The full extent of the vCJD outbreak of the mid-1990s might not yet be realised according to new findngs.

Although measures were taken to prevent further transmission to humans after the outbreak of variant Creutzfeldt–Jakob disease (vCJD) from infected cattle in the mid-1990s, prion diseases are controlled by genetic factors, and normal variations in DNA might influence susceptibility to prion diseases and affect the length of their silent incubation period, claim researchers from the UK Medical Research Council Prion Unit at University College London.

The two most likely routes of infection with prions are through eating infected tissue from the central nervous systems of animals or humans or through transfusions with contaminated blood, but whether a person will succumb, and when, are under genetic control.