Creutzfeldt-Jakob disease (CJD) is a rare, fatal neurodegenerative disease that occurs in sporadic, genetic, variant, and iatrogenic forms. The transformation of normal prion protein (PrP(C)) to the abnormal form (PrP(Sc)) is a key step in the pathogenesis of CJD and leads to the accumulation of amyloid and spongiform changes in the brain. The presence of PrP(Sc) in tissue is a surrogate marker for CJD infectivity. Sporadic CJD, whose cause is unknown, is by far the most frequent form with 1-2 cases per million population occurring every year-the genetic forms of CJD are rather rarer. The majority of variant CJD cases have occurred in the United Kingdom, where there have been four reports of transmission of vCJD by blood transfusion. The great majority of iatrogenic transmissions of CJD have resulted from the use of pituitary-derived hormones or dura mater with only a very few cases attributable to neurosurgical instruments or corneal transplants. In the absence of a validated test for CJD infectivity in eye donors, the application of appropriate donor selection criteria and the use of single-use instruments in eye banks are currently the most effective means of reducing the risk of CJD transmission. Onward transmission by reusable ophthalmic surgical instruments has not been reported, but the risk cannot be excluded. Use of appropriate cleaning and disinfection protocols and the ability to identify and quarantine instruments that may have been used on an infected patient are important safeguards.

• G0600953/MRC_/Medical Research Council/United Kingdom
• G0900580/MRC_/Medical Research Council/United Kingdom