[1] Ist Super Sanita, Dept Food Safety & Vet Publ Hlth, I-00161 Rome, Italy
[2] Univ Roma La Sapienza, Dept Biochem Sci, Rome, Italy
[3] Univ Roma La Sapienza, Ctr Eccellenza BEMM, Rome, Italy
[4] Ist Super Sanita, Dept Cell Biol & Neurosci, I-00161 Rome, Italy
[5] Vet Lab Agcy, TSE Mol Biol Dept, Weybridge, Surrey, England