Mad Cow Disease

Research findings from J.P. Clewley et al update understanding of opportunistic

"Study samples Anonymised tonsil pairs removed at elective tonsillectomy throughout U.K. and Scotland. National anonymous tissue archive for U.K. and Scotland. Main outcome measure Presence of PrPCJD determined by using two enzyme immunoassays based on different analytical principles, with further investigation by immunohistochemistry or immunoblotting of any samples reactive in either assay. Testing of 63 007 samples was completed by the end of September 2008. Of these, 12 753 were from the birth cohort in which most vCJD cases have arisen (1961-85) and 19 908 were from the 1986-95 cohort that would have been also exposed to bovine spongiform encephalopathy through infected meat or meat products. None of the samples tested was unequivocally reactive in both enzyme immunoassays. Only two samples were reactive in one or other enzyme immunoassay and equivocal in the other, and nine samples were equivocally reactive in both enzyme immunoassays. Two hundred and seventy six samples were initially reactive in one or other enzyme immunoassay; the repeat reactivity rate was 15% or less, depending on the enzyme immunoassay and cutoff definition. None of the samples (including all the 276 initially reactive in enzyme immunoassay) that were investigated by immunohistochemistry or immunoblotting was positive for the presence of PrPCJD. The observed prevalence of PrPCJD in tonsils from the 1961-95 combined birth cohort was 0/32 661 with a 95% confidence interval of 0 to 113 per million. In the 1961-85 cohort, the prevalence of zero with a 95% confidence interval of 0 to 289 per million was lower than, but still consistent with, a previous survey of appendix tissue that showed a prevalence of 292 per million with a 95% confidence interval of 60 to 853 per million," wrote J.P. Clewley and colleagues.

The researchers concluded: "Continuing to archive and test tonsil specimens, especially in older birth cohorts, and other complementary large scale anonymous tissue surveys, particularly of post-mortem tissues, will further refine the calculated prevalence of PrPCJD."

Clewley and colleagues published their study in British Medical Journal (Prevalence of disease related prion protein in anonymous tonsil specimens in Britain: cross sectional opportunistic survey. British Medical Journal, 2009;338():B1442).

For additional information, contact J.P. Clewley, Health Protect Agcy, Center Infection, London NW9 5EQ, UK.

The publisher of the British Medical Journal can be contacted at: B M J Publishing Group, British Med Association House, Tavistock Square, London WC1H 9JR, England.

Keywords: United Kingdom, London, BSE, Bovine Spongiform Encephalopathy, Bovine-spongiform Encephalopathy, Creutzfeldt-Jakob Disease, Immunoassay, Mad Cow Disease, Neurology, Opportunistic, Public Health, Surgery, Tonsillectomy.

This article was prepared by Pain & Central Nervous System Week editors from staff and other reports. Copyright 2009, Pain & Central Nervous System Week via NewsRx.com.