Atypical bovine spongiform encephalopathy: a review

ABSTRACT:

Bovine spongiform encephalopathy (BSE), caused by an infectious prion, emerged in the 1980s in Europe as a new disease in cattle and, since then, several actions are being taken for its prevention and control. Restricting the feeding of ruminants with animal by-products and the removal and destruction of specific risk materials (SRM) for the condition of carcasses in slaughterhouses have been proven effective to control the disease, in addition to the reduction of human exposure to the agent, as this is an important zoonosis. However, in 2004 the first atypical cases of BSE were diagnosed, in which the causative agents showed different molecular weights in Western blot (WB), compared to the classical form of the agent. In addition to the molecular differences, clinical presentations proved to be differentiated in atypical forms, affecting mainly cattle older than eight years. Because it is a new form of the disease, many studies are being conducted to elucidate the pathogenesis, epidemiology and zoonotic potential of atypical BSE. The aim of this study was to review the main aspects of atypical BSE emphasizing its etiology, epidemiology, clinical signs, diagnosis and control and prevention measures.

KEYWORDS:
prion; cattle; PrP^SC; L-BSE; H-BSE; BSE-SW