A SIMPLE blood test for the human form of mad cow disease may be within reach, thanks to a breakthrough announced by scientists.

Experts believe they may eventually be able to tell who is at risk by developing a test that will provide an answer to fears of a widespread epidemic once and for all.

But the mother of a North-East victim of variant CJD warned last night that a test could lead to the creation of an underclass of people denied access to insurance and mortgages.

For the first time, researchers have found a way to isolate the infectious agents behind diseases such as BSE and its human equivalent, vCJD.

The discovery paves the way for new diagnostic tests and may also provide an efficient method of cleaning up blood products.

If sensitive enough, it could lead to a straightforward blood test which would show whether a person was infected with vCJD.

The discovery could eventually open the door to the first treatment for vCJD.

Frances Hall, from Chester-le-Street, County Durham, who lost her 20-year-old son Peter to vCJD four years ago, said a test would reduce the agonising wait for a diagnosis but could be open to abuse.

"Will the insurance and mortgage companies insist that everyone will have to have this test? Unfortunately, I can see that coming," she said.

Mrs Hall said she would not wish to be tested until a cure was found.

Kevin Minto, from Sunderland, whose wife Mandi died from vCJD, said he was already worried that his two sons might encounter difficulties simply because of their mother's illness.

Variant CJD and related diseases such as BSE in cattle and scrapie in sheep are believed to be triggered by proteins, called prions, which have changed shape.

In their new form, they kill brain cells. A team of Swiss and Austrian scientists, led by BSE expert Professor Adriano Aguzzi, said that they had found a way to separate potentially deadly and harmless prions. The researchers reported their findings in the science journal Nature.

Experts know that vCJD can theoretically be transmitted in blood. White cells, thought to be the most likely carriers, are already filtered out of all donated blood in the UK as a safety precaution.

For the same reason, only imported plasma is used to make therapeutic blood products.

Yesterday, it was reported that in 1997 doctors running treatment centres for people with haemophilia were advised not to tell their patients that blood products about to be recalled could include tissue donated by vCJD victims.

A previously unpublished memo from a laboratory in the Home Counties recommended to doctors that "recipients should not be informed that the product that they have received has been recalled for this reason".

A spokesman for the regional pressure group Haemophilia North, who has already contracted HIV, hepatitis B and hepatitis C through infected transfusions said it was "a disgrace" that doctors had been advised to cover up the truth.

But a Department of Health spokeswoman pointed out that it had received advice from ethics experts that there is no need to inform patients because "it is thought unlikely that vCJD will be transmitted in this way. There is no diagnostic test and even if a test was available, there is no preventative treatment that could be offered."

Victims' ordeal - Page