Scientists predict CJD deaths for 30 years

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New scientific forecasts suggest the true figure for those dying of the "new variant" of Creutzfeldt-Jakob disease (v-CJD) - the human form of "mad cow" disease - will probably lie between 1,000 and 10,000, and may be spread over the next 30 years.

But Peter Smith, a member of Seac, the government's advisory body on Bovine Spongiform Encephalopathy (BSE) and CJD, and also one of the authors of the new research, said yesterday that it could take up to four years before a clear picture emerges of precisely how many people will eventually be affected. "But the longer the numbers of cases arising remains small, then the sooner we can rule out the worst case," he said.

Recent data from the CJD Surveillance Unit, where two of the research authors work, suggested that the number of "suspected" cases of v-CJD was not large, he added. "The signs are encouraging, but it's too soon to be enormously encouraged."

Hours before the research was released yesterday, the Government said that it would more than double the funding for research into BSE and CJD over the next three years, providing an extra pounds 17m of new funding in the latest science budget, to raise the total three-year funding to pounds 30m. Departmental sources insisted last night that the timing was accidental.

Details of some of the research findings, including the forecast of a total death toll of hundreds of people, were revealed exclusively by The Independent in November, after an earlier version of the paper had been sent to the medical journal The Lancet. That was subsequently rejected. "At the current stage of knowledge, it's probably too early to predict how v-CJD will evolve," said The Lancet's editor, Richard Horton. He declined to say why the paper had been rejected.

But a revised version is published today in the science journal Nature. "It has been rigorously peer-reviewed, just like any other paper," said Nick Short, Nature's biological sciences editor.

The paper is based on data gathered from the 14 confirmed victims of v-CJD in the UK. The authors used statistical techniques and tested them against a series of assumptions, both about the incubation period required for BSE-contaminated food to cause v-CJD in humans, and the effectiveness - or lack of it - of the government's ban in November 1989 on the use of cow parts such as brains and spinal cords in human food.

The forecasts investigate incubation periods of between 10 and 25 years. However, past data from people who have developed CJD from human growth hormone injections suggest it takes at least 13 years to develop the disease, while kuru, a CJD-like disease found in Papua New Guinea cannibals, took up to 30 years. Most of the paper's figures give death tolls of below 1,000, with only a few predicting totals greater than 10,000.

The authors said that despite the lack of precision in the answers, the paper was useful because it gave some guidance on when it would be possible to give more definite answers about the future size of any epidemic.