Framework programme:

 7

Contract/Grant agreement number:

223241

EC contribution:

1.000.000 €

Duration:

36 months

Funding scheme:

Collaborative Small Project

Starting date:

01/01/2009

 

 

Keywords: malaria, Anopheles, mosquito, Wolbachia, age

Background

There are estimated to be 500 million cases of malaria annually, and 1 million to 3 million deaths, primarily associated with Plasmodium falciparum infections in sub-Saharan Africa. Mosquitoes of the Anopheles gambiae complex (An. gambiae and An. arabiensis in particular) are the major vectors in Africa. Insecticide-based control programmes targeting the vector have been the most successful method of controlling the disease, but effectiveness has been greatly reduced by insecticide resistance.

Aims and expected results

Wolbachia pipientis is a maternally inherited bacterial symbiont found in mosquitoes and many other arthropods. It manipulates insect reproduction to spread itself through populations. A Wolbachia strain named wMelPop has been identified that shortens adult lifespan in Drosophila flies. The aims are to infect Anopheles cell lines with Wolbachia, examine intracellular interactions with host cells, and then use these cell lines in microinjection experiments to create Wolbachia-infected An. gambiae lines. The lines will be characterised including any effects on lifespan, and host gene expression will be examined in both cells and mosquitoes infected with Wolbachia.

A second set of experiments will aim to identify An. gambiae genes showing age-specific patterns of expression, and use them to develop molecular methods for age estimation. The method will be calibrated and assessed using laboratory-reared mosquitoes and wild african populations. Population age structure will be estimated in different ecological forms of An. gambiae at field sites in Burkina Faso, in different seasons and both with and without insecticide-treated net use. Mathematical models will be constructed that will allow the analysis of different interventions affecting adult mosquito longevity, the dynamics of the spread of Wolbachia and its potential effects on malaria transmission.

Potential applications:

The programme will assess a novel non-GM strategy for malaria vector control in Africa: the modification of Anopheles gambiae population age structure using virulent Wolbachia. It will also deliver new tools for the accurate assessment of Anopheles age in field-collected specimens, which will allow the assessment of the impact on population age structure not only of Wolbachia-based interventions, but also insecticide-based strategies or bio-control such as entomopathogenic fungi.

The establishment of stable greenhouse malaria vector populations viable over multiple generations will provide a tool for monitoring and evaluating the impact of innovative interventions. The mathematical models developed by the project will provide tools for the assessment of effectiveness, and operational planning.

Coordinator:

Steven Sinkins
Oxford
UK.
steven.sinkins@zoo.ox.ac.uk

Partners: