09/02/2017 2:09 PM AEDT | Updated 09/02/2017 3:17 PM AEDT

Long-Forgotten Virus Outbreak Kills More Than 50 Cats In Sydney

Make sure your kitty is vaccinated.

Andrew Wood
Cats are being infected with a long-forgotten virus.

More than 50 cats are dead as a long-forgotten virus sweeps across western Sydney.

The deadly virus, called feline panleukopenia, was thought to have been nearly eradicated with the advent of a vaccination in the 1970s, but four stray kittens were brought into Haberfield Veterinary clinic with the condition two weeks ago.

Owner Dr Tanya Stephens told the University of Sydney she had not diagnosed a case for 40 years.

In three animal shelters, meanwhile, the virus swept through, killing 50 cats and forcing Blacktown City Council to close its Animal Holding Facility to cats and placing a hold on adoptions and cat rescues until the outbreak was under control.

"This is a highly contagious, life-threating viral disease for the cat population," Blacktown Mayor Stephen Bali said.

University of Sydney Professor Vanessa Barrs said many of the infected cats were kittens that were too young to be vaccinated.

"The numbers are probably approaching closer to 100 cats by now," she told The Huffington Post Australia.

"Because it hasn't been around for 30 or 40 years in Sydney, I think the perceived risk for shelters was considered to be quite low, but it shows all cats entering the shelter need mandatory vaccination."

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All cats should be vaccinated.

"There were small outbreaks in Melbourne and Mildura in 2015 so it has been a little bit of a ticking time bomb since.

"It just shows the virus was not eradicated in the 70s and vaccination is the only way to stop the epidemic."

What is feline panleukopenia?

The symptoms are fever, lethargy and loss of appetite, followed by vomiting and diarrhoea.

In severe infections cats can die suddenly with no signs.

It was first discovered more than 100 years ago but vaccinations meant the disease virtually disappeared from Australia in the mid 1970s.

There is no risk for humans as the disease cannot be passed on to them.

Source: The University of Sydney

"The current outbreak is a timely reminder that maintaining immunity in populations of animals where effective vaccines are available is essential."