A mysterious illness that has killed tens of thousands of Tasmanian devils is caused by cancerous tumors that are spread by ferocious squabbling among the carnivorous marsupials, according to a research published yesterday.
The number of the black, fox-sized scavengers with a bloodcurdling growl and powerful jaws that crunch through the bones of much larger animals has plunged in the past decade on Australia's island state of Tasmania, which is their only natural habitat.
Researchers estimate the wild population has fallen from 140,000 in the 1990s to 80,000 due to devil facial tumor disease (DFTD), a mysterious illness that creates grotesque tumors on the animals' snouts that lead to starvation within a year.
But while many scientists had suspected a virus, the journal Nature published research yesterday that points to a unique, infectious cancer that is spread when devils bite each other, usually on the face, as they violently squabble over carcasses.
Cytogeneticist Anne-Marie Pearse, a researcher for the state of Tasmania who co-wrote the article, found that abnormalities in the chromosomes of the cancer cells were the same in every tumor.
The disease apparently began with a single sick devil, probably in the mid-1990s, that directly spread the cancer cells by biting rivals, which is natural devil behavior, she said.
"Devils jaw wrestle and bite each other a lot, usually in the face and around the mouth, and bits of tumor break off one devil and stick in the wounds of another," Pearse said.
"We've found out how the disease is transmitted, which is a breakthrough in how we manage the wildlife population," she said.
"Finding a vaccine would be the ultimate goal," she added.
She suspected the continual line of cancer cells that had outlived its original host by years would attract interest from researchers of human cancer.
The only other such cancer occurred in dogs but, unlike the devils' disease, could be overcome by the canine immune system.
"There will be implications for general cancer research because we've got ourselves an infectious cancer here which means it's going to keep going ... so that makes it easier to study," she said.
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