Scientists have shown that malaria -transmitting mosquitoes actively avoid feeding on certain animal species such as chickens, using their sense of smell. Odors emitted by species such as chickens could provide protection for humans at risk of mosquito-transmitted diseases, according to a study conducted in Ethiopia.
Testing the blood in mosquitoes that had recently fed, researchers from Sweden and Ethiopia, found just one out of nearly 1,200 had bitten a chicken with people and cattle seeming to bear the brunt of the insects’ attentions.
“We were surprised to find that malaria mosquitoes are repelled by the odors emitted by chickens,” Rickard Ignell, study author, said in a press release.
In the study, which was published in the open-access Malaria Journal, the researchers tested their theory on three Ethiopian villages where people often share their living quarters with their livestock. They also collected blood-fed mosquitoes to trace the blood source.
In each of the houses, the researchers asked a single volunteer aged between 27 and 36 to sleep under an untreated bed net. Traps were set up in the room to get a count of the mosquitoes that flew in. The experiment lasted for 11 days.
The researchers found that significantly fewer mosquitoes were caught in traps baited with chicken odors taken from their feathers compared with traps containing compounds from other host animals.
Moreover, the researchers found that suspending a live chicken in a cage next to a trap had a similar repellant effect.
Professor Ignell said: “People in sub-Saharan Africa have suffered considerably under the burden of malaria over an extended period of time and mosquitoes are becoming increasingly physiologically resistant to pesticides, while also changing their feeding habits for example by moving from indoors to outdoors.
“For this reason, there is a need to develop novel control methods. In our study, we have been able to identify a number of natural odor compounds which could repel host-seeking malaria mosquitoes and prevent them from getting in contact with people.”