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What is Devil Facial Tumour Disease (DFTD)?

Chapter 1 – The Tasmanian devil (Sarcophilus harrissi)

1.4 What is Devil Facial Tumour Disease (DFTD)?

In 2006 a novel hypothesis was proposed: that the devil cancer was a transmissible tumour – an allograft – spread from devil to devil via biting when they mate or feed. Anne Maree Pearse conducting cytogenic research at the Tasmanian Government DPIPWE Mt Pleasant laboratory in Launceston had arrived at this hypothesis from an observation in one devil.

Pearse had observed a chromosomal anomaly (a peri-centric inversion of chromosome 5) in all the cells of one devil that was not observable in any of its tumour cells where it would have been expected if the cancer had been initiated within its own body. Pearse and her laboratory assistant Kate Swift published these findings, the basis for the allograft theory, in the Brief Communications section of the prestigious scientific journal Nature in February 2006.62 In proposing that it was a transmissible tumour, they still acknowledged in their conclusion that a carcinogen may have been the initial cause of the disease.

associated with the disease is altered reproductive behaviour resulting in devils breeding at a younger age and with births scattered across the seasons.66

Figure 1:5 Cancer in the mouth seen here as a lesion under the tongue67

The pathology of the disease has yet to be confirmed but the original consensus strongly supported a tumour of neuroendocrine origin. This raised the possibility of chemical involvement particularly the type of chemicals used as herbicides in Tasmanian forestry.68 Richmond Loh, who at the time was a Tasmanian government DPIPWE pathologist, confirmed that there was ‘strong evidence for classifying DFTD as an undifferentiated neuroendocrine tumour which is unlike any other seen in humans or animals’.69 Loh also suggested that in devils the neuroendocrine tissues are derived from the embryonic neural crest, they are widely dispersed throughout the body and they are in especially high

66 ibid

67Source: Dr Richmond Loh (DPIPWE)

68 The IARC has accepted that ‘atrazine appears to disrupt neuroendocrine pathways in the hypothalamus by as yet undetermined mechanisms’ International Agency for Research on Cancer, 1999, Atrazine. Available at http://www.inchem.org/documents/iarc/vol173/73-03.html last accessed 23 August 2007

69 Loh R, 2006, ‘The Pathology of Devll Facial Tumour Disease in Tasmanian Devils (Sarcophilus harrisii)’, Master of Philosophy, Murdoch University, Perth, p. 90. Available at

http://wwwlib.murdoch.edu.au/adt/pubfiles/adt-MU20061019.131524/01Front.pdf last accessed 18 September 2007, p 90

concentrations in tactile tissues such as the finger tips and lips (Meuten, 2002) and in the whisker-bed (Halata et al., 2003). Loh observed it was these sites where DFTD neoplasms most commonly originate.7071

Whilst the majority of scientists concluded DFTD was of neuroendocrine origin, Stephen Pyecroft had suggested that the initial classification of a lyphosarcoma, the malignant and abnormal growth of cells in the infection-fighting lympathic system, may have indicated a type of cancer that he suspected was caused by a virus.72 But further investigations have not confirmed a viral cause.73 Loh confirmed ‘[i]t’s a confusing picture’ because ‘[t]he cells look like lymphosarcoma but aren’t strictly behaving that way’.74 This opinion is supported by Clare Hawkins, wildlife biologist, also of DPIPWE and colleagues who concluded that the ‘disease is an undifferentiated sub-epithelial sarcoma of possible neuroectodermal origin’.75 A devil with lymphosarcoma tumours is shown in Figure 1:6 below.

70 ibid, p 85

71 Richmond Loh, a fish veterinarian, had been employed as a veterinarian for DPIPWE when Margaret Williams, his manager, provided him with the opportunity to enrol in a Masters degree at Murdoch University in Western Australia. He was to study the pathology of the Tasmanian devil cancer. His thesis was submitted in 2006. The project was funded by the DPIPWE, the Commonwealth Research Training Scheme and supported by the Australian Wildlife Health Network. His academic supervisors were Shane Raidal and Amanda O’Hara and his workplace supervisor was Stephen Pyecroft, veterinary pathologist with DPIPWE.

Loh has since left Tasmania and the DPIPWE. Available at: http://www.thefishvet.com.au/index.html last accessed 25 November 2012

72 Australian Broadcasting Corporation Science Online Features, n.d., Tassie Devil Terror. Available at http://www.abc.net.au/science/features/tassiedevil/default.htm last accessed 12 August 2007

73 DFTD under the microscope, Devil Facial Tumour Disease Newsletter, March 2006, Tasmanian Government, Department of Primary Industries and Water. Available at

http://tassiedevil.com.au/docs/devilNews_March2006.pdf last accessed 9 June 2010

74 Australian Broadcasting Corporation Science Online Features, n.d, Tassie Devil Terror. Available at http://www.abc.net.au/science/features/tassiedevil/default.htm last accessed 12 August 2007

75 Hawkins CE, Baars C, Hesterman H, Hocking GJ, Jones ME, Lazenby A, Mann D, Mooney N, Pemberton D, Pyecroft S, Restani M & Wiersma J, 2006, Emerging disease and population decline of an island endemic, the Tasmanian devil Sarcophilus harrisii, Biological Conservation, Vol. 131(2), pp 325-337, p 309

Figure 1:6 Devil with lymphosarcoma tumours76

Whilst the classification of the Tasmanian devil cancer remains confusing, devils are not only succumbing to DFTD. There are two other cancers afflicting devils, which to date have not been fully documented, a mammary cancer in female devils and a skin lymphoma shown in Figure 1:7 below.

76 Source: Dr Richmond Loh, (DPIPWE)

Figure 1:7 Tasmanian devil with skin lymphoma77

Cancer is an extremely complicated disease involving a web of multiple causes but it is known that preventing exposure to known carcinogens prevents the disease.78 Among the possible causes are environmental factors, including heavy metals, certain chemicals, viral agents, the effects of radiation, and the regulation of hormones on cell growth and differentiation. DFTD as a cancer is necessarily the subject of much speculation and uncertainty but this has been exacerbated by its framing as a new and emerging disease.

DFTD manifests on the face and neck of affected devils, it is malignant, known to cause secondary cancers and is fatal in every case.

77 Source: Pearse, AM The trouble with devils unpublished

78 Clapp RW, Jacobs MM & Loechler EL, 2007, Environmental and Occupational Causes of Cancer, Lowell Center for Sustainable Production, Lowell, MA