Dr Brandner and colleagues from the United Kingdom carried out a survey of archived appendix samples to understand better the differences between existing estimates of the prevalence of subclinical infection with prions after the bovine spongiform encephalopathy epizootic.
The research team exmined whether a broader birth cohort was affected, to understand better the implications for the management of blood and blood products, and for the handling of surgical instruments.
The researchers evaluated archived appendix samples from the pathology departments of 41 UK hospitals participating in the earlier survey, and additional hospitals in regions with lower levels of participation in that survey.
|The overall prevalence was 493 per million population|
|British Medical Journal|
The team assessed a sample of 32,441 archived appendix samples fixed in formalin and embedded in paraffin, and tested for the presence of abnormal prion protein.
Of the 32,441 appendix samples 16 were positive for abnormal prion protein, indicating an overall prevalence of 493 per million population.
The researchers observed that the prevalence in those born in 1941-60 did not differ significantly from those born between 1961 and 1985, and was similar in both sexes and across the 3 broad geographical areas sampled.
Genetic testing of the positive specimens for the genotype at PRNP codon 129 revealed a high proportion that were valine homozygous compared with the frequency in the normal population, and in stark contrast with confirmed clinical cases of vCJD, all of which were methionine homozygous at PRNP codon 129.
Dr Brandner's team concludes, "This study corroborates previous studies and suggests a high prevalence of infection with abnormal prion protein, indicating vCJD carrier status in the population compared with the 177 vCJD cases to date."
"These findings have important implications for the management of blood and blood products, and for the handling of surgical instruments."