Where did Tassie Devils go?
During the mid-semester break I spent some days at Tasmania and had the opportunity of visiting a Tasmanian Devil park. Those animals are so cute (at least for me, ok?) that I felt inspired to use them as my topic and help you know about a serious problem they have been facing: the Devil tumor facial disease (DTFD).
But wait… Is cancer transmissible?
Typically, no. However, there are very rare types of cancer called “clonally transmissible cancer”, or “parasitic cancer”, which naturally spread from animal to animal without a bacterial or viral vector and are only known to occur on dogs and Tasmanian devils.
Despite the canine contagious cancer being nonfatal, DTFD is a very aggressive type of cancer which causes tumours on Devil’s face and can lead to death by inanition, since neoplasm can grow so much that the animals are unable to eat and drink; and can also metastasise, reaching different tissues on animal’s body. Usually Tasmanian devils die within six months after infection.
Such an invasive cancer had a great impact on decreasing Tassie Devil populations. “Nearly 450 mammals have been listed as Endangered, including the Tasmanian Devil (Sarcophilus harrisii), which moved from Least Concern to Endangered after the global population declined by more than 60 percent in the last 10 years due to a fatal infectious facial cancer”, according to the International Union for Conservation of Nature (IUCN).
Recent studies found that the major issue in DTFD infection is that this is a silent disease. The reason why is the lack of some substances called “major histocompatibility complex molecules” – or MHC molecules, to be friendly – that are exposed on cells’ surface and show the way to immune system start working. However, on DTFD cancer the genes responsible for expressing those molecules are switched off so immune system cannot recognise the tumoral cells.
Since DTFD started appearing, the main strategy to conserve healthy populations of Tassie Devils was keeping them in captivity, avoiding contact with sick individuals. But after years of research, fortunately scientists seem to be discovering and developing weapons against the disease, like a drug based on EBC-46 molecule (found on a Queensland plant), showing positive results after the pilot tests, as reported below:
“The pilot study on Tasmanian devils tested EBC-46 on the advanced primary DFTD lesions in four wild devils that were being held in captivity. The primary tumours in all four devils, which were injected directly with the compound, showed significant regression. Also, the ability to exploit the host’s response to disrupt the tumour blood supply and destroy tumour cells is crucial. This leaves surrounding healthy tissue virtually intact while destroying the tumour mass. Additionally, the tissue deficit left by the destruction of the tumour appears to undergo rapid and dramatic healing, including hair regrowth” (Adapted from Save The Tasmanian Devil Program website).
With these advances, it is expected to restore Tasmanian Devil as a least concerned species and start seeing them all aroung in a nearly future, not only inside a cage. Rawr!