For almost 50 years, flocks of sentinel chickens along the Murray River have formed the front line of defence against mosquito-borne viruses.
- Victoria’s last 175 sentinel chickens have been put out to pasture
- Mosquitos are now being trapped and 0tested directly
- The retired chooks have been rehomed by community members
Between mid-spring and mid-autumn, blood taken from the 20 birds at Robinvale in Victoria’s northwest would be forwarded to a laboratory to be tested for viruses including Ross River fever.
But it was not a quick turnaround.
“We’d take their blood from their wing, almost like a finger prick as you would have for a diabetes test,” Swan Hill Rural City Council’s authorised officer Emma Wright said.
It often took a week or more for scientists to identify whether viruses like Murray Valley encephalitis or West Nile were present in the samples.
Now scientists have found a better way.
Agriculture Victoria microbiologist Peter Mee said results can be known in days by directly testing mosquito samples.
“After we’ve identified what species we have … we run them through a range of extraction techniques and target viral fragments and really amplify those up,” he said.
Ms Wright said because the chickens were accustomed to being picked up – even by the local preschool children – because they were tested so frequently.
“They’ve helped us to feed them and care for them,” she said of the kids.
“And also with the rehoming of our chickens once they’ve done their duty for that year,.”
Three of the most recently retired hens – Chickaletta, Henny Penny and Tude – now spend their days roaming freely in a Robinvale backyard.
Victoria’s health department said there were 808 notifications for Ross River Virus in 2021.
The greatest risk is in rural and regional areas, including many coastal holiday areas.
“With this rain that’s been occurring of recent months, We assume that there is going to be quite a few mosquitoes this season,” Dr Mee said.