Factors associated with TB in an indigenous population in Brazil: the effect of a cash transfer program

The effect of conditional cash transfers on tuberculosis incidence and mortality is determined by ethnoracial and socioeconomic factors: a cohort study of 54 million individuals in Brazil

Background

Conditional Cash Transfers (CCT) are the world's most widely implemented interventions for poverty alleviation. Still, there is no solid evidence of the CCT effects on the reduction of the burden of Tuberculosis (TB) in marginalized and extremely vulnerable populations. We estimated the effect of the Bolsa Família Program (BFP), the largest CCT in the world, on TB incidence, mortality, and case-fatality rate using a nationwide cohort of 54.5 million individuals during a 12-year period in Brazil.

Methods

We selected low-income individuals who entered in the 100 Million Brazilians Cohort and were linked to nationwide TB registries between 2004 to 2015, and compared BFP beneficiaries and non-beneficiaries using a quasi-experimental impact evaluation design. We employed inverse probability of treatment weighting (IPTW) multivariable Poisson regressions, adjusted for all relevant socioeconomic, demographic, and healthcare confounding variables - at individual and municipal level. Subsequently, we evaluated BFP effects for different subpopulations according to ethnoracial factors, wealth levels, sex, and age. We also performed several sensitivity and triangulation analyses to verify the robustness of the estimates.

Findings

Exposure to BFP was associated with a large reduction in TB incidence in the low-income individuals under study (adjusted rate ratio [aRR]:0.59;95%CI:0.58-0.60) and mortality (aRR:0.69;95%CI:0.65-0.73). The strongest BFP effect was observed in Indigenous people both for TB incidence (aRR:0.37;95%CI:0.32-0.42), and mortality-aRR:0.35;95%CI:0.20-0.62), and in Black and Pardo people (Incidence-aRR:0.58;95%CI:0.57-0.59; Mortality -aRR:0.69;95%CI:0,64-0,73). BFP effects showed a clear gradient according to wealth levels and were considerably stronger among the extremely poor individuals for TB incidence (aRR:0.49, 95%CI:0.49-0.50) and mortality (aRR:0.60;95%CI:0.55-0.65). The BFP effects on case-fatality rates were also positive, however without statistical significance.

Interpretation

CCT can strongly reduce TB incidence and mortality in extremely poor, Indigenous, Black and Pardo populations, and could significantly contribute to achieving the End TB Strategy targets and the TB-related Sustainable Development Goals.

Prevalence and Spatial Autocorrelation of Tuberculosis in Indigenous People in Brazil, 2002-2022

Tuberculosis (TB) among indigenous populations in Brazil poses a multifaceted public health challenge influenced by geographical, social, institutional, economic, and cultural factors. This study scrutinized the prevalence and spatial distribution of TB among Brazilian indigenous communities from 2002 to 2022. Employing a cross-sectional and descriptive approach, we analyzed data from the Notifiable Diseases Information System (SINAN) and conducted spatial autocorrelation tests to identify clusters and outliers. The findings uncovered substantial disparities in TB prevalence between the North and Central-West regions, in contrast to the South and Southeast, mirroring social, economic, and cultural inequalities in Brazil. It is concluded that public health strategies should not only consider the epidemiological aspects of TB but also encompass social and environmental determinants, notably the impact of climate change. Holistic and context-sensitive approaches are imperative for addressing TB within indigenous communities, underscoring the need for adaptive and culturally sensitive interventions in the public health landscape.

Social protection as a right of people affected by tuberculosis: a scoping review and conceptual framework

BACKGROUND

Tuberculosis is an infectious disease strongly influenced by social determinants closely associated with cycles of poverty and social exclusion. Within this context, providing social protection for people affected by the disease constitutes a powerful instrument for reducing inequalities and enhancing inclusion and social justice. This study aimed to identify and synthesize strategies and measures aimed at ensuring social protection as a right of people affected by tuberculosis.

METHODS

This is a scoping review, with searches conducted in six databases in February 2023. We included publications from 2015 onwards that elucidate strategies and measures of social protection aimed at safeguarding the rights to health, nutrition, employment, income, housing, social assistance, and social security for people affected by tuberculosis. These strategies could be implemented through policies, programs, and/or governmental agreements in any given context. The data extracted from the articles underwent descriptive analysis and a narrative synthesis of findings based on the dimensions of social protection. Additionally, we developed a conceptual framework illustrating the organizational and operational aspects of measures and strategies related to each dimension of social protection identified in this review.

RESULTS

A total of 9317 publications were retrieved from the databases, of which sixty-three publications were included. The study's results highlighted measures and strategies concerning the social protection of people affected by tuberculosis. These measures and strategies revolved around the rights to proper nutrition and nourishment, income, housing, and health insurance, as well as expanded rights encompassing social assistance and social welfare. It was reported that ensuring these rights contributes to improving nutritional status and the quality of life for individuals with tuberculosis, along with reducing catastrophic costs, expanding access to healthcare interventions and services, and fostering TB treatment adherence, thereby leading to higher rates of TB cure.

CONCLUSIONS

Our findings identify social protection measures as a right for people affected by tuberculosis and have the potential to guide the development of evidence-based social and health policies through collaboration between tuberculosis control programs and governmental entities.

Social Protection Interventions for TB-Affected Households: A Scoping Review

Tuberculosis (TB) and poverty are inextricably linked. Catastrophic costs of TB illness drive TB-affected households into worsening impoverishment and hamper treatment success. The WHO's End TB Strategy recommends social protection for TB-affected households to mitigate financial shock and improve TB outcomes. This scoping review maps the landscape of social protection interventions for people with TB and their households in low- and middle-income countries with high TB burden. A systematic search of Medline, Embase, PubMed, and Web of Science for relevant articles was performed, supplemented with a gray literature search of key databases. Articles were included if they described social protection available to people with TB and TB-affected households in a low- or middle-income country. Data were synthesized in tabular form, and descriptive narrative outlined the successes and challenges of the social protection interventions identified. The search identified 33,360 articles. After abstract screening, 74 articles underwent full text screening, and 49 were included in the final analysis. Forty-three types of social protection were identified, of which 24 were TB specific (i.e., only people with TB were eligible). Varying definitions were used to describe similar social protection interventions, which limited cross-study comparison. Intervention successes included acceptability and increased financial autonomy among recipients. Challenges included delays in intervention delivery and unexpected additional bank transfer fees. A wide range of acceptable social protection interventions are available, with cash transfer schemes predominating. Use of standardized definitions of social protection interventions would facilitate consolidation of evidence and enhance design and implementation in future.

Identification of a predominant genotype of Mycobacterium tuberculosis in Brazilian indigenous population

After nearly a century of vaccination and six decades of drug therapy, tuberculosis (TB) kills more people annually than any other infectious disease. Substantial challenges to disease eradication remain among vulnerable and underserved populations. The Guarani-Kaiowá people are an indigenous population in Paraguay and the Brazilian state of Mato Grosso do Sul. This community, marginalized in Brazilian society, experiences severe poverty. Like other South American indigenous populations, their TB prevalence is high, but the disease has remained largely unstudied in their communities. Herein, Mycobacterium tuberculosis isolates from local clinics were whole genome sequenced, and a population genetic framework was generated. Phylogenetics show M. tuberculosis isolates in the Guarani-Kaiowá people cluster away from selected reference strains, suggesting divergence. Most cluster in a single group, further characterized as M. tuberculosis sublineage 4.3.3. Closer analysis of SNPs showed numerous variants across the genome, including in drug resistance-associated genes, and with many unique changes fixed in each group. We report that local M. tuberculosis strains have acquired unique polymorphisms in the Guarani-Kaiowá people, and drug resistance characterization is urgently needed to inform public health to ensure proper care and avoid further evolution and spread of drug-resistant TB.

The contribution of stigma to the transmission and treatment of tuberculosis in a hyperendemic indigenous population in Brazil

Background

The Guarani-Kaiowá are Brazil's second-largest indigenous group. Average annual tuberculosis (TB) incidence rates among the Guarani-Kaiowá are nearly 400/100,000 in Mato Grosso do Sul state, ten times the national average. Although stigma is considered crucial for TB control in indigenous communities, few studies have investigated TB stigma among indigenous populations. This study sought to understand the role of TB-related stigma and perceptions of TB in maintaining hyperendemic TB transmission in the Guarani-Kaiowá communities.

Methods

Various forms of stigma were explored through semi-structured interviews with 19 patients, 11 relatives, and 23 community members. Patients were identified from the registry of the healthcare service. Community members, selected by snowball sampling, were matched by gender and village of residence. Interviews were conducted in Guarani and Portuguese and later translated into English. Framework analysis was performed using NVivo.

Results

Traditional beliefs of a weakening of the body allowing the disease to enter were common, but the exact mechanism of transmission was unknown. Strong community/public stigma associated TB with uncleanliness, abuse, and irresponsibility. Anticipated stigma led to significant treatment delays for fear of exclusion and losing employment. While most patients felt supported by their families, nearly all patients related experienced/enacted stigma in the community such as gossip, avoidance, and social exclusion, leading to long-lasting internalized/self-stigma. Secondary stigmatization of relatives was widespread, and blanket latent TB infection (LTBI) treatment of patients’ households was a contributing factor in treatment delay. The healthcare service unnecessarily added to stigmatization by enforcing separate utensils and sleeping arrangements for patients.

Conclusions

Our findings suggest that stigma is a driver for treatment delay and continued transmission of TB in the community. The stigmatization of TB was rooted in a poor understanding of TB transmission, partly because of incorrect orientation by the healthcare service. Interventions to reduce TB-associated stigma are urgently needed.

Amerindian genetic ancestry as a risk factor for tuberculosis in an amazonian population

In recent years, the incidence of tuberculosis (TB) has declined worldwide, although this disease still occurs at relatively high rates in Amerindian populations. This suggests that the genetic ancestry of Amerindians may be an important factor in the development of infections, and may account for at least some of the variation in infection rates in the different populations. The present study investigated the potential influence of Amerindian genetic ancestry on susceptibility to tuberculosis in an Amazon population. The study included 280 patients diagnosed with tuberculosis and 138 asymptomatic hospital employees with no history of TB, but who were in contact with bacterially active TB patients. Ancestry analysis was run on a set of 61 Ancestry-Informative Markers to estimate European, African, and Amerindian genetic ancestry using STRUCTURE v2.2. The TB group had significantly higher Amerindian ancestry in comparison with the control group, and significantly lower European ancestry. Amerindian ancestry in the 20–60% range was found to be the principal risk factor for increased susceptibility to TB. The results of the study indicate that Amerindian ancestry is an important risk factor for susceptibility to TB in the admixed population of the Brazilian Amazon region.

Genetic Diversity and Molecular Epidemiology of Mycobacterium tuberculosis in Roraima State, Brazil

National border areas are special places for the spread of Mycobacterium tuberculosis (MTB). These regions concentrate vulnerable populations and constant population movements. Understanding the dynamics of the transmission of MTB is fundamental to propose control measures and to monitor drug resistance. We conducted a population-based prospective study of tuberculosis (TB) to evaluate molecular characteristics of MTB isolates circulating in Roraima, a state on the border of Venezuela and Guyana. Eighty isolates were genotyped by IS6110-RFLP (restriction fragment length polymorphism), spoligotyping, and 24-locus mycobacterial interspersed repetitive unit-variable number of repeats tandem (MIRU-VNTR). Drug susceptibility tests were performed by using the proportion method and GeneXpert^® MTB/RIF (Cepheid, Sunnyvale, CA). Isolates showing a phenotypic resistance profile were submitted to polymerase chain reaction (PCR) and sequencing. Spoligotyping showed 40 distinct patterns with a high prevalence of Latin-American and Mediterranean (LAM), Haarlem (H), and the "ill-defined" T clades. Mycobacterial interspersed repetitive unit -VNTR and IS6110-RFLP showed clustering rates of 21.3% and 30%, respectively. Drug resistance was detected in 11 (15.1%) isolates, and all were found to have primary resistance; among these, six (8.2%) isolates were streptomycin mono-resistant, four (5.4%) isoniazid mono-resistant, and one (1.3%) multidrug resistant. This is the first study on the molecular epidemiology and drug resistance profile of MTB from Roraima. Herein, we describe high diversity of genetic profiles circulating in this region that may be driven by the introduction of new strain types because of large population flow in this region. In summary, our results showed that analyses of these circulating strains can contribute to a better understanding of TB epidemiology in the northern Brazilian border and be useful to establish public health policies on TB prevention.