Creutzfeldt-Jakob disease latest unknown in struggle to restore faith in blood supply.

There was considerable medical interest in a recent Toronto conference on prion disease--and in Creutzfeldt-Jakob disease (CJD) in particular--because of the recent tainted-beef controversy in Britain. Although there is no proven link between a newly recognized variant form of CJD and "mad cow disease," and no evidence that CJD can be spread through the blood supply, the theoretical risk has scientists scrambling to understand how the disease is spread and policymakers struggling with the thorny issue of whether to notify persons who have received blood or blood products that may place them at risk. Until the mysteries of prion diseases and their transmission are unravelled, Dr. Peter Vaughan reports, physicians and their patients will have to live with uncertainty.