Bat behaviour sparks Hendra virus risk

Human activities are causing bats to adopt new behaviours and increasing the risk of Hendra virus spillover, a study has shown.

The study based on 25 years of land use data, shows encroachment into bat habitats has forced the nocturnal animals to move elsewhere.

Researchers from University of New South Wales and Griffith University say habitat destruction and climate change is driving bats into agricultural areas, thus increasing their contact with horses.

The major challenge now, they say, is ascertaining what causes pathogens to spill over from wildlife into human populations thereby generating a pandemic threat.

Dr Peggy Eby from UNSW said previous studies had associated spillover with human encroachment into natural landscapes, increasing the likelihood of contact between wildlife, domestic animals and ultimately, people.

"However, what's missing is the detail needed to predict periods when spillover risk is high."

Dr Eby said flying foxes have responded to land-use change by displaying different behaviours they would normally use to avoid climate-driven starvation associated with El Nino events.

These include feeding on introduced plants in horse paddocks which was causing them to shift into agricultural areas that did not provide native food over winter.

Dr Eby said flying foxes play a critical ecosystem role in pollinating native trees and large winter flowering events have a protective effect on the risk of spillover.

Extensive clearing of forests that flower in winter has led to a reduction in the number of years when abundant flowering occurs, reducing the reliability of this natural source of protection and increasing the risk of disease spread.

"Identifying the protective effect of mass winter flowering events offers hope - by replacing critical habitat that has been destroyed we can ensure that abundant winter flowering occurs more reliably," she said.

"We propose that restoration of this critical habitat will restore functioning ecosystems, improve the health of flying foxes, reduce their reliance on urban and agricultural areas, and protect horses and people against spillover of Hendra and other viruses."