"Mad Cow Strain Found in Tulare County Mysterious"

"Federal officials have been quick to reassure the public that there is no health threat from the mad cow disease discovered in the carcass of a Tulare County dairy cow. But there is a lot they don't know about the type of infection in that carcass -- including how the cow got the disease, how long it was ill, and the risk to the public if that strain gets into the food supply."

"The infection in the 10-year-old cow was found when the carcass was brought to a Hanford processing plant for rendering. Its brain was among those randomly screened for the disease. The carcass was not destined for human consumption.

The U.S. Department of Agriculture said lab tests found a rare "atypical" strain of bovine spongiform encephalopathy, which attacks the brain and is fatal to cows. The strain -- one of two rare types -- is different from the more common "classic" mad cow disease, which has been spread in the past by feed contaminated with animal protein. Such feed was banned in the United States in 1997.

The good news, researchers and agriculture officials say, is that the two strains of atypical mad cow disease are very rare. Officials don't know what causes atypical mad cow disease, but it appears to occur sporadically and maybe even spontaneously. And the current method for screening cattle for the disease has been able to catch it."

Barbara Anderson reports for the Fresno Bee April 29, 2012.

SEE ALSO:

"Mad Cow Discovery Reignites Debate: Are U.S. Food-Safety Laws Too Lax?" (San Jose Mercury News)

"Mad Cow: Latest Episode Raises Questions About Cattle Feed" (Christian Science Monitor)

"Mad Cow Laws: Is That Beef Safe?" (FindLaw/Reuters)

"Holstein With Mad Cow Disease Was Lame, Lying Down" (AP)

"Mad Cow Case Raises the Issue of Tracking Livestock" (Washington Post)

"Cattle Futures, BSE Don't Add Up" (Dow Jones)

Opinion: "U.S. Should Adopt Additional Protections Against Mad Cow Disease" (San Jose Mercury News/McClatchy-Tribune)