Novel risk factors associated with hepatitis E virus infection in a large outbreak in northern Uganda: results from a case-control study and environmental analysis

Control approach and evaluation framework of scaling in drinking water distribution systems: A review

The United Nations Sustainable Development Goals call for innovative proposals to ensure access to clean water and sanitation. While significant strides have been made in enhancing drinking water purification technologies, the role of drinking water distribution systems (DWDS) in maintaining water quality safety has increasingly become a focal point of concern. The presence of scale within DWDS can impede the secure and efficient functioning of the drinking water supply system, posing risks to the safety of drinking water quality. Previous research has identified that the primary constituents of scale in DWDS are insoluble minerals, such as calcium and magnesium carbonate. Elevated levels of hardness and alkalinity in the water can exacerbate scale formation. To address the scaling issue, softening technologies like induced crystallization, nanofiltration/reverse osmosis, and ion exchange are currently in widespread use. These methods effectively mitigate the scaling in DWDS by reducing the water's hardness and alkalinity. However, the application of softening technologies not only alters the hardness and alkalinity but also induces changes in the fundamental characteristics of water quality, leading to transition effects within the DWDS. This article reviews the impact of various softening technologies on the intrinsic properties of water quality and highlights the merits of electrochemical characteristic indicators in the assessment of water quality stability. Additionally, the paper delves into the factors that influence the transition effects in DWDS. It concludes with a forward-looking proposal to leverage artificial intelligence, specifically machine learning and neural networks, to develop an evaluation and predictive framework for the stability of drinking water quality and the transition effects observed in DWDS. This approach aims to provide a more accurate and proactive method for managing and predicting the impacts of water treatment processes on distribution system integrity and water quality over time.

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.

Hepatitis E Virus in Water Environments: A Systematic Review and Meta-analysis

Hepatitis E virus (HEV) is responsible for acute hepatitis in humans, through foodborne, zoonotic, and waterborne transmission routes. This study aimed to assess the prevalence of HEV in water matrices. Six categories were defined: untreated and treated wastewater, surface water (river, lake, and seawater), drinking water, groundwater, and other water environments (irrigation water, grey water, reservoir water, flood water, and effluent of pig slaughterhouse). We searched PubMed, Web of Science, Global Index Medicus, and Excerpta Medica Database. Study selection and data extraction were performed by at least two independent investigators. Heterogeneity (I²) was assessed using the χ² test on the Cochran Q statistic and H parameter. Sources of heterogeneity were explored by subgroup analysis. This study is registered with PROSPERO, number CRD42021289116. We included 87 prevalence studies from 58 papers, 66.4% of which performed in Europe. The overall prevalence of HEV in water was 9.8% (95% CI 6.4-13.7). The prevalence was higher in untreated wastewater (15.1%) and lower in treated wastewater (3.8%) and in drinking water (4.7%). In surface water, prevalence was 7.4%, and in groundwater, the percentage of positive samples, from only one study available, was 8.3%. Overall, only 36.8% of the studies reported the genotype of HEV, with genotype 3 (HEV-3) prevalent (168 samples), followed by HEV-1 (148 sample), and HEV-4 (2 samples). High-income countries were the most represented with 59/87 studies (67.8%), while only 3/87 (3.5%) of the studies were performed in low-income countries. The overall prevalence obtained of this study was generally higher in industrialized countries. Risk of bias was low in 14.9% of the studies and moderate in 85.1%. The results of this review showed the occurrence of HEV in different waters environments also in industrialized countries with sanitation and safe water supplies. While HEV transmission to humans through water has been widely demonstrated in developing countries, it is an issue still pending in industrialized countries. Better knowledge on the source of pollution, occurrence, survival in water, and removal by water treatment is needed to unravel this transmission path.

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.

Prevalence and Diversity of Hepatitis Virus Markers among Patients with Acute Febrile Jaundice in Chad

Only a minority of the patients with acute febrile jaundice evaluated through the Yellow Fever surveillance program were found positive for antibodies against Yellow Fever Virus (YFV). In order to characterize patients with acute febrile jaundice negative for YFV, we collected 255 sera between January to December 2019. We screened for HBV antigens, and antibodies against HCV and HEV. The seroprevalences observed were 10.6% (27/255) for HBV, 2% (5/255) for HCV, 17.3% (44/255) for HEV IgG, 4.3% (11/255) for HEV IgM, and 12.5% (32/255) for both IgG and IgM HEV. Prevalence of HEV was significantly higher in females than males (p < 0.01). HEV IgG prevalence was highest in those 20–29 years old, but the highest incidence rate (IgM positive) was in children 0–9 years old. Exposure to HEV was higher in the Sahelian zone (55.8%, 95% CI: 40.97–70.66) than in the Sudanese zone (30.2%, 95% CI: 24.01–36.37, p = 0.003). The high prevalence rates and hepatitis virus diversity underline the challenge of routine clinical diagnosis in Chad’s Yellow Fever surveillance program.

Relative risk factors for seropositive hepatitis E virus among blood donors and haemodialysis patients: The pivotal role of primary health care education

Background:

Hepatitis E virus is a zoonotic virus with a worldwide epidemic outbreak. The aim of the study was to identify relative risk factors and co-infections concerning the seropositive HEV IgG among blood donors and haemodialysis (HD) patients in the central blood bank and renal dialysis centre in Wad Medani city, Gezira State, Sudan.

Materials and Methods:

This was a cross-sectional study that included 600 participants, among them 180 showed strong seropositive HEV IgG. The structured questionnaire was used to collect data of the participants’ demographics, disease risk factors and HEV IgG co-infections with HBV, HCV, HIV and syphilis.

Results:

Among the 180 strong seropositive HEV IgG respondents, 84 were blood donors and 96 were haemodialysis patients. The gender and age (18–30 years) had a significant association with the virus exposure (P = 0.000, P = 0.000). Importantly, a significant association of HEV prevalence due to the localities effect exhibited with the highest rate among South Gezira (OR = 38, CI = 14.1–107; P = 0.000). This also observed in Wad Medani, Umm Algura, East Gezira and Managil localities (P = 0.000). The effect of the animal contact on HEV distribution exerted the significant association among the respondents for blood donors and haemodialysis patients in univariate (OR = 4.09, 95% CI 1.5–10.9; P = 0.005) and multivariate (OR = 3.2, CI = 1.1–9.4; P = 0.027) analysis.

Conclusion:

The relative risk factors of the HEV seroprevalence were gender, age, locality and animal contact. Besides the need of a regular survey for the virus seroprevalence, primary health care physicians can play pivotal role in health education, especially in rural areas of Sudan. In addition, primary health care physicians in Sudan are expected to establish strategies and plans to eradicate and minimise the health impact of HEV.

Hepatitis E and Pregnancy: An Unholy Alliance Unmasked from Kashmir, India

The adverse relationship between viral hepatitis and pregnancy in developing countries had been interpreted as a reflection of retrospectively biased hospital-based data collection by the West. However, the discovery of hepatitis E virus (HEV) as the etiological agent of an epidemic of non-A, non-B hepatitis in Kashmir, and the documenting of the increased incidence and severity of hepatitis E in pregnancy via a house-to-house survey, unmasked this unholy alliance. In the Hepeviridae family, HEV-genotype (gt)1 from genus Orthohepevirus A has a unique open reading frame (ORF)4-encoded protein which enhances viral polymerase activity and viral replication. The epidemics caused by HEV-gt1, but not any other Orthohepevirus A genotype, show an adverse relationship with pregnancy in humans. The pathogenesis of the association is complex and at present not well understood. Possibly multiple factors play a role in causing severe liver disease in the pregnant women including infection and damage to the maternal-fetal interface by HEV-gt1; vertical transmission of HEV to fetus causing severe fetal/neonatal hepatitis; and combined viral and hormone related immune dysfunction of diverse nature in the pregnant women, promoting viral replication. Management is multidisciplinary and needs a close watch for the development and management of acute liver failure. (ALF). Preliminary data suggest beneficial maternal outcomes by early termination of pregnancy in patients with lower grades of encephalopathy.

Setting a Course for Preventing Hepatitis E in Low and Lower-Middle-Income Countries: A Systematic Review of Burden and Risk Factors

BACKGROUND

Hepatitis E virus (HEV) is responsible for outbreaks of acute jaundice in Africa and Asia, many of which occur among displaced people or in crisis settings. Although an efficacious vaccine for HEV has been developed, we lack key epidemiologic data needed to understand how best to use the vaccine for hepatitis E control in endemic countries.

METHODS

We conducted a systematic review of articles published on hepatitis E in low-income and lower-middle-income countries in Africa and Asia. We searched PubMed, Scopus, and Embase databases to identify articles with data on anti-HEV immunoglobulin (Ig)G seroprevalence, outbreaks of HEV, or risk factors for HEV infection, disease, or death, and all relevant data were extracted. Using these data we describe the evidence around temporal and geographical distribution of HEV transmission and burden. We estimated pooled age-specific seroprevalence and assessed the consistency in risk factor estimates.

RESULTS

We extracted data from 148 studies. Studies assessing anti-HEV IgG antibodies used 18 different commercial assays. Most cases of hepatitis E during outbreaks were not confirmed. Risk factor data suggested an increased likelihood of current or recent HEV infection and disease associated with fecal-oral transmission of HEV, as well as exposures to blood and animals.

CONCLUSIONS

Heterogeneity in diagnostic assays used and exposure and outcome assessment methods hinder public health efforts to quantify burden of disease and evaluate interventions over time and space. Prevention tools such as vaccines are available, but they require a unified global strategy for hepatitis E control to justify widespread use.

Prevalence of hepatitis E virus in children from Northeast of Argentina

The aim of this study was to assess the prevalence of hepatitis E virus (HEV) in a young population from the Northeast region of Argentina. Four hundred and twelve patients under 18 years old, from rural areas of Chaco Province, were tested for anti-HEV immunoglobulin G (IgG) using enzyme-linked immunosorbent assay. Anti-HEV IgG antibodies were detected in 7 out of 412 patients, accounting for an overall 1.7% prevalence. HEV infection in developing countries is associated to lack of clean drinking water. Consequently, the seroprevalence observed in children in rural areas of Chaco, Argentina, where the access to tap water is less than 15%, was unexpectedly low.

Hepatitis E Virus Infection: Circulation, Molecular Epidemiology, and Impact on Global Health

Infection with hepatitis E virus (HEV) represents the most common source of viral hepatitis globally. Although infecting over 20 million people annually in endemic regions, with major outbreaks described since the 1950s, hepatitis E remains an underestimated disease. This review gives a current view of the global circulation and epidemiology of this emerging virus. The history of HEV, from the first reported enteric non-A non-B hepatitis outbreaks, to the discovery of the viral agent and the molecular characterization of the different human pathogenic genotypes, is discussed. Furthermore, the current state of research regarding the virology of HEV is critically assessed, and the challenges towards prevention and diagnosis, as well as clinical risks of the disease described. Together, these points aim to underline the significant impact of hepatitis E on global health and the need for further in-depth research to better understand the pathophysiology and its role in the complex disease manifestations of HEV infection.

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

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.

Synanthropic rodents as virus reservoirs and transmitters

This review focuses on reports of hepatitis E virus, hantavirus, rotavirus, coronavirus, and arenavirus in synanthropic rodents (Rattus rattus, Rattus norvegicus, and Mus musculus) within urban environments. Despite their potential impact on human health, relatively few studies have addressed the monitoring of these viruses in rodents. Comprehensive control and preventive activities should include actions such as the elimination or reduction of rat and mouse populations, sanitary education, reduction of shelters for the animals, and restriction of the access of rodents to residences, water, and food supplies.

Antiviral Candidates for Treating Hepatitis E Virus Infection

Globally, hepatitis E virus (HEV) causes significant morbidity and mortality each year. Despite this burden, there are no specific antivirals available to treat HEV patients, and the only licensed vaccine is not available outside China. Ribavirin and alpha interferon are used to treat chronic HEV infections; however, severe side effects and treatment failure are commonly reported. Therefore, this study aimed to identify potential antivirals for further development to combat HEV infection. We selected 16 compounds from the nucleoside and nonnucleoside antiviral classes that range in developmental status from late preclinical to FDA approved and evaluated them as potential antivirals for HEV infection, using genotype 1 replicon luminescence studies and replicon RNA quantification. Two potent inhibitors of HEV replication included NITD008 (half-maximal effective concentration [EC50], 0.03 μM; half-maximal cytotoxic concentration [CC50], >100 μM) and GPC-N114 (EC50, 1.07 μM, CC50, >100 μM), and both drugs reduced replicon RNA levels in cell culture (>50% reduction with either 10 μM GPC-N114 or 2.50 μM NITD008). Furthermore, GPC-N114 and NITD008 were synergistic in combinational treatment (combination index, 0.4) against HEV replication, allowing for dose reduction indices of 20.42 and 8.82 at 50% inhibition, respectively. Sofosbuvir has previously exhibited mixed results against HEV as an antiviral, both in vitro and in a few clinical applications; however, in this study it was effective against the HEV genotype 1 replicon (EC50, 1.97 μM; CC50, >100 μM) and reduced replicon RNA levels (47.2% reduction at 10 μM). Together these studies indicate drug repurposing may be a promising pathway for development of antivirals against HEV infection.

Occurrence of microbial indicators, pathogenic bacteria and viruses in tropical surface waters subject to contrasting land use

Fecal indicator bacteria, such as Escherichia coli (E.coli) and Enterococcus, have been widely used to indicate the presence of pathogens. However, the suitability of fecal indicator bacteria to represent health risks is still being challenged, particularly in tropical aquatic environments. The objective of this study is to understand the occurrence and prevalence of indicators and pathogens in areas with contrasting land use, as well as to identify the major correlations between indicators, pathogens and environmental parameters. The spatial and temporal variation of indicators and pathogens was studied to examine the distribution patterns for areas with different land use, and the impact of seasonal changes on microbial populations. A total of 234 water samples were sampled for two years from reservoirs and their tributaries, and tested for fecal indicator bacteria, coliphages, human specific markers, pathogenic bacteria and viruses. The prevalence of indicators and pathogens in reservoirs were generally low, while relatively high concentrations were observed in tributaries to varying degrees. Of the enteric viruses, norovirus GII was among the most prevalent and had the highest concentration. Although strong correlations were found between indicators, only relatively weak correlations were found between indicators and pathogens. The results in this study showed that none of the bacteria/phage indicators were universal predictors for pathogens. Inclusion of the alternative indicators, Methanobrevibacter smithii, Bacteroides and human polyomaviruses (HPyVs) to monitoring programs could help to determine whether the fecal source was human. The microbial distribution patterns allow the classification of sampling sites to different clusters and thus, help to identify sites which have poor water quality. This approach will be useful for water quality management to pinpoint factors that influence water quality and help to prioritize sites for restoration of water quality.

Seroprevalence of Hepatitis E Virus Infection Among People Living With HIV in the Central African Republic

Background

Hepatitis E virus (HEV) is a waterborne virus that causes acute hepatitis in immunocompromised patients and those who are immunocompetent. Few cases of chronic HEV have been described in industrialized countries. The Central African Republic is 1 of the few countries in the world that is endemic for both HIV and HEV. The prevalence of HIV infection is estimated to be 4.9% among adults aged 15-49 years, and hepatitis E is epidemo-endemic. The aim of this study was to characterize the epidemiology of HEV infection in people living with HIV (PLHIV) in Bangui.

Methods

A cross-sectional study was conducted between April and September 2015 based on answers to a questionnaire, and blood samples were collected for determination of immunological markers by enzyme-linked immunosorbent assay and molecular tests.

Results

Of the 200 PLHIV included, 15 (7.5%) had the IgM that characterizes acute HEV infection; 8.9% were women, and 2.2% were men. The overall seroprevalence of IgG was 68% (48% women and 70.4% men), indicating that men are statistically significantly more exposed to HEV than women. HEV infection had no effect on transaminase or T-CD4+ lymphocyte cell levels. The origin of infection could not be identified.

Conclusions

The seroprevalence of HEV is very high among PLHIV and in the general population of Bangui. This must be taken into account in studies of the risk factors of PLHIV infected with HEV.

Reactive and pre-emptive vaccination strategies to control hepatitis E infection in emergency and refugee settings: A modelling study

BACKGROUND

Hepatitis E Virus (HEV) is the leading cause of acute viral hepatitis globally. Symptomatic infection is associated with case fatality rates of ~20% in pregnant women and it is estimated to account for ~10,000 annual pregnancy-related deaths in southern Asia alone. Recently, large and well-documented outbreaks with high mortality have occurred in displaced population camps in Sudan, Uganda and South Sudan. However, the epidemiology of HEV is poorly defined, and the value of different immunisation strategies in outbreak settings uncertain. We aimed to estimate the critical epidemiological parameters for HEV and to evaluate the potential impact of both reactive vaccination (initiated in response to an epidemic) and pre-emptive vaccination.

METHODS

We analysed data from one of the world's largest recorded HEV epidemics, which occurred in internally-displaced persons camps in Uganda (2007-2009), using transmission dynamic models to estimate epidemiological parameters and assess the potential impact of reactive and pre-emptive vaccination strategies.

RESULTS

Under baseline assumptions we estimated the basic reproduction number of HEV in three separate camps to range from 3.7 (95% Credible Interval [CrI] 2.8, 5.1) to 8.5 (5.3, 11.4). Mean latent and infectious periods were estimated to be 34 (95% CrI 28, 39) and 40 (95% CrI 23, 71) days respectively. Assuming 90% vaccine coverage, reactive two-dose vaccination of those aged 16-65 years excluding pregnant women (for whom vaccine is not licensed), if initiated after 50 reported cases, led to mean camp-specific reductions in mortality of 10 to 29%. Pre-emptive vaccination with two doses reduced mortality by 35 to 65%. Both strategies were more effective if coverage was extended to groups for whom the vaccine is not currently licensed. For example, two dose pre-emptive vaccination, if extended to include pregnant women, led to mean reductions in mortality of 66 to 82%.

CONCLUSIONS

HEV has a high transmission potential in displaced population settings. Substantial reductions in mortality through vaccination are expected, even if used reactively. There is potential for greater impact if vaccine safety and effectiveness can be established in pregnant women.

Seroprevalence and risk factors of recent infection with hepatitis E virus during an acute outbreak in an urban setting in Chad, 2017

BACKGROUND

From September 2016-April 2017, Am Timan, Chad, experienced a large HEV outbreak in an urban setting with a limited impact in terms of morbidity and mortality. To better understand HEV epidemiology in this context, we estimated the seroprevalence of anti-HEV antibodies (IgM and IgG) and assessed the risk factors for recent HEV infections (positive anti-HEV IgM) during this outbreak.

METHODS

A serological survey using simple random sampling was implemented in Am Timan at the tail-end of the outbreak (sample size aim = 384 household). Household members provided us with blood samples and household heads answered questions around water, sanitation and hygiene practices and animal ownership. Blood samples were tested for HEV IgG and IgM antibodies using Enzyme-Immune-Assay (EIA). We calculated weighted prevalence estimates and prevalence ratios (PRs) for possible risk factors for recent infection using multivariate Cox regression.

RESULTS

We included 241 households (1529 participants). IgM prevalence decreased with age: 12.6% (< 5 years) to 4.3% (> 15 years). IgG prevalence increased with age: 23.5% (< 5 years) to 75.9% (> 15 years). Risk factors for recent HEV infections included: sharing the sanitation facility with other HHs (PR 1.72; 95%CI: 1.08-2.73), not systematically using soap for HW (PR 1.85; 95%CI: 1.30-2.63) and having animals sleeping inside the compound (PR 1.69; 95%CI: 1.15-2.50).

CONCLUSIONS

Evidence suggests that Am Timan was already highly endemic for HEV before the outbreak, potentially explaining the limited extent of the outbreak. Recent infection with HEV was linked to household level exposures. Future HEV outbreak response must include ensuring access to safe water, and reducing household level transmission through active hygiene and sanitation promotion activities.

Learning from water treatment and hygiene interventions in response to a hepatitis E outbreak in an open setting in Chad

In September 2016, Médecins Sans Frontières responded to a hepatitis E (HEV) outbreak in Chad by implementing water treatment and hygiene interventions. To evaluate the coverage and use of these interventions, we conducted a cross-sectional study in the community. Our results showed that 99% of households interviewed had received a hygiene kit from us, aimed at improving water handling practice and personal hygiene and almost all respondents had heard messages about preventing jaundice and handwashing. Acceptance of chlorination of drinking water was also very high, although at the time of interview, we were only able to measure a safe free residual chlorine level (free chlorine residual (FRC) ≥0.2 mg/L) in 43% of households. Households which had refilled water containers within the last 18 hours, had sourced water from private wells or had poured water into a previously empty container, were all more likely to have a safe FRC level. In this open setting, we were able to achieve high coverage for chlorination, hygiene messaging and hygiene kit ownership; however, a review of our technical practice is needed in order to maintain safe FRC levels in drinking water in households, particularly when water is collected from multiple sources, stored and mixed with older water.

Acute Hepatitis E Virus Infection in Two Geographical Regions of Nigeria

Hepatitis E virus (HEV) remains a major public health concern in resource limited regions of the world. Yet data reporting is suboptimal and surveillance system is inadequate. In Nigeria, there is dearth of information on prevalence of acute HEV infection. This study was therefore designed to describe acute HEV infection among antenatal clinic attendees and community dwellers from two geographical regions in Nigeria. Seven hundred and fifty plasma samples were tested for HEV IgM by Enzyme Linked Immunosorbent Assay (ELISA) technique. The tested samples were randomly selected from a pool of 1,115 blood specimens previously collected for viral hepatitis studies among selected populations (pregnant women, 272; Oyo community dwellers, 438; Anambra community dwellers, 405) between September 2012 and August 2013. One (0.4%) pregnant woman in her 3rd trimester had detectable HEV IgM, while community dwellers from the two study locations had zero prevalence rates of HEV IgM. Detection of HEV IgM in a pregnant woman, especially in her 3rd trimester, is of clinical and epidemiological significance. The need therefore exists for establishment of a robust HEV surveillance system in Nigeria and especially amidst the pregnant population in a bid to improve maternal and child health.

A large outbreak of Hepatitis E virus genotype 1 infection in an urban setting in Chad likely linked to household level transmission factors, 2016-2017

Background

In September 2016, three acutely jaundiced (AJS) pregnant women were admitted to Am Timan Hospital, eastern Chad. We described the outbreak and conducted a case test-negative study to identify risk factors for this genotype of HEV in an acute outbreak setting.

Methods

Active case finding using a community based surveillance network identified suspected AJS cases. Pregnant or visibly ill AJS cases presenting at hospital were tested with Assure^® IgM HEV rapid diagnostic tests (RDTs) and some with Polymerase Chain Reaction (PCR) in Amsterdam; confirmed cases were RDT-positive and controls were RDT-negative. All answered questions around: demographics, household makeup, area of residence, handwashing practices, water collection behaviour and clinical presentation. We calculated unadjusted odds ratios (ORs) and 95% confidence intervals (95% CI).

Results

Between September and April 2017, 1443 AJS cases (1293 confirmed) were detected in the town(attack rate: 2%; estimated 65,000 population). PCR testing confirmed HEV genotype 1e.

HEV RDTs were used for 250 AJS cases; 100 (40%) were confirmed. Risk factors for HEV infection, included: having at least two children under the age of 5 years (OR 2.1, 95%CI 1.1–4.3), having another household member with jaundice (OR 2.4, 95%CI 0.90–6.3) and, with borderline significance, living in the neighbourhoods of Riad (OR 3.8, 95%CI 1.0–1.8) or Ridina (OR 3.3, 95%CI 1.0–12.6). Cases were more likely to present with vomiting (OR 3.2, 9%CI 1.4–7.9) than controls; possibly due to selection bias. Cases were non-significantly less likely to report always washing hands before meals compared with controls (OR 0.33, 95%CI 0.1–1.1).

Discussion

Our study suggests household factors and area of residence (possibly linked to access to water and sanitation) play a role in HEV transmission; which could inform future outbreak responses. Ongoing sero-prevalence studies will elucidate more aspects of transmission dynamics of this virus with genotype 1e.

Seroprevalence and incidence of hepatitis E virus among blood donors: A review

Hepatitis E virus (HEV) is an RNA virus with 4 main genotypes. HEV-1 and HEV-2 infect solely humans, while HEV-3 and HEV-4 infect humans and various animals such as pigs, deer, and rabbits. HEV-5 and HEV-6 infect mainly wild boar. Recently, new genotypes, known as HEV-7 and HEV-8, were found to infect camels and humans. HEV is globally distributed into different epidemiological patterns based on socioeconomic factors and ecology. Although HEV is mainly transmitted through the fecal-oral route, it was also recognized as a transfusion-transmitted virus. Transmission through blood donation was documented worldwide with rising annual observations, accounting for more than 2.5% of all transmissions. HEV infection is usually asymptomatic or subclinical in immunocompetent individuals, so it remains questionable whether there is an urgent need to screen for HEV prior to blood transfusion. Moreover, recent studies conducted in the Middle East and North Africa (MENA) region indicate that HEV is highly endemic. Here, we provide a review on HEV epidemiology, transmission, and laboratory diagnosis, giving special emphasis to the newly discovered genotypes, HEV-7 and HEV-8. Furthermore, we underscore the findings of recent HEV seroprevalence and viremia studies among blood donors worldwide. We also shed light on similar studies performed among blood donors in the MENA region.

Risk factors, person, place and time characteristics associated with Hepatitis E Virus outbreak in Napak District, Uganda

BACKGROUND

Hepatitis E is self-limiting, but can cause death in most at risk groups like pregnant women and those with preexisting acute liver disease. In developing countries it presents as epidemic, in 2014 Hepatitis E Virus (HEV) outbreak was reported in Napak district Uganda. The role of factors in this setting that might have propagated this HEV epidemic, including host, agent, and environmental characteristics, were still not clear. This study was therefore conducted to investigate the risk factors, person, place and time characteristics, associated with the hepatitis E virus (HEV) epidemic in Napak district.

METHODS

Review of line lists data for epidemiological description and matched case control study on neighborhood and age in the ratio of 1:2 were used to assess risk factors for HEV outbreak in Napak. Cluster and random sampling were used to obtain a sample size of 332, (111 cases, 221 controls). Possible interaction and confounding was assessed using conditional logistic regression.

RESULTS

Over 1359 cases and 30 deaths were reported during 2013/2014 HEV outbreak. The mean age of patients was 29 ± years, 57.9% of cases were females. Overall case Fatality Ratio was 2.2% in general population but 65.2% in pregnant women. More than 94% of the cases were reported in the sub counties of Napak, 5.7% of cases were reported in the outside neighboring districts. The epidemic peaked in January 2014 and gradually subsided by December 2014. Risk factors found to be associated with HEV included drinking untreated water (OR 6.69, 95% CI 3.15-14.16), eating roadside food (OR 6.11, 95% CI 2.85-13.09), reported not cleaning utensils (OR 3.24, 95% CI 1.55-1.76), and being a hunter (OR 1.14, 95% CI 1.03-12.66).

CONCLUSION

The results of this study suggest that the virus is transmitted by the feco-oral route through contaminated water. They also suggest that active surveillance and appropriate measures targeting community and routine individual health actions are important to prevent transmission and decrease the deaths.

The global burden of hepatitis E outbreaks: a systematic review

Hepatitis E virus (HEV) is responsible for repeated water-borne outbreaks since the past century, representing an emerging issue in public health. However, the global burden of HEV outbreak has not been comprehensively described. We performed a systematic review of confirmed HEV outbreaks based on published literatures. HEV outbreaks have mainly been reported from Asian and African countries, and only a few from European and American countries. India represents a country with the highest number of reported HEV outbreaks. HEV genotypes 1 and 2 were responsible for most of the large outbreaks in developing countries. During the outbreaks in developing countries, a significantly higher case fatality rate was observed in pregnant women. In fact, outbreaks have occurred both in open and closed populations. The control measures mainly depend upon improvement of sanitation and hygiene. This study highlights that HEV outbreak is not new, yet it is a continuous global health problem.

Epidemiological investigation of a tap water-mediated hepatitis E virus genotype 4 outbreak in Zhejiang Province, China

An outbreak of acute hepatitis recently occurred in a nursing home in Zhejiang Province, China. The objectives of this study were to confirm the outbreak and identify the aetiology, source and transmission patterns. All residents and staff in or near the nursing home during the period from 1 October 2014 to 21 May 2015 were investigated regarding hygiene and for epidemiological information including water and food (eating meat especially pork products). Serum and stool specimens were collected for detection of hepatitis E virus (HEV) antibodies using ELISA and RNA using RT-PCR. Samples that were RNA positive were genotyped. Of 185 senior residents and 24 staff in the nursing home, there were 37 laboratory-confirmed cases during the outbreak. Of these cases, 12 patients (three deaths) were symptomatic with jaundice, a common clinical symptom for hepatitis E infection. HEV strains were isolated from three cases and they formed a single cluster within genotype 4d. A case-control study was conducted to investigate potential risk factors for the outbreak and the results revealed that cases more often washed their dishes and rinsed their mouths using tap water than the controls (P < 0·05). Based on hygiene investigation and meteorological information, it is likely that HEV-infected sewage and faeces contaminated the water network on rainy days. Collectively, these results suggest that the outbreak of HEV genotype 4 infection was most likely caused by contaminated tap water rather than food.

A Single Lineage of Hepatitis E Virus Causes Both Outbreaks and Sporadic Hepatitis in Sudan

Few studies have reported sporadic hepatitis E virus (HEV) infections during non-outbreak periods in Africa. In this study, the prevalence of HEV infection in Sudan was investigated in 432 patients with acute hepatitis from 12 localities in North Kordofan, and from 152 patients involved in smaller outbreaks of hepatitis in the neighbouring Darfur. HEV infection was diagnosed in 147 (25%) patients: 98 from Kordofan and 49 from Darfur. The mortality was 10%; six of the patients who died from the infection were pregnant women. HEV RNA was detected by quantitative real-time polymerase chain reaction (RT-qPCR) in 38 (26%) patients: 22 from Kordofan and 16 from Darfur. Partial open reading frame (ORF) 1 and ORF2 were sequenced from HEV from nine and three patients, respectively. Phylogenetic analysis showed that the Sudanese strains belonged to genotype 1 (HEV1), and confirmed the segregation of African HEV1 strains into one branch divergent from Asian HEV1. It also revealed that the Sudanese strains from this study and from an outbreak in 2004 formed a separate clade with a common ancestor, distinct from strains from the neighbouring Chad and Egypt. This HEV strain has thus spread in a large area of Sudan, where it has caused both sporadic hepatitis E and outbreaks from at least 2004 and onwards. These data demonstrate that hepatitis E is a constant, on-going public health problem in Sudan and that there is a need for hepatitis E surveillance, outbreak preparedness, and general improvements of the sanitation in these remote areas of the country.

UV disinfection and flocculation-chlorination sachets to reduce hepatitis E virus in drinking water

Hepatitis E Virus (HEV) is a major cause of waterborne outbreaks in areas with poor sanitation. As safe water supplies are the keystone for preventing HEV outbreaks, data on the efficacy of disinfection treatments are urgently needed. Here, we evaluated the ability of UV radiation and flocculation-chlorination sachets (FCSs) to reduce HEV in water matrices. The HEV-p6-kernow strain was replicated in the HepG2/C3A cell line, and we quantified genome number using qRT-PCR and infectivity using an immunofluorescence assay (IFA). UV irradiation tests using low-pressure radiation showed inactivation kinetics for HEV of 99.99% with a UV fluence of 232J/m(2) (IC 95%, 195,02-269,18). Moreover, the FCSs preparations significantly reduced viral concentrations in both water matrices, although the inactivation results were under the baseline of reduction (4.5 LRV) proposed by WHO guidelines.

Prophylaxis against hepatitis E: at risk populations and human vaccines

Hepatitis E is an emerging global disease caused by hepatitis E virus (HEV) infection. While in developing countries the infection was primarily due to poor sanitary conditions through intake of contaminated water or undercooked meats of infected animals, increasing cases of chronic hepatitis E resulting in rapidly progressive liver cirrhosis and end-stage liver disease have been reported in organ transplant patients or in immune compromised patients in developed countries. Fortunately, hepatitis E is now a vaccine preventable disease with a HEV239 based vaccine licensed for human use. Much work is needed to enable its use outside China. This review recounted the development process of the vaccine, outlined the critical quality attributes of the vaccine antigen and, most importantly, listed the populations at risk for HEV infection and the subsequent disease. These at risk populations could benefit the most from the vaccination if the vaccine is widely adopted.

Hepeviridae: an expanding family of vertebrate viruses

The hepatitis E virus (HEV) was first identified in 1990, although hepatitis E-like diseases in humans have been recorded for a long time dating back to the 18th century. The HEV genotypes 1-4 have been subsequently detected in human hepatitis E cases with different geographical distribution and different modes of transmission. Genotypes 3 and 4 have been identified in parallel in pigs, wild boars and other animal species and their zoonotic potential has been confirmed. Until 2010, these genotypes along with avian HEV strains infecting chicken were the only known representatives of the family Hepeviridae. Thereafter, additional HEV-related viruses have been detected in wild boars, distinct HEV-like viruses were identified in rats, rabbit, ferret, mink, fox, bats and moose, and a distantly related agent was described from closely related salmonid fish. This review summarizes the characteristics of the so far known HEV-like viruses, their phylogenetic relationship, host association and proposed involvement in diseases. Based on the reviewed knowledge, a suggestion for a new taxonomic grouping scheme of the viruses within the family Hepeviridae is presented.

Hepatitis E virus infection

Hepatitis E virus (HEV) infection is a worldwide disease. An improved understanding of the natural history of HEV infection has been achieved within the last decade. Several reservoirs and transmission modes have been identified. Hepatitis E is an underdiagnosed disease, in part due to the use of serological assays with low sensitivity. However, diagnostic tools, including nucleic acid-based tests, have been improved. The epidemiology and clinical features of hepatitis E differ between developing and developed countries. HEV infection is usually an acute self-limiting disease, but in developed countries it causes chronic infection with rapidly progressive cirrhosis in organ transplant recipients, patients with hematological malignancy requiring chemotherapy, and individuals with HIV. HEV also causes extrahepatic manifestations, including a number of neurological syndromes and renal injury. Acute infection usually requires no treatment, but chronic infection should be treated by reducing immunosuppression in transplant patients and/or the use of antiviral therapy. In this comprehensive review, we summarize the current knowledge about the virus itself, as well as the epidemiology, diagnostics, natural history, and management of HEV infection in developing and developed countries.

A systematic review of the epidemiology of hepatitis E virus in Africa

BACKGROUND

Hepatitis E Virus (HEV) infection is a newly recognized serious threat to global public health and Africa is suspected to be among the most severely affected regions in the world. Understanding HEV epidemiology in Africa will expedite the implementation of evidence-based control policies aimed at preventing the spread of HEV including policies for the use of available resources such as HEV vaccines.

METHODS

Here we present a comprehensive review of HEV epidemiology in Africa based on published data. We searched for articles on HEV epidemiology in Africa from online databases such as PubMed, Scopus, and ISI Web of Science and critically reviewed appropriate publications to extract consistent findings, identify knowledge gaps, and suggest future studies.

RESULTS

Taking a particularly high toll in pregnant women and their fetuses, HEV has infected human populations in 28 of 56 African countries. Since 1979, 17 HEV outbreaks have been reported about once every other year from Africa causing a reported 35,300 cases with 650 deaths.

CONCLUSIONS

In Africa, HEV infection is not new, is widespread, and the number of reported outbreaks are likely a significant underestimate. The authors suggest that this is a continent-wide public health problem that deserves the attention of local, regional and international agencies to implement control policies that can save numerous lives, especially those of pregnant women and their fetuses.

Hepatitis E: an emerging disease

Currently, the infection with the hepatitis E virus represents the most frequent cause for acute hepatitis and jaundice in the world. According to WHO estimations, around two billion people, representing one third of the world's population, live in endemic areas for HEV and, therefore, are at risk of infection. In developed countries, the circulation of the virus in both human and animal (swine, boar, deer) sewage has been confirmed; however, the incidence rate is low compared to that of developing countries where outbreaks of acute hepatitis transmitted via the fecal-oral route are originated, more frequently in the flooding season or after natural disasters, combined with deficient sanitary conditions. There are currently 4 known genotypes of HEV. Genotypes 1 and 2 are isolated in all human epidemic outbreaks in developing countries, while genotypes 3 and 4 are isolated not only in humans but also in animals, in both developing and industrialized countries. These data support genotypes 3 and 4 having zoonotic nature. The diagnosis of this disease is based in the detection of anti-HEV IgG and IgM in blood serum using enzyme-linked immunosorbent methods. However, the method that best confirms the diagnosis is the RT-PCR, which detects HEV RNA in blood serum and also provides the genotype. The clinical course is generally that of an acute hepatitis which in some cases may require hospitalization and that, in transplant patients or HIV infected individuals can become a chronic hepatitis. Furthermore, the virus constitutes an important risk for pregnant women. The hepatitis E can present a wide range of symptoms, from a subclinical case to chronic liver disease with extrahepatic manifestations. For this reason, the diagnostic is challenging if no differential diagnosis is included. There is no specific antiviral drug for hepatitis E, but satisfactory results have been observed in some patients treated with pegylated interferon alfa2a and/or ribavirin. This revision is an update of all the molecular, epidemiological, clinic and preventive knowledge on this emergent disease up to date.

Enteric pathogens in stored drinking water and on caregiver's hands in Tanzanian households with and without reported cases of child diarrhea

BACKGROUND

Diarrhea is one of the leading causes of mortality in young children. Diarrheal pathogens are transmitted via the fecal-oral route, and for children the majority of this transmission is thought to occur within the home. However, very few studies have documented enteric pathogens within households of low-income countries.

METHODS AND FINDINGS

The presence of molecular markers for three enteric viruses (enterovirus, adenovirus, and rotavirus), seven Escherichia coli virulence genes (ECVG), and human-specific Bacteroidales was assessed in hand rinses and household stored drinking water in Bagamoyo, Tanzania. Using a matched case-control study design, we examined the relationship between contamination of hands and water with these markers and child diarrhea. We found that the presence of ECVG in household stored water was associated with a significant decrease in the odds of a child within the home having diarrhea (OR = 0.51; 95% confidence interval 0.27-0.93). We also evaluated water management and hygiene behaviors. Recent hand contact with water or food was positively associated with detection of enteric pathogen markers on hands, as was relatively lower volumes of water reportedly used for daily hand washing. Enteropathogen markers in stored drinking water were more likely found among households in which the markers were also detected on hands, as well as in households with unimproved water supply and sanitation infrastructure.

CONCLUSIONS

The prevalence of enteric pathogen genes and the human-specific Bacteroidales fecal marker in stored water and on hands suggests extensive environmental contamination within homes both with and without reported child diarrhea. Better stored water quality among households with diarrhea indicates caregivers with sick children may be more likely to ensure safe drinking water in the home. Interventions to increase the quantity of water available for hand washing, and to improve food hygiene, may reduce exposure to enteric pathogens in the domestic environment.

Host immune status and response to hepatitis E virus infection

Hepatitis E virus (HEV), identified over 30 years ago, remains a serious threat to life, health, and productivity in developing countries where access to clean water is limited. Recognition that HEV also circulates as a zoonotic and food-borne pathogen in developed countries is more recent. Even without treatment, most cases of HEV-related acute viral hepatitis (with or without jaundice) resolve within 1 to 2 months. However, HEV sometimes leads to acute liver failure, chronic infection, or extrahepatic symptoms. The mechanisms of pathogenesis appear to be substantially immune mediated. This review covers the epidemiology of HEV infection worldwide, the humoral and cellular immune responses to HEV, and the persistence and protection of antibodies produced in response to both natural infection and vaccines. We focus on the contributions of altered immune states (associated with pregnancy, human immunodeficiency virus [HIV], and immunosuppressive agents used in cancer and transplant medicine) to the elevated risks of chronic infection (in immunosuppressed/immunocompromised patients) and acute liver failure and mortality (among pregnant women). We conclude by discussing outstanding questions about the immune response to HEV and interactions with hormones and comorbid conditions. These questions take on heightened importance now that a vaccine is available.

Epidemiology of mammalian hepatitis E virus infection

Mammalian hepatitis E virus (HEV), the etiological agent of hepatitis E in humans, is a recently discovered infectious agent. It was identified for the first time in 1983 using electron microscopy on a faecal specimen of a person infected with non-A, non-B enterically-transmitted hepatitis. Based on retrospective and prospective studies, HEV was long described as one of the leading causes of acute viral hepatitis in tropical and subtropical countries, whereas in developed countries hepatitis E was considered an imported disease from HEV hyperendemic countries. Data from studies conducted during the past decade have greatly shifted our knowledge on the epidemiology and clinical spectrum of HEV. Recently, it has been shown that contrary to previous beliefs, hepatitis E is also an endemic disease in several developed countries, particularly in Japan and in Europe, as evidenced by reports of high anti-HEV immunoglobulin G prevalence in healthy individuals and an increasing number of non-travel-related acute hepatitis E cases. Moreover, a porcine reservoir and growing evidence of zoonotic transmission have been reported in these countries. This review summarizes the current knowledge on the epidemiology and prevention of transmission of mammalian HEV.

Hepatitis E

Hepatitis E virus (HEV) was discovered during the Soviet occupation of Afghanistan in the 1980s, after an outbreak of unexplained hepatitis at a military camp. A pooled faecal extract from affected soldiers was ingested by a member of the research team. He became sick, and the new virus (named HEV), was detected in his stool by electron microscopy. Subsequently, endemic HEV has been identified in many resource-poor countries. Globally, HEV is the most common cause of acute viral hepatitis. The virus was not initially thought to occur in developed countries, but recent reports have shown this notion to be mistaken. The aim of this Seminar is to describe recent discoveries regarding HEV, and how they have changed our understanding of its effect on human health worldwide.

Genetic characteristics and pathogenicity of human hepatitis E virus in Nanjing, China

AIM: To investigate the genetic characteristics and pathogenicity of hepatitis E virus (HEV) and assess the potential risk factors for sporadic hepatitis E.

METHODS: Sixty-two serum samples from the patients with acute hepatitis E were collected, including 23 cases coinfected with hepatitis B virus. Anti-HEV detection and partial HEV RNA amplification were performed by enzyme immunoassays and reverse transcription-nested polymerase chain reaction (RT-nPCR) method, respectively, and PCR products were sequenced. The isolated human HEV sequences were analyzed phylogenetically.

RESULTS: The positive rate of serum HEV RNA were 21.0% (13/62), including 5 cases of liver failure. All the 13 isolates shared a 82.1%-98.0% nucleotide homology with each other and had identities of 74.7%-81.0%, 75.3%-78.6%, 75.3%-80.0% and 82.1%-96.1% with the corresponding regions of HEV genotypes 1-4, respectively. The human HEV strain GS-NJ-12 shared a 100% nucleotide identity with the swine HEV strain swIM6-43 isolated from Inner Mongolia, China.

CONCLUSION: Swine may be a principal risk factor for occurrence of sporadic hepatitis E in eastern China, and genotype 4 HEV can induce acute liver failure.