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 (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.

The Ecohealth strategy is a multidisciplinary data-driven approach used to improve the quality of people’s lives in Chagas disease endemic areas, such as regions of Central America. Chagas is a vector-borne disease caused by the parasite Trypanosoma cruzi. In Central America, the main vector is Triatoma dimidiata. Because successful implementation of the Ecohealth approach reduced home infestation in Jutiapa department, Guatemala, it was scaled-up to three localities, one in each of three Central American countries (Texistepeque, El Salvador; San Marcos de la Sierra, Honduras and Olopa, Guatemala). As a basis for the house improvement phase of the Ecohealth program, we determined if the localities differ in the role of sylvatic, synanthropic and domestic animals in the Chagas transmission cycle by measuring entomological indices, blood meal sources and parasite infection from vectors collected in and around houses. The Polymerase Chain Reaction (PCR) with taxa specific primers to detect both, blood sources and parasite infection, was used to assess 71 T. dimidiata from Texistepeque, 84 from San Marcos de la Sierra and 568 from Olopa. Our results show that infestation (12.98%) and colonization (8.95%) indices were highest in Olopa; whereas T. cruzi prevalence was higher in Texistepeque and San Marcos de la Sierra (>40%) than Olopa (8%). The blood meal source profiles showed that in Olopa, opossum might be important in linking the sylvatic and domestic Chagas transmission cycle, whereas in San Marcos de la Sierra dogs play a major role in maintaining domestic transmission. For Texistepeque, bird was the major blood meal source followed by human. When examining the different life stages, we found that in Olopa, the proportion bugs infected with T. cruzi is higher in adults than nymphs. These findings highlight the importance of location-based recommendations for decreasing human-vector contact in the control of Chagas disease. Blood feeding insects from the subfamily Triatomine are involved in the transmission of Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, a neglected tropical disease endemic from southern Mexico through Central to northern South America. Chagas disease mostly affects rural areas and especially people living in houses made of low-cost, natural materials such as bajareque or adobe that have mud walls and a dirt floor. A multidisciplinary data-driven Ecohealth vector control program that includes house improvements (wall plastering and cement flooring), as well as insecticide spraying, was developed in Jutiapa department, Guatemala, and has been shown to decrease vector-human contact. Because Chagas vectors feed on a wide variety of vertebrates, knowing the local feeding profiles of the insect vectors before interventions can strengthen Ecohealth program development. To facilitate scaling up the Ecohealth program developed in Jutiapa to three new locations in three different countries, Texistepeque, El Salvador; San Marcos de la Sierra, Honduras and Olopa, Guatemala, and with distinct ecological scenarios, we assessed the entomological indices, feeding profiles and parasite infection of vectors collected in and around houses in the new locations prior to any interventions. Our results show all three metrics varied among locations. The results highlight the importance of domestic, synanthropic and sylvatic blood meal sources on the disease transmission cycle and the need to consider local conditions for vector control.

The eradication of the vector Rhodnius prolixus from Central America was heralded as a victory for controlling transmission of Trypanosoma cruzi, the parasite that causes Chagas disease. While public health officials believed this milestone achievement would effectively eliminate Chagas disease, case reports of acute vector transmission began amassing within a few years. This investigation employed a cross-sectional serosurvey of children either presenting with fever for clinical care or children living in homes with known triatomine presence in the state of Sonsonate, El Salvador. Over the 2018 calendar year, a 2.3% Chagas disease seroprevalence among children with hotspot clustering in Nahuizalco was identified. Positive serology was significantly associated with dogs in the home, older participant age, and a higher number of children in the home by multivariate regression. Concomitant intestinal parasitic infection was noted in a subset of studied children; 60% having at least one intestinal parasite and 15% having two or more concomitant infections. Concomitant parasitic infection was statistically associated with an overall higher parasitic load detected in stool by qPCR. Lastly, a four-fold higher burden of stunting was identified in the cohort compared to the national average, with four-fifths of mothers reporting severe food insecurity. This study highlights that polyparasitism is common, and a systems-based approach is warranted when treating Chagas disease seropositive children.

Chagas disease is a complex vector borne parasitic disease involving blood feeding Triatominae (Hemiptera: Reduviidae) insects, also known as kissing bugs, and the vertebrates they feed on. This disease has tremendous impacts on millions of people and is a global health problem. The etiological agent of Chagas disease, Trypanosoma cruzi (Kinetoplastea: Trypanosomatida: Trypanosomatidae), is deposited on the mammalian host in the insect’s feces during a blood meal, and enters the host’s blood stream through mucous membranes or a break in the skin. Identifying the blood meal sources of triatomine vectors is critical in understanding Chagas disease transmission dynamics, can lead to identification of other vertebrates important in the transmission cycle, and aids management decisions. The latter is particularly important as there is little in the way of effective therapeutics for Chagas disease. Several techniques, mostly DNA-based, are available for blood meal identification. However, further methods are needed, particularly when sample conditions lead to low-quality DNA or to assess the risk of human cross-contamination. We demonstrate a proteomics-based approach, using liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify host-specific hemoglobin peptides for blood meal identification in mouse blood control samples and apply LC-MS/MS for the first time to Triatoma dimidiata insect vectors, tracing blood sources to species. In contrast to most proteins, hemoglobin, stabilized by iron, is incredibly stable even being preserved through geologic time. We compared blood stored with and without an anticoagulant and examined field-collected insect specimens stored in suboptimal conditions such as at room temperature for long periods of time. To our knowledge, this is the first study using LC-MS/MS on field-collected arthropod disease vectors to identify blood meal composition, and where blood meal identification was confirmed with more traditional DNA-based methods. We also demonstrate the potential of synthetic peptide standards to estimate relative amounts of hemoglobin acquired when insects feed on multiple blood sources. These LC-MS/MS methods can contribute to developing Ecohealth control strategies for Chagas disease transmission and can be applied to other arthropod disease vectors.