Thinking outside the box: reducing the risk for Chagas disease through integrated vector and reservoir control

Chagas disease vector-borne transmission persists in focalized areas after mass insecticide applications in Guatemala. Persistent Triatoma dimidiata infestations pose a challenge for sustainable disease control. We found that rodents are associated with vector persistence in one such region. Rodents were significant blood meal sources and parasite reservoirs. We developed a community-based participatory intervention to reduce vector and rodent infestations through residual insecticide applications, community-wide education regarding risk factors, environmental management and mechanical rodent control. Eighteen communities with over 15% baseline infestations were assigned to the intervention or control (insecticide alone), in a cluster randomized cohort study. From 2012 to 2014, improved rodent and environmental management practices were seen in the intervention group. Domestic vector densities and infestation levels were reduced over time but persisted above the 5% control target in both groups. Peridomestic vector densities increased only in the intervention group. The prevalence of triatomines with human blood meals increased only in the control, while the relative risk of infected bugs was reduced in the intervention compared to the control. Thus, integrating vector and reservoir control can improve Chagas disease control by reducing the risk of human contact with infected triatomines. Future studies should address the role of peridomestic infestations in transmission.