Devil facial tumour disease

Devil facial tumour disease causes tumours to form in and around the mouth.

Devil facial tumour disease (DFTD) is an aggressive non-viral clonally transmissible cancer which affects Tasmanian devils, a marsupial native to the Australian island of Tasmania.[1][2] The cancer manifests itself as lumps of soft and ulcerating tissue around the mouth, which may invade surrounding organs and metastasise to other parts of the body. Severe genetic abnormalities exist in cancer cells—for example, DFT2 cells are tetraploid, containing twice as much genetic material as normal cells. DFTD is most often spread by bites, when teeth come into contact with cancer cells; less important pathways of transmission are ingesting of infected carcasses and sharing of food. Adult Tasmanian devils who are otherwise the fittest are most susceptible to the disease.

DFTD is estimated to have first developed in 1986.[3] There are two currently existing strains, both appearing to be derived from Schwann cells.[4] DFT1 is the main and older strain that infects most of the devil population. It was first described in 1996 in an animal from Mount William National Park in northeastern Tasmania.[2] DFT2 appeared around 2011[3] and was first detected in 2014; all cases are limited to the area of southern Tasmania near the D'Entrecasteaux Channel.[5] There still remain disease-free pockets in the relatively isolated south-west of the island.[6]

The disease poses a direct threat to the survival of Tasmanian devils as a species as the disease is almost universally fatal. In the two decades since the disease was first spotted, population of Devils (Sarcophilus harrisii) declined by 80% (locally exceeding 90%), as the condition spread through virtually entire Tasmania. The Tasmanian Government, Australian universities and zoos are engaged in efforts to curb the disease. Culling infected individuals, the policy used by state officials until 2010, brought little success.[7][8] Thus the main prevention method became taking hundreds of devils into captivity and then releasing some of them into the wild. There is no cure for the cancer so far. Vaccination offers some promise in the fight against the pathogen, but researchers have not found a suitable candidate yet. A 2017 vaccine trial found that only 1 in 5 devils could resist DFTD; a DFT1 oral vaccine candidate is being tested in the captive devil population.[9]

  1. ^ Taylor RL, Zhang Y, Schöning JP, Deakin JE (August 2017). "Identification of candidate genes for devil facial tumour disease tumourigenesis". Scientific Reports. 7 (1): 8761. Bibcode:2017NatSR...7.8761T. doi:10.1038/s41598-017-08908-9. PMC 5562891. PMID 28821767.
  2. ^ a b Bender HS (2010). "23. Devil facial tumour disease (DFTD): Using genetics and genomics to investigate infectious disease in an endangered marsupial". In Waters PD, Deakin JE, Marshall Graves JA (eds.). Marsupial genetics and genomics. Dordrecht: Springer. pp. 499–516. ISBN 9789048190232.
  3. ^ a b Cite error: The named reference :0 was invoked but never defined (see the help page).
  4. ^ Patchett AL, Coorens TH, Darby J, Wilson R, McKay MJ, Kamath KS, et al. (May 2020). "Two of a kind: transmissible Schwann cell cancers in the endangered Tasmanian devil (Sarcophilus harrisii)". Cellular and Molecular Life Sciences. 77 (9): 1847–1858. doi:10.1007/s00018-019-03259-2. PMC 11104932. PMID 31375869. S2CID 199389366.
  5. ^ James S, Jennings G, Kwon YM, Stammnitz M, Fraik A, Storfer A, et al. (October 2019). "Tracing the rise of malignant cell lines: Distribution, epidemiology and evolutionary interactions of two transmissible cancers in Tasmanian devils". Evolutionary Applications. 12 (9): 1772–1780. doi:10.1111/eva.12831. PMC 6752152. PMID 31548856.
  6. ^ Cunningham CX, Comte S, McCallum H, Hamilton DG, Hamede R, Storfer A, et al. (May 2021). Ostfeld R (ed.). "Quantifying 25 years of disease-caused declines in Tasmanian devil populations: host density drives spatial pathogen spread". Ecology Letters. 24 (5): 958–969. doi:10.1111/ele.13703. PMC 9844790. PMID 33638597.
  7. ^ Beeton N, McCallum H (Dec 2011). "Models predict that culling is not a feasible strategy to prevent extinction of Tasmanian devils from facial tumour disease: Modelling removal of diseased devils". Journal of Applied Ecology. 48 (6): 1315–1323. doi:10.1111/j.1365-2664.2011.02060.x.
  8. ^ Cite error: The named reference cb2010 was invoked but never defined (see the help page).
  9. ^ Conroy G (June 2023). "Tasmanian devil cancer vaccine approved for testing". Nature. 619 (7969): 233–234. Bibcode:2023Natur.619..233C. doi:10.1038/d41586-023-02124-4. PMID 37391612. S2CID 259303561.