After exposure to contaminated beef, how long does it take for vcjd to develop?

Decades: Hi Member466, Creutzfeldt-Jakob Disease or mad cow disease is a form of dementia that can take 15-20 and sometimes up to 50 years to develop after eating contaminated meat. While a slow virus or " Prion" , an infectious protein particle may be involved, a definitive cause is still unknown. Hope this sheds some light on your question. Thank you.