[Seroprevalences of hepatitis A and E infections in Tunisia]

Emerging and Re-emerging Infectious Diseases in the WHO Eastern Mediterranean Region, 2001-2018

BACKGROUND

Countries in the World Health Organization (WHO) Eastern Mediterranean Region (EMR) are predisposed to highly contagious, severe and fatal, emerging infectious diseases (EIDs), and re-emerging infectious diseases (RIDs). This paper reviews the epidemiological situation of EIDs and RIDs of global concern in the EMR between 2001 and 2018.

METHODS

To do a narrative review, a complete list of studies in the field was we prepared following a systematic search approach. Studies that were purposively reviewed were identified to summarize the epidemiological situation of each targeted disease. A comprehensive search of all published studies on EIDs and RIDs between 2001 and 2018 was carried out through search engines including Medline, Web of Science, Scopus, Google Scholar, and ScienceDirect.

RESULTS

Leishmaniasis, hepatitis A virus (HAV) and hepatitis E virus (HEV) are reported from all countries in the region. Chikungunya, Crimean Congo hemorrhagic fever (CCHF), dengue fever, and H5N1 have been increasing in number, frequency, and expanding in their geographic distribution. Middle East respiratory syndrome (MERS), which was reported in this region in 2012 is still a public health concern. There are challenges to control cholera, diphtheria, leishmaniasis, measles, and poliomyelitis in some of the countries. Moreover, Alkhurma hemorrhagic fever (AHF), and Rift Valley fever (RVF) are limited to some countries in the region. Also, there is little information about the real situation of the plague, Q fever, and tularemia.

CONCLUSION

EIDs and RIDs are prevalent in most countries in the region and could further spread within the region. It is crucial to improve regional capacities and capabilities in preventing and responding to disease outbreaks with adequate resources and expertise.

Seroprevalence of hepatitis E virus among blood donors in eastern Algeria

Hepatitis E virus (HEV) is recognized worldwide as the leading cause of orofecal-transmitted hepatitis. However, blood transmission has been increasingly implicated in recent years raising health concerns. In Algeria, updated prevalence data are lacking. We aimed to determine the prevalence of anti-HEV antibodies in the sera of volunteer blood donors from the Setif region in eastern Algeria. A total of 434 Samples were analyzed for anti-HEV IgG and IgM antibodies using an enzyme-linked immunosorbent assay (Wantai). Logistic regression modelling was used to identify associated risk factors. The IgG seroprevalence rate was 17.05%. Seven sera (0.16%) were weakly positive for IgM. No HEV RNA was detected. The IgG prevalence was significantly correlated with increasing age (p < 1p.1000). Our data demonstrate a relatively high prevalence of anti-HEV IgG, indicating a possible risk of HEV blood transmission which requires vireamic seroprevalence studies to assess the real risk.

Hepatitis A in the Eastern Mediterranean Region: a comprehensive review

Introduction

With 583 million inhabitants, the Eastern Mediterranean Region (EMR) is a worldwide hub for travel, migration, and food trade. However, there is a scarcity of data on the epidemiology of the hepatitis A virus (HAV).

Methods

The MEDLINE and grey literature were systematically searched for HAV epidemiological data relevant to the EMR region published between 1980 and 2020 in English, French, or Arabic.

Results

Overall, 123 publications were extracted. The proportion of HAV cases among acute viral hepatitis cases was high. HAV seroprevalence rate ranged from 5.7% to 100.0% and it was decreasing over time while the average age at infection increased.

Conclusion

In the EMR, HAV remains a significant cause of acute viral hepatitis. The observed endemicity shift will likely increase disease burden as the population ages. Vaccinating children and adopting sanitary measures are still essential to disease prevention; vaccinating at-risk groups might reduce disease burden even further.

What is the context?

Hepatitis A is a viral liver disease caused by the hepatitis A virus.

It is generally transmitted by ingestion of contaminated food or water or through contact with an infected person.

Disease severity increases with age. Children under 6 years of age are usually asymptomatic, while adults are the most affected.

Limited information exists on the number of cases and transmission of hepatitis A in the Eastern Mediterranean region, which includes 21 countries and Palestine, as defined by the World Health Organization.

What is new?

We performed a literature review to summarize data on hepatitis A disease in the Eastern Mediterranean region over the last 40 years (1980-2020). As information for many countries is scarce or outdated, most of the data is from Egypt, Iran and Saudi Arabia.

We found that:

Hepatitis A virus is the most common cause of acute viral hepatitis.

Hepatitis A exposure varied according to the country’s income level.

Low- and middle-income countries showed a universal immunity to hepatitis A virus, although this is not the case anymore.

What is the impact?

Hepatitis A infections have decreased worldwide. Lower exposure to the virus has led to an increase in the susceptible population (including adolescent and adults).

Hepatitis A vaccination for children and high-risk groups such travelers should be considered in the Eastern Mediterranean region.

Epidemiological patterns of Hepatitis A infection during the pre-vaccination Era: A population-based survey in Tunisia in 2015

BACKGROUND

In the 1980s, Tunisia was considered a country of high endemicity for Hepatitis A virus (HAV). Since 2000, an epidemiological shift has led to an increased incidence of symptomatic and severe forms of HAV infection.

OBJECTIVE

In 2015, we conducted a cross-sectional nationwide household-based HAV seroprevalence study in the total population regardless of age, sex, or geographical origin using a stratified sampling design in order to make an overview of the HAV epidemiological situation in Tunisia before vaccine implementation.

RESULTS

A total of 6322 individuals were enrolled. The HAV prevalence was 78.8%. The anti-HAV IgG seropositivity rate increases from 16% for ages 5-9 years to 45% for ages 10-14, 67% for ages 15-19, 87% for ages 20-24, and >90% for older age groups, which suggests an age at midpoint of population immunity (AMPI) in late adolescence. It was significantly higher in rural areas (p<10^-3) and varied significantly between and within regions (p<10^-4).

CONCLUSIONS

In this study, although the overall AMPI suggests intermediate endemicity, the regional AMPI varies from intermediate to very high endemicity profiles attributable to different socio-economic determinants and conditions of sanitation and hygiene. Also it provides insights for the best decisions in terms of vaccinations strategies.

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.

Inactivation of Hepatovirus A in wastewater by 254 nm ultraviolet-C irradiation

Hepatovirus A is known as a waterborne and foodborne virus that can be transmitted from one person to another through contaminated water and raw food. Therefore, it is necessary to survey the circulation of this type of enteric virus in the wastewater to prevent prospective outbreaks. Wastewater samples collected from WWTP El Menzeh I and Charguia I have been the subject for physicochemical, bacteriological (MPN) and virological analyses. Hepatovirus A (HAV) detection was carried out using the standard reverse transcription-polymerase chain reaction (RT-PCR). Hepatovirus A was detected respectively in 62% (63/102) and 66% (92/140) of the collected wastewater samples at El Menzeh I and Charguia I WWTPs. The treated effluent by natural oxidizing lagoon procedure was characterized by a poor physical-chemical and virological qualities but with excellent bacteriological quality. Consequently, this effluent is not suitable to be recycled and reused in agriculture or even dismissed in the environment. The treated sewage by activated sludge and rotating biodisk procedures turned out to be of a very good physical-chemical quality but with a poor bacteriological and virological quality. After tertiary UV-C₂₅₄ nm irradiation, the faecal indicator bacteria concentration was mostly reduced and removed. These findings confirmed the need for improvement and upgrade of the treatment processes used in these two studied sewage purification plants and the necessity of implementation and establishment of a proper national virological standard to control the circulation rates of enteric viruses in Tunisian municipal wastewater.

Evidence of Circulation of Several HAV Genetic Variants and Emergence of Potential Antigenic Variants in an Endemo-Epidemic Country before Vaccine Introduction

Similar to several other countries in the world, the epidemiology of hepatitis A virus changed from high to intermediate endemicity level in Tunisia, which led to the occurrence of outbreaks. This study aimed to determine the genetic and antigenic variability of HAV strains circulating in Tunisia during the last few years. Genotyping using complete VP1 gene and VP1-2A junction confirmed the predominance of genotype IA, with co-circulation of several genetic and antigenic variants. Phylogenetic analysis including Tunisian and strains from other regions of the world showed the presence of at least two IA-variants within IA subgenotype. Amino-acid analysis showed several mutations in or close to epitope regions in the VP1-region. This study provides a baseline on the genetic and antigenic variability of HAV circulating strains before the introduction of vaccination into the national immunization schedule.

Seroprevalence of hepatitis A virus infection in Central-West of Tunisia

Hepatitis A infections still represent a major global health concern. During the past years, a transition pattern of the hepatitis A epidemiology was noted in many parts of the world. In Tunisia, there is not a recent survey on age-specific hepatitis A virus seroprevalence. This study aimed to investigate the seroprevalence of hepatitis A virus infection in Central-West Tunisia, representative of regions with lowest socioeconomic level in the country, before vaccine implementation. Sera obtained from the blood samples of subjects were screened for the detection of hepatitis A virus. The seroprevalence was evaluated by detection of total antibodies to hepatitis A virus using commercially available immunoassay kits. A total of 1379 subjects, aged 5-75 years (mean age: 29.0 ± 17.3 years) were studied. The global anti-hepatitis A virus seroplevalence was 84.7% (95% confidence interval: [82.6-86.5]). A higher hepatitis A virus seroprevalence was showed in subjects aged 10-14 years compared to those aged less than 10 years (50.0% vs. 31.0%). In subjects aged 20-29 years, a rapid increase in the hepatitis A virus prevalence was noted; it reached 97.0%. The seroprevalence of anti-hepatitis A virus differed by zone of residence (81.1% in rural area vs. 72.4% in urban area, p = .005) and increased significantly with lower level of education (p = .019). There was no statistical significant seroprevalence difference between male and female: 84.2% versus 85.2%, respectively. Our study confirm the transition pattern of the hepatitis A virus endemicity in Tunisia from high to intermediate and provide an evaluation of the hepatitis A virus epidemiological situation before vaccine implementation.

Hepatitis a virus infection in Central-West Tunisia: an age structured model of transmission and vaccination impact

BACKGROUND

The epidemiological pattern of hepatitis A infection has shown dynamic changes in many parts of the world due to improved socio-economic conditions and the accumulation of seronegative subjects, which leads to possible outbreaks and increased morbidity rate. In Tunisia, the epidemiological status of hepatits A virus is currently unknown. However, over the past years higher numbers of symptomatic hepatitis A virus infection in school attendants and several outbreaks were reported to the Ministry of Health, especially from regions with the lowest socio-economic levels in the country. The aim of this study was to investigate the current seroprevalence of hepatitis A virus antibodies in central-west Tunisia and assess the impact of hepatitis A virus vaccination on hepatitis A epidemiology.

METHODS

Serum samples from 1379 individuals, aged 5-75 years, were screened for hepatitis A virus antibodies. Adjusted seroprevalence, incidence and force of infection parameters were estimated by a linear age structured SEIR (Susceptible-Exposed-Infectious-Recovered) compartmental model. A vaccine model was then constructed to assess the impact on hepatitis A virus epidemiology of 3 scenarios of vaccination strategies: one dose at 12-months of age, one dose at 6-years and one dose at 12-months and another at 6-years of age during 6 years.

RESULTS

A rapid increase in anti-hepatitis A virus seroprevalence was noted during infancy and adolescence: 47% of subjects under 10-years-old are infected; the prevalence increases to 77% at 15-years and reaches 97% in subjects aged 30-years. The force of infection is highest between 10 and 30-years of age and the incidence declines with increasing age. The vaccine model showed that the 3-scenarios lead to a significant reduction of the fraction of susceptibles. The two doses scenario gives the best results. Single-dose vaccination at 6-years of age provides more rapid decrease of disease burden in school-aged children, as compared to single-dose vaccination at 12-months, but keeps with a non-negligible fraction of susceptibles among children < 6-years.

CONCLUSIONS

Our study confirms the epidemiological switch from high to intermediate endemicity of hepatitis A virus in Tunisia and provides models that may help undertake best decisions in terms of vaccinations strategies.

A systematic review of the epidemiology of hepatitis A in Africa

BACKGROUND

Hepatitis A, caused by the hepatitis A virus (HAV), is a vaccine preventable disease. In Low and Middle-Income Countries (LMICs), poor hygiene and sanitation conditions are the main risk factors contributing to HAV infection. There have been, however, notable improvements in hygiene and sanitation conditions in many LMICs. As a result, there are studies showing a possible transition of some LMICs from high to intermediate HAV endemicity. The World Health Organization (WHO) recommends that countries should routinely collect, analyse and review local factors (including disease burden) to guide the development of hepatitis A vaccination programs. Up-to-date information on hepatitis A burden is, therefore, critical in aiding the development of country-specific recommendations on hepatitis A vaccination.

METHODS

We conducted a systematic review to present an up-to-date, comprehensive synthesis of hepatitis A epidemiological data in Africa.

RESULTS

The main results of this review include: 1) the reported HAV seroprevalence data suggests that Africa, as a whole, should not be considered as a high HAV endemic region; 2) the IgM anti-HAV seroprevalence data showed similar risk of acute hepatitis A infection among all age-groups; 3) South Africa could be experiencing a possible transition from high to intermediate HAV endemicity. The results of this review should be interpreted with caution as the reported data represents research work with significant sociocultural, economic and environmental diversity from 13 out of 54 African countries.

CONCLUSIONS

Our findings show that priority should be given to collecting HAV seroprevalence data and re-assessing the current hepatitis A control strategies in Africa to prevent future disease outbreaks.

Sapovirus in Wastewater Treatment Plants in Tunisia: Prevalence, Removal, and Genetic Characterization

Sapovirus (SaV), from the Caliciviridae family, is a genus of enteric viruses that cause acute gastroenteritis. SaV is shed at high concentrations with feces into wastewater, which is usually discharged into aquatic environments or reused for irrigation without efficient treatments. This study analyzed the incidence of human SaV in four wastewater treatment plants from Tunisia during a period of 13 months (December 2009 to December 2010). Detection and quantification were carried out using reverse transcription-quantitative PCR (RT-qPCR) methods, obtaining a prevalence of 39.9% (87/218). Sixty-one positive samples were detected in untreated water and 26 positive samples in processed water. The Dekhila plant presented the highest contamination levels, with a 63.0% prevalence. A dominance of genotype I.2 was observed on 15 of the 24 positive samples that were genetically characterized. By a Bayesian estimation algorithm, the SaV density in wastewater was estimated using left-censored data sets. The mean value of log SaV concentration in untreated wastewater ranged between 2.7 and 4.5 logs. A virus removal efficiency of 0.2 log was calculated for the Dekhila plant as the log ratio posterior distributions between untreated and treated wastewater. Multiple quantitative values obtained in this study must be available in quantitative microbial risk assessment in Tunisia as parameter values reflecting local conditions.IMPORTANCE Human sapovirus (SaV) is becoming more prevalent worldwide and organisms in this genus are recognized as emerging pathogens associated with human gastroenteritis. The present study describes novel findings on the prevalence, seasonality, and genotype distribution of SaV in Tunisia and Northern Africa. In addition, a statistical approximation using Bayesian estimation of the posterior predictive distribution ("left-censored" data) was employed to solve methodological problems related with the limit of quantification of the quantitative PCR (qPCR). This approach would be helpful for the future development of quantitative microbial risk assessment procedures for wastewater.

Changes in prevalence of hepatitis A and associated factors in Setif-Algeria

Hepatitis A, a waterborne disease associated with fecal contamination, remains the most common acute hepatitis worldwide. Generally considered to be a disease affecting children living in poor sanitary conditions, hepatitis A affects the adult population if hygiene improves. Studies conducted during the 1980s ranked Algeria as a highly endemic area. Thirty years on, we conducted this cross-sectional epidemiological study with the main objective of estimating the seroprevalence of hepatitis A virus infection in the district of Setif, Algeria. A survey was carried out between June 2010 and September 2011 and focused on 1061 individuals aged 5-19 years old. The seroprevalence of hepatitis A was estimated at 72.3% and varied with age: 56.9% in children aged 5-9 years, 70.4% among those aged 10-14 years, and 85.4% for the 15-19-year-old age group. Factors associated with lower seroprevalence were mainly related to a higher socioeconomic level, including living in an urban area, small household size, parents with a higher educational level, and consumption of bottled mineral water. This study highlights an epidemiological change and predicts that Algeria is in a period of gradual transition to intermediary endemicity. This change is synonymous with a susceptible population growing older, suggesting that serious forms of hepatitis can be expected more frequently. The current preventive strategy against hepatitis A should be revisited.

Detection and Molecular Characterization of Hepatitis A Virus from Tunisian Wastewater Treatment Plants with Different Secondary Treatments

Hepatitis A virus (HAV) is the main causative agent of hepatitis infection associated with waterborne outbreaks worldwide. In Tunisia, there is no specific surveillance system for HAV and current secondary wastewater treatment processes are unable to remove viral particles, which present a potential public health problem. Qualitative and quantitative analysis of HAV in 271 raw and treated wastewater samples from five sewage treatment plants (STPs) during 13 months was performed. Moreover, the efficiency of three secondary wastewater treatment processes (conventional activated sludge, extended aeration, and oxidation ditch activated sludge) was evaluated. Data obtained demonstrated that HAV is endemic in Tunisia and circulates with high prevalence in both raw (66.9%) and treated (40.7%) wastewater. HAV circulates throughout the year in the coastal areas, with the highest rates found during summer and autumn, whereas in central Tunisia, high levels were shown in autumn and winter. Total virus removal was not achieved, since no difference in mean HAV loads was observed in effluents (6.0 × 10(3) genome copies [GC]/ml) and influents (2.7 × 10(3) GC/ml). The comparison of the HAV removal values of the three different wastewater treatment methods indicates that extended aeration and oxidation ditch activated sludge had better efficiency in removing viruses than conventional activated sludge did. Molecular characterization revealed that the vast majority of HAV strains belonged to subgenotype IA, with the cocirculation of subgenotype IB in wastewater treatment plants that collect tourism wastewater.

IMPORTANCE

This report provides important data on the incidence, behavior, seasonality, and genotype distribution of HAV in the environment in Tunisia, as well as the risk of infection derived from its occurrence in effluents due to inadequate wastewater treatment. In addition, these findings seem to confirm that the prevalence of HAV depends on socioeconomic level, sanitary conditions in the communities, sewage facilities, the locality, and the climate. The wide dispersion of HAV in effluents proves the inefficacity of the current wastewater treatment processes used in Tunisia to remove virus; therefore, establishment of tertiary treatment processes or replacement of the medium-charge activated sludge (conventional activated sludge) by the low-charge version (oxidation ditch activated sludge) is absolutely needed. Rapid detection of the HAV genome in wastewater may provide a timely warning sign to health authorities to implement population protection measures.

Efficiency of hepatitis A virus removal in six sewage treatment plants from central Tunisia

The efficiency of six Tunisian sewage treatment plants (STP) for the removal of hepatitis A virus (HAV) from wastewater was analysed in order to evaluate the potential risk for human health linked to reuse or discharge of treated wastewater into the environment. The STP utilize different biological wastewater treatments including primary treatment, which involves the physical removal of organic and inorganic solids, and secondary treatment that involves different processes, such as activated sludge or lagoon. Quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) and conventional RT-PCR were used for the analysis of the 325 wastewater samples (163 raw and 162 treated) obtained. Results revealed highest contamination in west-central of Tunisia in raw wastewater with 62.96 % of samples positive for HAV and predominance during winter and autumn, whereas east-central region showed 50.62 % of positive samples with high prevalence from winter through summer. The quantitative analysis revealed a range between 4.29 × 10(1) and 1.24 × 10(5) RNA copies/mL in treated wastewater, showing clearly the inefficiency for total removal of HAV regardless of the treatment method used. The vast majority of HAV sequences belonged to the sub-genotype IA, except one that was assigned to sub-genotype IB.

Hepatitis E virus in the countries of the Middle East and North Africa region: an awareness of an infectious threat to blood safety

PURPOSE

Hepatitis E virus (HEV) is mainly transmitted through contaminated water supplies which make the virus endemic in developing countries including countries of the Middle East and North Africa (MENA) region. Recent reports suggest potential risk of HEV transmission via blood transfusion.

METHODS

Related articles on HEV were collected by searching through the 25 countries of the MENA region using Pubmed and Medline within the past 14 years: January 2000-August 2014.

RESULTS

One hundred articles were extracted, of which 25 were not eligible. The articles discussed the seroprevalence of HEV and HEV markers in 12 countries. Eight articles provided data on HEV in blood donors. The seroprevalence of HEV in the general MENA population ranged from 2.0 to 37.5% and was higher in males than in females. Prevalence increased with age, but exposure seems to be in early life.

CONCLUSIONS

In the MENA region, the role of HEV as an infectious threat to blood safety is under-investigated. More data are needed to quantify the risk of transmission and to assess clinical outcomes. This requires, at least, surveillance screening of donors and recipients for HEV markers using sensitive and specific serological tests. At the present time, serious consideration should be given to selective screening for certain groups of patients (e.g., immunocompromised, pregnant women and others) who commonly require blood transfusion and are at high risk of hepatic failure or chronicity from HEV infection.

Migration pattern of hepatitis A virus genotype IA in North-Central Tunisia

Background

Hepatitis A virus (HAV) epidemiology in Tunisia has changed from high to intermediate endemicity in the last decades. However, several outbreaks continue to occur. The last reported sequences from Tunisian HAV strains date back to 2006. In order to provide an updated overview of the strains currently circulating in Tunisia, a large-scale molecular analysis of samples from hepatitis A cases was performed, the first in Tunisia.

Results

Biological samples were collected from patients with laboratory confirmed hepatitis A: 145 sera samples in Tunis, Monastir, Sousse and Kairouan from 2008 to 2013 and 45 stool samples in Mahdia in 2009. HAV isolates were characterised by nested RT-PCR (VP1/2A region) and sequencing. The sequences finally obtained from 81 samples showed 78 genotype IA and 3 genotype IB isolates.

A Tunisian genotype IA sequence dataset, including both the 78 newly obtained IA sequences and 51 sequences retrieved from GenBank, was used for phylogenetic investigation, including analysis of migration pattern among six towns. Virus gene flow from Sfax and Monastir was directed to all other towns; in contrast, the gene flows from Sousse, Tunis, Mahdia and Kairouan were directed to three, two, one and no towns, respectively.

Conclusions

Several different HAV strains co-circulate in Tunisia, but the predominant genotype still continues to be IA (78/81, 96% isolates). A complex gene flow (migration) of HAV genotype IA was observed, with Sfax and Monastir showing gene flows to all other investigated towns. This approach coupled to a wider sampling can prove useful to investigate the factors underlying the spread of HAV in Tunisia and, thus, to implement appropriate preventing measures.

Qualitative and Quantitative Assessment of Hepatitis A Virus in Wastewaters in Tunisia

Hepatitis A causes substantial morbidity in both industrialized and non-industrialized countries and represents an important health problem in several southern Mediterranean countries. The objectives of the study were as follows: (a) to assess the occurrence of hepatitis A virus (HAV) in Tunisia through the monitoring of urban wastewaters collected at wastewater treatment plants (WTPs); (b) to characterize environmental strains; and (c) to estimate the viral load in raw and treated sewages, in order to evaluate the potential impact on superficial waters receiving discharges. A total of 150 raw and treated wastewaters were collected from three WTPs and analyzed by both qualitative (RT-PCR/nested) and quantitative (qRT-PCR) methods. Of these, 100 (66%) were found to be positive for HAV by the qualitative assay: 68.3% in influents and 64.7% in effluents. The vast majority of HAV sequences belonged to sub-genotype IA, with 11 different strains detected found to be identical to clinical strains isolated from Tunisian patients with acute hepatitis. Five unique variants were also detected, not previously reported in clinical cases. Only two IB strains were found, confirming the rarity of this sub-genotype in this country. The results of the present study indicate a wide circulation of the pathogen in the population, most probably in the form of asymptomatic infections, a finding consistent with the classification of the country as having intermediate/high endemicity. Quantitative data showed high viral loads in influents (3.5E+05 genome copies/liter, mean value) as well as effluents (2.5E+05 genome copies/liter, mean value), suggesting that contaminated water could be a critical element in transmission.

A new method for imputing country-level estimates of hepatitis A virus endemicity levels in the Eastern Mediterranean region

BACKGROUND

Few country-level estimates for hepatitis A virus (HAV) seroprevlance are available for the 23 countries in the Eastern Mediterranean region (EMRO) of the World Health Organization.

METHODS

We used a three-stage approach to assign an HAV endemicity level to each country in North Africa and the Middle East based on the age at midpoint of population immunity. First, we conducted a systematic review to identify all age-seroprevalence studies conducted within the past 10 years. Second, for countries without first-stage evidence we searched for incidence data and older seroprevalence data. Third, for countries with no hepatitis A data, we estimated HAV endemicity based on socioeconomic and water indicators.

RESULTS

This three-stage method allowed us to estimate country-specific endemicity levels for every country in EMRO even though first-stage evidence was only available for nine countries and for three countries only third-stage evidence was available. The region has a heterogeneous hepatitis A risk profile, with 13 countries having very high endemicity (an age at midpoint of population immunity in early childhood), three having high endemicity (late childhood), and seven having intermediate endemicity (early adulthood).

CONCLUSIONS

The three-stage estimation approach enables the creation of a complete country-level map of HAV risk in EMRO. Given the heterogeneity of HAV endemicity levels in the region and the likelihood of transitions to lower incidence rates and greater adult susceptibility in the near future, enhanced surveillance for hepatitis A would strengthen decisions about vaccination policy in the region.

Hepatitis A virus in the Middle East and North Africa region: a new challenge

During the past three decades, a gradual shift in the age of infection with hepatitis A virus (HAV) from early childhood to adulthood has been observed. There is a general lack of updated data on HAV burden of disease, incidence and age-specific seroprevalence in countries of the Middle East and North Africa (MENA) region. The aim of this article is to review the published data on anti-HAV seroprevalence, an important tool to monitor infections rates, in countries of the MENA region and associated risk factors including water and socioeconomic data when available. Data on anti-HAV seroprevalence were found for 12 of 25 MENA countries. We show that MENA countries, similar to other areas in the world, have a clear shift in HAV incidence with a decline among young age groups and an increase among adults and older individuals. This would likely be associated with increased morbidity and increased risks of outbreaks among younger age groups. Consequently, the continuous surveillance of hepatitis A cases and the inclusion of hepatitis A vaccine in the expanded immunization programmes are needed in countries of the MENA.

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.

Seroprevalence of fecal-oral transmitted hepatitis A and E virus antibodies in Burkina Faso

Hepatitis A virus (HAV) and hepatitis E virus (HEV) infections occur chiefly as a result of unhygienic conditions. The purpose of this study was to assess the seroprevalence of antibodies to both viruses in central Burkina Faso in the absence of a recorded hepatitis epidemic. Serum samples from 178 blood donors (131 males and 47 females) and from 189 pregnant women were collected from November 2010 to March 2012, at blood banks and medical centers in Burkina Faso. An immunochromatography test was used to screen for Anti-HAV IgM and IgG in a subgroup of 91 blood donors and 100 pregnant women. The seroprevalence of anti-HAV IgG was 14.3% [CI95, 7.1-21.4%] for all blood donors and 23% [CI95, 14.8-31.2%] for pregnant women. Anti-HEV IgG were detected using the ELISA kits Dia.pro and Wantai and were found in 19.1% [CI95, 13.3-24.9%] of the blood donors and 11.6% [CI95, 7.1-16.2%] of the pregnant women. The seroprevalences of anti-HAV and anti-HEV IgGs did not differ significantly between men and women blood donors. Anti-HAV IgM was detected in 3.3% of the blood donors and in 2% of the pregnant women. These findings for asymptomatic individuals indicate that the HAV and HEV circulate at low but significant levels. This is the first evaluation of the acute hepatitis virus burden in Burkina Faso and the underlying epidemiologic status of the population.

Presence and fate of coliphages and enteric viruses in three wastewater treatment plants effluents and activated sludge from Tunisia

PURPOSE

The role of water in the transmission of infectious diseases is well defined; it may act as a reservoir of different types of pathogens. Enteric viruses can survive and persist for a long time in water, maintaining infectivity in many instances. This suggests the need to include virus detection in the evaluation of the microbiological quality of waters.

METHODS

In this study, enteric viruses (enteroviruses and hepatitis A virus (HAV)) were investigated by RT-PCR and coliphages (known as indicators of viral contamination) were enumerated with the double-layer technique agar in effluents and sewage sludge from three Tunisian wastewater treatment plants.

RESULTS AND DISCUSSION

The molecular detection of enteric viruses revealed 7.7% of positive activated sludge samples for enteroviruses. None of the samples was positive for HAV. Molecular virus detection threshold was estimated to be 10(3) PFU/100 ml. All samples contained high concentrations of coliphages except those of dry sludge. Reductions in the concentrations of bacteriophages attained by the wastewater treatment plants are of the order of magnitude as reductions described elsewhere. Peak concentrations in raw wastewater were associated with winter rains and suspended materials rate in analysed samples. Our data which is the first in North Africa showed that similar trends of coliphages distribution to other studies in other countries.

CONCLUSION

No clear correlation between studied enteric viruses and coliphages concentration was proved. Coliphages abundance in collected samples should raise concerns about human enteric viruses transmission as these residues are reused in agricultural fields.

Hepatitis A: Epidemiology and prevention in developing countries

Hepatitis A is the most common form of acute viral hepatitis in the world. Major geographical differences in endemicity of hepatitis A are closely related to hygienic and sanitary conditions and other indicators of the level of socioeconomic development. The anti-hepatitis A virus (HAV) seroprevalence rate is presently decreasing in many parts of the world, but in less developed regions and in several developing countries, HAV infection is still very common in the first years of life and seroprevalence rates approach 100%. In areas of intermediate endemicity, the delay in the exposure to the virus has generated a huge number of susceptible adolescents and adults and significantly increased the average age at infection. As the severity of disease increases with age, this has led to outbreaks of hepatitis A. Several factors contribute to the decline of the infection rate, including rising socioeconomic levels, increased access to clean water and the availability of a hepatitis A vaccine that was developed in the 1990s. For populations with a high proportion of susceptible adults, implementing vaccination programs may be considered. In this report, we review available epidemiological data and implementation of vaccination strategies, particularly focusing on developing countries.

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

The aim of the present study was to investigate the seroprevalence of Hepatitis A virus antibodies in patients with clinical symptoms of viral hepatitis and molecular characterization of the detected isolates. The present study deals with the seroprevalence and the genetic diversity of HAV in 400 Tunisian patients presenting in dispensaries (160 patients) and in University Hospitals (240 patients) with hepatitis symptoms between 2006 and 2008. The patients with acute hepatitis were mainly from rural regions. However, the total number of patients was decreased over time. The collected samples were from patients with hepatitis symptoms occurring mainly during January-March (36.7, 26, and 35.5%) and September-December (39.4, 43.4, and 35.5%) during the three years of study, respectively. However, HAV infection was established for only 110 among 400 patients. The detected isolates were clustered within sub-genotype IA. The present study constituted another report of the continued surveillance of HAV infection in the region of Monastir and the molecular characterisation of the detected strains.

Seroprevalence of hepatitis E virus infection in rural and urban populations, Tunisia

Hepatitis E virus (HEV) is one of the leading agents of acute hepatitis. This study investigated the prevalence and risk factors of HEV infection in the Tunisian adult general population, either in blood donors (n=687) or in patients hospitalized for acute hepatitis (n=202). The mode of transmission differed between these two populations: contact with animals and living in a rural habitat were the main risk factors for being in contact with HEV in asymptomatic blood donors, while HEV was contracted through contaminated water in symptomatic cases. HEV seroprevalence in adult blood donors in Tunisia was relatively low (5.4%) and increased with age.

Characterization of outbreak hepatitis a isolates in five Tunisian childcare centers

In the present study, epidemiological survey and molecular characterization of hepatitis A virus during an outbreak in five Tunisian childcare centers in El-Mahres during October and November 2006 were carried out. Five well-water and five drinking water samples were included in the present study. Serological investigation and molecular characterization were carried out. All patients were IgM seropositive and the viral genome was detected in all clinical and well-water samples whereas it was not detected in drinking water from the five childcare centers. Sequence analysis showed that all Tunisian strains belong to sub-genotype IA. The genetic profile of the VP1/2A junction showed that the outbreak isolates underwent an amino acid substitution which was absent in virus’s strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus’s strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.

[Viral infection risk in polytransfused adults: seroprevalence of seven viruses in central Tunisia]

The aim of this study is to evaluate the prevalence of seven transfusion-transmitted viruses in polytransfused adults and children comparatively with a group of healthy control subjects. We studied 107 polytransfused patients (59 adults and 48 children) and 160 control subjects (100 blood donors and 60 children). Immunoenzymatic tests were used for detection of HBs antigen (HBs Ag), antibodies against hepatitis C Virus (anti-HCV), and human immunodeficiency virus (anti-HIV), and IgG antibodies against human cytomegalovirus (IgG anti-CMV), human parvovirus B19 (IgG anti-PB19), and hepatitis E virus (IgG anti-HEV). An immunofluorescent assay was performed for the detection of human herpesvirus 8 antibodies (anti-HHV8). Prevalence of HBs Ag, anti-HCV, anti-HIV, IgG anti-CMV, IgG anti-PB19, IgG anti-HEV, and anti-HHV8 in polytransfused group was 8.4, 4.7, 0, 86.9, 60.7, 28.9, and 47.6%, respectively, and 1.8, 0.6, 0, 86.2, 53.1, 10, and 12.5%, respectively, in the control group. The difference in prevalence between the two groups was statistically significant for HBs Ag (P = 0.01), anti-HCV (P = 0.03), IgG anti-HEV (P < 10(-4)), and IgG anti-HHV8 (P < 10(-4)). Categorization according to age showed that hepatitis B and C risk was limited in adult polytransfused group. HHV8 infection was higher in polytransfused subjects born before the use of leucocyte-depleted blood components. Our results corroborate literature data on the risk of HEV and HHV8 infection by blood transfusion. Hepatitis B vaccination and improvement in screening tests have an important role in reduction of hepatitis B and C risk in transfusion, especially in young polytransfused persons. However, a residual risk of transmitting viral infections persists, and efforts are needed to improve transfusion safety.

Viral hepatitis a to e in South mediterranean countries

Viral hepatitis represents an important health problem in the South Mediterranean countries, Egypt, Libya, Tunisia, Algeria and Morocco. Emerging natural history and epidemiological information reveal differences in the overall epidemiology, risk factors and modes of transmission of viral hepatitis A, B, C, D, E infections in the South Mediterranean region. The differences in the in incidence and prevalence of viral hepatitis across North African countries is attributed to variations in health care and sanitation standards, risk factors and immunization strategies. The active continuous population movement through travel, tourism and migration from and to the South Mediterranean countries contribute to the spread of infections due to hepatitis viruses across borders leading to outbreaks and emergence of new patterns of infection or introduction of uncommon genotypes in other countries, particularly in Europe.

[Seroprevalence and risk factors of hepatitis E among pregnant women in central Tunisia]

OBJECTIVES

The study was conducted to investigate the prevalence and risk factors for hepatitis E virus (HEV) infection in Tunisian pregnant women.

METHODS

A total of 404 pregnant women were enrolled. Data were collected through a standard questionnaire which covered sociodemographic characteristics and risk factors. Blood samples were collected and were tested for HEV IgM and IgG antibodies, IgG against hepatitis A (anti-HAV IgG), hepatitis B virus surface antigen (HBsAg) and hepatitis C virus antibody (anti-HCV). Risk factors were analyzed using univariate and multivariate logistic regression models.

RESULTS

Prevalence of anti-HEV IgG, anti-HEV IgM, anti-HAV IgG, HBs Ag and anti-HCV was 12.1 %, 0 %, 97 %, 3 % and 0,5 %, respectively. In multivariate analysis age (>30 years) and the number of persons per room (>2) in the house were independent factors predicting HEV infection. History of agricultural work, kind of water, sewage treatment, use detergent to wash vegetables, contact with animals and parenteral risk factors were not correlated with the presence of anti-HEV IgG.

CONCLUSION

The important seropositive rate among pregnant women is compatible with endemicity of HEV in Tunisia. Hepatitis E should be considered in the diagnosis of acute hepatitis during pregnancy. Our result suggests that infection occurs sporadically by person-to-person transmission route but further investigations are needed to determine the natural reservoir of infection.