The triangular-shaped state of Tasmania is not very large, and much of it is outback or farmed land. The devil is difficult to spot outside of captivity, but the animals' geographic movements in recent years have been easier to track, which has proved imperative to understanding the spread of the facial tumor disease. As an emerging infectious disease (defined as a disease that is expanding in sheer numbers, in geography, in types of hosts, or in virility), DFTD does not sit in one place and can rapidly spread between devil populations. Researchers have mapped out where the devils are, which ones have been identified with the disease, and which ones have not. See an example below from 2004, when DFTD was gaining more momentum in geographic expanse:
And the updated map of where DFTD has been found in 2012:
Some had hoped that devils in other parts of the state would not encounter the disease, but its spread has proved imminent most everywhere. There are still some spots where it has not yet reached, but it seems that the disease is often a few steps ahead of researchers. The DFTD allograft that arose from a single Schwann cell in a devil more than 15 years ago has spread across the state, has passed through at least 100,000 hosts, and evolved and mutated all along the way. This may have happened so much that some devils in one area of Tasmania are not affected by the mutated tumor (while others still might be), and this is one possible way that the tumor could die out. Of course, there have to be some devils left for any population rebound.
The declining population of the devil:
The outlook may look bleak, but there are still some healthy devils out there, and we know more information now about devils' geography than ever before. Hopefully, this information can help us pinpoint areas to focus on preventing the disease from spreading the most.