Researchers studied specimens from appendicectomies and tonsillectomies carried out between 1995 and 1999. They also examined samples removed at autopsy or during surgery from patients with variant Creutzfeldt-Jakob disease. The samples were tested for lymphoreticular accumulation of prion protein, which is known to be a reliable marker of the disease in animals.
Prion protein was detected in one of the 8318 samples removed between 1995 and 1999. In the appendixes removed before the onset of symptoms in the patients with vCJD two out of three tested positive and in the specimens removed at autopsy, the figure was 19 out of 20. The results give an estimated detectable prevalence of prion protein accumulation of 120 per million.
The margin of error for this figure is high and the authors stress the need for large scale screening of tonsil tissue to obtain precise data. Because half of tonsillectomies are in children under 10, who have had little exposure to BSE, this opportunity will diminish over time, they conclude.