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The downer dairy cow recently found stricken with mad cow disease in California was infected with an “atypical” strain. Such cases are thought to arise spontaneously, a notion the USDA seized upon to explain how the disease could arise despite their regulations. If anything, that fact highlights the weaknesses in the current feed rules. If mad cow disease can arise out of nowhere, then it’s even more important to close the loopholes and stop the feeding of cattle blood to calves and chicken manure to cows to prevent it from spreading. And what the USDA didn’t mention about the atypical strain found in California is that there’s evidence it’s a more dangerous form of the disease

The California cow died of a particularly virulent form of mad cow disease known as BASE, bovine amyloidotic spongiform encephalopathy, also known as L-type atypical BSE. Typical BSE was first documented in the ’80s in Britain. Afflicted cows often became twitchy and aggressive, giving rise to the “mad cow disease” moniker, as their brains degenerated into a characteristic Swiss cheese-like appearance. Hence the scientific name, BSE: bovine (cow) spongiform (sponge-like) encephalopathy (brain disease).

Then cats started dying. Max, someone’s pet Siamese, was the first non-bovine victim of the disease. Infectious pet food was implicated as the cause of Max’s death from a never-before-described feline spongiform encephalopathy.

Then young people started succumbing to a human spongiform encephalopathy called Creutzfeldt-Jakob disease, a relentlessly progressive and invariably fatal dementia, often involving weekly deterioration into blindness and seizures as their brains became riddled with holes. CJD appears sporadically in one in a million people, but typically strikes only the elderly. The new cases among teenagers were dubbed “variant” CJD, a disease now understood to be caused by consuming contaminated meat (or by getting a blood transfusion from someone who did).