[Review of basic knowledge, surveillance and infectious control of prion disease]

Prion disease is developed by changing normal prion protein to transmissible abnormal prion protein and its accumulation in the brain. Drug development project using small chemical molecules is now progressing based on constitutional analysis of prion proteins, and a domestic network for clinical trial is consolidating. Prion disease is classified into 3 types, and the Japanese Prion Disease Surveillance Committee has identified 2,026 patients with prion diseases during 14 years from 1999 (sporadic: 77％, genetic: 19％, environmentally acquired: 4％). Compare with patients in other countries, relatively larger amount of patients with dura mater graft-associated Creutzfeldt-Jakob disease (CJD) and genetic prion diseases have been characteristically identified. Sporadic classical CJD patients, which present rapid progressive dementia, are identified in most of the cases. Genetic prion disease are classified into 3 major phenotypes such as genetic CJD, Gerstmann-Straeussler-Scheinker disease (GSS) mainly showing spinocerebellar ataxia, and fatal familial insomunia. All the 83 cases but 1 case of variant CJD were dura-grafted CJD in environmentally acquired prion disease. Accurate diagnosis and prevention of secondary infection are important according to those surveillance data and systems.