Bovine Spongiform Encephalopathy, commonly known as mad cow disease, is a progressive, fatal disease of the nervous system in cattle. The disease has a long incubation period (averaging four to five years) and there is currently no treatment or vaccine for the disease.

BSE is one of a group of diseases known as transmissible spongiform encephalopathy (TSE). Other TSEs include scrapie in sheep, chronic wasting disease in deer and elk, and Creutzfeldt-Jakob disease in humans.

The measures to deal with BSE are early detection and warning systems, prevention and rapid response measures and mechanisms. The steps include targeted surveillance of occurrences; awareness programs; screening tests at routine slaughter; transparency in reporting; safeguards on importation of live ruminant species and their products; and removal of specified risk materials.

BSE first came to the attention of the scientific community in November 1986 with the appearance in cattle of a new form of neurological disease in the United Kingdom. The first known U.S. occurrence came in December 2003. In June 2005, John Clifford, chief veterinary officer for the U.S. Department of Agriculture animal health inspection service, confirmed a fully domestic case of BSE in Texas. A new case of mad cow disease was found in a dairy cow on April 23 in California during a planned Agriculture Department surveillance program.

(Sources: OIE, WHO)