Information to Act: Household Characteristics are Predictors of Domestic Infestation with the Chagas Vector Triatoma dimidiata in Central America

Abstract

Abstract. The interruption of vectorial transmission of Chagas disease by Triatoma dimidiata in central America is a public health challenge that cannot be resolved by insecticide application alone. In this study, we collected information on previously known household risk factors for infestation in 11 villages and more than 2,000 houses in Guatemala, Honduras, and El Salvador, and we constructed multivariate models and used multimodel inference to evaluate their importance as predictors of infestation in the region. The models had moderate ability to predict infested houses (sensitivity, 0.32-0.54) and excellent ability to predict noninfested houses (specificity higher than 0.90). Predictive ability was improved by including random village effects and presence of signs of infestation (insect feces, eggs, and exuviae) as fixed effects. Multimodel inference results varied depending on factors included, but house wall materials (adobe, bajareque, and palopique) and signs of infestation were among the most important predictive factors. Reduced models were not supported suggesting that all factors contributed to predictions. Previous knowledge and information from this study show that we have evidence to prioritize rural households for improvement to prevent house infestation with Triatoma dimidiata in Central America. House improvement will most likely have other health co-benefits.

Implementation science: Epidemiology and feeding profiles of the Chagas vector Triatoma dimidiata prior to Ecohealth intervention for three locations in Central America

“…The biology and ethology of T. dimidiata have been well studied [20][21][22][23][24][25] and its domiciliary infestation has been associated with different bio-socio-ecological factors. These bio-socio-ecological factors include: I) the presence of domestic and synanthropic animals, such as bird (e.g., chicken, turkey and duck), rodents (mouse and rat), dog, and opossum, [20,[22][23][24]26]; II) house construction with natural materials specifically adobe or bajareque, and house wall conditions including rustic, unplastered walls or cracks in the wall plastering [27]; III) the location of chicken coops (next to the house or away from the house) or evidence of animals inside the house (i.e. rodent or bird nests), and IV) household characteristics including: the presence of dirt floors, poor hygiene (e.g., clutter), and signs of triatomines inside the house (insect feces, exuviae, eggs or dead insects) [26][27][28][29][30].…”

“…These bio-socio-ecological factors include: I) the presence of domestic and synanthropic animals, such as bird (e.g., chicken, turkey and duck), rodents (mouse and rat), dog, and opossum, [20,[22][23][24]26]; II) house construction with natural materials specifically adobe or bajareque, and house wall conditions including rustic, unplastered walls or cracks in the wall plastering [27]; III) the location of chicken coops (next to the house or away from the house) or evidence of animals inside the house (i.e. rodent or bird nests), and IV) household characteristics including: the presence of dirt floors, poor hygiene (e.g., clutter), and signs of triatomines inside the house (insect feces, exuviae, eggs or dead insects) [26][27][28][29][30]. House improvements that target these factors include not only replacing dirt floors with concrete and plastering the walls using local materials, but also removing blood meal sources by removing clutter and relocating chicken coops and other domestic animals outside and away from the house.…”

“…Establishing the baseline conditions of an ecosystemic intervention enhances vector control success by identifying risk factors for house infestation, and has been well reviewed [31]. The risk factors associated with domestic infestation for these localities have been identified [27]. Based on these risk factors, the aim of the present study was to: 1) document and understand the role of domestic, synanthropic and sylvatic animals in the occurrence of Chagas vector infestation in each location, and 2) use a research-based approach to determine if the locations vary in T. cruzi transmission risk factors and infestation indices prior to the Ecohealth interventions.…”

Cultivable Bacterial Diversity in the Gut of the Chagas Disease Vector Triatoma dimidiata: Identification of Possible Bacterial Candidates for a Paratransgenesis Approach

“…Triatoma dimidiata can be found within human dwellings, increasing the risk for Chagas disease transmission to humans (Dumonteil et al, 2002(Dumonteil et al, , 2013Weeks et al, 2013;Zamora et al, 2015). A study in Colombia described tolerance to pyrethroid insecticides in specimens of T. dimidiata (Reyes et al, 2007), which confirms the importance of developing new vector control tools for this domesticated species.…”

Evolving Probabilistically Significant Epistatic Classification Rules for Heterogeneous Big Datasets

“…However, many areas where the disease is endemic have limited resources for these preventative household improvements. Detailed entomologic and socioeconomic surveys are conducted to try to identify the drivers of infestation [1] in order to determine the most cost-effective strategies to reduce infestation. Mining these complex Chagas survey datasets for useful information has proven to be a major challenge, due to a variety of factors, including missing data, imbalanced class outcomes, heterogeneity of drivers of infestation, non-independence of some features, and complex, possibly highorder, nonlinear interactions between many of the potential predictive features.…”