| Summary: | Background & objectives: Field trials of lambda-cyhalothrin 10 CS (ICON 10 CS) in indoor residual spraying(IRS) with 25 mg a.i./m2 against Anopheles culicifacies was undertaken vs malathion IRS (25% WP–2 g a.i./m2) in Tumkur district, Karnataka; vs deltamethrin IRS (2.5% WP–20 mg a.i./m2) in Dharmapuri district; andvs lambda-cyhalothrin (10 WP–25 mg a.i./m2) in Ramanathapuram district, Tamil Nadu, India.Methods: Spray operations in the experimental villages were done by the National Institute of Malaria Research(NIMR) and in the control villages by the respective State Health Department staff. Persistence of efficacy ofinsecticide sprayed in villages was assessed by contact bioassays against vector mosquitoes. Entomologicalindicators such as per structure density, parity rates of vector mosquitoes and sporozoite rates were measuredin all the three study areas using standard procedures. Mass blood surveys and active fever case detectionswere carried out in experimental and control villages to study the impact of IRS on malaria transmission.Results: Persistence of effectiveness of ICON 10 CS was observed up to 2–3 months in all the three studyareas. ICON 10 CS was found effective at par with or better than the insecticides used in the national programmein reducing the mosquito densities and in interrupting malaria transmission in the study villages. Vectordensity, parity rates and malaria cases considerably reduced in the ICON 10 CS-sprayed villages.Conclusion: Field trials at three sites have established that ICON 10 CS formulation was relatively moreeffective than malathion 25% WP, deltamethrin 2.5% WP and lambda-cyhalothrin 10% WP in some evaluationparameters like indoor resting mosquitoes, parity rates in vector mosquitoes and persistence of effectiveness.It can be used for IRS for malaria vector control with two rounds of spray at an interval of 3 months forcurtailing the malaria transmission and an additional round is recommended in perennial malaria transmissionareas.
|
|---|
