Recently a research team headed by University of Tasmania immunologist Greg Woods has established how Devil Facial Tumour Disease (DFTD), thought to spread from devil to devil mainly by biting during fights and mating, manages to take hold and grow so rapidly.
The devils immune system should catch these tumour cells but it seems that expected immune response is not triggered. The key immune-triggering marker, called the major histocompatibility complex molecule (MHC), was not found in DTFD cells. Without this markerMHC markers the tumour’s cells were not seen as foreign by the devils’ immune systems and therefore not attacked and consequently allowed to increase rapidly.
The good news is that the genetic code for MHC is still intact meaning that these genes could theoretically be turned back on again. This highlights the potential for a vaccine.
In short, if these molecules can be switched back on then the Tasmanian devils immune system will recognise the invading tumour cells as foreign and give the ‘host’ devil a chance of overcoming the disease.
Although this is a positive step for the devils, a development of a vaccine is going to take time. How much time is unknown and it well might be that all wild populations will be diseased (unless otherwise protected) before a vaccine is available. Meanwhile, the species and its role in nature must be protected.
The population held in conventional captivity (small pens) seems secure but in this situation they are clearly not fulfilling their ecological functions and there is a risk some wild behaviours and survival skills will be lost. In addition, such intensive management is very expensive, perhaps unsustainable. Large, free-range pens (FREs) with lower densities of devils than conventional pens are a better option for preserving wild behaviours but this is still only a half-way measure to ideal conservation.
We are now entering an exciting new phase in the program to save the Tasmanian devil where due to the development of the vaccine we are able to see immunised devils being released into the wild in order to continue the research into the effectiveness of the vaccine.
Initial attempts at releasing immunised or insurance population bred devils into the wild have resulted in high numbers being lost to road kill. In order to minimise these losses the Devil Island Project Group is working with the Save the Tasmanian Devil Program to construct and supply a 3.2 kilometre long portable fencing system. This will enclose an area about 25 times the size of the MCG. It will allow the devils to become accustomed to the presence of wild devils and other animals through the bars of the fence. They will also get used to the noises, smells and other factors associated with their new environment before being fully released.
Devil Island Project Group is also working to provide the program and the research team with two smaller Devil Island enclosures to assist researchers with the vaccination process.