Evaluation of the long-term efficacy of K-Othrine PolyZone on three surfaces against laboratory reared Anopheles gambiae in semi-field conditions.

Background: In this semi-field study, a new polymer-enhanced deltamethrin formulation, K-Othrine PolyZone, was compared to a standard deltamethrin product for residual activity against a susceptible strain of laboratory-reared Anopheles gambiae using standard WHO cone bioassays.

Methods: Residual insecticide efficacy was recorded after exposure to metal, cement and wood panels maintained in experimental huts in sub-tropical environmental conditions in north central Florida, USA, and panels stored in a climate controlled chamber located at the Centers for Disease Control and Prevention, Georgia, USA.

Conclusions: K-Othrine PolyZone demonstrated 100% control on metal and cement panels 1 year post application and > 80% control on wood panels up to 6 mo. The new formulation should be considered for use in indoor residual spray programmes requiring long-term control of malaria vectors.