Search

Chagas disease is mainly transmitted by triatomine insect vectors that feed on vertebrate blood. The disease has complex domiciliary infestation patterns and parasite transmission dynamics, influenced by biological, ecological, and socioeconomic factors. In this context, feeding patterns have been used to understand vector movement and transmission risk. Recently, a new technique using Liquid chromatography tandem mass spectrometry (LC-MS/MS) targeting hemoglobin peptides has showed excellent results for understanding triatomines’ feeding patterns. The aim of this study was to further develop the automated computational analysis pipeline for peptide sequence taxonomic identification, enhancing the ability to analyze large datasets data. We then used the enhanced pipeline to evaluate the feeding patterns of Triatoma dimidiata, along with domiciliary infestation risk variables, such as unkempt piles of firewood or construction material, cracks in bajareque and adobe walls and intradomiciliary animals. Our new python scripts were able to detect blood meal sources in 100% of the bugs analyzed and identified nine different species of blood meal sources. Human, chicken, and dog were the main blood sources found in 78.7%, 50.4% and 44.8% of the bugs, respectively. In addition, 14% of the bugs feeding on chicken and 15% of those feeding on dogs were captured in houses with no evidence of those animals being present. This suggests a high mobility among ecotopes and houses. Two of the three main blood sources, dog and chicken, were significantly (p < 0.05) affected by domiciliary infestation risk variables, including cracks in walls, construction material and birds sleeping in the intradomicile. This suggests that these variables are important for maintaining reproducing Triatoma dimidiata populations and that it is critical to mitigate these variables in all the houses of a village for effective control of these mobile vectors.

The Pan American Health Organization (PAHO) has defined Chagas Disease hotspots in Central America associated with the vector Triatoma spp. Triatoma dimidiata is a native vector adapted to multiple environments, including intra-domestic and peri-domestic habitats. A multi-institutional project named "Alliances for the elimination of Chagas in Central America" was created to help reduce the incidence of the disease in the region. Activities performed in the field as part of the project included aspects of vector surveillance and control, improvement of houses, diagnosis and treatment of individuals, health promotion, training of human resources and identification of access barriers to diagnosis and treatment. As a base line study, eleven villages, comprised of 1,572 households, were entomologically evaluated (83.4% overall participation); five were found to have very high infestation rates (20%), three had high infestation rates (8-20%) and three had low-infestation rates (8%), coinciding with the category of infestation-risk of the houses within each village. Serological tests were carried out in 812 people (80% participation) in two of the 11 villages and none of the 128 children tested, less than 5 years of age, were positive for Trypanosoma cruzi infection. Community participation in all the activities was high (70%). The collaboration between several subnational, national, and international institutions, each with specific roles, promoted community participation in the activities of vector control and patient care, thus, establishing a baseline to continue implementing and monitoring project progress.