Tasmanian Devils Decimated by Facial Tumors

by Jordan Yerman | October 7, 2007 at 11:43 am

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Inbreeding amongst Tasmanian Devils has left them susceptible to a virulent, communicable tumor that that behaves almost like a virus, as the animals' immune systems don't recognize the malignant cells as foreign bodies. The picture shown via the link below is, for lack of a better word, gross.

Researchers have concluded that the rapid spread of the cancer, which has halved the devil population in just over a decade and may obliterate it altogether in another, is due to a lack of genetic diversity.

The flourishing Devil Facial Tumour Disease (DFTD) seems to pass easily from one animal to another during fights over food and mates. The devils are generally free with their teeth in such skirmishes, but the smallest of wounds to the mouth can result in death within six months as the cancer takes hold. Tumours sprout around the head and face, sometimes displacing eyes and teeth, and make it impossible for the animals to feed, inevitably leading to death from starvation.

The disease is one of only two known naturally-occurring infectious cancers - dogs and other canines can contract Canine Transmissable Venereal Tumour (CTVT) through copulation, but it is by no means always fatal.

Scientists have been struggling to find out the secret of DFTD's success in killing devils, whose population has fallen to around 75,000 from 150,000 in 1996. A collaborative project between the Sydney and Tasmania Universities, published this week online in the journal Proceedings of the National Academy of Sciences (pdf here), has made the breakthrough discovery that the devils' immune system - unlike that of dogs suffering from CTVT - simply does not fight the cancer because of a lack of genetic variation within the population.