SAN RAFAEL (KCBS) – A Marin County resident has died from – and another infected with – a brain disease related to what is sometimes incorrectly referred to as ‘mad cow disease.’

The woman who died had contracted Creutzfeldt-Jakob disease and was identified by the Marin Independent Journal as 59-year-old Aline Shaw of San Rafael.

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Creutzfeldt-Jakob disease (CJD) causes a dementia that progresses more rapidly than others such as Alzheimer’s disease or vascular dementia. Patients eventually go into a coma and die.

The variant form of CJD is the human version of bovine spongiform encephalophathy (BSE), commonly known as ‘mad cow disease.’  BSE is a progressive neurological disorder of cattle that become infected with an abnormal protein in the meat and bone meal they are fed, according to the Centers For Disease Control and Prevention. Humans get the variant version of CJD when eating the meat of animals infected with BSE.

Shaw passed away suddenly on Jan. 27 from non-variant – or classic – form of Creutzfeldt-Jakob disease, according to the Marin County Health Dept. The non-variant form has only two known causes: genetic mutation and contaminants introduced during a medical procedure, according to Dr. Craig Lindquist, Marin County’s interim public health officer.

Lindquist said state officials notified him of the two cases on Friday. Lindquist could not identify the victims, but confirmed to the newspaper that one had died.

BSE spread among cattle in Great Britain and peaked with almost 1,000 cases a week in 1993, according to the CDC. Through the end of 2010, more than 145,500 cases were confirmed among more than 35,000 herds.

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Lindquist said there is no link between the two Creutzfeldt-Jakob cases in Marin County, and it is not clear which form of the disease is afflicting the living victim.

“There is no threat or danger. Beef is very safe to eat,” Lindquist said.

Experts at the Centers For Disease Control and Prevention are aware of only 3 previous U.S. cases of variant Creutzfeldt-Jakob disease. CDC officials said those earlier victims were all exposed to BSE while abroad.

“We know that there have been no mad cow diseases originating in the United States,” said Dr. James Cullor, director of the UC Davis Veterinary Medical Teaching Center.

“The processing system, the surveillance system from the farm all the way through, is vigilant,” he said, making a local outbreak of mad cow very unlikely.

Marin County officials have yet to determine the source that infected the two Bay Area victims.

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