Assessing risk of vector transmission of Chagas disease through blood source analysis using LC-MS/MS for hemoglobin sequence identification

Abstract

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.

Sustainable, integrated control of native vectors: The case of Chagas disease in Central America

“…Vector feeding ecology studies were both DNA-and proteomics-based and indicate high mobility of vectors among ecotopes and houses. For example, in Anonito, Jutiapa, Guatemala 18-100% of the vectors had blood sources from animals (dogs, chicken, cats and cows) that were not present in the houses where the vectors were collected (40). Surprisingly, 50% of these vectors were nymphs, which are wingless, demonstrating mobility is not restricted to adults.…”

“…For example, dog, human, and bird (most likely chicken) were the major blood sources in the highly domesticated populations of T. dimidiata s.l. in southern Guatemala (37,40,48,49). In El Salvador, there was little feeding on dog and more feeding on mouse and pig; whereas in Honduras, there was less feeding on bird and more on mouse (48).…”