Efficacy of mosquito coils containing 0.3% and 0.4% pyrethrins against An.gambiae sensu lato mosquitoes.

Abstract

OBJECTIVE: To investigate the efficacy of a formulation containing 0.4% pyrethrins against registered mosquito coil containing 0.3% pyrethrins. DESIGN: Non intervention analytical study. SETTING: Four villages in Mashonaland East province, Mumurwi, Chitengu, Katiyo and Nyagande. SUBJECTS: Biological efficacy of Doom and IT mosquito coils. MAIN OUTCOME MEASURES: To measure insecticidal, knock down and inhibition of biting activities of the coils in the presence of mosquitoes. RESULTS: A two hour exposure of mosquitoes to both coils results in a 99% and 98.5% mortality rate for a 0.4% and a 0.3% formulation respectively. The KT50 and KT90 of a formulation containing 0.4% pyrethrins were half those of a 0.3% formulation, suggesting that a 0.4% formulation has a rapid knock down effect. A formulation containing 0.4% pyrethrins inhibited 92.5% from biting as compared to a 0.3% formulation (80%). CONCLUSION: A formulation containing 0.4% pyrethrins is more effective in repelling mosquitoes than a 0.3% formulation.