Prion Diseases

Prion diseases (Transmissible spongiform encephalopathies, TSE) are a group of diseases caused by a transmissible and disease-causing abnormal conformation of the prion protein (i.e., prion). Prion diseases exist in humans and other mammals and zoonotic infection is recognized in the case of variant Creutzfeldt-Jakob disease (vCJD). Human prion diseases fall under three general categories: sporadic, genetic, and acquired. The most common prion disease is sporadic Creutzfeldt-Jakob disease (sCJD) accounting for more than 85% of cases. Unfortunately, they are invariably fatal diseases with short illness duration. The only way to definitely diagnosis prion disease and determine its type is via neuropathologic examination at autopsy. Clinical diagnostic tests, including electroencephalogram (EEG), cerebrospinal fluid (CSF) protein assays, and brain magnetic resonance imaging (MRI) can achieve a diagnosis of prion disease with a great degree of accuracy. CSF 14-3-3 and total tau proteins are surrogate markers for neuronal injury, whereas real time quaking induced conversion (RT-QuIC) detects abnormal prion protein seeding activity and has excellent specificity. Certain infection control measures must be applied when dealing with high infectivity tissues. The incidence of vCJD and iatrogenic CJD have decreased dramatically through the implementation of preventive interventions. Whether or not chronic wasting disease (CWD), a prion disease of cervids (e.g., deer, elk), can be transmitted to humans remains to be seen.