Each sample (10% tissue homogenates) was inoculated by the intracerebral route (IC) to bovine PrP expressing mice (tgBov n = 6 per sample, 20 μL per mouse); a bioassay model identified in previous studies as a sensitive and robust approach for the detection and the quantification of vCJD infectivity [15, 17]. Here, PRNP is linked to variant Creutzfeldt-Jakob disease.