Project Lead(s): Clarence Mang'era
The Anopheles gambiae sensu stricto mosquito is the primary malaria vector.
Growing resistance to pyrethroids presents a real and immediate challenge to the efficacy of otherwise successful insecticide-treated net (ITN)-based malaria control intervention against the adult vector.
The interruption of mosquito-borne malaria transmission by targeting larval growth and the development of the mosquito using plant compounds, M. koenigii phytochemicals, has the potential of locally eliminating malaria.
Efficient, locally accessible phytochemicals have the potential to significantly reduce the malaria vectors and contribute to the reduction and eventual elimination of malaria in Kenya and the region.
This project bioprospected plants for novel anti-mosquito blends or compounds that show promise in integrated management of malaria vectors.
Specifically, the team carried out the following activities:
1) Determined molecular diversity, and developed molecular barcodes and spatial distribution maps of selected mosquitocidal M. koenigii from various regions of Kenya
2) Determined bioactivity, and the impact of M. koenigii phytochemical blends on biological fitness of An. gambiae s.s
3) Identified phytochemical components in M. koenigii plant extracts mosquitocidal or growth, disrupting to An. gambiae s.s (larvae and adults)
4) Determined molecular responses in the mosquito to the phytochemical blends.
A constituent was discovered in the non-volatile, bioactive fraction of M. koenigii that disrupts larval growth and development of the malaria vector.
There was significant repellent activity against adult mosquitoes.
A study showed the number of bites from mosquitoes were fewer on the treated arm compared to the control arm.
Fumigant activity tests showed increased mortality over a period of six hours.
The project suggests the value of intensive research on the potential of different phytochemicals of M. koenigii in mosquito control.
The research team plans on applying for Phase II Transition To Scale funding, in part to conduct field trials on the efficacy of non-volatiles on the immature stages of the mosquito with the plants grown around typical mosquito breeding sites, and to monitor their effects on the development of mosquito larvae.