Variant Creutzfeldt-Jakob disease (vCJD) is a type of prion disease. Bovine spongiform encephalopathy is a prion disease that affects cows; there is evidence that this illness can be transmitted to humans, producing vCJD. This illness is often called “mad cow disease.”


Prion diseases are a unique form of infectious diseases. The disease is not produced by a bacterial or viral infection; instead, the illness is related to progressive accumulation of prions (infectious protein particles). The central nervous system is progressively damaged as these prions accumulate.

The Nervous System

Nucleus factsheet image
© 2009 Nucleus Medical Art, Inc.

Risk Factors

Exposure to prion containing tissue is the primary risk factor. Other risk factors include:

  • Eating beef from infected cows
  • Receiving human growth hormone (HGH) injections prior to the mid-1980s—Changes in the preparation of HGH in the mid-1980s eliminated this risk.
  • Working with brain tissue
  • Receiving a corneal or dura mater (brain lining) transplantation

Five to ten percent of all cases of the nonvariant form of Creutzfeldt-Jakob are inherited.


The average age of people who get this disease is 29 years old. Rare cases have been reported in children.

Once you are exposed, it can take up to 20 years until symptoms develop. When symptoms develop they usually follow these three phases:

Early Phase (0 to 6 Months)

Psychiatric symptoms predominate:

Middle Phase

Neurologic symptoms predominate:

  • Abnormal gait
  • Ataxia (problems with coordination)
  • Involuntary movements (muscle jerks and stiffness)
  • Cognitive decline (impaired speech)

Late Phase

  • Mute
  • Immobility

The average length of time from first symptoms to death is 13 months (with a range of 6-39 months).


The clinical history and physical exam are the primary diagnostic tools. If your physician suspects vCJD, additional tests may be needed, such as:

  • Lumbar puncture —a procedure to collect cerebrospinal fluid
  • MRI scan —a test that uses magnetic waves to make pictures of structures inside the head
  • CT scan —a type of x-ray that uses a computer to make pictures of structures inside the head
  • Electroencephalogram (EEG) —a test used to evaluate brain function or disorders
  • SPECT or PET scan —tests that produces images showing the amount of functional activity in the tissue; used to differentiate vCJD from other diseases
  • Biopsy —removal of a sample of tonsil tissue to test to confirm vCJD
  • Blood tests and cerebrospinal fluid analysis—may be used to distinguish this disease from other disease, such as Alzheimer's disease

In many cases, final diagnosis requires autopsy and pathological studies.


Currently, there is no cure for vCJD. Treatment is primarily supportive, maximizing function and minimizing discomfort.


About 200 worldwide cases of vCJD have occurred to date, most of which were associated with beef consumption in the United Kingdom. There is a great deal of controversy regarding safety of US beef. Two cases of bovine spongiform encephalopathy have been detected in the US. But, no cases of vCJD have been attributed to eating US beef.

To minimize risk, it is generally recommended that you avoid beef products, particularly processed meat (eg, sausage and hotdogs), or beef items containing brain, spinal cord, or bone marrow.