Most of the hospitalized HEV-infected pregnant women (85.23%, 127/149) showed no obvious clinical symptoms and the disease outcome was generally benign with no liver failure or maternal mortality observed in the patients. By comparison, fewer (37.21%, 32/86) of the HEV-infected nonpregnant women were asymptomatic, and five cases (5.81%, 5/86) of liver failure were observed among them. The levels of serum alanine aminotransferase, aspartate aminotransferase, total bilirubin (TBiL), direct bilirubin (DBiL) and total bile acids (TBA) were significantly higher (P < 0.05) in nonpregnant women than those of the pregnant women. We found 42.99% (46/107) births had adverse foetal/neonatal outcome. Mothers who presented with adverse foetal/neonatal outcome showed higher (P < 0.05) serum TBiL, DBiL and TBA levels than those without.

CONCLUSION

We found that the clinical features of sporadic HEV infection in pregnant women in Shanghai, China are generally mild and no maternal mortality occurred. However foetal/neonatal adverse outcomes including preterm births and stillbirths were observed in HEV-infected pregnant women.

Progesterone-Mediated Enhancement of Hepatitis E Virus Replication in Human Liver Cells

Progesterone is crucial for the maintenance of pregnancy. During pregnancy hepatitis E virus (HEV) infection is associated with increased fulminant hepatic failure and mortality rates. In this study, we determined whether progesterone modulates HEV replication and HEV-induced innate cytokine response in Huh7-S10-3 human liver cells. We first demonstrated that Huh7-S10-3 liver cells expressed SH3-domain-containing progesterone receptor membrane component (PGRMC)1/2 receptors involved in the progesterone nonclassical signaling pathway, while the classical progesterone receptor isoforms progesterone receptor-A and -B protein levels were undetectable. We showed that the genotype 3 HEV (strain P6) induced mRNA expression of type III interferon (IFN-λ1), but not other innate cytokines in Huh7-S10-3 cells. Pretreatment with progesterone at concentrations of 80 nM, 160 nM, or 480 nM, which are the physiological concentrations typically seen in the first- to third-trimester during pregnancy, significantly increased HEV replication in Huh7-S10-3 cells. However, pretreatment of cells with progesterone (80 nM) did not affect the level of HEV-induced IFN-λ1 mRNA expression. We further showed that loss of PGRMC1/2 receptors by small interfering RNA (siRNA) knockdown leads to an increase in HEV-induced IFN-λ1 expression levels at early time points via the extracellular signal-regulated kinase pathway and thus resulted in a reduced level of HEV replication. Collectively, the results indicated that progesterone-mediated modulation of HEV replication in human liver cells is plausibly through SH3-domain containing proteins such as PGRMC1/2, but not likely through immunomodulation of HEV-induced interferon response in liver cells. The results have important implications in understanding the underlying mechanisms of high mortality and fulminant hepatitis in HEV-infected pregnant women.

Common European Origin of Hepatitis E Virus in Human Population From Eastern Romania

The purpose of this research was to improve the epidemiological data on HEV infection in the human population in Romania. The analysis targeted hospitalized subjects with acute hepatitis (n = 94) of unknown etiology from the Infectious Diseases Regional Hospital in Iasi. Moreover, patients without liver disease (n = 40) from a different county hospital located in Eastern Romania were included. The presence of HEV infection and first characterization of human HEV strains was determined using serological and molecular assays. The apparent HEV seroprevalence varied between 29.16% (95% CI, 16.31–42.03) and 32.5% (95% CI, 17.98–47.02) according to patient grouping. Molecular analysis enhanced the detection of two HEV isolates, that clustered in subtype HEV-3c, the most commonly identified subtype in Europe. Identification of acute hepatitis E cases, together with the first detection and molecular characterization of human HEV in Romania represent the originality attributes of the present study.

Hepatitis E virus: Epidemiology, diagnosis, clinical manifestations, and treatment

The hepatitis E virus (HEV) is the fifth known form of viral hepatitis and was first recognized as the cause of an epidemic of unexplained acute hepatitis in the early 1980s. Globally, it is one of the most frequent causes of acute viral hepatitis. The majority of HEV infections are asymptomatic and lead to the spontaneous clearance of the virus. Among the eight different genotypes identified to date, HEV genotype 1 (HEV1), HEV2, HEV3, and HEV4 are the most frequent genotypes causing infections in humans. HEV1 and HEV2 are prevalent in developing regions and able to result in large-scale outbreaks originating from contaminated water supplies. They are also responsible for severe hepatitis in pregnant patients and infants. In contrast, HEV3 and HEV4 are zoonotic, and the transmission of these genotypes to humans occurs mainly through the fecal contamination of water and consumption of contaminated meat from infected animals. Their main reservoir is the pig, and they are mostly encountered in developed countries. The major risk groups for HEV infection and its ensuing adverse consequences are pregnant women, infants, older people, immunocompromised individuals, patients with underlying chronic liver diseases, and workers that come into close contact with HEV-infected animals. In the clinical perspective, HEV infections have diverse clinical manifestations including acute and self-limiting hepatitis, acute-on-chronic liver disease, chronic hepatitis, cirrhosis, and liver failure. Although HEV mainly results in acute self-limiting infection, chronic HEV infection may occur among immunocompromised patients (e.g., solid-organ transplant recipients). Additionally, HEV-associated extrahepatic manifestations involving various organs have been reported in the last decade, although the causal link for many of them still needs to be proven. Ribavirin and interferon-alpha are the most widely used agents for the treatment of HEV infections with a certain level of success. However, ribavirin is contraindicated in pregnant patients, and interferon-alpha cannot be used in most transplant recipients. Therefore, there is an urgent need for novel antiviral compounds that are safe and effective particularly for patients having contraindications for ribavirin or interferon-alpha and infected by the ribavirin-resistant HEV. In this review article, a literature search using PubMed and MEDLINE databases was performed, up to March 2020. Only the articles published in English were reviewed.

Recent data on hepatitis E

PURPOSE OF REVIEW

Hepatitis E virus (HEV) has gained increased global recognition in recent years, particularly in developed countries. We summarized here a selection of the literature published since the 1st of June, 2017.

RECENT FINDINGS

Longitudinal studies are increasingly conducted in Europe, to determine trends in HEV prevalence. The spectrum of mammals infected with HEV and potentially capable to transmit it to humans has widened. New virological data on HEV repCon and pathogenicity have been reported and clinical features of HEV infections have been precised or newly described. Finally, there are some new data on the therapeutic management of HEV infections in various clinical settings.

SUMMARY

HEV emergence in developed countries appears to be based on improved diagnosis tools and increased awareness of clinicians that HEV transmission is essentially autochthonous and is a possible cause of life-threatening acute hepatitis, chronic hepatitis, cirrhosis, and extra-hepatic symptoms. In addition, the distribution of HEV strains evolves. Ribavirin remains to date the only specific treatment recommended for HEV infection, being efficient in the majority but not in all cases.

Clinical Manifestations, Pathogenesis and Treatment of Hepatitis E Virus Infections

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis throughout the world. Most infections are acute but they can become chronic in immunocompromised patients, such as solid organ transplant patients, patients with hematologic malignancy undergoing chemotherapy and those with a human immunodeficiency virus (HIV) infection. Extra-hepatic manifestations, especially neurological and renal diseases, have also been described. To date, four main genotypes of HEV (HEV1-4) were described. HEV1 and HEV2 only infect humans, while HEV3 and HEV4 can infect both humans and animals, like pigs, wild boar, deer and rabbits. The real epidemiology of HEV has been underestimated because most infections are asymptomatic. This review focuses on the recent advances in our understanding of the pathophysiology of acute HEV infections, including severe hepatitis in patients with pre-existing liver disease and pregnant women. It also examines the mechanisms leading to chronic infection in immunocompromised patients and extra-hepatic manifestations. Acute infections are usually self-limiting and do not require antiviral treatment. Conversely, a chronic HEV infection can be cleared by decreasing the dose of immunosuppressive drugs or by treating with ribavirin for 3 months. Nevertheless, new drugs are needed for those cases in which ribavirin treatment fails.

Hepatitis E virus: reasons for emergence in humans

Hepatitis E virus (HEV) infects both humans and other animal species. Recently, we have seen a steady increase in autochthonous cases of human HEV infection in certain areas especially in Europe, and large outbreaks in several African countries among the displaced population. This mini-review critically analyzes potential host, environmental, and viral factors that may be associated with the emergence of hepatitis E in humans. The existence of numerous HEV reservoir animals such as pig, deer and rabbit results in human exposure to infected animals via direct contact or through animal meat consumption. Contamination of drinking, irrigation and coastal water by animal and human wastes lead to emergence of endemic cases in industrialized countries and outbreaks in displaced communities especially in war-torn countries.