Wobbly possum disease is on the rise, and experts aren't sure why

The disease was first identified in a New Zealand research facility in 1995, but little is known about its impact on Tasmanian possums and marsupials.

While its name may suggest a cute sight, it's anything but.

According to Wildlife Health Australia, the neurological disease causes a host of problems for the possums, including blindness, "aimless wandering," stumbling, tremors and loss of various motor functions.

There are no known treatment options, and the disease is usually fatal in brushtail possums.

Ahead of a $3.5 million funding boost for research projects at the University of Tasmania, one team of scientist is investigating the disease.

Andrew Flies, a researcher from the Menzies Institute for Medical Research said the virus had likely existed in Australian marsupials for hundreds or thousands of years.

"It wasn't discovered until some possums in captivity in New Zealand started getting sick, and possums aren't native to New Zealand," Dr Flies said.

"So it's very likely that when the possum came over from Tasmania, they brought the virus with them."

He said the disease was caused by an RNA virus, with similar ones present in New Zealand, Tasmania and the mainland.

"It seems to have evolved pretty quickly since it got to to New Zealand, so that is a pretty big difference in the sequence of it and these RNA viruses are known for mutating rapidly," he said.

"It's mostly just the brushtail possum that we know about but there was a study done by the University of Melbourne a couple of years ago, and they found that there were antibodies for the virus and some other species in ringtail possums.

"So there's potential for it to infect other species, but we don't know if it causes disease in those other species or not."

Bonorong Wildlife Sanctuary are often on the front lines of wildlife emergencies in Tasmania, but Wobbly possum disease has proven difficult to diagnose, according to chief operations officer Suzy Nethercott-Watson.

She said the symptoms possums present in Wobbly possum disease are similar to that of a head trauma.

"Part of the problem with this disease is confirmation," Ms Watson said.

"It's currently not done quickly, it has to either be through euthanasia through brain tissue samples, or through a blood test that's sent off."

"It's actually really hard to confirm the sorts of numbers that we're seeing, but we're definitely seeing it at the moment."

Ms Watson said it was important to focus on Wobbly possum disease as an emerging disease, as there was no cure.

"We've seen a greater number since about 2019 in brushtail possums," she said.

"It's really important firstly, as an emerging disease, what it might mean and secondly in terms of treatment and protocol.

"Because it's a virus, we would treat an animal differently once we knew it was the case, because we'd obviously have much stricter quarantine protocols."

According to Dr Flies, the most solid research into the disease had been conducted by Massey University in New Zealand.

Researchers conducted transmission studies by inoculating one possum with the virus, and putting it in an enclosure with other possums.

"They found that all of the possums in that enclosure would end up with the virus and the disease," Dr Flies said.

"Whereas if they had a possum with the disease in one enclosure, and then another possum in a separate enclosure but very nearby, that possum in the other enclosure wouldn't get the disease.

"That suggests it's not respiratory or airborne...there needs to be some form of physical contact, either direct contact or through body secretion or excretion such as faeces or urine."

Dr Flies was part of a team that received $500,000 in funding to research a "toolbox" that would help to understand disease in marsupials, and how their immune system responds in a way that hasn't been possible before.

"That'll allow us to tell here in Tassie how many possums are being exposed to the virus, and then also to start drilling down into how their immune system is responding," he said.

As to why cases are increasing, Dr Flies said there was a lack of information that leaves a gap in the figures.

"It is possible that it's just being reported more and not actually increasing, there's not great data on it, but there are reports I think in mainland Australia going back even to the 1970s of possums that are are wobbling like this," he said.

"We just don't really know yet so our new grant will help us figure those kinds of things out."

The project is expected to get off the ground mid-next year.