There are numerous old wives tales for staving off disease: wearing amber beads to prevent common colds and keeping dried frog with you to avert epilepsy are just two unscientific pieces of advice. However, occasionally what sounds ludicrous can help save lives. New research has shown that sleeping with a chicken in your room could protect you against contracting mosquito-transmitted diseases, such as malaria.
Published in Malaria Journal, the research conducted by teams at the Swedish University of Agricultural Sciences and Addis Ababa University found that the mosquito species and malaria vector, Anopheles arabiensis, uses smell to actively avoid feeding on chickens.
“We were surprised to find that malaria mosquitoes are repelled by the odours emitted by chickens,” says corresponding author Rickard Ignell. “This study shows for the first time that malaria mosquitoes actively avoid feeding on certain animal species.”
To determine the mosquitoes’ favourite blood source the team amassed data on human and domestic animals in three Ethiopian villages, where all shared the same living quarters. They also collected blood-fed mosquitoes to source which species were being chosen as a tasty snack. In a competition that no-one wants to win, they found that when indoors the mosquitoes prefer human blood and when outdoors they randomly feed on sheep, goats and cattle. In both settings they actively avoid chickens, despite their high abundance.
As mosquitoes hone in on their hosts mainly through smell, chicken feather and other livestock odour compounds were identified, isolated and incorporated into traps. They set these up in 11 houses where a single human volunteer slept under an untreated bed net. Significantly fewer of the blood-suckers were caught in chicken-baited traps than in the controls, confirming the importance of odour.
Goodnight peck on the cheek
Looking forward, chickens may prove to be a useful and cheap mosquito repellent used in conjunction with established control methods, especially as A. arabiensis populations are notoriously difficult to control.
“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,” exclaims Ingall. “In our study, we have been able to identify a number of natural odour compounds which could repel host-seeking malaria mosquitoes.”
While sharing a room with Henrietta or Chicken Little may ruffle a few feathers, the odour associated with the fowls could certainly get mosquitoes to lay-off pecking at your skin.
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