Medical Research Council experts found memory and behaviour problems could be tackled by stopping production of the proteins corrupted in such diseases.
vCJD, BSE in cattle and scrapie in sheep are all caused by a build up of abnormally shaped versions of proteins called prions in the brain.
Normal prions have a very brief lifespan. But in prion diseases, they become malformed and start to accumulate.
They then damage the synapses, which pass messages between nerve cells in the brain, and eventually the cells themselves die.
He said it appeared that in the early stages of prion disease in the brain, synapses were frozen, rather than being destroyed immediately; and that halting the process then allowed function to be restored.
"It means that the prospect of being able to do something for people may be much better than we thought. We may be able to reverse the behavioural effects."
Another interesting point, which I seem to have missed, is that prions may actually be a normal part of an organism.
Back when I first heard about them, "prion" was short for "proteinaceous infections material". Now it seems it's not always an infection.