The long-term impact of an Ecohealth intervention: Entomological data suggest the interruption of Chagas disease transmission in southeastern Guatemala

Abstract

Triatoma dimidiata is the main vector of Chagas disease in southern Mexico, Central America and northern South America. As a native vector, it moves readily among domestic, peri‑domestic and sylvatic environments, making it difficult to control only using insecticide as this requires regular application, and re-infestation frequently occurs. Other social innovation alternatives such as those based on Ecohealth principles can be used to tackle the dynamics of the disease in an integral way. We asked whether an Ecohealth intervention, implemented beginning in 2001 in a highly infested village, 41.8%, in southeastern Guatemala, was sustainable in the long term. This intervention included initial insecticide treatments, followed by making low-cost house improvements to eliminate transmission risk factors such as repairing cracked walls, covering dirt floors with a cement-like substance and moving domestic animals outside. We assessed the long-term sustainability through entomological and house condition surveys, as well as an analysis of community satisfaction. We found over a 19-year period, infestation with T. dimidiata was reduced to 2.2% and maintained at a level below the level (8%) where vector transmission is unlikely. This long-term maintenance of low infestation coincided with a large proportion of villagers (88.6%) improving their houses and completing other aspects of the Ecohealth approach to maintain the village at low risk for Chagas transmission. There was unanimous satisfaction among the villagers with their houses, following improvements using the Ecohealth method, which likely played a role in the long-term persistence of the modifications. Although the infestation has remained low, 11 years following the last intervention and as the population grew there has been an increase in the proportion of “at-risk” houses, to 33%, pointing out the necessity of maintaining vigilance. The Ecohealth approach is a low-cost, sustainable approach for the long-term control of vector-borne Chagas disease. We recommend this approach including ongoing community monitoring and institutional response for the long-term, integrated control of Chagas disease.