A North-East mother who lost a son to the human form of mad cow disease, says she is shocked that the disease can be transmitted through infected blood.

Frances Hall, of Chester-le-Street, County Durham, was reacting to new evidence that the human form of the disease - variant Creutzfeldt-Jakob Disease - can be passed from person to person through infected blood.

Health Secretary John Reid told MPs of an incident in which a patient died after receiving blood years earlier from a donor who contracted vCJD.

He said the case was the first report from anywhere in the world of the possible transmission of the killer brain disease via blood transfusions.

Officials are now looking at whether further precautions need to be taken to reduce the risk of infection through blood transfusion.

Dr Reid said that so far there had been no sign of the thousands of cases of vCJD that some projections had forecast.

As of December 1 there had been a cumulative total of 143 vCJD cases in the UK, and over the past three years, the annual number of new cases had fallen.

Mrs Hall, who is secretary of the Human BSE Foundation, said: ''It's obviously very worrying. The information from this death seems to make it more likely that blood can carry the disease.

''It's going to be very frightening for people who have received blood transfusions from victims. That's something they are going to have to live with."

Mrs Hall, who lost her son, Peter, to the disease in 1996, said as far as she knew none of the 15 known recipients of blood from vCJD donors had been in touch with her organisation. But she said the Human BSE Foundation would offer any help possible.