Creutzfeldt-Jakob disease surveillance and diagnosis.

Creutzfeldt-Jakob disease (CJD) and other transmissible spongiform encephalopa­ thies, also known as “prion diseases,” came to the world’s attention after the emergence of bovine spongiform enceph­ alopathy (BSE) in Europe and the sub­ sequent revelation of scientific evidence indicating that its transmission to humans causes a variant form of CJD [1]. Since BSE first emerged in the 1980s in the United Kingdom, the disease has been found in native cattle in 23 other coun­ tries, most of which are in Western Europe [2]. Half of these countries, including Canada, Israel, and Japan, reported their first cases of BSE during 2001–2003. In the United States, BSE was identified for the first time in 2003 in a cow imported into Washington state from Canada, where 3 additional BSE cases were re­ ported in native cattle, 2 of them in Jan­ uary 2005 [1, 3]. In June 2005, BSE was reported in a cow born and raised in Texas. Strong epidemiologic and laboratory evidence supported a causal link between BSE and variant CJD cases that were rec­ ognized initially in the United Kingdom but were later also reported in other coun-