Chemical control of Triatoma dimidiata and Rhodnius prolixus (Reduviidae : Triatominae), the principal vectors of Chagas' Disease in Guatemala

Abstract

The insecticidal efficacy against Triatoma dimidiata and Rhodnius prolixus, the main vectors of Chagas' disease in Guatemala, was evaluated in six Guatemalan villages. A 0.075% lambda-cyhalothrine suspension was the most effective to both species when sprayed at 40ml/m^2 on the mud walls or 80ml/m^2 to straw thatched houses, followed by a 0.2% liquid or 1% powder of deltamethrin, 0.5% propoxur liquid or 0.5% diazinon suspension, spraying at 100ml/m^2,during 2 to 4 months following the treatment, as assessed by man-hour collection or a count of the spots of vector excrements on white papers placed on the walls. However, diazinon powder and fenitrothion suspension were less effective than the other insecticides for vector control. Deltamethrin powder and liquid caused ocular and nasal irritation to the sprayers and residents immediately after treatment and lambda-cyhalothrine caused less irritation. The permethrin smoking agent was not effective to Rh. prolixus bacause smoke could not stay in the houses. We recommend the use of lambdacyhalothrine suspension in the Guatemalan mud and straw thatched houses.