INTERMEDIATE ENDEMICITY OF HEPATITIS A VIRUS INFECTION IN RURAL SETTLEMENT PROJECTS OF SOUTHWEST GOIÁS, BRAZIL

Proposition and application of an environmental salubrity index in rural agglomerations

OBJECTIVE

Propose an Índice de salubridade ambiental (ISA_Rural – environmental salubrity index) that expresses the conditions experienced in rural agglomerations, including indicators and subindicators for its subsequent application in rural communities in the state of Goiás.

METHODS

We developed the research in three phases: 1) previous analysis for the proposition of an ISA_Rural, with the participation of seven specialists; 2) proposition of the ISA_Rural by means of the Delphi method, starting with 168 specialists from 26 federative units of Brazil and Distrito Federal; and 3) application of the ISA_Rural in 43 rural communities in the state of Goiás.

RESULTS

The proposed ISA_Rural resulted in the composition of eight indicators, four of which related to basic sanitation, and the others to health, socioeconomic conditions, public services offered, and housing conditions. The weight assigned to each indicator ranged from 22.82% for the water supply indicator to 6.35% for the service indicator, it is possible to apply the ISA_Rural fully or to evaluate each indicator individually. The application of ISA_Rural in communities of Goiás classified 86% of them with low salubrity, highlighting the worst conditions for quilombola communities. The sanitary sewage had the lowest score among the ISA_Rural indicators, requiring greater attention from public authorities.

CONCLUSIONS

This study contributed to the proposition of an index in line with the concept of environmental salubrity, useful in the scope of public policies as a conditioner for the prioritization of actions needed to improve the salubrity conditions identified. The proposed ISA_Rural can be fully applied or used in the individual evaluation of each indicator of its composition. The results of its application made it possible to identify the communities with the worst environmental salubrity conditions and the indicators that require greater priority attention in the communities studied.

Genetic diversity, haplotype analysis, and risk factor assessment of hepatitis A virus isolates from the West Bank, Palestine during the period between 2014 and 2016

BACKGROUND

Hepatitis A virus (HAV) infection is one of the major causes of acute viral hepatitis. HAV genotypes and its genetic diversity is rarely investigated in our region as well as worldwide.

AIMS

The aims of the present study were to determine the HAV genotypes and its risk factors and to investigate the genetic diversity of the HAV isolates in the West Bank, Palestine.

STUDY DESIGN

A cohort of 161 clinically and laboratory-confirmed HAV (IgM-positive) cases and 170 apparently healthy controls from all the districts of the West Bank, Palestine during the period of 2014 to 2016 were tested for HAV infection using IgM antibodies, RT-PCR and sequence analysis of the VP3/VP1 junction region of the HAV genome. Phylogenetic analysis, genetic diversity and haplotypes analysis were used to characterize the VP3/VP1 sequences.

RESULTS

All the 34 sequences of the HAV were found to be of HAV-IB sub-genotype. The phylogenetic analysis showed four main clusters with cluster III exclusively consisting of 18 Palestinian isolates (18/23-78%), but with weak bootstrap values. A high haplotype diversity (Hd) and low nucleotide diversity (π) were observed. Cluster III showed high number of haplotypes (h = 8), but low haplotype (gene) diversity (Hd = 0.69). A total of 28 active haplotypes with some consisting of more than one sequence were observed using haplotype network analysis. The Palestinian haplotypes are characterized by closely related viral haplotypes with one SNV away from each other which ran parallel to cluster III in the phylogenetic tree. A smaller Palestinian haplotype (4 isolates) was three SNVs away from the major haplotype cluster (n = 10) and closer to others haplotypes from Iran, Spain, and South Africa. Young age, low level of parent's education, infrequent hand washing before meals, and drinking of un-treated water were considered the major HAV risk factors in the present study.

CONCLUSION

Haplotype network analysis revealed haplotype variation among the HAV Palestinian sequences despite low genetic variation and nucleotide diversity. In addition, this study reconfirmed that age and parent's level of education as HAV risk factors, while hand washing and treating drinking water as protective factors.

Hepatitis A epidemiology in Latin American countries: a 2020 view from a systematic literature review

INTRODUCTION

The World Health Organization recommends vaccination against hepatitis A virus (HAV) for children aged 1 year and older in areas where endemicity has shifted from high to intermediate. There are no recent comprehensive reviews of the epidemiology of HAV infection in Latin America, but seroprevalence and socioeconomic data suggest that, with improved clean water and sanitation systems, countries are transitioning to intermediate endemicity.

AREAS COVERED

We conducted a systematic literature review of the epidemiology of HAV infection in 25 countries in the Latin American region, which included gray literature. We compiled data on HAV incidence and prevalence, including the identification of epidemiological changes observed in countries that established pediatric HAV vaccination programs.

EXPERT OPINION

We identified 59 relevant articles, including 34 peer-reviewed seroprevalence studies (12 recent studies from Brazil), three incidence studies, and six vaccine impact studies (three from Argentina). Based on the estimated age at midpoint of population immunity in each country, most have a high-intermediate, intermediate, or low-intermediate level of HAV endemicity, suggesting that national childhood immunization may be an appropriate disease prevention strategy. However, recent data were lacking for most countries. Improved data quality and continued epidemiological surveillance are required for this region.

Rodent-borne viruses survey in rural settlers from Central Brazil

Anthropogenic environmental changes arising from settlement and agriculture include deforestation and replacement of natural vegetation by crops providing opportunities for pathogen spillover from animals to humans. This study aimed to investigate the prevalence of rodent-borne virus infections in seven rural settlements from Midwestern Brazil. Of the 466 individuals tested 12 (2.57%) were reactive for orthohantavirus and 3 (0.64%) for mammarenavirus. These rural settlers lived under unfavorable infrastructure, socioeconomic disadvantages, and unsanitary conditions, representing a risk for rodent-borne infections. Development of public policies towards the improvement of health, sanitation and awareness of rodent-borne diseases in improvised camps and settlements is imperative, in order to reduce morbidity and mortality caused by these diseases.

The serological markers of acute infection with hepatitis A, B, C, D, E and G viruses revisited

Viral hepatitis is a liver infection caused by one of the six hepatitis viruses: hepatitis A, B, C, D, E, and G virus (HAV to HEV and HGV). These agents differ in their biological, immunological, pathological and epidemiological characteristics. They cause infections that, when symptomatic, lead to clinical manifestations and laboratory findings that are not specific to a particular virus, often making differential diagnosis difficult, especially when no knowledge is available regarding the patient's medical history or the epidemiological background. A number of acute-phase serological markers, such as anti-HAV, anti-HBc, anti-HDV and anti-HEV IgM antibodies, are able to provide a clear indication of an infection caused by HAV, HBV, HDV or HEV. Anti-HCV antibodies and HGV/RNA are used for the diagnosis of HCV and HGV infections. The importance of each of these markers will be reviewed, and different factors that can interfere with the diagnosis of acute infections caused by these viruses will be described.

Modeling the hepatitis A epidemiological transition in Brazil and Mexico

BACKGROUND

Many low- to middle-income countries have completed or are in the process of transitioning from high or intermediate to low endemicity for hepatitis A virus (HAV). Because the risk of severe hepatitis A disease increases with age at infection, decreased incidence that leaves older children and adults susceptible to HAV infection may actually increase the population-level burden of disease from HAV. Mathematical models can be helpful for projecting future epidemiological profiles for HAV.

METHODS

An age-specific deterministic, dynamic compartmental transmission model with stratification by setting (rural versus urban) was calibrated with country-specific data on demography, urbanization, and seroprevalence of anti-HAV antibodies. HAV transmission was modeled as a function of setting-specific access to safe water. The model was then used to project various HAV-related epidemiological outcomes in Brazil and in Mexico from 1950 to 2050.

RESULTS

The projected epidemiological outcomes were qualitatively similar in the 2 countries. The age at the midpoint of population immunity (AMPI) increased considerably and the mean age of symptomatic HAV cases shifted from childhood to early adulthood. The projected overall incidence rate of HAV infections decreased by about two thirds as safe water access improved. However, the incidence rate of symptomatic HAV infections remained roughly the same over the projection period. The incidence rates of HAV infections (all and symptomatic alone) were projected to become similar in rural and urban settings in the next decades.

CONCLUSION

This model featuring population age structure, urbanization and access to safe water as key contributors to the epidemiological transition for HAV was previously validated with data from Thailand and fits equally well with data from Latin American countries. Assuming no introduction of a vaccination program over the projection period, both Brazil and Mexico were projected to experience a continued decrease in HAV incidence rates without any substantial decrease in the incidence rates of symptomatic HAV infections.

Comparison of the Prevalence and Risk Factors of Hepatitis A in 10 to 18-Year-Old Adolescents of Sixteen Iranian Provinces: The CASPIAN-III Study

BACKGROUND

Hepatitis A is a common health concern both in developing and developed countries. Hygienic and socioeconomic parameters deeply impact the prevalence and transmission of this disease. Evaluating the epidemiological distribution and risk factors for Hepatitis A virus (HAV) is necessary for policy makers to improve local and national preventive measures.

OBJECTIVES

The aim of this study was to compare the prevalence of hepatitis A infection in a sample of Iranian adolescents living in different provinces of Iran and to assess its family- and community-related risk factors.

METHODS

In this cross-sectional study, serum samples of 10 to 18-year-old adolescents, who were studied in a national health survey, were examined for anti-HAV antibodies. A total of 2,494 subjects were included from 16 provinces by multistage random cluster sampling. Demographic and socioeconomic factors related to HAV transmission were extracted by valid questionnaires. A multilevel analysis using mixed-effects logistic regression (melogit) was used to evaluate the association of risk factors with HAV infection.

RESULTS

The weighted prevalence of HAV varied significantly across the studied provinces (P = 0.001), ranging from 50.43% in the Fars province to 78.81% in Markazi province. HAV was significantly more prevalent in children whose mothers worked outside of the home (OR, 1.73; 95% CI, 1.14-2.62; P = 0.009).

CONCLUSIONS

The risk of symptomatic HAV infection is considerable in adolescents of all studied provinces; thus, universal HAV vaccination is recommended for all adolescents, regardless of their socioeconomic level. However, the risk is higher in some provinces, which seem to be transitioning from intermediate to low endemicity.