All surgery at a hospital in Ontario Canada has been halted after it was discovered that a patient undergoing neurosurgery on November 30th may have had the fatal brain-wasting disease Creutzfeldt-Jakob (CJD).
The neurosurgery took place at University Hospital, London and officials say there was a chance that instruments used in that patient's surgery could have been used in other procedures on other patients, so as a precaution all surgery has been cancelled.
CJD is a disease caused by protein-like particles called prions which attack the brain, killing cells and creating gaps in tissue; it is always fatal and anyone can potentially develop it.
There are two main types of CJD; classical and variant.
Before the mad cow disease epidemic in the mid-1990s in Britain, few people had heard of CJD and it was always considered rare.
However a decade ago the unusually large number of people in Britain who developed what appeared to be CJD who were relatively young, had all eaten meat from cattle suspected of having bovine spongiform encephalopathy (BSE), the medical term for mad cow disease.
Scientists eventually concluded that the new ailment named variant Creutzfeldt-Jakob disease (vCJD), was a form of Creutzfeldt-Jakob disease resulting from exposure to BSE.
Since then a number of cases of vCJD have been linked to contaminated beef in Great Britain and in other countries, including Spain, Portugal, France and Germany.
Although "classic" Creutzeldt-Jakob disease has not been linked to infected beef, it is similar to vCJD in many respects. No treatment exists for either type of CJD, and nothing can slow the progression of the disease.
Classical CJD occurs in the general population at a rate of about one case per million people per year throughout the world.
In Canada, about 30 cases of classical CJD are diagnosed each year.
Officials said there was a chance that instruments used in the patient's surgery could have been used in other procedures on other patients.
They emphasized chances of contamination are low, and say the problem is that routine sterilization in hospitals does not necessarily inactivate CJD particles, the prion.
While modern hospital washes do remove probably more than 99.9 per cent of prion particles from surgical instruments, the risk of transmission on surgical instruments is considered extremely low.
The hospital believes the patient may have the more common, sporadic form of the disease known as classical CJD, not the variant CJD, which is linked to mad cow disease.
He apparently did not have the symptoms of the disease and was suspected of having another medical condition for which brain biopsy is an indication.
Although there is no evidence that blood from people with sporadic CJD is infectious, studies have found it is possible that blood from people with vCJD may be infectious.