A new test that can reduce the risk of transfer of variant Creutzfeld Jakob Disease (vCJD), or Mad Cow disease, through blood transfusions among humans by detecting prions in blood samples of humans with vCJD and in animals at early stages of the (asymptomatic) incubation phase has been developed, according to a new study published in the journal PLOS Pathogens.
To develop the assay, Olivier Andréoletti, from the Ecole Nationale Vétérinaire de Toulouse, France, and colleagues first optimized a method called PMCA (for Protein Misfolding Cyclic Amplification). The method mimics in a test tube the process by which misfolded (toxic) prions propagate, and the researchers determined experimental conditions that enable efficient PMCA amplification of the vCJD agent in the blood.
Having defined such conditions, they show that the assay can detect vCJD in asymptomatic but infected animals in the early phase of the incubation period. They examined blood samples collected from infected sheep and macaques (vCJD-infected macaques are considered the best model of the human disease). In both models, the assay can accurately identify infected animals and detect the presence of vCJD prions in blood from macaques shortly after the initial infection (and several years before clinical disease onset).
The authors say their "results represent substantial progress towards an applicable vCJD blood detection assay. Such assay could be used to identify vCJD infected but asymptomatic individuals and/or for screening donated blood for the presence of the vCJD agent".