Biological and integrated vector management for the control of dengue vectors in Punjab, Pakistan

Dengue epidemics are annually occurring in Pakistan since 2006 along with > 400 deaths and over 15000 cases so far. Dengue viruses are transmitted to humans by the bite of an infected female mosquito. Aedes aegypti and Ae. albopictus are the most important vectors of dengue viruses in tropical and sub-tropical areas of the world including Pakistan. With neither vaccine nor proper treatment for dengue, prevention of the disease depends upon the control of dengue vectors. Novel tools and techniques are needed for the effective control of these mosquito vectors. Research was conducted using many biological control agents such as different formulations of Bti (WDG, TP), IGRs, various species of predatory copepods (Mesocyclops) alone and mixed with Bti WDG in laboratory and field experiments as larvicides. In addition “Lethal Ovitraps” were also tested for suppressing the adult Aedes mosquitoes in specific localities of Lahore. Results were evaluated on the base of lethal concentrations: LC₅₀ and LC₉₅, percent larval mortalities and pupae / adult emergence inhibition both in laboratory and field bioassays. Aedes mosquitoes were found highly susceptible to Bti WDG by 0.1– 0.05 ppm. Mixtures of two larvicides (diflubenzuron and Buprofezin) integrated with Bti WDG completely inhibited adult emergence by 0.0001ppm. In addition four species of Mesocyclops identified from Punjab have high potential for biological control of Aedes larvae. Integration of Bti (TP) with Mesocyclops leukarti reduced first instar Aedes aegypti up to 100% in 10 weeks post exposure. The use of Lethal Ovitraps with integration of Bti and buprofezin was the most effective method for controlling immature and adult stages of Ae. aegypti population in two selected localities of Lahore. The integration have shown more rapid onset of death thus controlling larvae more efficiently. Moreover, efforts to develop Wolbachia as a biological agent to control dengue transmission are currently ongoing in our laboratory.