Scotland's red squirrels are being threatened by leprosy.

Researchers at the University of Edinburgh said they have observed six cases since 2006, the Telegraph reported. The species is already being threatened by the exploding population of gray squirrels and the squirrel pox they carry. The researchers have urged the public to report any squirrels that look like they have the disease.

"There is no pattern to the distribution so it is very widespread. It's serious to the effected squirrels but it is a cryonic disease and means they will die slowly," Professor Anna Meredith of the Royal Dick School of Veterinary Studies at Edinburgh University, told the Telegraph. "At the moment we are looking to find out how bad it is and urging people to look out for it."

There have only been a few cases so far, but the threat is relatively new. The disease is believed to be Mycobacterium lepromatosis, and has not been reported in gray squirrels.

The disease causes "hair loss and severe swelling to the snout, eyelids, ears and feet," the Telegraph reported.

"Research indicates that Squirrelpox disease is responsible for accelerating the rate with which grey squirrels have replaced red squirrels throughout most of England and Wales," Mel Tonkin, a project manager at Saving Scotland's Red Squirrels (SSRC) told the Telegraph. "However, the conservation community has shown that red squirrel populations can be protected in the midst of grey squirrels carrying the virus by keeping the grey squirrel population density at a very low level.

Since 1952 about 95 percent of red squirrels in England and Whales have disappeared ane the majority of today's population live in Scotland, the Independent reported. Gray squirrels have almost replaced their red counterparts because they are more successful in competing for food.

The leprosy is not believed to pose a threat to humans.