Why mosquitos like to bite humans

Scientists at the University of California, Davis, have discovered why mosquitoes like to feast on the blood of humans.

They have identified a dominant odour naturally produced in humans and birds that attract the blood-feeding Culex mosquitoes, which transmits West Nile virus and other life-threatening diseases.

The groundbreaking research explains why mosquitoes shifted hosts from birds to humans and paves the way for key developments in mosquito and disease control.

Entomology professor Walter Leal and postdoctoral researcher Zain Syed, of the UC Davis Department of Entomology, found that nonanal (pronounced "no-nan-al") found in human blood is the powerful semiochemical that triggers the mosquitoes' keen sense of smell, directing them toward a blood meal. A semiochemical is a chemical substance or mixture that carries a message.

"Nonanal is how they find us. The antennae of the Culex quinquefasciatus are highly developed to detect even extremely low concentrations of nonanal," Leal said.