MOLE CREEK, Tasmania, Oct 30 (AFP) - Wildlife experts battling a mystery disease which has killed half the world's population of Tasmanian devils said Thursday that the illness could prove as hard to eliminate as HIV or SARS.
Devil Facial Tumor Disease (DFTD) has nearly eliminated the marsupial predators from the eastern half of Tasmania and there are signs it is spreading to populations in the west, said Nick Mooney, a wildlife management officer with the island state's conservation department.
The disease manifests itself as small lesions and lumps around devils' mouths which grow into cancerous tumors on the face and eventually spread throughout the entire body.
Death occurs within three to five months, usually from starvation as weakened animals lose the ability to compete for food.
Mooney estimated that from a high of about 150,000 in the mid-1990's, the population of Tasmanian devils has been slashed to 75,000 by DFTD, an illness about which pathologists know little.
"The state population has halved already," he said.
Devils -- muscular, short-legged animals the size of a small dog but with jaws powerful enough to crush bones -- live wild only in Tasmania. There are only about 120 of the animals in captivity, all but one of them in Australia.
The threat to Tasmanian devils is such that the Hollywood entertainment giant Warner Brothers -- which made the feisty creatures internationally famous through the cartoon character "Taz" -- approached state officials to learn more about the crisis.
"Warner Brothers are interested in the welfare of Taz's cousins and there might be something more formal they could offer to help," said Tony Scott, an aide to state Environment Minister Bryan Green.
Experts from around Australia and beyond gathered in the Tasmanian city of Launceston earlier this month to develop a strategy for finding the causes of DFTD and battling the disease.
"Our big problem is that we don't even know for sure if this is an infectious disease or not," Mooney told AFP.
"A retrovirus seems the most obvious suspect, but not all the cancers are caused by these," he said.
"The thing which seems clear is that there is a suppression of the animals' immune system for dealing with cancer, but the pathologists say we might be years away from finding the answer," he said.
"It's not very different to HIV and SARS," Mooney said, referring to the virus which causes AIDS and the Severe Acute Respiratory Syndrome which is also believed caused by a retrovirus that raged across parts of Asia this year.
Androo Kelly, who cares for and breeds devils at his Trowunna Wildlife Park in Mole Creek, said there is evidence DFTD may have always been around and that environmental factors may be responsible for the extent of the current epidemic.
"The ecology of the Tasmanian devil is an annual boom and bust, boom and bust, with numbers going up in breeding season and then falling because of the animals' short life span -- just five or six years," he said.
"The devils and other animals of the same marsupial family like spotted tail quolls are prone to carcinomas, it's a natural, debilitating disease. Cancers are a part of the devil," he said.
"What we may be seeing now is a nasty manifestation of a cancer which is environmentally induced, possibly due to overpopulation or stress from population density," he said.
The disease has been most prevalent among older males and appears to be spread in part when devils "scrap", or bite each other around the mouth and face during group feeding, Kelly said.
Kelly and Mooney both say it is unlikely DFTD will wipe out the iconic Australian marsupial.
"There have been no clear examples of infectious diseases wiping out whole populations of animals because as the animals become rarer, the rate of transmission falls and the population recovers," Mooney said.
But Kelly is taking no chances, building up an "insurance population" of devils through his breeding program which already contains 55 animals.
"I don't think they are facing extermination in the wild, but it's prudent to have the insurance population," he said.
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