CJD

NZ Ministry of Health Web Page
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Creutzfeldt-Jakob Disease (CJD)

What is Creutzfeldt-Jakob Disease (CJD)?
Creutzfeldt-Jakob Disease is a rare fatal brain disorder which was first recognised more than 80 years ago.

There is no effective treatment and no reliable test to predict the disease. Approximately 85 percent of Creutzfeldt-Jakob Disease illnesses occur spontaneously without any known cause.

Other causes include certain medical treatments that are no longer used such as human growth hormone injections and dural grafts (brain membrane). The symptoms may take 30 years to develop.

Since the disease was identified by Dr. Alfons Maria Jakob in the 1920's, over 3,000 cases have been reported world-wide.

What is variant Creutzfeldt-Jakob Disease (vCJD)?
A new and more aggressive strain of the disease which was identified in the United Kingdom in 1996. It produces similar symptoms to classical CJD though the disease develops more rapidly.

Variant CJD is thought to be contracted by eating meat infected with bovine spongiform encephalitis (BSE) which has been described as "mad cow disease". It historically has affected people in the 16 to 52 year age group. The mean age is 28 years.

What are the unique differences between CJD and vCJD?
CJD tends to affect people aged from 60 years and over and symptoms may take 30 years to develop, whereas vCJD has been found in teenagers and young adults and it develops more rapidly. A striking early feature of vCJD is prominent psychiatric disturbance.

What causes variant CJD?
The agent that causes vCJD is believed to be an abnormal form of a protein, known as a prion. Prions are normal cellular proteins that are present in many organs and tissues, including the brain, spinal cord and eyes of healthy humans and animals.

The abnormal form of prion causes surrounding proteins to change their shape. The abnormal protein collects in central nervous tissue and by an unknown mechanism causes the nerve cells to die. This results in the characteristic holes in the brain tissue that can be seen under the microscope.

Have there been any cases of CJD in New Zealand?
Since 1980 approximately two to three cases of Creutzfeldt-Jakob Disease have been identified in New Zealand each year. This figure represents approximately one case per million people per year - the expected rate seen internationally.

In 1996 CJD was made a notifiable disease and a case register for CJD established. The register is similar to those already operating in Australia and the United Kingdom. This means all cases of CJD are notified so that cases can be reviewed and investigated to ensure consistent diagnosis and risk factor identification. Since 1996 to 2008 there has been a total of 41 cases of definite (14) or probable (27) CJD documented by the Registry.

Have there been any cases of vCJD in New Zealand?
No.

How is vCJD diagnosed?
Once a suspected case of vCJD is reported New Zealand’s CJD Registry, the Registry coordinates testing and works with case physicians and international experts to confirm the diagnosis. The diagnosis of vCJD is very difficult, but brain scans, using magnetic resonance imaging (MRI), and tonsil biopsy are two types of tests used to establish a probable diagnosis. However, the final confirmation of vCJD can only be done by examining brain tissue, generally after the patient has died.

Is there a test for vCJD?
Not yet. The types of tests that are used to screen blood donations for viruses cannot be applied to vCJD because it is a different type of disease. Several international groups of research workers are working to try and develop a blood test but it is unclear what the time frame is likely to be.

How many people in the UK have vCJD?
Figures released as at May 2009 for the UK indicated that the total number of definite or probable cases of vCJD (dead or alive) was 168.

Have there been any other reports internationally of vCJD?
As of February 2009 there were cases reported in France (23), Hong Kong (1*), Ireland (4), Italy (1), United States of America (3) and Canada (1), Netherlands (3), Portugal (2), Spain (5), Saudi Arabia (1), Japan (1).

* individual who has spent long periods in the UK .

What are health authorities doing to protect New Zealanders from CJD and vCJD?
On 17 February 2000 New Zealand commenced excluding donors from giving blood if they had spent six months or more in the UK between January 1980 and December 1996. The six-month period is cumulative. New Zealand has also introduced leucodepletion - which is white blood cell filtering for all other blood donations.

A review of the preventative measures to reduce possible risk of transmission of vCJD by blood and blood products was carried out in 2002. As a result of that review donors with a history of transfusion in the UK since 1980 and the present are now also excluded from blood donation.

In April 2006 additional measure based on concerns relating to the increasing number of cases of vCJD report in France and Ireland. These measures reflect those introduced earlier relating to travel/residency and transfusion in the United Kingdom.

From 24th April 2006 prospective donors who have:

visited or lived in the UK (England, Wales, Northern Ireland, Isle of Man and Channel Islands) or in France or the Republic of Ireland between 1 January 1980 and 31 December 1996 for a total period of 6 months or longer will be permanently deferred from donating blood in New Zealand
received a blood transfusion in UK, France or the Republic or Ireland since 1980 will be permanently deferred from donating blood in New Zealand.

Are health authorities being over-cautious?
Safety is our key priority. These steps have been taken to maintain public confidence and safety of the blood supply.

Why was the period 1980 to 1996 chosen?
The first cases of bovine spongiform encephalopathy (BSE) were identified in 1986. Because scientists believe that the incubation period for the disease is five years, it likely appeared in cattle in 1980. Variant CJD is related to BSE. It is possible that people were exposed to BSE through food when cattle were fed bovine offal. Although the UK introduced a ban on bovine offal in 1989, the ban was not fully enforced until 1996 following identification of the first cases of vCJD.

Why is six months the cut-off for deferring donors?
The period of 6 months was chosen on the basis that it will greatly reduce the exposure of donors to BSE risk. The policy is expected to reduce the risk of vCJD without jeopardising the safety of the blood system.

What impact did the deferral policy have on blood donors?
The New Zealand Blood Service lost approximately 10%, or 12,000 of its active donors as a result of the deferral policy based on cumulative residency in the UK and introduced in February 2000.

The anticipated impact of the policy extended to include France and the Republic of Ireland is that 0.25% of current donars will be lost by these new measures.

If I received a blood transfusion, should I be concerned?
No. There is no need to be alarmed about your health. There have been no cases of vCJD reported in New Zealand.

In the UK authorities have been following closely a small group of about 30 patients who received blood components from donars who subsequently developed vCJD. By February 2006, three of these people developed vCJD. This cluster indicates that vCJD must now be considered as a transfusion transmissable infection.

To date all cases of probable transfusion associated vCJD have received red call tranfusions. No cases have been reported from patients who received manufactured plasma products such as Factor VIII or immunoglobin.

If I have spent time in the UK, can I donate organs?
Yes. The Ministry sought advice on the issue and it was decided to maintain the status-quo but with informed consent.

Should I have a check up if I have lived in the UK?
No. There is no need to be concerned about your health, and the Ministry does not believe it is necessary to see a doctor.

Page last updated: 28 May 2009

Creutzfeldt-Jakob Disease (CJD)

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