Bioassay evaluation on the efficacy of α–cypermethrin impregnated into long lasting insecticide treated nets using Anopheles stephensi

ObjectiveTo evaluate the bioefficacy of α-cypermethrin impregnated into long lasting insecticide treated nets (LLITNs-INTERCEPTOR®) against main malaria vector, Anopheles stephensi (An. stephensi).MethodsThe effectiveness of bed net impregnated with α-cypermethrin (INTERCEPTOR®) with washing was evaluated. The washing procedure and bioassay tests were carried out according to the WHO-recommended methods. Malaria vector, An. stephensi was exposed to impregnated bed net for three minutes and then mortality measured after 24 h recovery period. Knockdown was also measured according to the logarithmic times.ResultsResult of cone bioassay method showed that bioefficacy of α-cypermethrin decreased from 100% in unwashed to 15% in 20 washes. KT50 was measure as one minute in one wash and increased to 40 min in 20 washes.DiscussionFindings of this study provide guideline for malaria vector control authorities and people using pyrethroid-impregnated bed nets.