Project Lead(s): Abdoulaye Diabate
Issue
Between 2000 and 2015, malaria incidence rates fell by 37% globally and by 42% in Africa, but there were still an estimated 214 million new cases of malaria in 2015.
Resistance to pyrethroids – the only insecticide class approved for the treatment of bed nets – has emerged in anopheline mosquitoes.
Resistance to the alternative insecticides approved for public health use (such as organophosphates, carbamates and particularly organochlorine) has also been reported in the principal malaria vector, Anopheles gambiae.
No novel insecticides have reached the public health market in over 20 years and there is a need to develop effective supplementary malaria control tools that are easy to implement in the community.
Solution
Implemented in Burkina Faso, the project team developed a prototype device to screen and trap mosquitoes indoors.
The Lehman trap does not require an insecticide or an attractant, but effectively collects mosquitoes and kills them.
A funnel, made of a metal frame, is inserted at the top of the trap in a way that mosquitoes approaching the window in a house go first through the big opening of the funnel and enter the trap passing through the small opening. The way the funnel is inserted in the cage allows mosquitoes to enter easily but prevents them from escaping.
The project team worked with a local window manufacturer to improve the design of existing traps to fit into local houses, developed six prototypes and tested four of them in two ecological settings (high- versus low-vector density).
The most promising prototype was selected and then deployed in a case-control study in two villages (one village was an intervention village and the other was a control).
A total of eight houses in the control village were selected to install the traps at windows and to assess their performances against that of the intervention village.
Mosquito density was followed up monthly for four months.
Outcome
At individual houses, the Lehmann’s trap performed very well in both the intervention and control village, as mosquito density in individually equipped houses with traps was reduced by 78%–96% throughout the four-month study period.
Assessment of the impact of the trap on vector density at the community level showed a 68% reduction in August and 55.5% in October, but there was no reduction in September.
Qualitative and quantitative data showed a good level of acceptance of the Lehmann Trap by the interviewees.
About 98% of respondents claimed to have slept peacefully since the traps were installed and 98.91% of the respondents believe that the trap will help reduce the disease in the area.
Next steps for the project team will be to promote the trap, build a business plan around it and get local entrepreneurs to invest in it.