Bovine spongiform encephalopathy: a tipping point in One Health and Food Safety.

Bovine spongiform encephalopathy (BSE) is a protein misfolding disease of cattle which belongs to the group of transmissible spongiform encephalopathies (TSEs) or prion diseases. This group also includes scrapie in sheep and goats, chronic wasting disease (CWD) of cervids and Creutzfeldt-Jakob disease (CJD) humans. The first case of BSE was recognised in England in 1986 as a progressive, neurological condition where affected animals behaved abnormally, exhibited anxiety, ataxia, hypersensitivity to touch and noise and poor body condition. Spongiform change was observed in the brain stem of cattle at post-mortem and its similarity to scrapie in sheep stimulated biochemical investigation and transmission studies which confirmed it as a novel prion disease of cattle. Epidemiological analysis of the initial cases of disease implicated a common extended source of infection, likely to be related to feed, and stimulated a series of control measures designed to restrict feeding of mammalian-derived protein to ruminants in various parts of the United Kingdom and to prevent the use of various bovine offals in feed or food production. This article outlines the rise and fall of the incidence of BSE in the UK and Europe, its classification as a zoonotic disease with the emergence of variant CJD, the implications of it as a prion disease and challenge its diagnosis and control continues to represent worldwide.