Efficacy of pyriproxyfen-treated nets in sterilizing and shortening the longevity of Anopheles gambiae (Diptera: Culicidae).

Pyrethroid-resistant malaria vectors have become a serious threat for malaria control, and bed nets that reduce the development of resistance are urgently needed. Here, we tested the effects of bed nets treated with the insect growth regulator pyriproxyfen against adult female Anopheles gambiae Giles (Diptera: Culicidae) under laboratory conditions. Noninsecticidal nets made of 195 denier monofilament polyethylene with a mesh size of 75 holes per square inch (equivalent to the Olyset Net) were dipped in a 0.1, 0.01, or 0.001% (wt:vol) alcohol solution of pyriproxyfen and dried overnight. Adult females of an insecticide-susceptible An. gambiae strain were exposed to treated and untreated nets before and after a bloodmeal. Bioassays showed that females were completely sterilized after exposure to 0.1% (35 mg [AI]/m2) and 0.01% pyriproxyfen-treated nets both before and after a bloodmeal. In addition, adult longevity decreased after exposure to the pyriproxyfen-treated nets in a concentration-dependent manner. The sterilizing and life-shortening effects of pyriproxyfen on the vector mosquito indicate that the combined use of pyriproxyfen and pyrethroids on bed nets has the potential to provide better malaria control and prevent the further development of pyrethroid resistance in malaria vectors.