Manitoba- Chronic wasting disease, a fatal neurological disorder similar to mad cow disease, has been found in a wild deer in an area previously thought free of it, officials in the Canadian Prairie province of Saskatchewan said on Thursday.

Since 1990, three cases of the disease had been found in wild mule deer clustered in the west-central part of the province.

But the new case, a 2-year-old buck shot by a hunter this fall, was about 255 kilometers (160 miles) away, raising concerns the disease has spread.

“We’re disappointed,” said Kevin Omoth, who monitors the disease for the Saskatchewan government.

“We were becoming guardedly optimistic that it was existing only in that area of the (province),” he said.

The government will reduce deer herds by allowing more hunting, and step up testing efforts, Omoth said.

The brain-wasting illness belongs to the same family of diseases as bovine spongiform encephalopathy, more commonly known as mad cow disease. A deadly human version of BSE, new variant Creutzfeldt-Jakob disease, killed dozens of people in Britain after they ate BSE-tainted beef.

In August, a Saskatchewan man died of the disease. Health officials believe he consumed tainted beef during visits to the Britain in the late 1980s and early 1990s.

Health officials say chronic wasting disease in deer poses no known risk to humans or domestic livestock, Omoth said.

“But you’ll never find a scientist who says there’s (categorically) no risk, and that’s what makes people uncomfortable,” he said.

The provincial government has tested about 5,500 mule deer for the disease during the past four years. Hunters submit deer heads, since there is no live test for the illness.

The disease has not been found in wild animals in other provinces, Omoth said, nor in other species of wild animals in Canada, although it is present in the wild in the United States.

The disease has decimated the domestic elk farming industry since it was first detected on a ranch in 1996. More than 7,500 animals have been destroyed.

Elk are raised for meat and antler velvet, which is used in homeopathic remedies and as aphrodisiacs, especially in Asia. Markets for elk meat and velvet have evaporated since the disease outbreak.

Scientists do not know what causes the disease or how it spreads. Omoth said

Some scientists think the disease has always existed at low levels in the wild, but been undetected until recently, Omoth said.

Others believe it spread from game farms, although Omoth said there is no evidence to support that theory.