Project Lead(s): Sheila Barasa
Despite advances, there were still 214 million new cases of malaria worldwide in 2015, with an estimated 438,000 deaths.
In rural Africa, most people live in houses that are not properly sealed to prevent entry of mosquitoes. In addition, most human activities (such as cooking and eating) take place outside in the early evenings.
People remain greatly exposed to infection with malaria and other mosquito-borne diseases during times when they are not using bed nets, either indoors or outdoors.
The main goal of the project was to test the concept of using transfluthrin-impregnated sisal decorative pieces as a complementary approach to permethrin-treated bed nets, to confer additional protection against mosquito bites that occur indoors before people go to bed and outdoors during early evenings.
Decorative sisal baskets and flags were produced locally by a women's group specializing in hand weaving sisal products, providing a business opportunity to the local communities in east Africa, where sisal is grown commercially.
The percentage reduction of the density of mosquitoes in experimental huts with long-lasting insecticidal nets (LLINs) and transfluthrin-treated sisal decorative pieces was compared with huts equipped only with LLINs.
The experimental design included three experimental huts and three treatments. Treatments included:
1) Control: permethrin-treated LLIN and four untreated sisal baskets
2) Four transfluthrin-treated sisal baskets (2.5 mL) with a permethrin LLIN
3) Four transfluthrin-treated sisal baskets (5 mL) with a permethrin LLIN.
The baskets were hung approximately 1m off the floor in the corner of the huts.
The project successfully demonstrated that using transfluthrin-impregnated sisal decorative pieces, as a complementary approach for permethrin bed nets, confers additional protection against mosquito bites that occur indoors.
Both low- and high-doses of transfluthrin baskets reduced entry of An. arabiensis mosquitoes by almost three quarters, relative to huts that had LLINs alone. Transfluthrin-treated sisal baskets also reduced exposure to bites of An. arabiensis to volunteers inside huts before they retired to bed.
Adding transfluthrin-treated baskets in huts that had LLINs increased the mortality of An. arabiensis mosquitoes by more than 50% but the mortality of Culex spp. and An. funestus s.s. mosquitoes was below 25%, even in those huts that had transfluthrin-treated baskets.
Results from this research have been widely disseminated in conferences and publications.
The project team wishes to continue investigating and expanding this approach, and will require an estimated $800,000 to do so.