Ovitraps evaluation for surveillance and control of Aedes aegypti in two urban settlements of Urabá, Antioquia

Abstract

Introduction: Aedes (Stegomyia) aegypti is the main vector of dengue. Chemical insecticides have been used to control the mosquito and it has developed resistance. It is necessary to evaluate alternative strategies that are efficient, economical and easy to apply, such as ovitraps with Bacillus thuringiesis israeliensis.

Objective: To evaluate the impact of ovitraps loaded with B. t. israeliensis on traditional indexes, as strategies for surveillance and control of A. aegypti.

Materials and methods: We selected eight neighborhoods from the municipalities of Apartadó and Carepa. Two neighborhoods in each municipality were chosen for intervention and two for control. The intervention consisted in the installation of ovitraps with B. t. israeliensis in every house. The traps were visited each month between September, 2009, and March, 2010. Traditional indexes were obtained and compared among the neighborhoods. Ovitrap positivity index and egg density index were calculated and we generated density maps.

Results: Five hundred and nineteen ovitraps were placed monthly; 3,114 samples were obtained, from which 76.4% were positive. We collected 501,425 eggs. In Apartadó, statistically significant differences were observed in the house, container and Breteau indexes. The ovitrap positivity index showed high risk of A. aegypti infestation and traditional indexes showed medium and low risk levels.

Conclusions: Ovitraps had an impact on traditional indexes and proved to be useful strategies for surveillance and control of A. aegypti in Urabá, Antioquia.