Possum images above are Ringtail Possums Pseudocheirus peregrinus.

In April 1995 our friends at Taylor & Francis published an article  in the New Zealand Veterinary Journal Te Hautaka Tākuta Kararehe o Aotearoa entitled A newly discovered disease of the Brushtail Possum: Wobbly Possum Syndrome by C G  Mackintosh, J L Crawford, E G Thompson, B J McLeod, J M Gill and J S O’Keefe.

“We wish to report a new fatal disease of the possum, Trichosurus vulpecula, for which we have coined the name “wobbly possum syndrome”. Clinically it is characterised by progressive ataxia, apparent blindness, raised head carriage and head “bobbing”. Initially the signs are subtle, with vague signs of dullness and slightly raised head carriage, but over a period of 1–6 weeks they progress to an exaggerated rolling gait, dullness, slowed reactions, poor balance, inability to judge distances, difficulty in climbing, apparent blindness and feeding during the daytime. Terminally they become weak, sleep on the ground, are disinterested in their surroundings and become semi-comatose”.

NOTE: The Brushtail Possum was introduced to New Zealand to create a fur trade in the late 1830s. In 2013 New Zealand exported 30,000 Possum skins.

Meanwhile in Tasmania where the disease is also taking hold the Department of Natural Resources and Environment Tasmania has this to say:

“Wobbly Possum Disease (WPD) is a neurological disease affecting brushtail possums in Tasmania. It was first reported in New Zealand in 1995 and the first cases were confirmed in Tasmania in 2019. The disease is known to be caused by an RNA virus. Transmission between possums is likely to occur through close contact. Signs of this virus have only been reported in Brushtail Possums, although antibodies to the virus (indicating exposure to the virus) have been found in other species of possums including Ringtail Possums”.

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Business as usual

“Denials regarding wildlife risks coming from Australian Governments for a range of Australian species look remarkably similar. That is, large scale commercial exploitation on top of large scale killing for mitigation has no impact on a species population and that adding commercial exploitation does not result in an increase of the killing rate, populations are increasing because of human delivered benefits from development, including large scale land clearing, farming and the extensive use of chemicals and poisons. That major climate events, bush fires, floods, droughts and extreme heat have little or no impact. And last, there is no zoonotic disease risk to other animals or humans”. Peter Hylands

There is a low level of concern at a national level for WPD. There is no evidence that it is transmissible to livestock or people, and it is a slow spreading disease among Brushtail Possums. Long-term monitoring of the species has not detected any decreases in population size that is likely to be associated with the virus. Tasmanian Government

Possums on the menu

Possum meat is being served in restaurants in both Australia and New Zealand. In Victoria it would be illegal to use Possums from Victoria so they must be imported from Tasmania? That is a question. 1080 risks aside, zoonotic risks aside, the fact that this is tolerated is yet more to add to the totally unbelievable list.

Trading up

Meanwhile the Tasmania Government and Australian Government come up with a new export plan for Brushtail Possums:

The total export of possum from Tasmania will be set at a maximum of 100,000 animals annually. It is not expected this take will be in addition to the existing cull, rather a diversion from the existing cull to a commercial harvest. Permits are required from both NRE and DCCEEW to export any possum ...

The Australian and Tasmanian Governments have this to say:

"Possum have been commercially harvested and culled under damage mitigation permits for domestic purposes on mainland Tasmania at rates of over 200,000 per year over the past twenty years. These rates of harvest clearly have had no adverse impact on the viability of the Tasmanian possum population which has undergone no long-term decline over this period and particularly so over the past decade

In Tasmania the Brushtail Possum is currently listed as partly protected wildlife under the Wildlife (General) Regulations 2010 of the Nature Conservation Act 2002. As such, they may be taken only under the authority of a permit or licence issued for commercial use, crop protection or other approved purposes.

Annual quotas were applied in Tasmania for the number of individual Brushtail Possums allowed to enter the commercial trade from 1983. The state-wide quota remained constant at 250,000 animals a year, until the expiry of an earlier management plan in 2004. The estimated commercial possum harvest reached this quota on only one occasion in 1987. In 1995, the quota remained at 250,000 but was expanded to also include all possums taken under commercial or crop protection permits (including 1080 poisoning). The total reported take approached this figure only once in 1997-98, however, not all holders of crop protection permits submit a return and the estimated crop protection take (based on percentage of permit returns) exceeded the quota on five occasions.

For the 10 years from 1998-99 to 2007-08, estimated take under crop protection permits in Tasmania has averaged 274,000 possums per year (average permit return rate 66 per cent). 1080 poison baits have been used widely in Tasmania since the 1960’s to control damage to crops by browsing animals including wallabies and brushtail possums. Since 2000, the amount of 1080 used for browsing animal control has declined substantially in line with Tasmanian Government policy to substantially reduce the use of 1080 poison for native browsing animal control".

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Back to Possum Wobbly Disease

From the National Library of Medicine: Serological evidence for the presence of wobbly possum disease virus in Australia:

Wobbly possum disease virus (WPDV) is an arterivirus that was originally identified in common brushtail possums (Trichosurus vulpecula) in New Zealand, where it causes severe neurological disease. In this study, serum samples (n = 188) from Australian Brushtail, Mountain Brushtail (Trichosurus cunninghami) and Ringtail (Pseudocheirus peregrinus) Possums were tested for antibodies to WPDV using ELISA. Antibodies to WPDV were detected in possums from all three species that were sampled in the states of Victoria and South Australia….. Further research is needed to characterise the virus in Australian possums and to determine its impact on the ecology of Australian marsupials.

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Status of Australia’s Possum species

Possums (super family Phalangeroidea) comprise the Brushtail Possums, the Ringtail Possums and the Pygmy Possums. Gliding Possums are related to Ringtail Possums. The Honey Possum is a distinct species in its own super family Tarsipedoidea.

The Australian Possums are:

• Ringtail Possum Pseudocheirus peregrinus;
• Herbert River Ringtail Possum Pseudocheirus herbertensis;
• Green Ringtail Possum Pseudocheirus archeri;
• Rock Ringtail Possum Pseudocheirus dahlia;
• Western Ringtail Possum Pseudocheirus occidentalis;
• Greater Glider Petauroides volans;
• Yellow-bellied Glider Petaurus australis;
• Sugar Glider Petaurus breviceps;
• Squirrel Glider Petaurus norfolcensis;
• Mahogany Glider Petaurus gracilis;
• Leadbeater’s Possum Gymnobelideus leadbeateri;
• Stripped Possum Dactylopsila trivirgata;
• Coppery Brushtail Possum Trichosurus johnstonii;
• Brushtail Possum Trichosurus vulpecula;
• Northern Brushtail Possum Trichosurus arnhemensis;
• Mountain Brushtail Possum Trichosurus caninus;
• Scaly-tailed Possum Wyulda squamicaudata;
• Spotted Cuscus Phalanger maculatus;
• Grey Cuscus Phalanger orientalis;
• Eastern Pygmy Possum Cercartetus nanus;
• Western Pygmy Possum Cercartetus concinnus;
• Little Pygmy Possum Cercartetus lepidus;
• Long-tailed Pygmy Possum Cercartetus caudatus;
• Mountain Pygmy Possum Burramys parvus;
• Feathertail Glider Acrobates pygmaeus; and
• Lemuroid Ringtail Possum Hemibelideus lemuroides Near threatened listing (Queensland listing - of least concern in 2017) but White Lemuroids are in deep trouble, particularly climate change related.

• Honey Possum Tarsipes rostratus.

The species in bold are of the greatest concern, but even the Brushtail Possum has suffered a significant contraction in range since European settlement.

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Footnote

Given that Australian Government’s have not given this matter the attention it deserves we should recognise that any claims that Possum species have a negative impact on agricultural production in Australia or anything else needs a great deal more work (beyond the hype). Marsupial Possums are yet another very Australian family of animals not much admired and over-exploited for mitigation, recreation and commercial gain. There is no doubt that populations are declining and the most populous species are suffering the most. Even the endangered species get short shrift when it comes to the duty of care towards the environments in which they live. We should be wary that those engaged in the exploitation of native Australian animals will be supported by State and Federal Government environment departments and the ‘science’ that always supports their claims.

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