Chinese pregnant women in their third trimester are more susceptible to HEV infection

Severe maternal-fetal pathological damage and inflammatory responses contribute to miscarriage caused by hepatitis E viral infection during pregnancy

BACKGROUND

Hepatitis E virus (HEV) infection causes serious adverse pregnancy outcomes during pregnancy. However, the maternal and fetal damage induced by HEV infection is rarely reported.

METHODS

A BALB/c pregnant mouse model was established to explore the maternal and fetal pathological damage and inflammatory responses caused by HEV infection.

RESULTS

Notably, miscarriages and stillbirths were observed in HEV-infected pregnant mice. HEV infections were identified by qRT-PCR, immunohistochemical analysis and immunofluorescence assay in the uterus, placenta, umbilical cords and livers and brains of fetuses. Serious inflammatory responses and pathological damage were triggered in the uterus and placenta of HEV-infected pregnant mice. Vertical transmission of HEV resulted in severe pathological damage and inflammatory responses in the livers and brains of fetuses, as well as emerging apoptosis cells in the brains of fetuses. Most of the cytokines/chemokines in the sera were significantly increased in the HEV-infected pregnant mice. Remarkably, cytokines/chemokines were significantly different between HEV-infected pregnant and miscarriage mice; IL9, GM-CSF and IL1α were the most important three cytokines/chemokines in determining the pregnancy outcomes.

CONCLUSION

HEV infections cause serious maternal/fetal pathological damage, inflammatory responses and apoptosis, which may be responsible for adverse pregnancy outcomes.

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.

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.

Prevalence and clinical features of hepatitis E virus infection in pregnant women: A large cohort study in Inner Mongolia, China

BACKGROUND AND AIM

Hepatitis E virus (HEV) infection causes severe maternal and fetal outcomes in pregnant women. These patients are exclusively from resource-limited regions with genotype 1 HEV infection, but not from western countries with genotype 3 prevalence. Since the circulating strains in China have evolved from the waterborne genotype 1 to the zoonotic genotype 4 HEV in the past decades, this study aims to evaluate the prevalence and clinical features of HEV infection in a large cohort of pregnant women in Inner Mongolia, China.

METHODS

A total of 3278 pregnant women who visited the Inner Mongolia Maternal and Child Care hospital during 2018 were enrolled. Serum samples were examined for anti-HEV IgG and anti-HEV IgM antibodies using ELISA. Demographic information, results of clinical biochemical tests, maternal and neonatal outcomes were collected.

RESULTS

Among the recruited 3278 pregnant women, 6.0% were anti-HEV IgG antibody positive, 0.3% were anti-HEV IgM antibody positive and 0.3% were positive for both anti-HEV IgG and anti-HEV IgM antibodies. HEV viral RNA was not detected. Pregnant women with recent/ongoing HEV infection indicated by anti-HEV IgM positivity have slightly higher ALT level, and potential risk of developing hyperlipidemia, preterm delivery and neonatal jaundice.

CONCLUSIONS

These findings indicated that HEV infection is associated with a possible increase in adverse maternal, fetal and neonatal outcomes in our cohort. Thus, the burden of HEV infection in pregnant women in China appears distinct from resource-limited regions and western countries. Nevertheless, future studies are required to confirm and extend our findings.

Burden of hepatitis E virus infection in pregnancy and maternofoetal outcomes: a systematic review and meta-analysis

Background

There is still a dearth of knowledge on the burden of HEV infection in the global population of pregnant women. Therefore, we conducted a systematic review and meta-analysis to estimate the global burden of HEV infection in pregnancy.

Methods

We searched PubMed, Embase, Web of Knowledge, and Global Index Medicus to identify articles published until January 26, 2020. We considered cross-sectional, case-control, and cohort studies reporting the immunoglobulins M HEV seroprevalence in asymptomatic and symptomatic (jaundice or elevated transaminases) pregnant women or investigating the association between HEV infection and maternofoetal outcomes. We used a random-effects model to pool studies. This review was registered with PROSPERO, CRD42018093820.

Results

For HEV prevalence estimates, we included 52 studies (11,663 pregnant women). The seroprevalence was 3.5% (95% confidence interval: 1.4–6.4) in asymptomatic women (most of whom from high endemic areas). The prevalence in symptomatic women was 49.6% (42.6–56.7) with data only from HEV high endemic countries. In the multivariable meta-regression model, the prevalence was higher in symptomatic women compared to asymptomatic (adjusted prevalence odds ratio [aPOR]: 1.76; 95%CI: 1.61–1.91) and decreased with increasing year of publication (by 10-year) (aPOR: 0.90; 95%CI: 0.84–0.96). The proportion of HEV vertical transmission was 36.9% (13.3–64.2). Risk of bias was low, moderate and high respectively in 12 (23%), 37 (70%), and 4 studies (7%) addressing HEV prevalence estimation. HEV infection was associated with maternal deaths (pooled OR 7.17; 3.32–15.47), low birth weight (OR: 3.23; 1.71–6.10), small for gestational age (OR: 3.63; 1.25–10.49), preterm < 32 weeks (OR: 4.18; 1.23–14.20), and preterm < 37 weeks (OR: 3.45; 2.32–5.13), stillbirth (OR: 2.61; 1.64–4.14), intrauterine deaths (OR: 3.07; 2.13–4.43), and not with miscarriage (OR: 1.74; 0.77–3.90). All studies which assessed the association between HEV infection and maternofoetal outcomes had a moderate risk of bias.

Conclusions

Findings from this study are suggestive of a high burden of HEV infection in pregnancy in high endemic countries, its association with poor maternofoetal outcomes, and a high rate of vertical transmission. This study supports the need for specific strategies to prevent exposure of pregnant women to HEV infection, especially in high endemic areas.

Implications of Hepatitis E Virus in Blood Transfusions, Hemodialysis, and Solid Organ Transplants

Hepatitis E Virus (HEV) is emerging as the primary cause of acute viral hepatitis in humans. The virus is commonly transmitted by the fecal-oral route via contaminated water in endemic regions or through the consumption of inadequately cooked swine products or game meats in industrialized regions. HEV genotypes 1 and 2 are predominantly associated with waterborne transmission in developing countries, whereas HEV3 and HEV4 are mainly zoonotically transmitted in industrialized countries. Seroprevalence in populations determined by detecting anti-HEV antibodies and serum HEV RNA is commonly used to analyze the presence of HEV. Although HEV RNA-based detection is now standardized, there is a lack of agreement between the assaying methods used for gathering seroprevalence data. Since 2004, HEV has been considered as a transmissible infectious agent through blood transfusion. Recent seroprevalence studies in European countries indicate an underestimated risk for blood transfusion and hence warrant testing the blood supply. HEV infection is usually self-limiting and spontaneously cleared. However, in about 60% of recipients of solid organ transplants, HEV progresses to chronic hepatitis. Immunosuppressive drugs such as tacrolimus are a major cause of chronic hepatitis and reducing its dosage results in viral clearance in about 30% of patients. In hemodialysis patients, the parenteral route is implicated as an important mechanism of transmission. In this review, we explore the clinical and epidemiological characteristics of various HEV genotypes in blood donors, hemodialysis patients, and transplant recipients.

Successful Establishment of Hepatitis E Virus Infection in Pregnant BALB/c Mice

Worldwide, the Hepatitis E virus (HEV) is the main pathogen of acute viral hepatitis, with an extremely high mortality in pregnant women. However, the pathogenesis of HEV infection in pregnant women remains largely unknown. We established an HEV-infected pregnant mice animal model to explore the adverse pregnancy outcomes of HEV infection. Mice were infected with HEV in their early, middle and late stages of pregnancy. HEV RNA was detected in the tissues (liver, spleen, kidney, colon, uterus and placenta) of pregnant mice. HEV antigens were also detected in these tissues of HEV-infected pregnant mice. Miscarriages (7/8, 87.5%) occurred in pregnant mice infected with HEV in the middle of pregnancy. Th1-biased immune status was found in these aborted mice. Vertical transmission was confirmed by HEV replication in the uterus and placenta, as well as in the positive HEV RNA and HEV antigen positive in fetal livers. The successful establishment of HEV infection in pregnant mice is beneficial for further study of HEV pathogenesis, especially the adverse pregnancy outcomes caused by HEV infection.

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).