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Home > Weeds, Pests & Diseases > Animal Diseases > Mucormycosis - Platypus Fungal Disease

Platypus Fungal Disease



NEW Project Update - June 2009
About Platypus Fungal Disease
History of Platypus Fungal Disease
How is the Disease Spread?
Map Showing Distribution of the Disease
Effect of the Disease on Platypus Populations

About Platypus Fungal Disease

The platypus (Ornithorhynchus anatinus) is the last surviving species of a number of platypus-like ancestors that existed on the super continent of Gondwanaland over 100 million years ago, when dinosaurs roamed the earth1. Some scientists feel that platypus are now so specialised, and so far out on the evolutionary tree, that they are vulnerable to environmental change. Certainly they are dependent on aquatic habitats for their survival, and may be susceptible to a range of environmental changes arising from human activities2.

Platypuses generally suffer from few diseases in the wild3, however there is widespread public concern in Tasmania about the potential impacts of a disease caused by the fungus Mucor amphibiorum. This platypus fungal disease (termed Mucormycosis) only affects Tasmanian platypuses, and has not been observed in over 2000 platypuses captured in mainland Australia4. Affected platypuses can develop ugly skin lesions or ulcers on various parts of the body including their backs, tails and legs.

Dorsal Ulcer on Platypus
Dorsal ulcer on platypus
Photo: Josh Griffiths

Platypus with ulcer on hind leg
Platypus with ulcer on hind leg
Photo: Nick Gust

Close up of ulcer on foreleg of Platypus
Close up of ulcer on foreleg
Photo: Nick Gust

These photos were taken in north central Tasmania and show platypuses with ulcerated lesions caused by Mucormycosis.

This fungal disease can kill platypuses5, with death arising from secondary infection and by affecting the animals’ ability to maintain body temperature and forage efficiency.

It is an unfortunate coincidence that one of Tasmania's other iconic mammals, the Tasmanian Devil, is also suffering from a disease. Platypus Mucormycosis and Devil Facial Tumour Disease both cause ugly deformities and can kill the infected animals. However these diseases are caused by different pathogens. Devil Facial Tumor Disease is taking a heavy toll on Tasmanian devil populations, but we do not yet know what impact Mucormycosis is having on platypus populations.

History of platypus fungal disease

Mucormycosis disease was first observed in platypuses in 1982 in the Elizabeth River near Campbell Town in the north of Tasmania6. However it wasn't until 1993 that the causative agent Mucor amphibiorum was positively identified5. Mucor amphibiorum is a native Australian fungus previously restricted to mainland Australia (in particular northern New South Wales and Queensland). On the mainland it is known to infect and kill frogs and toads7. Recent research indicates the positive mating strain of this fungus present in Tasmanian platypuses is particularly virulent8. It seems likely that the fungus was introduced to Tasmania via infected frogs transported from mainland Australia. Further speculation exists that the fungus arrived via green tree frogs amongst banana shipments from Queensland. However it could also have arrived via the illegal introduction of frogs as pets into the State. We will never know for sure.

Since 1982, the disease seems to have spread in Tasmanian platypus populations. It is now known to infect platypuses in a variety of locations through the north central part of the state including the Supply, Meander, Liffey, South Esk and Elizabeth rivers, and Brumby's creek.3,4,5,6

Additional anecdotal reports of diseased platypus in southern and north-western river systems have fuelled fears the disease may be spreading, and may impact platypus populations in other parts of Tasmania including the Tasmanian Wilderness World Heritage Area.

Known historical distribution of diseased platypus in TasmaniaGo to top of page

Platypus disease distribution map - thumbnailBlue points indicate locations where apparently healthy platypuses have been recorded, red points indicate confirmed cases of Mucormycosis, orange indicates ulcerated platypuses likely to be caused by Mucormycosis, and yellow indicates sightings of possibly diseased platypuses.

Click on the image for a larger view.


How is the Disease Spread?

We don't know yet.

An unusual feature of this disease is that it affects platypuses only in Tasmania and not on the Australian mainland where the same pathogen infects frogs and toads. Although amphibians are susceptible to this fungus, and are likely to be the vector for originally transporting the pathogen to Tasmania, there are no records of Tasmanian frogs infected with the fungus. We do not know yet how the disease is spread amongst platypuses. A number of potential vectors exist that could possibly be transmitting the disease in Tasmania. Determining how the disease is spread, and what the vectors are is an area of renewed research involving collaboration between a number of Tasmanian ecologists, vets, and disease researchers.

What Effect is the Disease Having on Platypus Populations?


Platypuses are currently considered common and widespread in Tasmania, although they are potentially vulnerable to a number of human-mediated changes to their environment9.

Mucormycosis may represent one of the most significant threats both to the health of individuals, and persistence of platypuses in the 100 years since they were first protected in Tasmania in 1907. However, we currently lack fundamental information on the epidemiology of the disease to interpret the magnitude of threat.

For instance although the disease has previously been confirmed from a series of rivers in north and central Tasmania, limited sampling means it is currently unclear how far Mucormycosis has already spread, or how fast it is spreading around Tasmania. It is a major concern for the conservation of this unique species that so little is known about the impact and significance of Mucormycosis fungal disease.

At the moment we are not sure how Mucormycosis disease affects the abundance or distribution of platypuses in Tasmania. Determining the impact of the disease is an important focus of this research program and involves collaboration amongst a series of researchers across two Tasmanian government departments and two Australian universities. We are currently collecting baseline information on the spatial extent of the disease, proportion of platypuses infected within the range of the fungus, the fate of diseased individuals and their survival prospects once infected. We require fundamental information on how the disease adversely impacts platypus numbers, or whether there are detectable effects on population densities or demographics. Indeed the broad impacts at a population level are yet to be quantified, with the result that platypus numbers may well have declined in parts of Tasmania where the disease occurs.


Project Update - June 2009
Platypus Survey Sites Map 2009
Map of 2008-09 survey sites and platypus captures (click on image for larger view)
  • The Platypus Partnership Project has now completed the field surveys underlying its investigations into platypus mucormycosis disease.
  • Through 2008-09, we conducted 32 field surveys across Tasmania to assess the current distribution and prevalence of mucormycosis.
  • This survey effort involved almost 100 nights of trapping and over 10,000 hours of netting spread across 19 river catchments, and represents the largest scale platypus trapping survey ever conducted in Tasmania.
  • Locations surveyed include Brumby’s Creek, Salmon Ponds, Geeveston, Connorville, 41o South Salmon Farm, Mole Creek, Mt Field National Park, Campbelltown, Deloraine, Lake St Clair, Melrose Creek, Latrobe, Bushy Park, Mountain Stream Fishery, Upper Blessington, Upper Esk, Longford, Carrick, Ross, Scottsdale, Springfield Hatchery, King Island, Queenstown, Strahan, Zeehan, Corinna, Perth, Lilydale, and Wynyard. See the adjacent map for trapping locations.
  • Surveys used a combination of fyke and gill nets to capture platypuses, (depending on the size and flow of the rivers).
  • We captured 167 individual platypuses and also received 12 dead individuals from members of the public.
  • All captured platypuses were fitted with individual microchips for identification, and had their sex, weight, condition, body length and bill dimensions recorded.
  • We also took a number of samples for analysis including blood, faeces, and ticks, as well as a small DNA sample for population genetics. Animals were released at the capture location soon after capture.
  • Only 7 of the 179 animals examined were ulcerated. Disease prevalence (the infected proportion of the population) appears to have declined since the mid to late 1990s.
  • Ulcerated platypuses captured in this study were from the Meander, Brumby’s-Lake, South Esk and North Esk catchments.
  • We also conducted a pilot study to test survey methods for a large-scale platypus monitoring program using volunteers from the community. Platypus can be very secretive and difficult to detect with behaviour and activity patterns varying widely between sites. Further work is required to develop an appropriate method of monitoring platypus populations. Thank you to everyone who gave up their time to participate.
  • Preliminary results from this study were presented at national scientific conferences in 2008 and 2009. There is also a peer-reviewed research paper currently in press that reviews current understanding of platypus mucormycosis (Gust, N. and Griffiths, J. (2009) Platypus mucormycosis and its conservation implications. Australian Mycologist 28, 1-8).
  • Additional manuscripts are currently being prepared or have been submitted for peer-review in scientific journals.
  • We are continuing to record and map sightings of healthy and diseased platypuses throughout Tasmania. Please report any sightings you make of platypuses in your area.

Acknowledgements


Further Information

Contact: Platypus Conservation - Partnership Program
Nick Gust
Project Leader (Platypus Conservation Project)
134 Macquarie Street HOBART TAS 7000
Phone: 03 6233 6556
Fax: 03 6233 3477
Email: PlatypusEnquiries@dpipwe.tas.gov.au

References

1. Grant T, Fanning D. 2007. Platypus. Fourth edition. CSIRO publishing: Australian Natural History Series. 157 pages. (available from www.publishing.csiro.au)
2. Long J, Archer M, Flannery T, Hand S. 2002. Prehistoric mammals of Australia and New Guinea: one hundred million years of evolution. Sydney: University of NSW Press.
3. Munday BL, Whittington RJ, Stewart NJ. 1998. Disease conditions and subclinical infections in the platypus (Ornithorhynchus anatinus). Transactions of the Royal Society of London Series B 353:1093-1099.
4. Connolly JH, Obendorf DL, Whittington RJ, Muir DB. 1997. Causes of morbidity and mortality in platypus (Ornithorhynchus anatinus) from Tasmania, with particular reference to Mucor amphibiorum infection. Australian Mammalogy 20:177-187.
5. Obendorf DL, Peel BF, Munday BL. 1993. Mucor amphibiorum infection in platypus (Ornithorhynchus anatinus) from Tasmania. Journal of Wildlife Diseases 29(3): 485-487.
6. Munday BL, Peel BF. 1983. Severe ulcerative dermatitis in platypus (Ornithoryhchus anatinus). Journal of Wildlife Diseases 19(4): 363-365.
7. Speare R, Thomas A, O'Shea P, Shipton W. 1994. Mucor amphibiorum in the toad (Bufo marinus) in Australia. Journal of Wildlife Diseases 30: 399-407.
8. Stewart, N. J. and B. L. Munday (2005). 'Possible differences in pathogenicity between cane toad-, frog- and platypus-derived isolates of Mucor amphibiorum, and a platypus-derived isolate of Mucor circinelloides.' Medical Mycology 43(2): 127-132.
9. Grant TR, Temple-Smith PD. 2003. Conservation of the Platypus, Ornithorhynchus anatinus: Threats and Challenges. Aquatic Ecosystem Health & Management 6(1): 5-18.


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This page - http://www.dpipwe.tas.gov.au/inter.nsf/WebPages/SSKA-7AH66E?open - was last published on 19 October 2009 by the Department of Primary Industries, Parks, Water and Environment. Questions concerning its content can be sent to NatureConservation Enquiries by using the feedback form, by mail to GPO Box 44, Hobart, Tasmania, Australia 7001, or by telephone to 03 6233 6556.

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