Planting Seeds - Food & Farming News from CDFA

Robust testing for BSE (Mad Cow Disease) in California and U.S.

There was some confusion this week about bovine spongeform encephalopathy (BSE), or, as it’s commonly known, mad cow disease. Humans who are exposed to it by eating infected animal tissues–the only way it can be contracted–develop a disease called Variant Creutzfeldt-Jakob Disease (VCJD), which is frequently confused with Creutzfeldt-Jakob Disease (CJD), a neurological illness that is not associated with VCJD.

California and the United States have a robust surveillance system in place for BSE. In 2011, the California Animal Health and Food Safety Laboratory at UC Davis tested about 8,000 animals from seven western states, with the vast majority coming from California.  Nationwide, about 70,000 tests have occurred since 2009. None were positive for BSE. Just three Americans are known to have contracted VCJD, and none of those cases came from consumption of U.S. beef.

To address confusion about suspected CJD in two residents of Marin County,  the health department there issued the following statement:

San Rafael, CA – Marin County Public Health is investigating reports of suspected cases of Creutzfeldt-Jakob Disease (CJD) involving two adults in Marin County. At this time, we have excluded variant CJD (the type related to Mad Cow Disease) as the cause of CJD in one of the two cases based upon the information available to us. This conclusion is based upon test results at a national reference laboratory. Furthermore, we have no evidence that suggests a causal link age between the suspect cases nor is there any evidence to suggest a risk in food supply.

We want to emphasize that CJD is extremely rare affecting approximately 1 adult in a million, or between 279 and 352 cases each year in the U.S. , according to the Centers for Disease Control and Prevention. Virtually all of these cases are “classic” CJD and unrelated to Bovine Spongiform Encephalopathy (BSE, also known as “Mad Cow Disease”). The type of CJD related to BSE, known as “variant” CJD has only been reported in 3 cases in the United States.

Furthermore, there is no evidence to suggest that classic CJD is contagious between humans, including close contacts. “This is an ongoing investigation entailing the collection of medical records, laboratory results as well as expert consultation,” said Craig Lindquist, MD, PhD, Interim Public Health Officer for Marin County. “While our  investigation of both of these reported cases continues, we want to emphasize that we have no evidence of any environmental or public health risk in Marin County. The Department will continue its investigations of both cases and will update the public as the information becomes available,” said Lindquist.

Contact the Marin County Department of Public Health with any questions at (415) 473-4163. For more information on CJD,

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