Blinded by a mysterious virus, a kangaroo stumbled over brush, bounced off a tree trunk, and finally fell into a thicket as it tried to escape the footsteps of an approaching ranger.
The kangaroo’s misery ended moments later with a shot.
At least a tenth of the 500,000 western gray kangaroos in South Australia and the 2.8 million gray kangaroos in neighboring New South Wales have gone blind this year, officials say.
In this lush bushland along the Murray River, about 120 miles northeast of Adelaide near the New South Wales border, up to a third of the animals have been stricken.
Ranchers and farmers around the remote New South Wales mining town of Broken Hill were the first to notice the odd behavior of some kangaroos in March 1994.
The affliction spread quickly to the north and the south, and a virus became the key suspect.
‘It wasn’t until early this year that we started to panic,” said Tim Fraser, a ranger with South Australia’s Department for Environment and Natural Resources.
A severe drought this year is believed to have physically stressed the kangaroos, and perhaps has crowded them near remaining water holes and streams, speeding the spread of the disease.
Red and European kangaroos as well as wallabies also have been afflicted, but to a much lesser extent than the gray kangaroos.
So far, the disease does not threaten the plentiful kangaroo population, but wildlife officials worry that it may spread to endangered marsupials, like the yellow-footed rock wallaby. Only a few hundred of them are believed still alive.
Bill Hartley, a pathologist at the Taronga Park Zoo in Sydney, examined the carcasses of kangaroos found around Broken Hill back in 1994.
He found no sign of poisoning. Rather, the animals had severe inflammation and lesions on their retinas and optic nerves, and sometimes in their brain. Under the microscope, the retina looks like it is dissolving.
But there was no pus, a telltale sign of bacteria. That seemed to point toward a virus.
“As it spread so rapidly over a couple of months, we are of the opinion that the only possible way it could have spread was by insects,” Hartley said. Peter Durham, a veterinary virologist with the Department of Agriculture Laboratories in Adelaide, said the disease appears to be from the Bunya family of more than 80 viruses that afflict marsupials.
That finding won’t be confirmed until Durham can test the cultivated virus on kangaroos. Then, perhaps a vaccine could be developed to protect endangered marsupial species.
“It’ll take months to sort this out,” Durham said.
Anecdotal evidence suggests there may have been undiagnosed outbreaks of the disease in the 1930s and 1950s.
Meanwhile, there’s little that can be done to relieve the stricken animals.
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