Nearly 70 percent of the world's Tasmanian devils (Sarcophilus harrisii) have been killed in the past 10 years by an infectious cancer called devil facial tumor disease (DFTD). So far, no cure has been found, and the disease has spread to almost every corner of the remote island off the southeastern coast of Australia, the only place on Earth where they live in the wild.
But now a colony of devils living near Cradle Mountain in northwestern Tasmania has displayed immunity against DFTD, and scientists say this could be the hope the species needs.
The northwestern population, says lead researcher Katherine Belov of the University of Sydney, is genetically distinct from the eastern devils. So far, the former have not contracted DFTD.
"We think these devils may be able to see the cancer cells as foreign and mount an immune response against them," Belov said when announcing the research that found the disease-free population.
The research was published March 10 in the journal, Proceedings of the Royal Society B: Biological Sciences.
Belov and her team have found that, in general, Tasmanian devils do not display a broad genetic diversity, and that in terms of immunity most devils are essentially "clones" of each other. But this northwestern population shows enough genetic differentiation that they might be able to resist the disease.
Belov was quick to caution that this genetic distinction does not guarantee permanent immunity, as DFTD has started to evolve, but she called her team's findings a "glimmer of hope" in the fight against the disease.
This isn't the first time that a Tasmanian devil has displayed immunity to DFTD. For several months in 2008 a seemingly immune devil named Cedric was hailed as the possible savior of his species, but he eventually contracted the cancer. That sad discovery did have a silver lining: Cedric's life was saved by surgery, the first time DFTD had been treated in that way.
Previously on ScientificAmerican.com, "Genetic analysis reveals parasitic origin of contagious cancer devastating Tasmanian devils"
Image: Tasmanian devil afflicted with devil facial tumor disease, via Wikimedia Commons