Hepatitis E virus infection among pregnant women in Africa: systematic review and meta-analysis

Diagnostic Approach to Elevated Liver Function Tests during Pregnancy: A Pragmatic Narrative Review

Liver disease is not uncommon during pregnancy and is associated with increased maternal and fetal/neonatal morbidity and mortality. Physiological changes during pregnancy, including a hyperestrogenic state, increase in circulating plasma volume and/or reduction in splanchnic vascular resistance, and hemostatic imbalance, may mimic or worsen liver disease. For the clinician, it is important to distinguish among the first presentation or exacerbation of chronic liver disease, acute liver disease non-specific to pregnancy, and pregnancy-specific liver disease. This last group classically includes conditions such as hyperemesis gravidarum, intrahepatic cholestasis of pregnancy, liver disorders associated with the pre-eclampsia spectrum, and an acute fatty liver of pregnancy. All of these disorders often share pathophysiological mechanisms, symptoms, and laboratory findings (such as elevated liver enzymes), but a prompt and correct diagnosis is fundamental to guide obstetric conduct, reduce morbidity and mortality, and inform upon the risk of recurrence or development of other chronic diseases later on in life. Finally, the cause of elevated liver enzymes during pregnancy is unclear in up to 30-40% of the cases, and yet, little is known on the causes and mechanisms underlying these alterations, or whether these findings are associated with worse maternal/fetal outcomes. In this narrative review, we aimed to summarize pragmatically the diagnostic work-up and the management of subjects with elevated liver enzymes during pregnancy.

Epidemiology of Hepatitis E

Hepatitis E virus (HEV) is globally prevalent with relatively high percentages of anti-HEV immunoglobulin G-positive individuals in the populations of developing and developed countries. There are two distinct epidemiological patterns of hepatitis E. In areas with high disease endemicity, primarily developing countries in Asia and Africa, this disease is caused mainly by genotypes HEV-1 or HEV-2; both genotypes transmit predominantly through contaminated water and occur as either outbreaks or sporadic cases of acute hepatitis. The acute hepatitis has the highest attack rate in young adults and is particularly severe among pregnant women. In developed countries, sporadic cases of locally acquired HEV-3 or HEV-4 infection are observed. The reservoir of HEV-3 and HEV-4 is believed to be animals, such as pigs, with zoonotic transmission to humans. The affected persons are often elderly, and persistent infection has been well documented among immunosuppressed persons. A subunit vaccine has been shown to be effective in preventing clinical disease and has been licensed in China.

Seroprevalence and burden of hepatitis E viral infection among pregnant women in central Nigeria attending antenatal clinic at a Federal Medical Centre in Central Nigeria

Introduction

HEV infection may be life threatening in pregnant women and has been linked with 20–30% mortality, especially in the third trimester of pregnancy. HEV infection leads to elevated levels of preterm labour and other immunological parameters. It is vertically transmitted and could lead to poor feto-maternal outcomes. especially in fulminating viral hepatitis where both the mother and foetus could be lost. There is currently no known treatment or vaccine for HEV. There is therefore a need to study HEV seroprevalence and burden among vulnerable groups, such as pregnant women and their newborns in Nigeria, where maternal mortality is highly significant.

Methods

A total of 200 samples were collected from pregnant women attending antenatal clinic at Federal Medical Centre (FMC) Keffi, in central Nigeria, of which (156/200) samples were from HIV-negative pregnant women and (44/200) were from HIV-positive pregnant women, using a simple random sampling method.

Results

In total, 200 pregnant women [78.0% (156/200) HIV-negative pregnant women and 22.0% (44/200) HIV-positive pregnant women] were recruited for this study. The ages of the pregnant women ranged from 15-49 years, with a mean age of 26.4 years (± 6.23). The overall HEV IgG seropositivity in the study population was 31.5% (63/200); 95% CI (30-33).

Conclusion

This study highlighted an unexpectedly high seroprevalence of HEV and poor feto-maternal outcomes in pregnant women residing in a rural and urban setting of central Nigeria. The study showed that the inherently high HEV seropositivity and poor feto-maternal outcomes may not be attributed to HEV viral hepatitis only but may be a combination of extrinsic and intrinsic factors.

Hepatitis E, Schistosomiasis and Echinococcosis-Prevalence in a Cohort of Pregnant Migrants in Germany and Their Influence on Fetal Growth Restriction

Background: Infections, as well as adverse birth outcomes, may be more frequent in migrant women. Schistosomiasis, echinococcosis, and hepatitis E virus (HEV) seropositivity are associated with the adverse pregnancy outcomes of fetal growth restriction and premature delivery. Methods: A cohort study of 82 pregnant women with a history of migration and corresponding delivery of newborns in Germany was conducted. Results: Overall, 9% of sera tested positive for anti-HEV IgG. None of the patients tested positive for anti-HEV IgM, schistosomiasis, or echinococcus serology. Birth weights were below the 10th percentile for gestational age in 8.5% of the neonates. No association between HEV serology and fetal growth restriction (FGR) frequency was found. Conclusions: In comparison to German baseline data, no increased risk for HEV exposure or serological signs of exposure against schistosomiasis or echinococcosis could be observed in pregnant migrants. An influence of the anti-HEV serology status on fetal growth restriction could not be found.

First molecular detection of hepatitis E virus genome in camel and pig faecal samples in Ethiopia

BACKGROUND

Hepatitis E is an enteric and zoonotic disease caused by hepatitis E virus (HEV) that is mainly transmitted via the faecal-oral route through contaminated food or the environment. The virus is an emerging infectious agent causing acute human infection worldwide. A high seroprevalence of the disease was reported in pregnant women in Addis Ababa, Ethiopia, raising significant public health concern. The presence of HEV specific antibodies were also reported in dromedary camels in the country; however, the infectious virus and/or the viral genome have not been demonstrated to date in animal samples.

METHODS

To address this gap, a total of 95 faecal samples collected from both apparently healthy pigs of uncharacterised types (50 samples) in Burayu and Addis Ababa areas and camels (Camelus dromedarius, 45 samples) in west Hararghe were screened for the presence of HEV genome using universal primers in a fully nested reverse transcription polymerase chain reaction (nRT-PCR). The protocol is capable of detecting HEV in faecal samples from both pigs and camels.

RESULTS

The nRT-PCR detected HEV genes in six (12%) pig faecal samples and one camel sample (2.2%). Therefore, the results indicate that HEV is circulating in both pigs and camels in Ethiopia and these animals and their products could serve as a potential source of infection for humans.

CONCLUSION

The detection of HEV in both animals could raise another concern regarding its public health importance as both animals' meat and camel milk are consumed in the country. Further studies to determine the prevalence and distribution of the virus in different animals and their products, water bodies, food chain, and vegetables are warranted, along with viral gene sequencing for detailed genetic characterisation of the isolates circulating in the country. This information is critically important to design and institute appropriate control and/or preventive measures.

Prevalence and clinical correlation of hepatitis E virus antibody in the patients' serum samples from a tertiary care hospital in Thailand during 2015-2018

Background

Prevalence and incidence of hepatitis caused by HEV infection are usually higher in developing countries. This study demonstrated the HEV seroprevalence and incidence of HEV infection in patients with clinical hepatitis in a tertiary hospital in Thailand.

Methods

A laboratory-based cross-sectional study was conducted using 1106 serum samples from patients suspected of HEV infection sent to the Serology laboratory, Siriraj Hospital, for detecting HEV antibodies during 2015–2018. Prevalence of anti-HEV IgG and IgM antibodies in general patients, including organ transplant recipients and pregnant women in a hospital setting, were determined using indirect enzyme-linked immunosorbent assay (ELISA) kits. Comparison of laboratory data between groups with different HEV serological statuses was performed.

Results

HEV IgG antibodies were detected in 40.82% of 904 serum samples, while HEV IgM antibodies were detected in 11.75% of 1081 serum samples. Similar IgG and IgM antibody detection rates were found in pregnant women. Interestingly, anti-HEV IgM antibodies were detected in 38.5% of patients who underwent organ transplantation. Patients who tested positive for anti-HEV IgM antibodies had higher alanine aminotransferase levels than those who had not. In contrast, patients who tested positive for anti-HEV IgG had more elevated levels of total bilirubin than those who tested negative.

Conclusions

HEV seroprevalence and incidence in patients with clinical hepatitis were relatively high in the Thai population, including the pregnancy and organ transplant subgroups. The results potentially benefit the clinicians in decision-making to investigate HEV antibodies and facilitating proper management for patients.

Hepatitis E: An update on One Health and clinical medicine

The hepatitis E virus (HEV) is one of the main causes of acute hepatitis and the de facto global burden is underestimated. HEV-related clinical complications are often undetected and are not considered in the differential diagnosis. Convincing findings from studies suggest that HEV is clinically relevant not only in developing countries but also in industrialized countries. Eight HEV genotypes (HEV-1 to HEV-8) with different human and animal hosts and other HEV-related viruses are in circulation. Transmission routes vary by genotype and location, with large waterborne outbreaks in developing countries and zoonotic food-borne infections in developed countries. An acute infection can be aggravated in pregnant women, organ transplant recipients, patients with pre-existing liver disease and immunosuppressed patients. HEV during pregnancy affects the fetus and newborn with an increased risk of vertical transmission, preterm and stillbirth, neonatal jaundice and miscarriage. Hepatitis E is associated with extrahepatic manifestations that include neurological disorders such as neuralgic amyotrophy, Guillain-Barré syndrome and encephalitis, renal injury and haematological disorders. The risk of transfusion-transmitted HEV is increasingly recognized in Western countries where the risk may be because of a zoonosis. RNA testing of blood components is essential to determine the risk of transfusion-transmitted HEV. There are currently no approved drugs or vaccines for HEV infections. This review focuses on updating the latest developments in zoonoses, screening and diagnostics, drugs in use and under development, and vaccines.

Hepatitis E-Associated Hospitalizations in the United States: 2010-2015 and 2015-2017

Hepatitis E is considered rare in the United States (US) despite its widespread occurrence in Asian and African countries. The objective of this study was to describe the characteristics of hepatitis E-related pregnancies and acute-on-chronic liver failure and analyse trends for hepatitis E diagnosis among hospitalized patients in the US. We examined data from the 2010-2017 National Inpatient Sample from Healthcare Cost and Utilization Project to determine mortality, morbidity, pregnancy diagnoses, chronic liver disease diagnoses, and other conditions during hospitalization. Data were extracted for hospitalizations with hepatitis E as defined by ICD-9 codes 070.43 and 070.53 and ICD-10 code B17.2. Of 208,462,242 hospitalizations from 2010-2015, we identified 960 hepatitis E hospitalizations. The hospitalization rate of hepatitis E was 3.7 per 10 million in 2010 and 6.4 per 10 million in 2015 (β = 0.60, p = 0.011). From 2015 to 2017, the hospitalization appeared to increase with slope (β) of 0.50. Among those hospitalizations, 34 (4%) died and 85 (9%) had acute-on-chronic liver failure. Ninety-five (10%) had a diagnosis of pregnancy, there were no reports of maternal or foetus/neonate deaths, but there was a high proportion of adverse events for both during hospitalization. Having a chronic liver disease was associated with hepatic coma diagnosis (OR = 10.94, p = 0.002). Although the hospitalization rate of hepatitis E in the US is low, it appears to be increasing over time. Further studies are necessary in order to conclude a causal association of hepatitis E with adverse events and mortalities in pregnancy and chronic liver disease in the US.

Hepatitis E should be a global public health priority: recommendations for improving surveillance and prevention

INTRODUCTION

Hepatitis E virus (HEV) is an important cause of enterically transmitted viral hepatitis and a significant contributor to maternal mortality in endemic regions around the world, yet the global response has been limited. HEV is a disease of poverty, and the populations experiencing the greatest burden of HEV-associated illness are not benefitting from existing interventions, including WASH strategies and immunization.

AREAS COVERED

Though a vaccine exists (HEV 239, Hecolin®, Xiamen Innovax Biotech, China), it is only licensed and available in the private market in China and has yet to be prequalified by the WHO for use in endemic settings and outbreaks. This review of the current state of HEV disease and subsequent recommendations for a coordinated public health response are intended to guide the global health community towards breaking the current 'vicious cycle,' in which a lack of data prevents actions that would improve health outcomes.

EXPERT OPINION

Vaccine implementation in future outbreaks, targeted studies assessing vaccine effectiveness and immunogenicity in endemic regions and populations, improved understanding of the global burden, and improvements in diagnostic and epidemiologic tools are urgently needed. Strategies for implementing routine vaccination programs, improving water, sanitation, and hygiene in endemic regions.

A systematic review of the epidemiology of Hepatitis E virus infection in South - Eastern Asia

Hepatitis E virus (HEV) infection is an emerging zoonotic viral disease, with an increasingly international public health challenge. Despite the concerns that the global disease burden may be underestimated. Therefore, evaluation of the disease epidemiology in South – eastern Asia through a systematic review will assist in unraveling the burden of the disease in the subregion. A priori protocol was prepared for the systematic review and followed by a literature search involving five electronic databases. Identified publications were screened for high quality studies and the elimination of bias and relevant data extracted. A total of 4157 citations were captured, and only 35 were included in the review. A wide range of HEV seroprevalence was recorded from 2% (urban blood donors in Malaysia) to 77.7% (lowland communities in Lao PDR). Sporadic HEV infection and epidemics were also detected in the subregion. Indicating hyperendemicity of the disease in South – eastern Asia.

Innate Immune Responses to Acute Viral Infection During Pregnancy

Immunological adaptations in pregnancy allow maternal tolerance of the semi-allogeneic fetus but also increase maternal susceptibility to infection. At implantation, the endometrial stroma, glands, arteries and immune cells undergo anatomical and functional transformation to create the decidua, the specialized secretory endometrium of pregnancy. The maternal decidua and the invading fetal trophoblast constitute a dynamic junction that facilitates a complex immunological dialogue between the two. The decidual and peripheral immune systems together assume a pivotal role in regulating the critical balance between tolerance and defense against infection. Throughout pregnancy, this equilibrium is repeatedly subjected to microbial challenge. Acute viral infection in pregnancy is associated with a wide spectrum of adverse consequences for both mother and fetus. Vertical transmission from mother to fetus can cause developmental anomalies, growth restriction, preterm birth and stillbirth, while the mother is predisposed to heightened morbidity and maternal death. A rapid, effective response to invasive pathogens is therefore essential in order to avoid overwhelming maternal infection and consequent fetal compromise. This sentinel response is mediated by the innate immune system: a heritable, highly evolutionarily conserved system comprising physical barriers, antimicrobial peptides (AMP) and a variety of immune cells—principally neutrophils, macrophages, dendritic cells, and natural killer cells—which express pattern-receptors that detect invariant molecular signatures unique to pathogenic micro-organisms. Recognition of these signatures during acute infection triggers signaling cascades that enhance antimicrobial properties such as phagocytosis, secretion of pro-inflammatory cytokines and activation of the complement system. As well as coordinating the initial immune response, macrophages and dendritic cells present microbial antigens to lymphocytes, initiating and influencing the development of specific, long-lasting adaptive immunity. Despite extensive progress in unraveling the immunological adaptations of pregnancy, pregnant women remain particularly susceptible to certain acute viral infections and continue to experience mortality rates equivalent to those observed in pandemics several decades ago. Here, we focus specifically on the pregnancy-induced vulnerabilities in innate immunity that contribute to the disproportionately high maternal mortality observed in the following acute viral infections: Lassa fever, Ebola virus disease (EVD), dengue fever, hepatitis E, influenza, and novel coronavirus infections.

The Vaginal Virome-Balancing Female Genital Tract Bacteriome, Mucosal Immunity, and Sexual and Reproductive Health Outcomes?

Besides bacteria, fungi, protists and archaea, the vaginal ecosystem also contains a range of prokaryote- and eukaryote-infecting viruses, which are collectively referred to as the "virome". Despite its well-described role in the gut and other environmental niches, the vaginal virome remains understudied. With a focus on sexual and reproductive health, we summarize the currently known components of the vaginal virome, its relationship with other constituents of the vaginal microbiota and its association with adverse health outcomes. While a range of eukaryote-infecting viruses has been described to be present in the female genital tract (FGT), few prokaryote-infecting viruses have been described. Literature suggests that various vaginal viruses interact with vaginal bacterial microbiota and host immunity and that any imbalance thereof may contribute to the risk of adverse reproductive health outcomes, including infertility and adverse birth outcomes. Current limitations of vaginal virome research include experimental and analytical constraints. Considering the vaginal virome may represent the missing link in our understanding of the relationship between FGT bacteria, mucosal immunity, and adverse sexual and reproductive health outcomes, future studies evaluating the vaginal microbiome and its population dynamics holistically will be important for understanding the role of the vaginal virome in balancing health and disease.

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

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