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Tasmanian Devil: Extinction Imminent Owing To Cancer?

EnolaGaia

I knew the job was dangerous when I took it ...
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Not sure where to put this ... I don't recall ever encountering cancer as a claimed species extinction factor. Can anyone else cite a similar example?

Tasmanian Devil falling prey to cancer

Mon Oct 8, 2007 2:58am EDT

SYDNEY (Reuters) - A lack of genetic diversity in Australia's Tasmanian Devil means it has failed to launch an immune defense response to a facial cancer decimating populations, Australian researchers say.

The facial cancer produces large tumors on the face and neck of the Tasmanian Devil, found only on the southern Australian island state of Tasmania, which interfere with feeding. Death usually occurs within six months.

The Tasmanian Devil is a carnivorous marsupial about the size of a small muscular dog. It has black fur, gives off a skunk-like odor when stressed, and earns its name for its ferocious temperament and disturbing call.

"We found that the Devils do not mount an immune response against the tumor," said Katherine Belov from Sydney University's School of Veterinary Science.

"Essentially, there are no natural barriers to the spread of the disease, so affected individuals must be removed from populations to stop disease transmission," said Belov.

"Loss of genetic diversity in these genes just opens the door for emergence and rapid spread of new and old disease," Belov said in a statement on the Tasmanian Devil research.

The study also found that the facial cancer was genetically identical in every animal and had originated from a single contagious cell line, spread throughout the population by biting during fights for food and mates.

The Tasmanian Devil faces extinction in 10 to 20 years due to the facial cancer, the report said.

The research by Sydney University, the University of Tasmania, the Australian Museum and the Tasmanian government was published online by the Proceedings of the National Academy of Sciences of the United States of America.

SOURCE: http://www.reuters.com/article/scienceN ... 0320071008
 
It's very depressing. I really hope someone finds a vaccine or something th help the devils.

I can't think of anything similar involving cancer, although ISTR reading that myxamatosis in Australia killed up to 98% of the rabbits alive at the time.
 
Not that it helped. They breed like rabbits.
 
Cedric is only hope as disease hits Tasmanian devil
Kathy Marks in Sydney
Tuesday, 1 April 2008

He has a blood-curdling scream and he fought like a devil when he was trapped, but Cedric may hold the key to the survival of his species.

Australia's population of Tasmanian devils has been devastated by a mysterious disease that causes disfiguring and usually fatal muzzle tumours. Wildlife experts say the carnivorous marsupials face extinction in the wild within 10 to 20 years unless the spread of the disease can be halted.

Now Cedric has given scientists new hope. When he was injected with dead facial tumour cells he produced antibodies – the first devil to do so. That means other devils with his mix of genes may be resistant to the disease, or capable of responding to a vaccine.

Researchers at the University of Tasmania described this as the most promising development of their five-year battle to prevent the creatures from going the way of the extinct Tasmanian tiger. "I think this is the most exciting thing that has happened in this programme," Greg Woods told The Australian newspaper. "The devils could be their own saviours."

Cedric and his half-brother, Clinky, were captured nine months ago and injected with dead cells. While Cedric produced an immune response, Clinky did not. Scientists say the two males have a different genetic make-up. Only Cedric's recognised the disease as an invader.

Two months ago, the pair were injected with live tumour cells. The disease has a six-month incubation period. Clinky is expected to develop tumours soon, but it is hoped that Cedric's immune system will fight them off.

If Cedric and other devils with similar genetic make-up prove resistant to the disease, scientists may establish a breeding programme to propagate the genes through the population.

The disease has wiped out an estimated half of the devil population in the past decade. There may be as few as 20,000 left, with the disease prevalent in two-thirds of the island. Cedric and Clinky were caught on the west coast, which remains disease-free. On the east coast, the devils are genetically similar but when exposed to the cancer, they have no resistance because their genes do not recognise the disease as foreign.

The cancer is believed to be transmitted mouth to mouth when the snarling, cantankerous creatures fight over food. It takes root in the mouth and pushes out the teeth. Many affected devils die of starvation.

Alex Kriess, another researcher, told ABC radio that if Cedric remains healthy, it would indicate that "either we can immunise some devils with the vaccine, or that some devils might be resistant to the disease".

Dr Woods believes there are three genetic groups of devils. The first are genetically very similar to the tumour cells, and there is probably no hope for them. The second, like Cedric, are completely different and therefore naturally resistant. The third group would need a vaccine to protect them.

http://www.independent.co.uk/environment/nature/cedric-is-only-hope-as-disease-hits-tasmanian-devil-803124.html
 
Newly published research indicates the facial cancer previously expected to make Tasmanian extinct has faded into an endemic condition rather than the species-killer it was once believed to be.
A highly contagious face cancer may not wipe out Tasmanian devils after all

Tasmanian devils were supposed to be extinct by now. With a deadly, highly contagious face cancer tearing through devil populations, forecasts over the past decade or so spelled imminent doom for the iconic marsupial.

Only 25,000 or so devils (Sarcophilus harrisii) remain, down from about 150,000 in the 1990s, but a new analysis offers hope. Devil facial tumor disease has become far less transmissible since the peak of the epidemic, suggesting it won’t wipe out the species, researchers report in the Dec. 11 issue of Science.

Instead, the disease may stick around at lower levels, or “the tumor itself might eventually go extinct,” says Andrew Storfer, an evolutionary geneticist ...

Storfer and his colleagues reconstructed the history of the tumor’s spread by analyzing changes in tumor genes that evolve in a regular, clocklike manner. Samples from 51 tumors dating back to 2003 helped calibrate this timeline.

Though the disease was discovered in 1996 ... , the study found that it probably originated years earlier, in the ‘80s, slowly circulating at first. At its peak in the late ‘90s, each afflicted devil was infecting 3.5 other devils, on average, usually through biting. Recently, that number has fallen to one, suggesting the epidemic may peter out.

The slowdown may stem from population decline — fewer devils means fewer transmission opportunities for a disease that spreads fastest within dense groups. Additionally, the tumor itself might have become less transmissible; the researchers identified some genes that could underlie this shift. Finally, the devils themselves seem to have evolved resistance to the disease. ...

FULL STORY:
https://www.sciencenews.org/article/tasmanian-devils-highly-contagious-face-cancer-endemic

PUBLISHED REPORT:
A transmissible cancer shifts from emergence to endemism in Tasmanian devils
https://science.sciencemag.org/content/370/6522/eabb9772
 
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