Tasmanian devil facial tumour lineages

What are Tasmanian devil facial tumour lineages?

Tasmanian devils are affected by two independent transmissible cancers known as devil facial tumour 1 (DFT1) and devil facial tumour 2 (DFT2). Both cancers are spread by biting and cause the appearance of tumours on the face or inside the mouth of affected Tasmanian devils. The tumours often become very large and usually cause death of affected animals. DFT1 has spread widely around Tasmania and has caused declines in the Tasmanian devil population; DFT2, on the other hand, appears to be confined to a peninsula in south-east Tasmania. As a result of the impact of DFT1, Tasmanian devils are now considered endangered.

What is the Tasmanian devil?

The Tasmanian devil is the world’s largest living carnivorous marsupial. About the size of a small dog, Tasmanian devils are well known for their piercing nocturnal shriek and their strong jaws. Tasmanian devils are found only on the island of Tasmania, to the south of the mainland of Australia. Being marsupial mammals, Tasmanian devils give birth to tiny, underdeveloped young, which complete their development in the mother’s pouch.

Tasmanian devil young in the pouch [Photo credit: Save the Tasmanian devil Program]	Tasmania marked in red [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0), via Wikimedia Commons]

Where are DFT1 and DFT2 found?

DFT1 was first observed in the 1990s in north-east Tasmania. The DFT1 epidemic has subsequently spread throughout most of Tasmania, and currently only areas of western and northwestern Tasmania are confirmed to have remained disease-free.

DFT2 was first observed in 2014 in the south-east of Tasmania. To date, it has only been observed on the Channel Peninsula in south-east Tasmania.

How are DFT1 and DFT2 spread?

DFT1 and DFT2 are spread by the transfer of living cancer cells by biting. Devils bite each other frequently, particularly in fights over mates and food. Direct contact between devils is necessary for the disease to spread. Right: DFT1 cancer cells (credit: Prof Greg Woods).

How old are DFT1 and DFT2?

DFT1 was first observed in 1996. Prior to this there was no evidence of transmissible cancers in the devil population. DFT2 was first observed in 2014.

How do DFT1 and DFT2 escape the immune system?

DFT1 and DFT2 are spread by living cancer cells; thus DFT1 and DFT2 cells should be rejected by the devils’ immune system because of its status in its hosts as a foreign graft. The mechanisms whereby DFT1 and DFT2 escape destruction by the immune system are incompletely understood; however, down-regulation of MHC molecules from the cell surface of DFTD cells probably plays a role.

How are DFT1 and DFT2 treated?

There are no established treatments for DFT1 and DFT2. A number of chemotherapeutic agents have been trialled for DFT1, but none have shown any efficacy in treating the disease. Preliminary immunotherapy trials have shown some promise for DFT1.

What is being done to save the Tasmanian devil?

The Save the Tasmanian Devil Program is a government-funded initiative with the goal of saving the Tasmanian devil and maintaining the species as a viable member of the Tasmanian ecosystem. An insurance population has been established in order to ensure survival of the species. Research is directed towards understanding the cause, evolution and impacts of the disease with the goal of developing a vaccine, therapy or other intervention. 

Where can I find more information about DFTD?

Save the Tasmanian devil website.