Finding infected cattle in the U.S. is exceedingly rare, too. The last time that happened was 2012, when a dairy cow in California turned up positive for mad cow disease. The others occurred in the early 2000s, in Washington state, Alabama and Texas. In the U.K., on the other hand, at least 184,500 cows have contracted the disease since it was identified in 1986.
Source: smithsonian.com By Rachel Nuwer