17. Devils in Distress
I heard that the dreaded Devil Facial Tumour Disease (DFTD) afflicting Tasmanian Devils (Sarcophilus harrisii) for more than 20 years was practically curable. Unfortunately, it seems there is a new version: DFTD2. (Warning: a graphic image of DFTD appears below.)
What we know about DFTD
The world human population knows only too well that viruses (think COVID-19) can mutate. Yet, DFTD is non-viral. According to the Menzies Institute for Medical Research at the University of Tasmania (UTAS) website:
DFTD is an aggressive non-viral, transmittable parasitic cancer that affects Tasmanian Devils. Small lesions or lumps, in and around the mouth, quickly develop into large tumours on the face and neck (and sometimes other parts of the body). The tumours interfere with feeding and the affected animal may starve to death. Once the cancer becomes visible, it is almost always fatal. It is estimated the Tasmanian devil population has declined by as much as 50 per cent since the onslaught of the disease, and has affected devil populations in 65 per cent of Tasmania, with concentrations highest across the eastern part of the state. Menzies researchers are investigating treatments for the prevention of DFTD.
A Tasmanian Devil wracked with DFTD. Credit: Dr David Hamilton (Twitter)
Vaccinating due to poor genetic diversity
A UTAS project is currently being undertaken by a research group led by Professor Greg Woods (Senior Research Fellow). The seriousness of the DFTD to the Devil population is outlined in the following extract from the site:
The Tasmanian Devil is under threat of extinction by a contagious cancer called Devil Facial Tumour Disease. This is a unique situation as cancer is not contagious but this tumour is transmitted between Devils through biting. Because the tumour is passed between Devils it suggests there is something wrong with the immune system of the Devil. However, our studies have clearly shown the Tasmanian devil has a healthy immune response. By performing studies on lymphocytes from Devils around the state, we have good evidence to indicate there is limited genetic diversity among the devil population hence the tumour is not recognised and eliminated by the immune system. Our immediate aim is to determine how we can encourage the devil's immune system to recognise and destroy the tumour. We are also screening wild Devils to determine if any Devils in the wild might be naturally resistant to Devil Facial Tumour Disease. The tumour itself is also unique so studies are underway to understand the unique features of this mysterious cancer.
We determined that the Tasmanian Devil has a competent immune response and that the transmission between Devils is most likely due to a lack of genetic diversity. West coast Devils have a much greater diversity than the diseased east coast and we immunised two Tasmanian Devils with irradiated DFTD tumour cells. One of these Devils responded to the immunisation and when challenged with live tumour cells, resisted the disease. Hence it might be possible to protect some Devils by vaccinating. Mixed lymphocyte reactions among eastern and western Devils were performed, and some experiments (especially between West vs East Devils) showed high reactions, supporting the evidence for increased genetic diversity in the western population.
A lesson from bananas
Coincidentally, I watched a YouTube clip on how the Cavendish bananas most people eat today are in danger of being wiped out too: Bananas As We Know Them Are Doomed (March 1, 2020).
It’s because the banana stools (trees) are all clones. They originated from a glasshouse at Chatsworth House in the UK. Imported from Mauritius in 1829, ‘dwarf Cavendish’ banana (Musa acuminata) clones were sent to Samoa via a missionary and they are now grown commercially all over the world. These bananas contain no seeds, and are sterile.
Since they lack genetic variability, Cavendish bananas are susceptible to attack from such diseases as Fusarium wilt, or Panama Disease aka Tropical Race 4 (TR4), caused by a fungus. Scientists say there is 100% certainty that Cavendish bananas will become uncommercially viable. They know this because it happened before, with ‘Gros Michel’ bananas, the dominant variety sold in the world up to the 1950s. The solution appears to be to find a banana plant (from another banana cultivar) that has immunity from this disease, grow it and cross breed it with the Cavendish. The particular banana plants with immunity have viable seeds, but it is only one plant in every 2000. I would never have guessed that Devils and bananas have so much in common: a lack of genetic variability.
Can statins control cancers?
On 9th April, 2021, scientists from Spain and Australia at Queensland Institute of Medical Research (QIMR) revealed that they have been working on a new project of using statins, commonly used as cholesterol-lowering drugs in humans, to reduce the tumours in Devils. The statins work by limiting the supply of glucose that is converted to cholesterol. Without the cholesterol, the cancers did not grow. While, this occurred under laboratory conditions, it remains to be tested in the wild Devil populations. Moreover, the implications for the parallel use of such drugs to control human cancers is enormous.
A new Devil Facial Tumour Disease
Twenty days later, 29th April, 2021, it was announced on ABC Tasmania radio that Dr Rodrigo Hamede is leading a collaboration of UTAS (and the Save the Tasmanian Devil Program, STDP), citizens and councils in a study that has uncovered a new facial tumour disease in Tasmanian Devils: DFTD2. So far it's confined to southern Tasmania. The survey, and solution, is reliant on the good-will of landholders, researchers, councils and donations.
We can all help
Tasmanian Soap Farm is able to contribute to the Save the Tasmanian Devil Appeal (administered by the University of Tasmania) as a result of funds raised from our soap sales. If you would like to learn more and donate directly to the Appeal, please click here.
GENERAL DISCLAIMER
The contents of this sharing are for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment . . . Read More →
