What causes progressive neurological diseases like “mad-cow” disease or vCJD?
vCJD is caused by an unusual protein called a prion (proteinaceous infectious particle). Prions are found in the brains of cows with “mad-cow” disease and in the brains of humans with vCJD. Prions can also be found in the spinal cord and in the back of the eye (retina). However, blood from infected animals or blood from infected people has never been shown to be a source of infection to humans.
