Self-made smoke formulae for an exophagic Anopheles farauti in the malaria control program in Solomon Islands

Abstract

A persistent DDT residual spray in the past made Anopheles farauti, a major vector of malaria in Solomon Islands, exophagic and early evening biting. To cope with these adverse behaviors of mosquitos, we tested a series of self-made inexpensive smoke formulae for the entomological and epidemiological effectiveness. Mosquito candles, saw dust of 0.4% d-allethrin packed in empty beer cans, repelled 75% of mosquito bites at Tenaru Mala of 127 population in Guadalcanal. Mosquito bars, the similarly treated saw dust molded in a bar shape with tapioca starch, reduced PCD malaria incidence ratios of bar users to non-users from 0.39-0.65 to 0.06-0.14 at Gibert Camp of 914 population in Honiara. Fortified mosquito coils of 0.4% d-allethrin also reduced malaria prevalence of 450 students from 32.7% to 8.8% at the dorms of Ruavatu Secondary School. Nightly lighting of the coils kept the new malaria incidences lower than the recovery rates. These inexpensive smoke formulae could provide an effective antimalaria measure for exophagic and pre-bednet time biting mosquitos in supplement of mosquito nets.