Adaptation of the bovine spongiform encephalopathy agent to primates and comparison with Creutzfeldt-Jakob disease: Implications for human health

There is substantial scientific evidence to support the notion that bovine spongiform encephalopathy (BSE) has contaminated human beings, causing vari ant Creutzfeldt-Jakob disease (vCJD). This disease has raised concerns abou t the possibility of an iatrogenic secondary transmission to humans, becaus e the biological properties of the primate-adapted BSE agent are unknown. W e show that (i) BSE can be transmitted from primate to primate by intraveno us route in 25 months, and (ii) an iatrogenic transmission of vCJD to human s could be readily recognized pathologically, whether it occurs by the cent ral or peripheral route. Strain typing in mice demonstrates that the BSE ag ent adapts to macaques in the same way as it does to humans and confirms th at the BSE agent is responsible for vCJD not only in the United Kingdom but also in France. The agent responsible for French iatrogenic growth hormone -linked CJD taken as a control is very different from vCJD but is similar t o that found in one case of sporadic CJD and one sheep scrapie isolate. The se data will be key in identifying the origin of human cases of prion disea se, including accidental vCJD transmission, and could provide bases for vCJ D risk assessment.