Sub-Saharan Africa bares the brunt of the world's malaria burden, with nearly 80% of all cases occurring in this region. However, we are now at a turning point in the history of malaria control in Africa. For the first time in a generation reports of malaria declining have become common due to high coverage with long-lasting insecticide treated nets and the prompt and effective treatment of clinical cases. In order to maintain these hard won gains and to make further reductions in malaria transmission it is important to improve and develop new strategies for vector control, which will be applicable in different environments, affordable, and complement existing interventions, so that greater reductions in malaria transmission can be achieved. This project aims to develop more efficient and cost-effective methods for controlling and monitoring Anopheles gambiae populations, the major vector of malaria in Africa. This approach is underpinned by multi-disciplinary research to identify the visual and olfactory stimuli that cause female An. gambiae to lay eggs at certain sites and not others. Such knowledge will be used to (1) identify important breeding sites and selectively treat preferred sites with novel, long-lasting and environmentally friendly larvicides and (2) provide a rational basis for developing traps to monitor adult mosquitoes. Specifically we propose to test: (1) if bacteria-generated volatiles from aquatic habitats function as oviposition semiochemicals;(2) whether the bacterial communities and chemicals released from and present in stagnant water bodies differ between sites with and without An. gambiae larvae, (3) test novel residual larvicides (pyriproxyfen, an insect growth regulator and a silicon-based monomolecular surface film) against An. gambiae and (5) develop an oviposition trap for collecting gravid An. gambiae. Therefore, the performance of two relatively novel agents, will be evaluated under laboratory and field conditions and their potential in an `attract-and-kill' strategy combining findings from all specific objectives tested. Most of these studies will be carried out in the laboratory, in enclosed greenhouses and in the field in Kenya. However, some of the detailed chemical analysis will need to be carried out in specialised laboratories in Sweden. The findings from this study may lead to the development of new sampling and control tools for malaria vectors. Such tools would be valuable additions to an Integrated Vector Management package for the control of malaria in sub-Saharan Africa.

Public Health Relevance

Integrated vector management (IVM) is seen as the future for vector control. This project aims to develop and test new tools for sampling and killing gravid malaria mosquitoes as well as test the efficacy of two new larvicides. Attacking gravid females and the aquatic stages of the vector are potential strategies that could be incorporated into IVM programmes in the future. Not only would attacking both adult and larval stages result in much greater control than can be achieved with insecticide-treated bednets and indoor-residual spaying alone, they may also offer mechanisms for the management of pyrethroid- resistance and alternatives to DDT usage.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI082537-05
Application #
8318530
Study Section
Special Emphasis Panel (ZAI1-GSM-M (J3))
Program Officer
Costero, Adriana
Project Start
2009-09-24
Project End
2013-08-31
Budget Start
2012-09-01
Budget End
2013-08-31
Support Year
5
Fiscal Year
2012
Total Cost
$468,734
Indirect Cost
$34,721
Name
University of Durham
Department
Type
DUNS #
236427159
City
Durham
State
Country
United Kingdom
Zip Code
DH1 3-HP
Eneh, Lynda K; Okal, Michael N; Borg-Karlson, Anna-Karin et al. (2016) Gravid Anopheles gambiae sensu stricto avoid ovipositing in Bermuda grass hay infusion and it's volatiles in two choice egg-count bioassays. Malar J 15:276
Dugassa, Sisay; Lindh, Jenny M; Lindsay, Steven W et al. (2016) Field evaluation of two novel sampling devices for collecting wild oviposition site seeking malaria vector mosquitoes: OviART gravid traps and squares of electrocuting nets. Parasit Vectors 9:272
Eneh, Lynda K; Saijo, Hiromi; Borg-Karlson, Anna-Karin et al. (2016) Cedrol, a malaria mosquito oviposition attractant is produced by fungi isolated from rhizomes of the grass Cyperus rotundus. Malar J 15:478
Okal, Michael N; Lindh, Jenny M; Torr, Steve J et al. (2015) Analysing the oviposition behaviour of malaria mosquitoes: design considerations for improving two-choice egg count experiments. Malar J 14:250
Okal, Michael N; Herrera-Varela, Manuela; Ouma, Paul et al. (2015) Analysing chemical attraction of gravid Anopheles gambiae sensu stricto with modified BG-Sentinel traps. Parasit Vectors 8:301
Lindh, Jenny M; Okal, Michael N; Herrera-Varela, Manuela et al. (2015) Discovery of an oviposition attractant for gravid malaria vectors of the Anopheles gambiae species complex. Malar J 14:119
Mbare, Oscar; Lindsay, Steven W; Fillinger, Ulrike (2014) Pyriproxyfen for mosquito control: female sterilization or horizontal transfer to oviposition substrates by Anopheles gambiae sensu stricto and Culex quinquefasciatus. Parasit Vectors 7:280
Herrera-Varela, Manuela; Lindh, Jenny; Lindsay, Steven W et al. (2014) Habitat discrimination by gravid Anopheles gambiae sensu lato--a push-pull system. Malar J 13:133
Mbare, Oscar; Lindsay, Steven W; Fillinger, Ulrike (2014) Aquatain® Mosquito Formulation (AMF) for the control of immature Anopheles gambiae sensu stricto and Anopheles arabiensis: dose-responses, persistence and sub-lethal effects. Parasit Vectors 7:438
Dugassa, Sisay; Lindh, Jenny M; Oyieke, Florence et al. (2013) Development of a gravid trap for collecting live malaria vectors Anopheles gambiae s.l. PLoS One 8:e68948

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