Chagas Disease in Central America: Recent Findings and Current Challenges in Vector Ecology and Control

Abstract

In Central America, most new human Trypanosoma cruzi infections (Chagas disease) are vector-borne, primarily by native vector species. Given the importance of vector control in reducing Chagas disease incidence, here, we provide an updated report on the recent advances and the latest research in vector ecology and control in Central America. Our objective is to present a panorama of the current situation that includes vector control program details, recent public health activities and academic research, and current challenges faced by each country and the region as a whole. With the elimination of the introduced species Rhodnius prolixus from the region, the primary vector control challenge is control of native species that move between sylvan and domestic environments, namely Triatoma dimidiata and Rhodnius pallescens. These species cannot be eliminated from domestic/peridomestic settings in a sustainable way using insecticide alone, as residual members of domestic populations and/or sylvatic foci allow the species to persistently reinfest following insecticide application. Implementation of integrated, multidisciplinary methods for native vector species control has yielded promising results. In particular, projects using the Ecohealth method have been scaled up and expanded to endemic areas in multiple countries through partnerships between international stakeholders and ministries of health (MoHs). Additionally, the recent description of two new triatomine bug species that were once classified as T. dimidiata may help to tailor vector control methods to interspecies variations, and the discovery of a dark morph of R. pallescens may provide further insight into vector control in Panama. Finally, associations between deforestation and vector T. cruzi infection and abundance in Panama call attention to associations between human land use change and Chagas disease risk. The elimination of R. prolixus contributed to significant reductions in human T. cruzi infection incidence in Central America over the past 20 years, but native vector species still pose a significant public health threat. New methods and collaborations present promising solutions, but sustained partnerships, long-term commitment, and strong regional leadership are required to see them through.