“Tasmanian Devils” and their transmissible tumors

For those interested in transmissable viral-caused cancer, this is a recent article from TheGuardian.com –

Tasmanian devils can catch second strain of facial cancer
New strain of tumour – the fourth transmissible cancer found anywhere – makes devils the only species known to be affected by more than one strain.
Scientists have discovered a second strain of cancer causing the fatal facial tumour disease in Tasmanian devils, making the endangered marsupial the only species to be affected by two types of transmissible of cancer. Calla Wahlquist Tues 29 December 2015

The devil facial tumour disease (DFTD) was first recorded in 1996 and has spread rapidly through the island state, wiping out 95% of affected colonies and bringing the species to the point of extinction.

The new disease, dubbed DFTD2, was discovered by University of Tasmania researcher Dr Ruth Pye in a devil sampled in the D’Entrecasteaux channel area, south of Hobart, and found to be genetically different to the original cancer, or DFTD1.

Dr Elizabeth Murchison, from Cambridge University’s department of veterinary medicine, is an expert in transmissible cancers. She confirmed it was a new strain, making it only the fourth transmissible cancer found in nature. Of the four, two affect devils, one affects dogs, and one plagues soft-shelled clams.

“It makes us wonder whether transmissible cancers may not be as rare in nature as we previously thought,” Murchison said.

“Alternatively, perhaps Tasmanian devils are particularly vulnerable to the emergence of transmissible cancers.”

The findings were published in an article in the Proceedings of the National Academy of Science, published on Tuesday. Pye is part of a team, led by University of Tasmania’s Prof Greg Woods, that has developed a vaccine against DFDT1.  Trials of the vaccine began this year, and Woods said he hoped the new disease could be similarly managed.

“Fortunately this is similar to DFTD and the procedures in place to deal with DFTD will be used to investigate this new cancer,” he said. “Vaccine research will not be affected as the new cancer can be incorporated into the vaccine.”

Bruce Englefield is the chief executive of the Devil Island Project which builds sanctuaries, called “islands”, for disease-free devil populations. He told Guardian Australia that the discovery of a new cancer meant conservationists should redouble efforts to preserve the species.

“It’s just incredible that it would happen twice,” Englefield said.  The carnivorous marsupials died out on the Australian mainland before European settlement, as did Australia’s most famous extinct species, the Tasmanian Tiger.

Englefield said attempts to preserve disease-free populations of devils have suffered a number of setbacks in recent months. In September, four of the 20 newly-immunised devils released into Narawntapu national park in the state’s north were killed by cars within weeks of their release, and in October plans to build a $1.3m, 26 km fence to protect a disease-free population of 800 devils in Woolnorth, Tasmania’s far north-west, were mothballed in favour of a $500,000 “transportable” fence.

Englefield hoped the transportable fence, which will be known as the fifth devil island, would contain newly released, vaccinated devils within its 4km perimeter for long enough for them to settle into their new territory, “so that they don’t just take off and end up as roadkill”.

“When you have spent $25,000 to $30,000 per devil to put them through the vaccination project only to have them killed by a car in the first few weeks, the financial impact, let alone the psychological toll, is high,” he said.

A population of 100 disease-free devils lives on Maria Island, the island for which the rest of the sanctuaries were named, and another 40 or so live on the Tasman peninsula. A sixth sanctuary will be built near Hobart so Woods’s research team has a nearby population to study.

Englefield said vaccinating against both strains of the disease was now the animal’s best chance.  “It’s like if you immunize 90% of children at a school – it makes it very likely that the remaining 10% will be protected from the disease,” he said. “It seems crazy to me that we ever sent them to the mainland when we could have transplanted them here, bred them undiseased and then immunized and released them. The place for devils is Tasmania.”



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