TWIN FALLS, Idaho -- In late May, Marjorie Skinner played golf well enough to place fourth in a Memorial Day weekend tournament. Yet within weeks, the previously vibrant retiree started losing her ability to speak.
By the time her family buried her Friday, she was the fifth suspected victim in the same sparsely populated area of Idaho of Creutzfeldt-Jakob disease, a rare brain-wasting disease that typically afflicts only one in a million people.
As word of the latest death spread yesterday, local and federal health specialists sifted through clues about an illness different from variant Creutzfeldt-Jakob disease, the human form of mad cow disease.
''Five [cases] in one valley is pretty serious," said Sue Skinner, Marjorie's daughter-in-law. ''It's a grave concern in our family."
The mystery has deepened in recent weeks. At the end of May, another elderly woman died of the incurable disease involving a malformed protein, or prion, that kills brain cells. After that, health officials learned of three other suspected cases, including one CJD death in February that was reported only last month.
''Is what is happening in Idaho an anomaly, a statistical fluke? That is possible," said Ermias Belay, a top CJD expert with the Centers for Disease Control and Prevention in Atlanta who is helping advise officials in Idaho. ''But once it exceeds 1.5 or 2 per million, you start asking questions."
''If they are all confirmed, it could be odd," he said.
In a year, the United States typically has fewer than 300 CJD cases, which mete out rapid death to the elderly, according to the Centers for Disease Control.
In Twin Falls, Cheryle Becker, epidemiology manager for Idaho's South Central District Health, is going to families with detailed questionnaires aimed at finding the roots of a disease that could date back 30 years.
She asks about past travels, unusual hobbies, and dietary habits, including eating organ meats, brain, and venison.
''We're asking them if they've consumed elk," Becker said, adding that many people hunt venison in Idaho. ''We're not having many people say that they have."
Specialists said they do not expect to find a link to eating meat, although locals are asking whether there is any connection to the human variant of mad cow disease. ''It's very frightening to the community," said Cheryl Juntunen, director of the South Central District Health.
Two confirmed US cases of mad cow disease, one in a Washington state dairy animal in 2003 and the other in a Texas beef cow this year, have further heightened concern.
Health specialists have found few parallels among the women, all of European heritage. Four were Idaho natives, all had children, and none had experienced neurological disease.
One had spent time in Britain before the outbreak of mad cow disease there, officials said. Several husbands were involved in farming, as is commonplace in a rural farmland region.
''There are things that lead you to believe this is not variant CJD," Becker said.