An international team of scientists will in the coming five years set up aresearch project on developing diversions to mislead malaria mosquitoes withodours. With these the number of cases of malaria in tropical Africa may bereduced strongly. Scientists at Wageningen University will be working withcolleagues in the USA, Tanzania and Gambia on a project led by Vanderbilt researchersthat has received $8.5 million dollars (approximately 7 million Euro) fromthe U.S. Foundation for the National Institutes of Health and the Bill andMelinda Gates Foundation as part of their Grand Challenges in Global HealthInitiative.
In the team are scientists from Vanderbilt University, Yale University andWageningen University who will be co-operating with researchers from the IfakaraHealth Research and Development Centre in Tanzania and the Medical ResearchCouncil Laboratories in Gambia (Africa). They aim at reducing the populationof malaria transferring mosquitoes by setting up odour traps and effectiverepellents that keep malaria mosquitoes away from potential human hosts. Inthis fashion, they hope that the risk of malaria transfer may be reduced substantially.
To find a proper host (the human being) female malaria mosquitoes head forthe odours they intercept with their antennas. After they recognise the host’sodour, they suck up blood that hey need for egg production. As the mosquitois drawing blood, parasites from the mosquito enter the human body. A smallpercentage of malaria mosquitoes are infected by the Plasmodium parasite. Theseparasites (Plasmodium spp.) are responsible for the malaria disease. When aninfected person, after an incubation period of ten to fourteen days, is bittenagain by a mosquito, the malaria parasite is transmitted to the mosquito andso is spread more widely throughout the mosquito population. The change forother people of being infected will increase. The number of malaria cases isworld-wide between 300 and 660 million per year and is the most important life-threateningdisease in the world, causing more than a million fatal victims pro year.
Odour insect trap
The malaria mosquito Anophels gambiae heads for a complex of odours to finda host. The research team of Vanderbuilt University (Nashville, Tennessee)and Yale University (New Haven, Connecticut) in the USA will develop odourmaterial for which the mosquito antennas are very sensitive. This team willidentify and test either attractive or repellent odour materials or materialscausing confusion. After that the Wageningen University team will look atthe effect of the interesting odour materials from the American researchon mosquito behaviour. The materials (substances) giving the strongest reaction(attracting, repelling or causing confusion) will then be tested in a simulatednatural situation in Ifakara, Tanzania. The ideal blend of odours will findits way to African villages for full-scale, practical tests as part of theproject. The villages are located in the Gambia and Tanzania and are situatedin different geographical extremes with different mosquito populations. Theresults of the research project should therefore be applicable for much oftropical Africa. If the experiments are successful African households willhave an added degree of protection provided by strong new repellents or odorantsthat confuse the mosquito’s sense of smell, causing less mosquito biting,while outside the villages insect traps are baited with attractive odorantsthat the insects can’t ignore. The ultimate goal is to reduce malariatransmission by the use of odorant devices.
The eventual products can be deployed against other pathogenic mosquitoes,such as the mosquito Aedes aegypti spreading dengue fever and against Culexpipiens, carrier of the West-Nile virus.
Earlier this month news spread about a new biological approach for fightingmalaria mosquitoes developed by the entomology team of Wageningen University.Its research identified a fungus that seriously weakens or kills the mosquitoesbefore they can infect people with malaria parasites. This illustrates thefact that the Wageningen team is working on several methods of fighting themalaria mosquito that could be combined to form an integrated strategy forfighting this deadly disease.
NOTE FOR THE EDITOR
For more infomation please contact Willem Takken, Wageningen University, tel. +31 317 484652 or +31 610 534 463, or Bart Knols, tel +43 1 2600 28246 . You can also contact Bouke de Vos, Press Officer, Wageningen University, tel. +31 317 480 180.
For more information on the American part of the project please contact David Salisbury (Vanderbilt University), tel. +1 615 343 6803, or Janet Emmanuel (Yale University) +1 203 432 1333.