Letter: Test for BSE

Sir: Of course there is a theoretical risk of blood donors who are incubating CJD transmitting the disease (report, 8 October). The subsequent fate of some of the patients who, between 1959 and 1985, received injections of CJD-contaminated human growth hormone suggests that it can be transmitted in this way.

The statement that it has "never occurred" through blood transfusion is meaningless. Here is a disease whose incubation period is measured in years and whose infective agent cannot be identified because it cannot be grown in an incubator and observed under the microscope in the usual way. There is only one way to prevent blood transfusions from transmitting CJD and that would be to use a test on all blood donors.

There is a possible test, devised by a distinguished virologist, Dr Harash Narang, who has devoted more than 25 years to the study of this mysterious infective agent. He first offered a test to the Ministry of Agriculture in 1988 and they refused to try it. It would have revealed that for every cow destroyed with florid BSE there would be hundreds incubating the disease but going into the food chain.

More recently the test would have identified cattle incubating BSE so that the cull policy could have been restricted to them instead of the arbitrary, unscientific and ultimately unsuccessful cull policy which has so far cost the suicides of three farmers and the taxpayer pounds 4bn. And his urine test has now been shown to be positive in 15 out of 15 humans who were subsequently proved to have CJD. Why is this test not being used to screen all blood donors?

H C GRANT MD FRCP

London NW3