Britain may be facing a staggering number of patients with vCJD, the human form of BSE.
A new study suggests there could be as many as 6,600 cases, a figure which an Irish expert described as "frightening". Attempts to run a similar study here have so far been slow to progress.
Details of the study are published this morning in the British Medical Journal. A large team looked for signs of variant Creutzfeldt-Jakob (vCJD) disease in discarded tissues collected after tonsil and appendix surgery, analysing some 11,228 anonymous samples.
They screened for the disease in people aged between 10 and 50 and who were showing no clinical signs of vCJD, an invariably fatal illness linked to the consumption of BSE-infected meat. The prion protein that causes the disease was detected in one in 8,318 tissue samples, the researchers found, equivalent to 120 cases per million population. This would give Britain a caseload of about 6,600 cases.
"It is a very big figure and a very reputable source and the implications for Ireland will have to be teased out locally," said Dr Michael Farrell, consultant neuropathologist at Beaumont Hospital and member of the Government's National CJD Surveillance Committee.
"One hundred and twenty per million is ferocious. It is worrying," he said, but added that these figures could not be reapplied in the Republic. "We can't apply the British results to Ireland. You can't make assumptions."
The Republic had a much lower BSE rate than Britain, he said, and only one confirmed vCJD case. Britain had a very high BSE incidence in cattle and has had 115 vCJD deaths to date, according to the BMJ paper.
Just how many cases of vCJD to expect in the coming years remains one of the most important unanswered questions arising from the BSE crisis. This study was set up to answer that question by testing tissue types known to accumulate the vCJD prion long before the person begins to show signs of the disease.
Attempts to run a similar study here have been stymied by concerns over ethical issues, however, according to informed sources. Tissues from appendicectomies and tonsillectomies were universally discarded in the past, according to hospital staff, but hospital authorities are reluctant to become involved in an anonymous screening programme.
They cite ethical concerns related to the retention of tissues, particularly given the controversy related to retained organs which were taken in the past without the consent of patients or next of kin.
Anonymity poses another hurdle, according to sources. If a patient's tissue tests positive for the vCJD prion, and the onset of the disease is certain, should they be warned? Lessons from the Lindsay Tribunal and the blood product scandals suggest they should be warned - but voluntary participation in such a screening programme would then be low.
The authors warn that this first estimate of the number of people in Britain who may be potential sources of vCJD carries a margin of error. They call for large-scale screening to get a better idea of the future caseload.
The surprisingly high result from the UK study also meant that the Republic should undertake a similar programme, Dr Farrell said.
"This is all the more reason why we have to do the study here now."