Field Efficacy Of Peridomestic Insecticide Space Spraying Against Two Aedes Populations In Tahiti, French Polynesia

In the absence of specific treatments or vaccines, vector surveillance and control are the only measures available to suppress vector borne disease transmission. In French Polynesia, current public health interventions are based mostly on the use of chemical insecticides. The effectiveness of vehicle-dispensed peridomestic space spraying of insecticides in reducing Aedes populations was investigated in the rural village of Toahotu, Tahiti. Mean 24 hr Aedes catches using BG-Sentinel™ traps were used to evaluate the outcome of permethrin space spraying. Outdoor entomological sampling was performed before and after a single insecticide ULV application at a control and treatment site. No significant differences were observed in Aedes trap catches between control and treatment during the 3 weeks preceding the insecticide application. Immediate reduction of Aedes polynesiensis females was observed after spraying with mean trap catches significantly different between treatment and control sites. However, this difference was only transient with adult female population returning to pre-spray level after 4 to 7 days post-treatment. For Aedes aegypti, no
significant difference was observed between treatment and control after spraying. A significant increase in Aedes aegypti female trap catches was observed at the treatment site 4-7 days after ULV application. Altogether, our results indicate that the effectiveness of peridomestic space spraying is very limited in time and particularly unsuitable for the control of the (indoor) population of Ae aegypti. Our results support the development and field evaluation of innovative, more efficient, and more
sustainable control methods to reduce the risk of dengue and other arbovirus transmission.