More people may be at risk from Mad Cow disease

The death of a thirty year old man from Creutzfeldt-Jacob disease (vCJD) has raised fears that more people in the UK may be at risk from the disease than previously thought.

vCJD, often referred to as the human "mad cow disease", is strongly linked to eating meat infected with bovine spongiform encephalopathy.

It is caused by a type of infectious agent called prions, which consist mostly of protein. Prion protein is normally found on the surface of human cells, including those found in the brain.

However, disease-causing prions contain proteins with an abnormal structure, which cause other normal prion proteins on the surface of cells to change shape and spread, causing fatal brain disease.

To date, all 166 people who have died as a result of vCJD have had the same type of human prion gene. As this gene is found in around a third of the UK population, it was assumed that two thirds were more resistant to the vCJD prion.

But the recent vCJD victim, as reported in today's Lancet, was found to have a form of the prion gene which differed from all other cases. This raises the possibility that more people are at risk from the disease than previously thought.

The scientists also pointed out that other prion diseases such as kuru, or other types of CJD tend to have longer incubation periods in people with a similar form of the prion gene. With kuru, it can take up to 50 years before the disease becomes apparent.

This could also be the case for people with the same form of prion gene as the latest victim. It may be that more people in the UK are infected, but have yet to show signs of the disease, said the scientists.

This article was published on Fri 18 December 2009