Assessing the entomo-epidemiological situation of Chagas disease in rural communities in the state of Piauí, Brazilian semi-arid region

Predictor Variables in the Spread of Chagas Disease in Rural Areas

Over a hundred years ago after the discovery of Chagas disease (CD) in Brazil, the World Health Organization estimates a number of 6 to 7 million people infected by Trypanosoma cruzi worldwide. Therefore, the goal of this work was to identify variables related to the spread of infection by T. cruzi in humans living in rural areas, seeking predictor variables. A systematic review of the literature has been conducted, with a search in the Scopus platform, using the search string "Chagas disease" and "rural", resulting in 85 valid and analyzed scientific studies (1977 and 2022). Twenty-seven predictor variables have been acquired, and 19 of them have been grouped, such as: socioeconomic and educational, housing, environmental, sanitary, and cultural; and 8 variables related to T. cruzi seropositive individuals. The predictor variables yielded significant results (p-value < 0.05) in 59.5% of the cases (195/328), with a median of 66.7%. In other words, studies relating to 50% of the 27 variables showed significance equal to or greater than 66.7% of the time. The independent variables with the highest proportion of significant data (p-value < 0.05) were Education (87.6%), Intradomicile building (70%), Domestic animals (69.6%), and Triatomines (69.2%) in the households. Some variables reached 100%; however, few articles were found, indicating the need for further research, especially for Sanitation and Culture. It has been concluded that, in the several contexts found, the social vulnerability and lack of information led the individual to living in environments where inhabitability is inadequate, to perform limited work activity and develop habits and behaviors which impair them in an environmental insalubrity situation, favorable to the access of vectors and pathogens of anthropozoonoses such as CD.

[Estimation of prevalence of chronic Chagas disease in Brazilian municipalitiesEstimación de la prevalencia de la enfermedad de Chagas crónica en los municipios brasileños]

Objective

The objective of this study is to estimate the prevalence of chronic Chagas disease (CCD) in Brazil: in the general population, in women, and in women of childbearing age.

Methods

A meta-analysis of the literature was conducted to extract data on the prevalence of CCD in municipalities in Brazil in the 2010-2022 period: in the general population, in women, and in women of childbearing age. Municipal-level CCD indicators available in health information systems were selected. Statistical modeling of the data extracted from the meta-analysis (based on data obtained from information systems) was applied to linear, generalized linear, and additive models.

Results

The five most appropriate models were selected from a total of 549 models tested to obtain a consensus model (adjusted R2 = 54%). The most important predictor was self-reported CCD in the primary health care information system. Zero prevalence was estimated in 1 792 (32%) of Brazil's 5 570 municipalities; in the remaining 3 778 municipalities, average prevalence of the disease was estimated at 3.25% (± 2.9%). The number of carriers of CCD was estimated for the Brazilian population (~3.7 million), for women (~2.1 million) and for women of childbearing age (~590 000). The disease reproduction rate was calculated at 1.0336. All estimates refer to the 2015-2016 period.

Conclusions

The estimated prevalence of CCD, especially among women of childbearing age, highlights the challenge of vertical transmission in Brazilian municipalities. Mathematical projections suggest that these estimates should be included in the national program for the elimination of vertical transmission of Chagas disease.

Temporal assessment of entomological surveillance of Trypanosoma cruzi vectors in an endemic area of northeastern Brazil

Entomological surveillance is essential for the control of triatomines and the prevention of Trypanosoma cruzi infection in humans and domestic animals. Thus, the objective of this study was to evaluate entomological indicators and triatomine control during the period from 2005 to 2015 in an endemic area in the state of Rio Grande do Norte, Brazil. This observational and retrospective study was developed based on data analysis related to active entomological surveillance activities and chemical control of infested housing units (HU) in the Agreste mesoregion of the state of Rio Grande do Norte, Brazil, in the period between 2005 to 2015. The quantitative analysis of housing units surveyed for entomological indicators was performed by linear regression of random effects (p < 0.05). The effect of the number of HU surveyed on the entomological indicators was analyzed by fitting a linear random effects regression model and an increasing intradomiciliary colonization rate was significant. In the period evaluated 92,156 housing units were investigated and the presence of triatomines was reported in 4,639 (5.0%). A total of 4,653 specimens of triatomines were captured and the species recorded were Triatoma pseudomaculata (n = 1,775), Triatoma brasiliensis (n = 1,569), Rhodnius nasutus (n = 741) and Panstrongylus lutzi (n = 568), with an index of natural infection by T. cruzi of 2.2%. Only 53.1% of the infested HU were subjected to chemical control. Moreover, there was a decrease in the total number of HU surveyed over time associated with an increase in the index of intradomiciliary colonization (p = 0.004). These data demonstrated that entomological surveillance and control of vectors in the Agreste mesoregion of the state has been discontinued, emphasizing the need for more effective public policies to effectively control the vectors, in order to avoid the exposure of humans and domestic animals to the risk of T. cruzi infection.

Epidemiological aspects of Chagas disease in the state of Piauí (Northeast Brazil) in the period 2010-2019

Chagas disease (ChD), caused by the hemoflagellate protozoan Trypanosoma cruzi, is an important morbidity that affects approximately six million people in the American continent. T. cruzi parasites are mainly transmitted to human by the infected feces of blood-sucking triatomine insects. The persistent disease is endemic in many regions of South America, mostly affecting residents of rural areas. The aim of this study was to evaluate epidemiological aspects of ChD in the state of Pi-auí located in northeastern Brazil. This is an analytical cross-sectional study carried out from the collection of data of the Notifiable Diseases Information System (SINAN, in Portuguese, Sistema de Informações de Agravos de Notificação) of suspected and confirmed cases of acute ChD in the state of Piauí, in the period 2010-2019. Associations between T. cruzi positivity and the study variables were determined by the chi-square test or Fisher's exact test and were raised as prevalence ratios (PR) with 95% confidence interval. According to this survey, 517 suspected cases of acute ChD were reported in Piauí, with 70 cases (13.5%) confirmed. In 88.5% of confirmed cases, confirmation occurred by laboratory diagnosis. Most of the confirmed cases occurred in municipalities located in the semiarid region, with the municipality of São João do Piauí presenting the highest number of cases. Regarding sociodemographic data, females represent 55.7% of cases, people over 50 years of age (55.7%), being three cases in people up to 18 years of age, and less than 8 years of schooling (67.1%). 77.9% of confirmed cases had vector transmission as the probable form of infection. The data available in this study conclude that vectorial transmission of ChD in the state of Piauí remains active. This fact is corroborated by the number of notified and confirmed cases of acute ChD, requiring housing improvement programs and more effective epidemiological surveillance to control the transmission of the disease in the state.

Community-based entomological surveillance in three Chagas disease-endemic regions in sub-Andean Bolivia

BACKGROUND

Chagas disease is endemic throughout most of Bolivia, with prevalence rates of 25% observed in some geographic areas located mainly in the sub-Andean region.

METHODS

Community-based entomological surveillance was carried out in the sub-Andean departments of Cochabamba (municipalities of Cochabamba, Punata and Sacaba), Tarija (municipality of Tarija) and Chuquisaca (municipality of Sucre). The surveillance parameters evaluated were: (i) the proportion of cards with the presence of triatomines; (ii) the distribution of positive cards by area; and (iii) the proportion of cards with the presence of infected triatomines.

RESULTS

Of the cards returned, in 852 (3.1%) there was a mention of the presence of triatomines. The species Triatoma infestans, Triatoma sordida and Triatoma guasayana were identified in 812 (95.3%), 39 (4.6%) and 1 (0.1%), respectively. The median monthly positivity rate of the cards during 2011-2018 was higher in Punata (9.1%; IQR=3.2-15.4%). The median monthly rate was highest in 2012 (2.7%; IQR=0-5.6%). Fifty positive cards (5.8%) presented insects that were positive for trypanosomatids, mainly in Cochabamba and Punata.

CONCLUSIONS

The report of triatomines foci by inhabitants represents an effective surveillance system coordinated by a network of specialized and multidisciplinary health centers. These strategies, which should be included in the health policies of endemic countries, enable extending and deepening the dialogue among technicians, communities and their local authorities.

"Chagas Express XXI": A new ArtScience social technology for health and science education-A case study in Brazilian endemic areas of Chagas disease with an active search of chronic cases

BACKGROUND

Chagas Disease (CD) affects 6-7 million people worldwide and is related to poverty-promoting conditions. Chronic asymptomatic cases are mostly invisible to health systems. Aiming (1) to translate CD discoveries into education/information practices to raise alertness and empowerment of affected people; and (2) to perform an active search of CD cases, articulating intersectoral actions to improve the access of infected people to the local health service for the treatment of CD; our research group developed and tested under field conditions as innovative social technology: an itinerant education interdisciplinary setting named "Chagas Express XXI" (CE21).

METHODOLOGY

CE21 was created as an "imaginary train" with ~40 ArtScience workshops, games, laboratory activities and conversation circles. An entry/exit plus six activity modules combined associations of affected people, microscopic observations, One Health education, and wellness activities. CE21 was conceived as a social technology, since all the processes were co-created with CD patients and inter-sector local partners. Descriptive statistics showed quantitative data collected throughout the expeditions (CD knowledge, serological results). Qualitative data accessed the public perceptions about the education activities.

PRINCIPAL FINDINGS

CE21 was exhibited in local educational institutions (schools, universities) in four cities, engaging 2,117 people that evaluated the 41 activities carried out. Citizens and health professionals enjoyed acquisition of information related to blood, parasites, vectors, reservoirs, environmental changes, and social determinants of CD. Further, local legacies of 600 participants volunteer for health promotion groups and CD associations, local empowerment groups to fight for better health conditions, and 05 mural paintings. We observed that 81% of the participants ignored the possibility of treating CD while 52% of the participants requested a blood test for CD showing seropositivity in 20% of them.

CONCLUSIONS

CE21 is a social technology potentially useful for health and science education and active search of asymptomatic CD chronic cases. Moreover, this technology may be adapted to understand and to cooperate in other potentially epidemic situations, especially NTDs related.