Elk, deer, mink, rodents and other wild animals are known to develop variants of "mad cow" disease that are collectively known as transmissable spongiform encephalopathies. In the 4 years leading up to 1997, 11 cases of the human form of the disease, Creutzfeldt-Jakob disease were diagnosed in western Kentucky, USA, where the patients were known to enjoy the local delicacy, squirrel brains, raising the alarm to the presence of a potential "mad squirrel disease."