A Marin County resident recently died of a rare brain illness known as Creutzfeldt-Jakob disease, but it is not the form of the disease commonly called mad cow disease, a county health official said today.
"In the last 24 hours, we received information from a lab analysis of tissue samples from the deceased that rules out mad cow disease," Dr. Craig Lindquist, Marin County's interim public health officer, said this morning.
"It appears to be a rare, one-in-a-million form of Creutzfeldt-Jakob disease. It's not from eating beef. It's not contagious or spread by intimate contact or transmissible by common contact," Lindquist said.
A Marin County physician recently notified the California Department of Public Health of two suspected cases of Creutzfeldt-Jakob disease, Lindquist said. State public health officials then notified the Marin County Division of Public Health Services on Friday, Lindquist said.
The other Marin County resident with the suspected case is still alive, and a definitive diagnosis is not possible, Lindquist said.
"We have to examine the brain tissue post-mortem," Lindquist said.
He said he cannot identify the two residents or say when the death occurred.
"It was recently," he said.
There are two forms of Creutzfeldt-Jakob disease, according to the Centers for Disease Control and Prevention.
"Classic CJD" is a human prion, or abnormal protein disease. It is rapidly progressive, with death occurring within one year of the outset of the illness, according to the CDCP. There is one case per million people worldwide per year, and there have been known cases since the early 1920s, according to the CDC.
It is caused by the spontaneous transformation of normal prion proteins into abnormal prions, according to the agency.
It is not related to a variant form of Creutzfeldt-Jakob disease known as "mad cow disease", or bovine spongiform encephalopathy (BSE), a progressive neurological disorder of cattle that become infected with a transmissible prion in the meat and bone meal they are fed, according to the CDC. Humans, in turn, contract the disease by eating the meat of infected cattle.
BSE spread among cattle in Great Britain and peaked with almost 1,000 cases a week in 1993, according to the CDCP. Through the end of 2010, more than 145,500 cases were confirmed among more than 35,000 herds.
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.