Science27 Jan 2011 12:56 pm
Scientists have discovered the true identity of a contagious form of cancer that is killing off the once-ferocious Tasmanian devil. This horrific disease, known as Devil facial tumor disease (DFTD), is an aggressive non-viral transmissible parasitic cancer—which likely originated in cells that normally insulate nerve fibers, called Schwann cells. DFTD has been responsible for a 70% decline in the Tasmanian devil population since 1996.
Visible signs of DFTD begin with lesions and lumps around the mouth. These develop into cancerous tumors that may spread from the face to the entire body. The tumors interfere with feeding, and the affected animal may starve to death. Scientists are now convinced that the cancer is spread when animals inject cancer cells into each other during their feisty mating battles. Pound for pound, the Tasmanian devil is reportedly the most powerful biter alive today, and mating is no exception. When they are in heat, Tasmanian devils are notoriously feisty, and their duels often involve bloody mouth-to-mouth combat.
Amazingly, genetic analysis of tumors taken from infected devils in different parts of Tasmania reveals that this plague originated in a single Tasmanian devil and has since passed from devil to devil. How the cancerous Schwann cells became contagious is still a mystery, though. However, devils are known to be prone to cancers, and inbreeding has made them so genetically similar to one another that their immune systems don’t recognize infectious cancer cells from another individual as foreign. This could help explain how the disease was able to spread so quickly, and has been so disastrous for the devil population.
While concerted efforts are being made to quarantine the few remaining healthy devils from the infected ones, it remains an uphill battle without an effective vaccine or treatment.
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