A cure for the Tasmanian devil’s strange and fatal cancer?
Jeremy Hance, mongabay.com
November 21, 2008
Researchers have announced that two Tasmanian devils have survived a cancer devastating their species after receiving inoculations of dead tumor cells, according to the International Herald. However, the inoculations have not worked on every devil – despite being inoculated four devils died from the cancer during the work.
Whether a devil survives or succumbs after inoculation has little to do with luck; the scientists believe that Tasmanian devils with greater genetic diversity have a more potent resistance to the cancer.
Since 1996 when the cancer was first noted, it has ravaged devil populations. Population estimates have dropped from 150,000 to 50,000. Tasmanian devils in the wild rarely live beyond one year before contracting and dying from the cancer. And, until now, no Tasmanian devil was known to have survived after being struck by the disease.
Tasmanian devil, the largest extant carnivorous marsupial, is afflicted with a consistently fatal infectious cancer, facial tumour disease, that is predicted to threaten extinction of wild populations and has caused an abrupt transition from iteroparity towards single breeding. Devils have responded to this disease-induced increased adult mortality with a sixteen-fold increase in precocious sexual maturity. Photograph courtesy of Menna Jones.
The cancer itself has stunned scientists. It is the first known cancer that spreads from contact with a cancerous individual. Tasmanian devils often eat their own dead, and by doing so ingest tumor cells which in turn infect them with the cancer. Mating also poses problems. During mating devils become incredibly aggressive, tearing and biting at their partner. Such behavior also spreads tumor cells from one individual to the next.
While the inoculation shows promise, researchers remain concerned. It is unknown how many devils may posses the genetic diversity necessary to fight off the disease after being inoculated. To make matter worse, there are fears that the tumor cells are already adapting to the new circumstances.
In May, the Tasmanian devil was listed as endangered. Hamish McCallum, senior scientist with the Devil Facial Tumor Disease Program at the University of Tasmania, told The International Herald that he believed devils would be extinct in with wild within five years unless solutions are found.
In order to save the species, scientists will have to beat the clock.