Dr. Buynder expressed concern that social media, the press and TV are reporting the small number of possible CJD cases being investigated as being connected to Bovine Spongiform Encephalopathy (BSE), otherwise known as "mad cow disease".
Fraser Health has looked into six possible cases of CJD over the last twelve months. After a case review on Friday 14th June, Buynder confirmed that the one patient who died had CJD, the other two who are in hospital probably have CJD, and the remaining three most likely do not.
The patient who died had been in a residential long-term care home and died one year ago. It is impossible to confirm CJD until after the person has died - a sample of brain tissue must be taken post-mortem and tested at a specialized laboratory.
An initial diagnosis can be made when the patient is alive, based on MRI images, an electroencephalogram, and testing the blood for specific proteins.
Dr. Buynder said:
"I want to be clear there is absolutely no evidence that these three confirmed or probable cases are linked to food consumption."
According to Fraser Health, there are approximately 30 cases of CJD in the whole of Canada each year. British Columbia would expect a "handful" each year, and Fraser Health about two cases. If the other two probable CJD cases are included, the total over the last twelve months will be 3, which Buynder described as "within statistical likelihood".
What concerns some people is that there are suddenly several CJD cases occurring all at once. Buynder says he is sure this in not a foodborne cluster of cases.
These are classical and not variant CJD casesAccording to Dr. Buynder, tests conducted on the patients show that these are classical cases of CJD, and not variant CJD (which is linked to mad cow disease). He added that this is not surprising given that Canada has never had a confirmed case of variant CJD that originated in Canada. There was one in 2003 and another in 2011, but in both cases CJD was contracted in the United Kingdom.
Dr. Buynder added "We have a strong public health surveillance system in B.C. and a review of the cases has not revealed any links between them which would suggest a common source of any kind. The patients investigated come from a number of different cities and settings."
What is CJD?Creutzfeldt-Jakob Disease, more commonly referred to as CJD is an extremely rare degenerative brain disorder which is invariably fatal.
Globally, about 1 in every 1,000,000 people develop CJD each year - approximately 200 cases in the USA, 30 in Canada, and 90 in the UK.
In the vast majority of cases, signs and symptoms of CJD (onset) start when the patient is about 60 years old. According to the National CJD Research & Surveillance Unit at the University of Edinburgh, UK, 90% of affected individuals die within 12 months.
Initial CJD symptoms include:
- failing memory
- changes in behavior
- coordination problems
- vision problems (visual disturbances)
- mental deterioration
- weakness of the extremities
There are four types of CJDGenetic CJD - caused by an inherited abnormal gene, the patient does not "catch" genetic CJD. The illness is usually known within the family because of the family history. There are some cases of genetic CJD with no family history identified. A blood test can identify the genetic abnormality.
Iatrogenic CJD - also a very rare disease. It is transmitted via a medical or surgical procedure. An example of a medical procedure is during Human Growth Hormone therapy in childhood. Diagnosis is not difficult, because the doctor/researcher can check what relevant medical or surgical treatment the patient has had.
Sporadic CJD (Classical CJD) - the most common form of CJD. Nobody is sure what the cause is. Experts believe that the normal prion brain protein undergoes a spontaneous change to the abnormal form. If this is the case, then Sporadic CJD is not human transmissible.
Variant CJD - this type was first described in the UK in March 1996, and has been associated with exposure to a TSE of cattle called BSE (Bovine Spongiform Encephalopathy), also known as Classical BSE or "mad cow disease".
Scientists from the UK, Australia and Papua New Guinea reported that the CJD incubation period could be more than 60 years.
Written by Christian Nordqvist