Comparison of plant products and pyrethroid-treated bed nets for protection against mosquitoes (Diptera: Culicidae) in Guinea Bissau, West Africa.

In Guinea Bissau, West Africa, the shrub Hyptis suaveolens Poit. (Lamiaceae) and smoke of the bark of the tree Daniellia oliveri Rolfe (Caesalpiniaceae) traditionally are used to reduce numbers of mosquitoes indoors at night. We recorded the numbers of mosquitoes in the bedrooms of 30 households in a rural village, Mandinka-Rá in central Guinea Bissau. Each household was provided with bed nets and allocated randomly to 1 of 6 treatments as follows: (1) lambda-cyhalothrin-treated bed nets (10 mg/m2), (2) permethrin-treated bed nets (500 mg/m2), (3) burning of H. suaveolens, (4) burning of the bark of D. oliveri, (5) fresh H. suaveolens, and (6) control group using untreated bed nets and no plant products. In treatment groups 1-4, the mean number of mosquitoes was significantly less than the mean of the control. These results indicated that the use of burning H. suaveolens or D. oliveri indoors at night repelled endophagic mosquitoes and may contribute significantly to reducing the prevalence of diseases caused by pathogens transmitted by house-frequenting, nocturnally blood-feeding arthropods.