You may have seen recent media reports that wombats are under threat from a mysterious killer disease. That disease is sarcoptic mange, and while it affects the two wombat species that are not in immediate danger of extinction, it threatens to wipe out local populations.
Of the three wombat species, the northern hairy-nosed wombat is in the most precarious position overall – it is officially listed as critically endangered, with only about 200 individuals left. The other two, the southern hairy-nosed wombat and bare-nosed wombat, are both listed as of “least concern”, although all wombats have been affected by threats associated with the advent of European settlement.
Although the southern hairy-nosed and bare-nosed wombats are not in danger of extinction, both are under threat from sarcoptic mange, and some local populations are at risk of dying out.
Mange is a severely debilitating disease that affects a range of different mammals. It is caused by an infestation of mites, which burrow into the skin, causing severe itching, abnormal thickening of the skin, and loss of fur.
Usually the first sign of wombat mange is hair loss and thickened skin on the head, then progression to thickened crusty skin on the shoulders, flanks and limbs. Often the wombat will become deaf and blind due to thickening of the skin in and around its ears and eyes. Over the following months, the disease progresses to the point where all of the wombat’s skin is severely thickened, and eventually death occurs.
Some wildlife groups have begun treating wombats with anti-parasitic treatments, with varying success. This typically involves invasive techniques (physically capturing the wombats and administering an injection), or administering “pour-on” products using treatment flaps. Both these techniques are very labour-intensive, as wombats require several treatments over a period of weeks or even months.
In addition, wombats can use several different burrows in a night, and some burrows are used by different wombats at different times, which makes it difficult to ensure that only the affected wombat is treated. And of course, these treatments are only possible in areas where wombats can be accessed by humans – treatment in remote areas is virtually impossible.
In the longer term, some of these treatments are likely to lead to resistance in the mites, further endangering the wombat populations. Both techniques may also raise the wombats' stress levels over time, which can hamper their ability to maintain immunity against other parasites and diseases.
Healthy wombats are the aim. JJ Harrison/Wikimedia Commons, CC BY-SA
A National Wombat Strategy
We therefore need to develop a nationwide management strategy to ensure the long-term survival of wombats, an iconic Australian marsupial that through its burrowing activities also helps to create valuable habitat for a host of other animals.
To develop this strategy, we first need to understand how big the sarcoptic mange problem really is. Field research to assess the levels of mange in the populations is limited by the large distribution area of wombats throughout parts of southern and eastern Australia. However, in combination with data currently being collected from citizen-scientists using an online system called WomSAT, much more information can be gained.
WomSAT allows anyone to log sightings of wombats (dead or alive, and if alive their level of mange) and wombat burrows. Together, field research and citizen-science information can be used to determine the distribution and severity of mange, and to identify other threats to wombats throughout Australia.
Second, we need to learn more about why wombats are so badly affected by mange, and why their immune system fails to fight the parasites. Unbelievably, little is currently known about the wombat immune system, most probably because of a lack of funding and research on wombats in general – especially when compared with other quintessentially Australian animals such as koalas and kangaroos.
It is clear that more is needed to ensure the survival of a truly unique Australian animal, as part of the wider effort to preserve Australia’s biodiversity. There has never been a better time to work towards a nationwide strategy to save the wombat, with recent genome technology coming to the forefront of marsupial immunology research and our ever-increasing need to preserve our unique wildlife. We need to act now.