Comparison of the effectiveness of two formulations of deet against Anopheles flavirostris

The effectiveness of 2 formulations of deet (diethylmethylbenzamide) was tested against the principal vector of malaria in the Philippines, Anopheles flavirostris. A new extended duration repellent formulation (EDRF) was compared with the standard military-issue liquid formulation. The EDRF was significantly more effective than the liquid formulation between 6 and 12 h post-application. There was no difference between the 2 formulations in the first 6 h following application, or between 12 and 15 h post-application. The continued usefulness of the liquid formulation is discussed in light of these results.