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Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob Disease

28 February 2019

Causative agent

Creutzfeldt-Jakob disease (CJD) is a rare disease that affects the brain. It belongs to a group of diseases called Transmissible Spongiform Encephalopathies (TSEs) that affect humans and other animals. TSEs are thought to be caused by the buildup of an abnormal, transmissible protein called 'prion' in the brain.

CJD can be grouped under four categories according to their aetiologies: sporadic (about 85% of all CJD cases), familial (5 - 15%), iatrogenic and variant.

Clinical features

The clinical feature of CJD is characterised by progressive dementia and difficulties in walking. Early symptoms include memory loss, unsteady gait and loss of coordination of limbs. These dementia-like symptoms will worsen and twitching of limbs and trunk will occur. Besides, visual disturbance, abnormal behaviours and seizures can occur. Most patients die within 1 year after onset of symptoms. 

Mode of transmission

The mode of transmission depends on the category of CJD:

  • The mode of transmission of sporadic CJD is unknown.
  • Familial CJD is caused by an inherited abnormal gene.
  • Iatrogenic CJD is transmitted during medical or surgical procedures, e.g. human tissue/organ transplant.
  • Variant CJD (vCJD) is linked to the consumption of food products from cattle infected with a type of TSE called Bovine Spongiform Encephalopathy (BSE, commonly known as 'Mad Cow Disease'). There were also overseas vCJD cases associated with blood transfusion.

Incubation period

Incubation periods for CJD are typically long, measured in terms of years and may be as long as 30 years.


Currently, there is no treatment or cure for any forms of CJD. Management remains supportive. No specific therapy has been shown to stop the progression of these diseases.


  • To prevent the disease from spreading, persons with CJD or vCJD must not be donors of organs, tissues or blood components or source of biologic products.
  • Use disposable instruments and disposable protective gears (for persons and work surfaces) wherever possible. Re-use of potentially contaminated surgical instruments should be avoided.

Based on the understanding that vCJD is linked to the consumption of bovine products contaminated with the BSE agent, the World Health Organization recommended that countries should not permit tissues that are likely to contain the BSE agent to enter any food chain.