Flying fox dispersal not linked to virus

FLYING foxes whose roosts have been disrupted are not more likely to develop the Hendra virus, according to researchers who studied colonies in Queensland and New South Wales.

Biosecurity Queensland's principal scientist Dr Hume Field said the 12-month research project assessed the impact of colony dispersal on stress and Hendra virus infection levels in affected flying foxes.

"A key finding of the project found there was no association between the disturbance to a colony from dispersal and an increase in the excretion of Hendra virus," Dr Field said.

"Researchers measured the stress hormones and virus levels in flying foxes by collecting and testing urine before, during and after the dispersal of a colony.

"Of the 13 colonies monitored, (10 in Queensland, and three in New South Wales), 10 were dispersed or disturbed as a result of the submission of a Damage Mitigation Permit."

In Queensland, colony dispersal may only occur after a comprehensive assessment is completed by the Department of Environment and Heritage Protection and under a Damage Mitigation Permit.

Dr Field said the study provided scientific evidence that disturbed colonies typically had measurable, short-lived stress of a similar level to that seen with natural stress events such as mating.

"Research also highlighted that Hendra virus excretion was much less in little red flying foxes and in grey-headed flying foxes," Dr Field said.

"The level of Hendra virus excretion was found to be higher in black and spectacled flying-foxes, suggesting these species may be a more important source of infection for horses than the little red or grey-headed flying foxes."

Dr Field said Queensland Centre for Emerging Infectious Diseases was commissioned by the National Hendra Virus Research Program to investigate any association between colony dispersal, stress and Hendra virus excretion. The National Hendra Virus Research Program is funded by the Commonwealth, New South Wales and Queensland governments.

"Studies will continue to clarify the role of flying fox species, the role of environmental factors, and the role of horse behaviour in the transmission of Hendra virus from flying foxes to horses," Dr Field said.