Risk of oral infection with bovine spongiform encephalopathy agent in primates

Summary The uncertain extent of human exposure to bovine spongiform encephalopathy (BSE)—which can lead to variant Creutzfeldt-Jakob disease (vCJD)—is compounded by incomplete knowledge about the efficiency of oral infection and the magnitude of any bovine-to-human biological barrier to transmission. We therefore investigated oral transmission of BSE to non-human primates. We gave two macaques a 5 g oral dose of brain homogenate from a BSE-infected cow. One macaque developed vCJD-like neurological disease 60 months after exposure, whereas the other remained free of disease at 76 months. On the basis of these findings and data from other studies, we made a preliminary estimate of the food exposure risk for man, which provides additional assurance that existing public health measures can prevent transmission of BSE to man. Published online January 27, 2005 http://image.thelancet.com/extras/05let1056web.pdf