The famous mad cow disease is caused by prions. Such prion diseases not only affect animals, but also seriously endanger...The famous mad cow disease is caused by prions. Such prion diseases not only affect animals, but also seriously endanger...The famous mad cow disease is caused by prions. Such prion diseases not only affect animals, but also seriously endanger...The famous mad cow disease is caused by prions. Such prion diseases not only affect animals, but also seriously endanger...