Comparative field trial of alternative vector control strategies for non-domiciliated Triatoma dimidiata

Abstract

Chagas disease is a major vector-borne disease, and regional initiatives based on insecticide spraying have successfully controlled domiciliated vectors in many regions. Non-domiciliated vectors remain responsible for a significant transmission risk, and their control is a challenge. We performed a proof-of-concept field trial to test alternative strategies in rural Yucatan, Mexico. Follow-up of house infestation for two seasons following the interventions confirmed that insecticide spraying should be performed annually for the effective control of Triatoma dimidiata; however, it also confirmed that insect screens or long-lasting impregnated curtains may represent good alternative strategies for the sustained control of these vectors. Ecosystemic peridomicile management would be an excellent complementary strategy to improve the cost-effectiveness of interventions. Because these strategies would also be effective against other vector-borne diseases, such as malaria or dengue, they could be integrated within a multi-disease control program.

Figure 1.

Examples of insect screens and impregnated curtains used. A, Insect screens were fixed on the outside of the houses. B, Long-lasting impregnated curtains were hung from a metal wire on the inside of the windows. This figure appears in color at www.ajtmh.org.

Figure 2.

Temporal variations in triatomine abundance. Bimonthly variations in triatomine collections per house with the 95% confidence interval (CI) based on a Poisson distribution is shown for houses with (closed circles) and without (open circles) vector control interventions. A, Insecticide spraying, B, insect screens, C, long-lasting impregnated curtains, and D, peridomicile management. The arrows indicate the time when interventions were applied. Shaded areas indicate the seasonal infestation period used to calculate the efficacy of each intervention, which is also given with its 95% CI.