Todd's correct - the cow was a "downer." It was already suspected as being ill. It went into slaughter - as do all cows - but toward "rendering." There, its tissue was tested, and the results came up that it had BSE (mad cow disease).
But it was still processed - into feed for other animals. Since this news, "feed," as a product, has grown to mean not just what other livestock eat, but pet food too.
So it's figured that in the least, more cows are eating feed partially made from this infected cow, while the other bits and pieces are being forward-traced to where they could have gone.
The scary part is the incubation period in cows is three years or so.
In humans, the incubation period is six to ten years. People could already have it and not know.
Of course, our government is saying the possibility of human infection is "very low."
I'll take the Chicken McNuggets, please.