As the deadly facial cancer that has drastically reduced the population of Tasmanian devils continues to spread through the species, the main hope for scientists trying to save them from extinction has been to hunt for devils that might be resistant to the disease, and to try to take advantage of that immunity. Reporting in the Proceedings of the Royal Society B, Kathy Belov and her team say they may finally have done just that: Some devils from northwest Tasmania, they say, are genetically distinct from the rest and could be resistant to the disease.
Belov says that most Tasmanian devils have immune systems so closely related that they’re all susceptible to the disease, which spreads when the devils bite each other on the face and leave behind tumor cells. The bitten devils’ immune systems don’t recognize the tumor cells as foreign, allowing them to take hold. Scientists have given the iconic marsupial as little as 25 years left if efforts are not made to solve the cancer riddle. The population has dwindled by a whopping 70 per cent since the first reported case of devil facial tumour disease in 1996 [Sydney Morning Herald]. Previous research showed that the marsupials are more socially linked that researchers initially believed, which is bad news for those trying to contain the disease.
However, Belov’s findings provide some hope. While earlier studies had looked at devils in eastern Tasmania, this time they took a wider sampling of 400 devils across the state. Twenty percent of those were found to be genetically different from the eastern devils, and so far have not caught the disease [AP]. Belov believes these resistant devils may be able to identify the cancer cells as foreign, which triggers their immune systems to mount a defense. She notes that the situation is still dire, but adds that “now we can say that we’ve got a glimmer of hope. There may be some animals that may survive this epidemic” [AP].
Hopefully those findings will hold true; a few years ago researchers thought they’d found the first disease-resistant devil, which they named Cedric, but it didn’t pan out. Cedric caught the disease in December of 2008.
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