Zebra finches (C) University of South Florida/USF Health

Stress hormones could represent an important link between individuallevel infection outcome, population-level parasite transmission and zoonotic disease risk. Although much work has been conducted on how stress affects an individual’s immunity, we know relatively little about how stress can affect host-vector interactions.

In this study, Gervasi et al. examined a host-vector system made up of Culex mosquitoes (which transmit the West Nile virus) and a common host species, the songbird Taeniopygia guttata or zebra finch. They manipulated the birds’ stress levels to assess what effect this had on the mosquitoes’ feeding behaviour.

Birds with higher corticosterone levels were twice as likely to be fed on by the mosquitoes compared to controls, despite these birds showing more defensive behaviours to avoid being bitten. These mosquitoes subsequently went on to lay different clutch sizes at different rates compared to mosquitoes that only fed on control birds.

Although the biological mechanisms through which these findings are mediated are unclear, it provides us with an intriguing insight into how host stress can affect the transmission dynamics via multiple pathways.

Read the full article in Proceedings of the Royal Society B 2016 doi:10.1098/rspb.2016.1278