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

Itani, Taha; Jacobsen, Kathryn H.; Nguyen, T D; Wiktor, Stefan Z.

doi:10.1016/j.vaccine.2014.09.006

Cited by 21 publications

(28 citation statements)

References 31 publications

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“…These results are in line with those found in our previous report of a study performed using environmental samples (4) and in other seroprevalence studies demonstrating that higher HAV rates were found in the inland region and in the south of Tunisia (37,41) than in big coastal cities (36,37). It has been reported that HAV infection is still highly endemic in developing countries, with differences in epidemiological patterns that are mainly associated with the development of socioeconomic and hygienic conditions (3,6,7,12).…”

Section: Discussionsupporting

confidence: 91%

“…Thus, the geographic distribution pattern of HAV is highly correlated to the socioeconomic level and sanitary conditions (5-7). In fact, HAV infection is highly endemic in developing regions, e.g., in South Mediterranean regions (6,8), where it is still frequently detected in wastewaters (9), while it is much less frequently detected in industrialized countries. However, HAV can easily contaminate the environment due to the large quantities of viral particles excreted by infected people, symptomatic or not, which pass through the inefficient sewage treatment plants (STPs) and reach water environments such as rivers, lakes, and seas.…”

mentioning

confidence: 99%

“…It was previously demonstrated that areas with inadequate water supply and poor wastewater facilities and hygienic conditions generally have very high HAV prevalence (3,4). Thus, the geographic distribution pattern of HAV is highly correlated to the socioeconomic level and sanitary conditions (5)(6)(7). In fact, HAV infection is highly endemic in developing regions, e.g., in South Mediterranean regions (6,8), where it is still frequently detected in wastewaters (9), while it is much less frequently detected in industrialized countries.…”

mentioning

confidence: 99%

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

Ouardani

Turki

Aouni

et al. 2016

Appl Environ Microbiol

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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. IMPORTANCEThis 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. H epatitis A virus (HAV) is one of the most important human waterborne viruses and constitutes the main cause of human enteric hepatitis transmitted via the fecal-oral route (1). It is widely prevalent in the world, as millions of new cases of HAV infections occur worldwide every year (2). It was previously demonstrated that areas with inadequate water supply and poor wastewater facilities and hygienic conditions generally have very high HAV prevalence (3, 4). Th...

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Section: Discussionsupporting

confidence: 91%

mentioning

confidence: 99%

mentioning

confidence: 99%

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

Ouardani

Turki

Aouni

et al. 2016

Appl Environ Microbiol

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“…Water and sanitation access do not adequately explain the differences in HAV endemicity levels between countries with moderate or high water-access rates. In these locations, economic indicators such as the gross national income per capita or the human development index (which combines economic, education, and life expectancy data into one metric) appear to be better predictors of HAV endemicity than water access (Itani et al 2014;Koroglu et al 2017). This relationship between socioeconomic status and HAV risk is also observed at the individual and household levels, with higher incomes, higher levels of education, smaller family sizes and less crowding in the home, and other indicators of higher socioeconomic status associated with a reduced likelihood of exposure to HAV (Jacobsen and Koopman 2004).…”

Section: Risk Factors For Havmentioning

confidence: 99%

Globalization and the Changing Epidemiology of Hepatitis A Virus

Jacobsen

2018

Cold Spring Harb Perspect Med

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170

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Increased economic interdependence, social integration, and other aspects of globalization are contributing to significant changes in hepatitis A epidemiology. Globally, the incidence of hepatitis A virus (HAV) infection is decreasing, the age at midpoint of population immunity (AMPI) is increasing, and the proportion of symptomatic cases is increasing as the average age at infection increases. In low-income countries, HAV remains endemic but improved water and sanitation systems are reducing transmission rates among young children. In high-income countries, most adults remain susceptible to HAV and foodborne outbreaks are becoming more frequent. Middle-income countries have diverse epidemiological profiles, and they play important roles in the global spread of HAV through international trade and travel. Future changes in the epidemiology of hepatitis A will be heavily influenced by globalization processes.

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“…For each study, critical information about the study site, study design, data collection years, sampling method, sample size, study population, and age-seroprevalence rates was extracted. All of the studies were then graded based on their sampling methods and the representativeness of the study population, as per the method proposed by Itani et al 11 in a previous paper about hepatitis A in the Middle East region (Table I).…”

Section: Methodsmentioning

confidence: 99%

Hepatitis A virus epidemiology in Turkey as universal childhood vaccination begins: seroprevalence and endemicity by region

et al. 2016

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This paper presents the results of a comprehensive examination of current distribution of Hepatitis A virus (HAV) seroprevalence and endemicity in Turkey and the possible links between HAV endemicity and socioeconomic development. We performed a systematic search in online resources published between January 2000 and August 2015. The 22 provinces were able to be assigned a hepatitis A endemicity level based on this systematic review. The incidence rates for symptomatic hepatitis A infection are higher in the eastern part of Turkey than in the western and central region. These differences in socioeconomic indicators by region suggest the likelihood of lower seroprevalence rates in the western parts of the country and higher rates in the eastern region. Turkey's current policy of recommending hepatitis A immunization for all children without contraindications is an appropriate one and is likely to remain the best option for at least the next decade or two.

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

Cited by 21 publications

References 31 publications

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

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

Globalization and the Changing Epidemiology of Hepatitis A Virus

Hepatitis A virus epidemiology in Turkey as universal childhood vaccination begins: seroprevalence and endemicity by region

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