Variant CJD: the present position and future possibilities.

Variant Creutzfeldt-Jakob disease (CJD) is one of the transmissible spongiform encephalopathies (TSEs), or prion diseases, and is thought to be due to transmission of BSE from cattle to man via diet. These are characterized by the tissue deposition of an abnormal isoform of the normal cellular prion protein, a progressive, fatal neurological course and having the potential for infectivity. Infectivity is difficult to inactivate, and instances of iatrogenic CJD have been reported. The involvement of the tonsil, appendix and other lymphoid tissue in variant CJD has increased concerns about possible human-to-human spread.