Variable residual activity of K-Othrine® PolyZone and Actellic® 300 CS in semi-field and natural conditions in the Democratic Republic of the Congo.

Background: Indoor Residual Spray (IRS) against vector mosquitoes is a primary means for combating malaria transmission. To combat increased patterns of resistance to chemicals against mosquito vectors, alternative candidate insecticide formulations should be screened. With mortality as the primary endpoint, the persistence of residual efficacy of a polymer-enhanced pyrethroid suspension concentrate containing deltamethrin (K-Othrine® PolyZone-KOPZ) applied at 25 mg active ingredient (ai)/m was compared with a microencapsulated organophosphate suspension formulation of pirimiphos-methyl (Actellic® 300CS-ACS) applied at 1 g ai/m.

Indoor residual spray bio-efficacy and residual activity of a clothianidin-based formulation (SumiShield 50WG) provides long persistence on various wall surfaces for malaria control in the Democratic Republic of the Congo.

Background: Bio-efficacy and residual activity of SumiShield 50WG (50%, w/w) with active ingredient clothianidin, a neonicotinoid compound, was assessed using an insecticide-susceptible laboratory strain of Anopheles arabiensis. Implications of the findings are examined in the context of potential alternative insecticides for indoor residual spraying in Lualaba Province, Democratic Republic of the Congo.

Methods: Contact surface bioassays were conducted for 48 weeks on four types of walls (unbaked clay, baked clay, cement, painted cement) in simulated semi-field experimental conditions using two different doses of clothianidin active ingredient (200 mg ai/sq m and 300 mg ai/sq m).