Thousands Face New Tonsil
Test For Mad Cow/CJD Infection
ITV Teletext Service UK
Thousands of people are to be tested for CJD after scientists discovered evidence of the human form of cow disease in people's tonsils.
The find means it may be possible in the next three years to establish if a CJD time bomb is ticking within Britain's population.
It also raises concerns about the rise of infection from surgical equipment.
BBC News Health 1-15-99
New variant CJD is believed to be linked to BSE in cows
Scientists have developed a test for CJD which could show the extent of the disease in the population.
Until now it has only been possible to diagnose cases of new variant CJD, the disease linked to BSE in cattle, after death.
The test involves taking tissue from the tonsils and can be conducted on living people.
The findings could eventually mean scientists will be able to develop a test which could diagnose people with nvCJD as soon as they are infected.
Research can now be done on material from tonsillectomies to estimate the extent of nvCJD - which has a long incubation period - in the general population.
But the findings also raise concern about infection caused by the rogue proteins that spread the disease and cannot be cleaned from surgical instruments no matter how thoroughly they are sterilised.
Writing in The Lancet, the scientists led by Professor John Collinge at the Imperial College School of Medicine at St Mary's Hospital in London, say they tested tonsil tissue from 20 patients in the late stages of suspected prion disease.
An abnormal form of the protease-resistant prion protein is thought to cause the breakdown of brain cells associated with nvCJD.
Prions reproduce in the tissues of the immune system, including the tonsils.
Because of the theoretical possibility that the disease could be spread by surgery to the infected organs Professor Collinge recommends that for such operations only disposable surgical instruments be used.
The infection can withstand high temperatures which make the usual sterilisation procedures ineffective.
Dr Stephen Dealer, from the BSE Research Campaign, said the findings would help to assess the risk from surgical instruments.
"This is one of the reasons why John Collinge's test may be so wonderful. It will give use some insight into just how big that risk is. This is a very important finding," he told BBC Radio 5 Live.
Thirty-three cases of nvCJD in the UK and one case in France have been confirmed since 1996.
The researchers also tested tonsil, spleen and lymph node tissues from patients who had died of the disease.
They found that all immune system tissue obtained from dead patients whose CJD had been confirmed by brain biopsies contained the rogue prion.
Different progression
Tonsil biopsies of living patients found the tissue was positive for the prion in the three cases which were confirmed on death to have the disease.
The research also showed that nvCJD has a different progression from normal CJD and may spend longer in the immune system.
This suggests it could present greater dangers of infecting people through blood tranfusions, organ transplants and tissue-sharing.
They believe the difference in progression may be due to the suspected root of exposure - through eating BSE-infected meat.
This could suggest that the people who have developed nvCJD have immune systems which are particularly susceptible to nvCJD.
The scientists believe they may eventually be able to develop a test which is sensitive enough to detect prion infection at an early stage of infection.
Definite diagnosis
Professor Collinge, whose research is funded by the Wellcome Trust and the Medical Research Council, said: "This new test has already proven very helpful in the diagnosis of new variant CJD.
"While, unfortunately, we have at present no means to treat this dreadful disease, we can at least now provide a definite diagnosis at an earlier stage."
He said research needed to continue to identify whether it would be possible to detect the disease through a simple blood test.
Excite UK Channels News New CJD Fears After Test Finds Disease In Tonsils 1-15-99
Scientists have discovered evidence of CJD, the human form of mad cow disease, in people's tonsils.
The find means it may be possible in the next three years to establish if a CJD time bomb is ticking within Britain's population.
But it also raises renewed concerns about the risk of infection from surgical equipment in hospitals, the expert behind the discovery said.
Scientists plan to screen thousands of people using the new test. A significant positive result would provide early warning of a major epidemic to come and allow time for action aimed at averting the disaster.
Professor John Collinge, from St Mary's Hospital, London, said: "If we were to screen several thousand tonsils and found that several were positive that would be a real cause for concern."
The concern about infection raised by the new findings centres on rogue prion proteins that spread the disease and cannot be cleaned from surgical instruments no matter how thoroughly they are sterilised.
In future therefore it may be necessary to introduce disposable instruments for certain procedures. A special committee of experts advising the Government is already looking at this issue.
Animal studies have shown that spongiform encephalopathy diseases, which include different forms of CJD, BSE in cattle and the sheep infection scrapie, tend to reside in the lymph system before attacking the brain. Tonsils are linked to the lymph system.
The new research by Professor Collinge's team showed this also appeared to be the way new variant CJD behaved in humans.
But only the new variant form of CJD, which is effectively mad cow disease transferred to humans through infected beef, was detected in tonsils. The "classical" form of CJD, which appears for no known reason in one person in a million, was not seen in the tissue samples.