Mad Cow/CJD Can Be
Transmitted Through Surgery!
By Steve Connor
Science Editor
The Independent UK
Scientists have found new evidence to suggest that the human version of "mad cow" disease might be transmitted during surgery via contaminated surgical instruments.
A test for the new variant form of Creutzfeldt-Jakob disease (nvCJD) shows the infectious agent responsible for the brain disorder is present in tonsils and certain other tissues handled in thousands of routine operations. Experts fear the nvCJD agent could survive the sterilisation procedures for surgical instruments and bepassed from person to person during hospital treatment.
Government experts are drawing up a set of new guidelines on the use of disposable scalpels, forceps and other surgical instruments to limit the risks to patients. An anonymous mass screening programme is also planned for later this year to detect people incubating nvCJD.
Thousands of tonsils are to be tested at random over the next few years to try to determine how many in the general population are infected with the human form of bovine spongiform encephalopathy (BSE). At present there are 35 confirmed cases of nvCJD, which scientists believe developed as a result of people eating beef contaminated with BSE, but there are fears that this might be the first signs of an epidemic. Attempts to estimate the future course of the disease have been hampered by a lack of knowledge and a suitable test for early diagnosis.
Professor John Collinge, a consultant neurologist at the Imperial College School of Medicine at St Mary's hospital in London, said yesterday he has developed a tonsil test for nvCJD which will be used in the mass screening programme to diagnose the infectious agent, believed to be a rogue "prion" protein. Previously, doctors could only reliably confirm nvCJD with an examination of the brain after death. "[The prion] is present in every tissue of every case of nvCJD [we studied] and it's present at quite considerable levels," Professor Collinge said. "This has implications for the risk of the infection passing from one person to anothers. We don't know yet the level of infectiousness in those tissues."
This raised the prospect of using disposable instruments wherever possible because "there is no means of sterilising surgical instruments adequately against prions".
Research funded by the Medical Research Council and the Wellcome Trust, published in The Lancet, shows that although the tonsil test could detect the infectious prion protein in nvCJD cases, this was not the case for "classical" CJD. Professor Collinge said this shows how the rogue prion protein behaves quite differently to CJD.
Professor Liam Donaldson, the Chief Medical Officer, said last night: "Current policy based on advice from the Advisory Committee on Dangerous Pathogens published in April 1998 is that when any patient with symptoms of nvCJD, or suspected of having nvCJD, undergoes surgical operation, the instruments must be removed so that they cannot be used again."
How many more will die?