Hepatitis A incidence rate estimates from a pilot seroprevalence survey in Rio de Janeiro, Brazil

Assessment of socioeconomic inequality based on virus-contaminated water usage in developing countries: A review

Water is an essential resource required for various human activities such as drinking, cooking, and other recreational activities. While developed nations have made significant improvement in providing adequate quality water and sanitation devoid of virus contaminations to a significant percentage of the residences, many of the developing countries are still lacking in these regards, leading to many death cases among the vulnerable due to ingestion of virus-contaminated water and other waterborne pathogens. However, the recent global pandemic of COVID-19 seems to have changed the paradigm by reawakening the importance of water quality and sanitation, and focusing more attention on the pervasive effect of the use of virus-contaminated water as it can be a potential driver for the spread of the virus and other waterborne diseases, especially in developing nations that are characterized by low socioeconomic development. Therefore, this review assessed the socioeconomic inequalities related to the usage of virus-contaminated water and other waterborne pathogens in developing countries. The socioeconomic factors attributed to the various waterborne diseases due to the use of virus-contaminated water in many developing countries are poverty, the standard of living, access to health care facilities, age, gender, and level of education. Some mitigation strategies to address the viral contamination of water sources are therefore proposed, while future scope and recommendations on tackling the essential issues related to socioeconomic inequality in developing nations are highlighted.

Assessment of socioeconomic inequality based on virus-contaminated water usage in developing countries: A review

Water is an essential resource required for various human activities such as drinking, cooking, and other recreational activities. While developed nations have made significant improvement in providing adequate quality water and sanitation devoid of virus contaminations to a significant percentage of the residences, many of the developing countries are still lacking in these regards, leading to many death cases among the vulnerable due to ingestion of virus-contaminated water and other waterborne pathogens. However, the recent global pandemic of COVID-19 seems to have changed the paradigm by reawakening the importance of water quality and sanitation, and focusing more attention on the pervasive effect of the use of virus-contaminated water as it can be a potential driver for the spread of the virus and other waterborne diseases, especially in developing nations that are characterized by low socioeconomic development. Therefore, this review assessed the socioeconomic inequalities related to the usage of virus-contaminated water and other waterborne pathogens in developing countries. The socioeconomic factors attributed to the various waterborne diseases due to the use of virus-contaminated water in many developing countries are poverty, the standard of living, access to health care facilities, age, gender, and level of education. Some mitigation strategies to address the viral contamination of water sources are therefore proposed, while future scope and recommendations on tackling the essential issues related to socioeconomic inequality in developing nations are highlighted.

Assessment of Macro-Level Socioeconomic Factors That Impact Waterborne Diseases: The Case of Jordan

The Hashemite Kingdom of Jordan is an example of a country that suffers from high water scarcity. Additionally, due to the economic drivers in the country, such as phosphate and potash extraction and pharmaceutical production, the little fresh water that remains is generally polluted. The infrastructure, often antiquated in urban areas and non-existent in rural areas, also contributes to poor water conditions and to the spread of waterborne diseases. This paper examines the socioeconomic factors that contribute to diarrhea and hepatitis A on a macro level in Jordan and discusses the public-policies that government officials could use to abate those problems. Ordinary least squares time series models are used to understand the macro-level variables that impact the incidence of these diseases in Jordan. Public health expenditure has a significant impact on reducing their incidence. Furthermore, investment in sanitation facilities in rural regions is likely to reduce the number of cases of hepatitis A. Perhaps the most surprising outcome is that importation of goods and services likely results in a decrease in cases of hepatitis A. However, income has little impact on the incidence of diarrhea and hepatitis A.

Modelling the force of infection for hepatitis A in an urban population-based survey: a comparison of transmission patterns in Brazilian macro-regions

Background

This study aimed to identify the transmission pattern of hepatitis A (HA) infection based on a primary dataset from the Brazilian National Hepatitis Survey in a pre-vaccination context. The national survey conducted in urban areas disclosed two epidemiological scenarios with low and intermediate HA endemicity.

Methods

A catalytic model of HA transmission was built based on a national seroprevalence survey (2005 to 2009). The seroprevalence data from 7,062 individuals aged 5–69 years from all the Brazilian macro-regions were included. We built up three models: fully homogeneous mixing model, with constant contact pattern; the highly assortative model and the highly assortative model with the additional component accounting for contacts with infected food/water. Curves of prevalence, force of infection (FOI) and the number of new infections with 99% confidence intervals (CIs) were compared between the intermediate (North, Northeast, Midwest and Federal District) and low (South and Southeast) endemicity areas. A contour plot was also constructed.

Results

The anti- HAV IgG seroprevalence was 68.8% (95% CI, 64.8%–72.5%) and 33.7% (95% CI, 32.4%–35.1%) for the intermediate and low endemicity areas, respectively, according to the field data analysis. The models showed that a higher force of infection was identified in the 10- to 19-year-old age cohort (∼9,000 infected individuals per year per 100,000 susceptible persons) in the intermediate endemicity area, whereas a higher force of infection occurred in the 15- to 29-year-old age cohort (∼6,000 infected individuals per year per 100,000 susceptible persons) for the other macro-regions.

Conclusion

Our findings support the shift of Brazil toward intermediate and low endemicity levels with the shift of the risk of infection to older age groups. These estimates of HA force of infection stratified by age and endemicity levels are useful information to characterize the pre-vaccination scenario in Brazil.

Antioxidant defense and oxidative stress in children with acute hepatitis A

BACKGROUND AND OBJECTIVES

Published data on oxidative stress in children with acute hepatitis A are still very scarce. This study aims to evaluate the oxidant/antioxidant status of these patients.

DESIGN AND SETTING

Prospective, case-control study, over 2.5 years in patients under hospitalized and ambulatory care.

PATIENTS AND METHODS

The levels of a whole-blood antioxidant, reduced glutathione; and plasma antioxidants, β-carotene, retinol, ascorbic acid, α-tocopherol; and the biomarker of oxidative stress, malondialdehyde, were evaluated in 50 pediatric patients (age range, 5-16 years; 29 males and 21 females) with acute hepatitis A and in 50 healthy children as control subjects (age range, 5-16 years; 25 males and 25 females).

RESULTS

Plasma levels of reduced glutathione, β-carotene, retinol, α-tocopherol and ascorbic acid were significantly lower, while malondialdehyde plasma levels were significantly increased in the patient group when compared to the controls (P<.0001 for all parameters).

CONCLUSIONS

Our findings show that pediatric patients with acute hepatitis A were influenced by oxidative stress, resulting in significantly lower levels of plasma antioxidants and increased lipid peroxidation. In the absence of other therapeutic options, antioxidant vitamin supplements could be added to the therapy for these patients to help reestablish the oxidant status balance. Further investigations to confirm this suggestion are recommended.

Multilevel analysis of hepatitis A infection in children and adolescents: a household survey in the Northeast and Central-west regions of Brazil

Background The objectives were to estimate the prevalence of hepatitis A among children and adolescents from the Northeast and Midwest regions and the Federal District of Brazil and to identify individual-, household- and area-levels factors associated with hepatitis A infection.

Methods This population-based survey was conducted in 2004–2005 and covered individuals aged between 5 and 19 years. A stratified multistage cluster sampling technique with probability proportional to size was used to select 1937 individuals aged between 5 and 19 years living in the Federal capital and in the State capitals of 12 states in the study regions. The sample was stratified according to age (5–9 and 10- to 19-years-old) and capital within each region. Individual- and household-level data were collected by interview at the home of the individual. Variables related to the area were retrieved from census tract data. The outcome was total antibodies to hepatitis A virus detected using commercial EIA. The age distribution of the susceptible population was estimated using a simple catalytic model. The associations between HAV infection and independent variables were assessed using the odds ratio and corrected for the random design effect and sampling weight. Multilevel analysis was performed by GLLAMM using Stata 9.2.

Results The prevalence of hepatitis A infection in the 5–9 and 10–19 age-group was 41.5 and 57.4%, respectively for the Northeast, 32.3 and 56.0%, respectively for the Midwest and 33.8 and 65.1% for the Federal District. A trend for the prevalence of HAV infection to increase according to age was detected in all sites. By the age of 5, 31.5% of the children had already been infected with HAV in the Northeast region compared with 20.0% in the other sites. By the age of 19 years, seropositivity was ∼70% in all areas. The curves of susceptible populations differed from one area to another. Multilevel modeling showed that variables relating to different levels of education were associated with HAV infection in all sites.

Conclusion The study sites were classified as areas with intermediate endemicity area for hepatitis A infection. Differences in age trends of infection were detected among settings. This multilevel model allowed for quantification of contextual predictors of hepatitis A infection in urban areas.

Changing epidemiology of hepatitis A in Brazil: reassessing immunization policy

Recent studies have shown that the prevalence of antibody to hepatitis A virus (HAV) is decreasing in several Latin American countries. Brazil is a very large and heterogeneous country, showing striking regional differences. With regard to sanitary facilities, 81.7% of the districts in the south-eastern region have sewage systems, compared with only 5.8% in the northern region. Results of sero-epidemiological studies and reported hepatitis A outbreaks indicate a change in the epidemiological pattern of hepatitis A in the country. Individuals, especially those under the age of 10, are mostly unprotected from HAV infection, regardless of their socioeconomic status. During 2000-2005, approximately 14 000-21 000 cases of hepatitis A were reported annually in Brazil, a rate of 7.5-11 cases per 100 000 population. Nationwide, hepatitis A mortality rates declined progressively from 1980 to 2002. As fatal cases constitute a small, but predictable, portion of all acute hepatitis A cases, which are in turn part of the total number of HAV infections, these data suggest that there has been a decline in HAV circulation in all Brazilian regions over the last two decades. Taken together these facts point out that the epidemiological pattern of hepatitis A is changing in Brazil. Besides improvements in sanitary conditions in the poorest Brazilian regions, the introduction of hepatitis A vaccination of young children could be a strategy for controlling HAV infection in the country.

Estimativa de áreas de risco para hepatite A

Este estudo estimou áreas de risco de hepatite A e de variáveis associadas em região de Duque de Caxias, Rio de Janeiro, Brasil. Foi realizado um inquérito soroepidemiológico para hepatite A e domiciliar em 19 setores censitários. Destes, foram selecionados 11 setores contíguos com diferentes cotas altimétricas e todas as 1.298 crianças com idade menor que dez anos foram incluídas no estudo. Construiu-se semivariogramas para a hepatite A, não uso de filtro, número de pontos de água e tempo de encanamento de água. A estimativa espacial foi obtida por krigagem indicadora e ordinária. O ajuste dos modelos foi avaliado por meio de validação cruzada. Os quatro modelos ajustados de semivariogramas do desfecho e das três variáveis sócio-econômicas apresentaram um padrão isotrópico; mapas do risco estimado segundo a krigagem para hepatite A e para as variáveis sócio-econômicas foram construídos; a validação cruzada mostrou um bom ajuste. A utilização do método de estimativa espacial usando-se a krigagem possibilitou a detecção de áreas com maior probabilidade de ocorrência da hepatite A, independentemente da divisão político-administrativa dos setores censitários.

Estimated Incidence of Hepatitis A Virus Infection in Catalonia

PURPOSE

Hepatitis A normally is underreported by statutory disease reporting systems. The objective of this study is to estimate the incidence of hepatitis A virus (HAV) infection from prevalence surveys of infection carried out in representative samples of the population in 1989, 1996, and 2002 and the reported disease incidence during 1991 to 2003 in Catalonia.

METHODS

The real incidence of the infection was estimated from the reported incidence adjusted by the prevalence of susceptible individuals and the probability of presenting clinical manifestations. The bootstrap resampling technique was used to calculate 95% confidence intervals (CIs) of reported, clinical, and all infection cases.

RESULTS

The infection rate estimated by the bootstrap method was 31.1/100,000 person-years (bootstrap studentized 95% CI, 19.4-56.0), and the rate of clinical hepatitis was 20.0/100,000 person-years (95% CI, 11.8-39.9), rates that were 6.3 and 4.1 times greater than the reported rate during the same period, respectively.

CONCLUSIONS

In children younger than 5 years, the estimated infection rate was 13.8 times greater than the reported rate. Combined use of reported cases and results of seroprevalence surveys suggest that underreporting of HAV infection is substantial in Catalonia, especially in children younger than 5 years.

Epidemiological pattern and mortality rates for hepatitis A in Brazil, 1980-2002: a review

The prevalence of hepatitis A virus (HAV) infection is high in developing countries, in which low standards of sanitation promote the transmission of the virus. In Latin America, which is considered an area of high HAV endemicity, most HAV-positive individuals are infected in early childhood However recent studies have shown that prevalence rates are decreasing. Herein, we review the data on HAV prevalence and outbreaks available in scientific databases. We also use official government data in order to evaluate mortality rates in Brazil over the last two decades. Studies conducted in the northernmost regions of Brazil have indicated that, although improved hygiene has led to a reduction in childhood exposure to HAV, the greatest exposure still occurs early in life. In the Southeastern region, the persistence of circulating HAV has generated outbreaks among individuals of low socioeconomic status, despite adequate sanitation. Nationwide, hepatitis A mortality rates declined progressively from 1980 to 2002. During that period, mortality rates in the Northern region consistently exceeded the mean national rate and those for other regions. Excluding the North, the rates in all regions were comparable. Nevertheless, the trend toward decline observed in the South was paralleled by a similar trend in the North.

Experiments with mathematical models to simulate hepatitis A population dynamics under different levels of endemicity

Heterogeneous access to sanitation services is a characteristic of communities in Brazil. This heterogeneity leads to different patterns of hepatitis A endemicity: areas with low infection rates have higher probability of outbreaks, and areas with higher infection rates have high prevalence and low risk of outbreaks. Here we develop a mathematical model to study the effect of variable exposure to infection on the epidemiological dynamics of hepatitis A. Differential equations were used to simulate population dynamics and were numerically solved using the software Stella. The model uses parameters from serological surveys in the Greater Metropolitan Rio de Janeiro, in areas with different sanitation conditions. Computer simulation experiments show that the range of infection rates observed in these communities are characteristic of high and low levels of hepatitis A endemicity. We also found that the functional relationship between sanitation and exposure to infection is an important component of the model. The analysis of the public health impact of partial sanitation requires a better understanding of this relationship.

Prevalence of anti-hepatits A antibodies in children of different socioeconomic conditions in Vila Velha, ES

This report describes the prevalence of anti-HAV antibodies in children from elementary school in the Municipality of Vila Velha, ES, Brazil. Anti-HAV antibodies were investigated by ELISA method in the serum of 606 children (four to fourteen years old) from three elementary schools, located in neighborhoods with varying household monthly income levels: São José School, 200 children, household income higher than US$700; São Torquato School, 273 children, US$200 to 300; and Cobi School, 133 children, less than US$200. From each children data on age, gender, skin color, sanitary conditions, frequency of contact with sea or river water and family history of hepatitis were recorded. Anti-HAV antibodies were present in 38.6% of all children, 9% in São José School, 49.1% in São Torquato School and 61.7% in Cobi School. Logistic regression analysis demonstrated a positive correlation of positive anti-HAV test with age, non white color of the skin, absence of sewage treatment and domestic water filter, and a past history of hepatitis. The prevalence of anti-HAV antibodies in school children in Vila Velha, ES, was lower than that observed in the same age group in North and Northeast Brazil and was significantly higher in children from families with low socioeconomic status. In addition the results indicate a changing epidemiologic pattern of hepatitis A in our country, with an increasing number of children and adolescents with high risk for HAV infection, mainly in high socioeconomic class. A consideration must be given to the feasibility of vaccination programs for children and adolescents in our country.

The effects of socioeconomic development on worldwide hepatitis A virus seroprevalence patterns

BACKGROUND

Hepatitis A virus (HAV) infection confers long-term immunity, so mathematical analysis of age-specific seroprevalence in populations can reveal changes in the infection rate over time. HAV transmission is related to access to clean drinking water, personal hygiene and public sanitation.

METHODS

We used an SIR (susceptible-infectious-recovered) compartmental model with age structure to fit a time-dependent logistic function for HAV force of infection for 157 published age-seroprevalence data sets. We then fit linear regression models for socioeconomic variables and infection rate.

RESULTS

The proportion of the population with access to clean drinking water, the value of the human development index (HDI), and per capita gross domestic product (GDP) are all inverse predictors of HAV infection rates. Declining infection rates were observed in 65.6% of the surveys. Discussion This work demonstrates the utility of HAV seroprevalence studies to reveal patterns of change in force of infection and to assess the association between socioeconomic risk factors and transmission rates.

Environmental risk factors for hepatitis A infection in the Zenica-Doboj Canton, Bosnia and Herzegovina

In the Zenica-Doboj Canton, 1106 hepatitis A virus (HAV) infections were reported during 2000 (an incidence rate of 252/100 000 population), with 996 (90.1%) cases occurring in nine community-wide outbreaks. Analysis of water supplies showed that 398 (19.1%) samples contained coliforms, including 202 (50.8%) that were contaminated with thermotolerant Escherichia coli. Sewage sanitation systems were absent or substandard in 53 910 (81.8%) rural households. The group most affected during outbreaks comprised children aged 7-14 years (incidence rate of 598/100 000). The development of health promotion and prevention initiatives in schools, combined with rigorous hygiene measures, will be necessary to achieve control of the spread of HAV.

The relation between anti-hepatitis A virus antibodies and residence water access in Rio de Janeiro, Brazil

OBJECTIVES

The objective of this study was to analyse the relation between residence water access (water taps) and hepatitis A virus (HAV) antibodies, associated with socio-economic, environmental and demographic factors.

METHODS

A logistic regression model was used for estimating the relation between residential water access (presence of water taps inside the house) and HAV antibodies, related to confounding effects of selected variables. The odds ratios estimated by the model were used as incidence density ratios (IDR) for the analysis of the water access-antibody association. Data were obtained from a cross-sectional study on the seroprevalence of hepatitis A in 3779 volunteers from Duque de Caxias city, greater Rio de Janeiro, Brazil. Participants were selected according to an age-specified random sampling survey.

RESULTS

Besides water access (main variable of interest), age, monthly family income, housewife schooling, persons per room, proximity to open sewage channels and consumption water treatment were statistically associated to hepatitis A seroprevalences. An interaction between water access and proximity to open sewage channels was detected. Persons living in residences distant from an open sewage channel had a water access-antibody IDR of 2.5 (95% CI [1.4; 4.3]), in contrast to 1.1 for those living close to such channels.

CONCLUSIONS

Although indirectly measured through the proxy variable water access, personal hygiene, in conjunction with the absence of open sewage channels in the proximity of the residence, was an important factor for low HAV seroprevalence study population.

[Hepatitis A]

Hepatitis A infection is known since the ancient Chinese, Greek and Roman civilizations but the first documented report was published in the eighteenth century. The hepatovirus belongs to the Picornaviridae family, and carries a single strand RNA. There are 7 genotypes. Antibodies of the IgM and IgA classes, during natural infections, appear early in the serum, together with the first clinical manifestations of the disease, but they may also appear at the end of the first week of infection. There is a spectrum of clinical presentation: asymptomatic infection, symptomatic without jaundice and symptomatic jaundiced. A rare fatal form of hepatitis has been described. Diagnosis of the hepatitis A infection is confirmed by the finding of IgM anti-HAV antibodies, routinely performed using an ELISA test. Treatment is supportive. Intramuscular anti-A gamma globulin is used for passive immune prophylaxis, and there is an efficient vaccine for active immune prophylaxis.

The intensity of transmission of hepatitis A and heterogeneities in socio-environmental risk factors in Rio de Janeiro, Brazil

The objective of this work was to assess the intensity of transmission of hepatitis A in Rio de Janeiro, Brazil. We also used the estimation of the parameters of a deterministic model to study the effects of risk factors. Age-specific seroprevalence of antibodies against hepatitis A virus (HAV) was obtained from a survey screening in a city of the metropolitan area of Rio de Janeiro, in 1997. From the seroprevalence data, we estimated the age-dependent force of infection (lambda) and the average age of first infection (A), using a deterministic model. To evaluate the influence of the environmental risk factors, we estimated the same parameters stratifying the sample for the selected socio-environmental risk factors: the number of years of schooling of the female responsible for the house, crowding within the bedroom, number of water taps and fittings, and the presence of sewage in front of the house. For the whole sample, the maximum force of infection estimated was 0.12/year and the average age of infection was 10.1 years. This last parameter decreased as the number of persons per bedroom increased, and also when the number of water taps and the number of years of schooling of the woman responsible for the house decreased. The proposed environmental interventions may lead to a decrease in the intensity of transmission of HAV and an increase in the average age of first infection in the next few years. This may have public health implications, since hepatitis A is more severe in adults. In this context, specific vaccination programmes may be necessary, as in developed countries.