Creutzfeld-Jakob Disease dissolves the brain, as seen in this X-ray.

From San Francisco Bureau Chief Greg Lefevre

SALT LAKE CITY (CNN) -- Doug McEwen is dying, and his family and doctors are helpless to save him.

An illness known as Creutzfeld-Jakob Disease is dissolving McEwen's brain. Doctors don't have a clue how McEwen contracted the disease, which has taken his memory, his personality and much of his voice.

"You can't tell me how, and you can't tell me why," McEwen's wife, Tracie, said.

McEwen's speech is affected so badly that his wife has to interpret for him.

"Now sometimes, we'll go for hours and he won't even look at me. I'll try and talk to him and he won't answer me back," she said.

Creutzfeld-Jakob Disease is a rare cousin of Mad Cow disease. On average, it strikes one in a million people in the United States each year. But it hit six victims in Utah alone last year -- a rate three times higher than national figures.

Traci McEwen says doctors are unsure of how her husband, Doug, got the disease.

"Some may say that is just a coincidence, and it's likely that that is just a blip on the screen," said Dr. Kathleen Digre, a neurology professor at the University of Utah. "But it is possible that there is some other factor playing a role."

In another case, Ellie Steiner died from the disease even before her doctors could diagnose what it was.

"I don't think we know how many of our people really have the disease," said her husband, Mel Steiner. "And that's what scares me."

Among the possible factors under scrutiny are game animals -- deer and elk in particular. McEwen was an avid hunter, and scientists say wildlife in Colorado and Wyoming carry a chronic wasting disease related to Mad Cow Disease.

But there's no evidence, so far, that eating wildlife transmits Crutzfeld-Jakob Disease: Scientists have yet to prove even that CJD can be passed from animals to humans.

The malady, nicknamed CJD, is so rare that precious few scientists study it.

"CJD and all diseases like it are very mysterious," said Andrew Kimbrell of the Center for Food Safety. "We don't really understand how animals get them, we don't really understand how they're transferred to people."

With little more to learn from doctors, Tracie McEwen awaits the only certainty she knows.

"At this point to me, death will be welcome because this is not how I want to remember my husband," she said.