ETHIOPIA - For the first time, scientists have shown that malaria-transmitting mosquitoes actively avoid feeding on certain animal species such as chickens, using their sense of smell.
Odours emitted by species such as chickens could provide protection for humans at risk of mosquito-transmitted diseases, according to a study in the open access Malaria Journal.
Researchers at the Swedish University of Agricultural Sciences and Addis Ababa University, Ethiopia found that Anopheles arabiensis mosquitoes, one of the predominant species transmitting malaria in sub-Saharan Africa, avoids chickens when looking for hosts to feed on.
Rickard Ignell, the corresponding author, said: “We were surprised to find that malaria mosquitoes are repelled by the odours emitted by chickens. This study shows for the first time that malaria mosquitoes actively avoid feeding on certain animal species, and that this behaviour is regulated through odour cues.”
Using blood taken from mosquitoes, the researchers found that while An. arabiensis strongly prefers human over animal blood when seeking hosts indoors, it randomly feeds on cattle, goats and sheep when outdoors, but avoids chickens in both settings, despite their relatively high abundance.
Identifying certain compounds that were only present in chicken feathers, the researchers used these and other compounds obtained from all species to test their ability to repel mosquitoes from mosquito traps.
The researchers found that significantly fewer mosquitoes were caught in traps baited with chicken compounds than in control traps. Suspending a living chicken in a cage next to a trap had a similar repellent effect, suggesting chicken odours could prove useful in controlling this type of mosquito.
Rickard Ignell said: “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 odour compounds which could repel host-seeking malaria mosquitoes and prevent them from getting in contact with people.”ThePoultrySite News Desk