West Coast Raccoons Experiencing Outbreak Of Brain Cancer After Discovery Of New Virus

LAKE BUENA VISTA, FL - NOVEMBER 12:  A racoon watches is seen on the course during the first round of the Children's Miracle
LAKE BUENA VISTA, FL - NOVEMBER 12: A racoon watches is seen on the course during the first round of the Children's Miracle Network Classic at the Disney Palm and Magnolia courses on November 12, 2009 in Lake Buena Vista, Florida. (Photo by Sam Greenwood/Getty Images)

A mysterious new virus on the West Coast is believed to be causing fatal brain cancer in raccoons -- an alarming sign given the animals' frequent interactions with humans and the fact that tumors of any type were previously rarely found in the animals.

The discovery is documented in the Centers for Disease Control and Prevention's January 2013 issue of "Emerging Infections Diseases," wherein a team of researchers report brain tumors have been detected in 10 raccoons between March 2010 and May 2012 in Northern California and Oregon.

"Previous to this, there had been two reports of a raccoon with a brain tumor over the past two decades," said Patricia Pesavento, a pathologist at the UC Davis School of Veterinary Medicine and the study's principal author, according to the Los Angeles Times. “Now, we're getting one every month.”

Unlike most raccoons, which forage primarily at night and hide when they fall ill, the cancerous animals have been documented directly approaching humans, spending ample time in the daylight, and generally behaving unnaturally.

As Wired notes, researchers have determined the pathogen to be a previously unknown form of polyomavirus, the known variants of which have caused a rare skin cancer in humans.

At this point, there's no reason to believe the raccoon version may spread to humans, though it does raise frightening questions regarding its potential in the future. Additionally, there are signs the raccoon virus may be related to the human polyomavirus -- to the extent it may have originated in our own species.

"Of all wildlife, raccoons are especially good sentinels about how we are disturbing the environment because they have always thrived in neighborhoods," Pesavento added to the LA Times. "So when raccoons get sick, we should listen and see how we might have contributed."

While the odds of a human contracting raccoon polyomavirus is a matter of some debate, there are plenty of other good reasons to give the animals a wide berth. Chief among them: rabies. A study published in the Journal of the American Veterinary Medical Association in 2007 determined that nearly 40 percent of all rabies cases occur in raccoons. Comparatively, dogs account for only 1.1 percent.



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