The efficacy and residual life span of two alphacypermethrin insecticide formulations (Fendon 6% Suspension concentrate and Fendona Dry 15%) treated on mosquito bed nets

OBJECTIVE: To compare the effects of mosquito nets treated with two formulations of alpha-cypermethrin insecticide with a view to recommending the most appropriate formulation for use to treat mosquito nets. DESIGN: Assessment of insecticide potency under conditions of ordinary use. SETTING: Chilonga rural irrigation community in south east Lowveld Zimbabwe, a holoendemic area of year round malaria transmission. SUBJECTS: Convenience sample of 20 household heads (volunteers) was issued with treated mosquito nets. INTERVENTION: Following mosquito net treatment and distribution, bioassay tests were carried out monthly for a period of six months on insecticide and placebo treated nets. Questionnaires were administered once, one month post treatment of nets. MAIN OUTCOME MEASURES: Median mosquito knock down times of mosquitoes exposed to insecticide treated nets and community attitude towards the use of insecticide treated nets. RESULTS: Average time taken to knock down the median mosquito progressed from 2.3 minutes to 13.0 minutes for Fendona Dry 15% and from 4.1 minutes to 7.8 minutes for Fendona 6% SC over the six month period. The average time taken to knock down the median mosquito three months post-washing were 13.0 minutes and 7.4 minutes for Fendona Dry 15% and Fendona 6% SC respectively as against more than 30 minutes in controls. Both insecticides exhibited some wash resistance properties. The side effects reported were sneezing, itching, skin rash and smelling. Questionnaire data suggested that alphacypermethrin treated mosquito nets were welcomed. CONCLUSIONS: Both insecticide formulations proved to be suitable candidates. This was because of their insecticidal potency, wash resistance properties and acceptance by the community.