Why Disease and Biosecurity Matter for Tasmania’s Wildlife

Tasmania’s island geography provides some protection from pests and diseases found elsewhere, but it does not make the state immune from wildlife disease. Some diseases are already established here, while others can arrive or emerge through the movement of animals, people, equipment, water, soil and other pathways. Once a pathogen reaches a wild population or natural environment, controlling its spread can be extremely difficult.

The consequences can extend far beyond an individual sick animal. Disease can contribute to population declines, place additional pressure on threatened species and change the ecosystems on which wildlife depends. The arrival of highly pathogenic H5 avian influenza in Australia in 2026 provided a recent reminder that new wildlife diseases can emerge quickly, while Tasmania continues to manage diseases that have been present for decades.

Biosecurity is therefore about more than what crosses Tasmania’s border. It includes reducing the risk of diseases reaching new places, recognising unusual illness or mortality when it occurs, and understanding how established diseases are affecting wildlife populations. For an island with many species found nowhere else, keeping diseases and pathogens out of unaffected populations and habitats can be just as important as responding to them after they appear.

Devil Facial Tumour Disease (DFTD)

Few wildlife diseases have had as profound an impact in Tasmania as Devil Facial Tumour Disease. First observed in north eastern Tasmania in 1996, DFTD is an unusual form of cancer that spreads between Tasmanian devils through the transfer of living tumour cells. Biting during mating and fighting provides an important pathway for transmission, allowing the disease to spread through wild devil populations.

Tumours generally develop around the face, mouth and neck and can grow large enough to interfere with feeding. Once visible disease develops, affected devils usually die within several months. In populations where DFTD has been present for many years, devil numbers have declined by up to around 80 per cent, dramatically changing the age structure of some populations and contributing to the Tasmanian devil being listed as endangered.

There are now two known transmissible cancers affecting Tasmanian devils. DFT1 is the original disease first recorded in 1996 and has spread widely across Tasmania. DFT2 is a genetically distinct cancer, first detected in 2014, that remains much more restricted in its distribution. Remarkably, the two cancers arose independently rather than DFT2 developing from the original disease.

Despite the scale of the decline, Tasmanian devils have persisted in areas where DFTD has been present for decades. The Save the Tasmanian Devil Program continues to monitor wild populations, maintain a genetically diverse insurance population and support research into the disease and the long term future of devils in the wild.

H5 Avian Influenza

Australia recorded its first detection of highly pathogenic H5N1 avian influenza clade 2.3.4.4b in June 2026, after years of preparation for its expected arrival. The globally circulating strain was first confirmed in a brown skua found near Esperance in Western Australia and was subsequently detected in wildlife across several states. Tasmania recorded its first confirmed case in August 2026, in a brown skua found at Rocky Cape National Park.

H5N1 primarily affects birds, but it can also infect mammals. Australian detections have included marine and terrestrial mammals as well as a growing range of wild bird species. Overseas, the virus has caused large mortality events in some wildlife populations, particularly where seabirds, waterbirds and marine mammals gather in large numbers.

In Tasmania, H5N1 has since been detected in multiple bird species and in different parts of the state. Its presence creates a very different challenge from a disease such as DFTD: migratory wildlife can carry the virus across vast distances and international borders, making it impossible to manage through Tasmania’s border controls alone. Surveillance of sick and dead wildlife is now an important part of understanding where the virus is occurring and how it is affecting native species.

There have been no detections in Tasmanian poultry. For wildlife, however, H5N1 is now part of an evolving national outbreak, and its longer term consequences for Australian species are still being understood.

Toxoplasmosis

Toxoplasmosis is caused by the microscopic parasite Toxoplasma gondii and can affect a wide range of warm blooded animals. Cats play a unique role in its life cycle because they are the only hosts in which the parasite can reproduce sexually. Infected cats can shed microscopic oocysts in their faeces, contaminating soil, water and vegetation where the parasite may later be encountered by wildlife.

Australian marsupials can be particularly susceptible to toxoplasmosis. Infection can cause neurological problems, loss of coordination, blindness, respiratory illness and other serious disease, although its effects vary between species and individual animals. Wallabies, pademelons and bandicoots are among the native mammals that can be affected. Importantly, they do not need to come into direct contact with a cat to become infected, as Toxoplasma oocysts can persist in the environment and spread through contaminated soil and water.

Reducing this risk is one of the reasons responsible cat management matters for wildlife beyond preventing predation. Keeping pet cats contained limits their interaction with wildlife and the wider environment, while appropriate disposal of cat waste can reduce opportunities for contamination. Managing feral cats is also part of addressing the broader impacts introduced cats have on Tasmania’s native wildlife.

Sarcoptic Mange in Wombats

Sarcoptic mange can affect many mammal species, but wombats are particularly susceptible to severe disease. It is caused by the parasitic mite Sarcoptes scabiei, which burrows into the skin and causes intense irritation. Infected wombats can develop persistent scratching, hair loss, thickened and crusted skin, open wounds and declining body condition. Severe infections can eventually lead to death, often following secondary infection and deterioration in the animal’s overall health.

Mange has been present in Tasmania for more than a century and occurs across much of the state. In most wombat populations the proportion of visibly affected animals is relatively low, but localised outbreaks can be devastating. At Narawntapu National Park, University of Tasmania monitoring recorded a 94 per cent decline in the wombat population between 2010 and 2016 during a severe outbreak of sarcoptic mange.

Wombat burrows appear to be one reason the disease can have such a significant impact on the species. Although wombats are largely solitary, the same burrows may be used by different animals at different times. The cool, humid conditions inside a burrow can allow mange mites to survive away from a host, creating opportunities for another wombat using the burrow to become infected. Researchers are still investigating why severe outbreaks develop in some locations while mange remains at much lower levels elsewhere.

Individual wombats can be treated, but controlling mange across wild populations is considerably more difficult. Treatment of wild wombats in Tasmania requires appropriate methods and permits, and other skin conditions can sometimes resemble mange. Anyone who suspects a wombat is affected should seek advice from NRE Tasmania before attempting treatment.

Other Diseases Affecting Tasmania’s Wildlife

Platypus mucormycosis is a fungal disease caused by Mucor amphibiorum that has only been recorded in wild platypuses in Tasmania. Affected animals can develop ulcerated skin lesions on the body, limbs and tail, while severe infections can interfere with their ability to maintain body temperature and forage effectively. The disease was first observed in Tasmania in 1982, but much about it remains uncertain, including how it spreads and what impact it has on platypus populations over time.

Tasmania’s frogs face a very different fungal threat. Chytridiomycosis, caused by Batrachochytrium dendrobatidis, infects the skin of amphibians and has contributed to serious population declines and extinctions around the world. The fungus is established in parts of Tasmania, while some remote areas remain free of it. Because it can be moved in contaminated water and mud, people can inadvertently carry it between wetlands on footwear, equipment and vehicle tyres.

Psittacine Beak and Feather Disease, or PBFD, affects parrots and related birds. The viral disease can cause abnormal feather development, feather loss, beak abnormalities and suppression of the immune system, with young birds particularly vulnerable to severe infection. The virus can also persist in contaminated nesting material and nest hollows, providing another pathway for transmission.

For Tasmania, PBFD is particularly relevant because both orange-bellied parrots and swift parrots are susceptible. The disease is recognised nationally as a key threatening process affecting endangered psittacine species and is an identified threat to the critically endangered orange-bellied parrot, which breeds in south-west Tasmania. For species already under pressure from habitat loss, predation and small population size, disease can further complicate their recovery.

Plant Diseases and the Wider Ecosystem

Disease and biosecurity threats are not limited to animals. Plant pathogens can alter entire habitats, changing the vegetation that wildlife relies on for food, shelter and breeding. In Tasmania, one of the most significant is Phytophthora cinnamomi, an introduced soil borne pathogen that causes dieback in susceptible native vegetation.

Phytophthora attacks the roots of susceptible plants and can cause extensive plant death. In Tasmania it poses a particular threat to heathlands, moorlands, dry sclerophyll forests and scrub, where infection can change the composition and structure of native vegetation. More than 180 Tasmanian plant species have been recorded as hosts, including dozens of threatened species.

Once Phytophthora becomes established in an area it cannot currently be eradicated. It can spread naturally through water and soil, but people can carry it much greater distances in mud on boots, vehicles, tools and equipment. Walking tracks, roads and other disturbed areas can therefore become pathways into previously uninfected habitat, including remote natural areas.

Myrtle rust presents a different biosecurity challenge. Caused by the fungus Austropuccinia psidii, it affects plants in the Myrtaceae family and has been detected in Tasmania since 2015. Confirmed infections in the state have so far been restricted to introduced or cultivated plants, with the disease not detected in Tasmania’s native bushland. Keeping new strains out of Tasmania and detecting any spread into native vegetation remain important parts of the state’s response.

The effects of plant disease can reach well beyond the infected plants. Changes to the abundance or distribution of native vegetation can alter food sources, shelter and breeding habitat, meaning a plant pathogen can ultimately affect animals that are never directly exposed to it.

How Diseases and Pathogens Spread

There is no single pathway by which disease moves through wildlife or the environment. Some pathogens pass directly between animals, while others persist in soil, water, faeces, nesting material or other parts of the environment. Wildlife itself can carry disease across considerable distances, sometimes without showing obvious signs of infection.

People can extend those pathways much further. Mud on boots and vehicle tyres can carry soil borne pathogens between locations, while wet fishing, boating and field equipment can move organisms between waterways. Plants, animals, soil and other biological material can also carry pathogens into places they would be unlikely to reach on their own.

This matters in Tasmania because some remote and relatively undisturbed areas remain free from diseases already established elsewhere in the state. Chytrid fungus and Phytophthora are two examples where keeping a pathogen out of unaffected habitat offers far more protection than trying to control it after it arrives. Cleaning footwear, vehicles and equipment, using hygiene stations and observing track closures or movement restrictions can all help protect those areas.

Biosecurity does not end at Tasmania’s airports and ports. It continues in the way people move through farms, waterways, forests, wetlands and wildlife habitat. Sometimes something as simple as cleaning mud from a pair of boots before visiting another location can help prevent a pathogen travelling with you.

What to Do If You Find Sick or Dead Wildlife

Unusual illness or deaths in wildlife can sometimes provide an early indication of a disease event. This may include animals behaving abnormally, several animals found sick or dead in the same location, or an unexplained increase in deaths. Reporting what you find can help authorities determine whether investigation or testing is needed.

Avoid handling sick or dead wildlife unless you have been specifically advised to do so. Keep children and pets away and, where possible, record the species, number of animals, location and any unusual behaviour you observed. Photographs can also be useful, provided they can be taken without approaching or disturbing the animal.

Unusual illness or deaths that could indicate an emergency animal disease can be reported to the Emergency Animal Disease Hotline on 1800 675 888. Follow any instructions provided about approaching, collecting or disposing of an animal rather than moving it yourself.

If you find an individual native animal that is injured or requires rescue, contact Bonorong Wildlife Rescue on 0447 264 625. Our What to Do If You Find Injured or Orphaned Wildlife guide also explains how to respond safely while arranging assistance.

Protecting Tasmania From Wildlife Disease

Disease is a natural part of wildlife populations, but introduced and emerging pathogens can present very different challenges. Tasmania’s isolation offers some protection, yet wildlife migration, environmental pathways and the movement of people, animals and materials mean that isolation alone cannot keep every disease out.

Once a pathogen becomes established in a wild population or natural environment, controlling it may be difficult or impossible. That makes prevention, early detection and an understanding of how diseases move through Tasmania particularly important, especially where threatened species or disease free habitats are involved.

Protecting wildlife from disease ultimately extends beyond any single species. It means protecting the health of the animals, plants and habitats that make up Tasmania’s ecosystems, while recognising that keeping a disease out is often far easier than trying to manage it after it arrives.

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Cover Image by Steven Penton / Wikimedia Commons / CC BY 2.0.