'Exciting' new odour sensors found in malaria mosquitoes
[SANTIAGO] An array of new mosquito repellents and lures may be possible following the discovery by researchers of a new set of sensors that the principal species of malaria-carrying mosquito uses to sniff out its targets.
Until now, research has focused on a family of odour receptors found in the antennae and other head appendages of Anopheles gambiae, the main carrier of the malaria parasite.
Work by researchers at Vanderbilt University in the United States, published in PLoS Biology last month (August), confirmed that this set of receptors is sensitive to DEET, the most commonly used repellent, and to a large number of other scents.
These receptors do not detect other important odours released by people, such as ammonia, butylamine and lactic acid. The researchers discovered a new set of receptors can detect these smells. Mike Lehane, head of the vector group at Liverpool School of Tropical Medicine in the United Kingdom, described the research as "highly skilful and exciting".
Fredros Okumu, a researcher at the Ifakara Health Institute, Tanzania, and the London School of Hygiene and Tropical Medicine, said the findings "open up even greater possibilities to screen for more compounds that could be used to compose blends of synthetic human odours that are super-attractive to human-biting mosquitoes".
The next step is to develop substances that these new receptors — known as ionotropic receptors — will respond to.
Laurence Zwiebel, senior author of the study, told SciDev.Net his team is already working on novel compounds that can both attract and repel mosquitoes. "We expect to bring these tools online in the next five to ten years," he said.
These substances could be used to lure mosquitoes to traps. Traps are being investigated to clear tsetse flies that transmit sleeping sickness and are in use to control biting mosquitoes around salt marshes in the United States.
"An efficient push-pull approach – repelling and attracting/trapping – to malaria vector control would be particularly useful in countries where mosquitoes bite outside the home, as in parts of Asia," Lehane told SciDev.Net.
"Given the good results of indoor methods for malaria control such as insecticidal nets and spraying, traps fitted with synthetic odours should especially target outdoor transmission," Okumu agreed.
"Once we have enticing lures we will need to find the best places to locate the traps and, perhaps more importantly, ensure that they at least match the cost of existing interventions," he said.