Epidemiological features of the bovine spongiform encephalopathy epidemic in Japan.

On 10 September 2001, the first case of bovine spongiform encephalopathy (BSE) in Japan was confirmed in a five-year-old dairy cow born in Hokkaido and raised in Chiba prefecture. Subsequently, BSE surveillance was enhanced. As a result, 35 additional cases were detected by the end of March 2009, with two to ten cases being detected each year up to the end of 2007. The epidemic appeared to peak in 2006. Cases are detected mostly in dairy cattle; in cattle born in 1996 and 2000; and in cattle born in Hokkaido. Two were atypical cases of BSE and the remainder classical cases. This paper describes and discusses the demographic structure of dairy and beef cattle, surveillance programmes in place and the epidemiological features of the BSE epidemic in Japan.