This is a major scientific breakthrough and has potential applications in improving tests for prion diseases

Silvano Fumero Serano

This is because it is caused by an abnormal protein, called a prion, which exists in tiny quantities until it begins to affect the brain.

But the Swiss researchers say their work could make it possible to recognise the disease from a blood sample.

The abnormal prions which cause BSE and vCJD spread by "converting" other prions which they come into contact with in a chain reaction.

They are present in the blood and tissues other than the brain in such small amounts as to be undetectable, until now.

'Fast-forward mode'

But Claudio Soto and colleagues at the SerOno Pharmaceutical Research Institute in Geneva say they have managed to accelerate the conversion process in the laboratory.

This offers hope of detecting prion diseases where previously they would be invisible.

Silvano Fumero, a senior executive at SerOno, said: "The procedure mimics the replication of abnormal prion proteins in the body in 'fast-forward' mode, compressing years of real-life time into a few hours in the laboratory.

"This is a major scientific breakthrough and has potential applications in improving tests for prion diseases, as well as identifying targets against which future drugs should be aimed."

The researchers believe the method could lead to the identification of abnormal prions in vCJD victims by testing spinal fluid or blood.

Their work may also open up new avenues for identifying other similar diseases in animals, such as BSE in cattle and scrapie in sheep.

The breakthrough was reported in the scientific journal Nature.

'Root and branch' reform

Meanwhile, one of the UK's leading food safety experts has blamed the government for the scale of diseases such as BSE and foot-and-mouth.

Professor Hugh Pennington, of Aberdeen University, says the lessons of the outbreaks have still not been learned.

And he said that without "root and branch reform", another disaster was waiting to happen.