Bovine spongiform encephalopathy (BSE)

Bovine spongiform encephalopathy (BSE) is a progressive, fatal disease of the nervous system of cattle that is caused by the accumulation of an abnormal protein called ‘prion’ in nervous tissue. Two forms can be distinguished: the classical BSE occurs in cattle after ingesting prion contaminated feed, while the atypical BSE is believed to occur spontaneously in all cattle populations. The classical form was first detected in 1986, and the implementation of appropriate control measures resulted in its decline worldwide. To date, the incidence of both forms is negligible and estimated to approach zero cases per million cattle. BSE is considered zoonotic due to its assumed link with the emergence of variant Creutzfeldt-Jakob disease in humans. BSE is a WOAH-listed disease, for which the WOAH has established official recognition of sanitary risk status for its classical form.