Research shows stressed-out birds more attractive to mosquitoes, raising fears birds exposed to stressors such as road noise, pesticides and light pollution, will be bitten more often and spread more West Nile virus
Date: August 10, 2016
Source: University of South Florida (USF Innovation)
When researchers from the University of South Florida (USF) and colleagues investigated how the stress hormone, corticosterone, affects how birds cope with West Nile virus, they found that birds with higher levels of stress hormone were twice as likely to be bitten by mosquitoes that transmit the virus. Their studies have implications for the transmission of other viruses such as Eastern Equine Encephalitis, and perhaps even Zika, both known to be carried by the kind of mosquitoes used in this study.
A paper describing their research was published in the Proceedings of the Royal Society B.
"Few studies have considered how stress hormone effects on individuals might influence population dynamics," said study lead author Dr. Stephanie Gervasi, who conducted the studies while carrying out her postdoctoral work at USF and is now at the Monell Chemical Senses Center in Philadelphia. "For vector-borne diseases such as West Nile virus, the presence of corticosterone could influence pathogen spread through effects on contact rates with the mosquitoes that transmit it. In addition, stress hormones have negative effects on animals including immunosuppression and increased susceptibility to infections, which is why we are now also studying how corticosterone affects the birds' immune response to the virus."
According to the researchers, mosquitoes use a variety of cues to locate a target, including carbon dioxide output, body size and temperature. They hypothesized that these signals coming from a bird could convey information about stress hormones making the birds more appealing targets for the insects.