Spotlight:

You are here: Home > Spotlight > Mad Cow Disease in Canada

Background on Mad Cow Disease in Humans

What is the Human Form of Mad Cow Disease?

The human form of Mad Cow disease is called Creutzfeldt-Jakob disease (CJD). As in the cattle form of the disease, scientists suspect that CJD is caused by abnormal protein in the brain. CDJ also results in damage to brain tissue, nervous system disorders, and is fatal.

What are the Different Types of CDJ?

There are two types of CDJ: classical CDJ and variant CDJ.

Classical CDJ

• Classical CDJ has been present in human populations for many years. On average, one person in a million dies of CJD every year.
• Classical CJD tends to be transmitted only by contact with infected people’s brains.
• It is thought that classical CDJ cannot be contracted from animals.

Variant CDJ

• Variant CDJ was discovered following the Mad Cow outbreak in Great Britain, and represents a different strain of the infection.
• Unlike classical CDJ, variant CDJ can be transmitted from animals to humans by ingesting cattle products infected with the Mad Cow disease.

More information on CDJ

How is Variant CDJ Transmitted?

Humans contract variant CDJ by ingesting cattle tissue that is infected with the Mad Cow disease. Risk of transmission depends on the cut of meat ingested. Concentration of the prion protein that causes Mad Cow and variant CDJ is highest in the brain and spinal cord of an infected cow. Whole cuts of meat without the bone (such as steaks and roast) provide a lower level of risk of potential Mad Cow contamination. Processed cow products (such a ground beef or burgers) may contain brain or spinal cord parts, and thus present a higher risk of contamination. Unlike other food-born pathogens, simply cooking the infected meat cannot kill Mad Cow. Milk and milk products from cows are not believed to pose any risk for transmitting Mad Cow disease to humans. Furthermore, there is yet no evidence that variant CDJ can be transmitted between humans by blood or through casual contact, such as kissing or sexual contact.

What are the Symptoms of Variant CDJ?

Early variant CJD symptoms include anxiety, depression, withdrawal, behavioural changes, persistent pain, or odd sensations in the face or limbs. Later symptoms include motor difficulties, involuntary movements and mental deterioration. A person infected with CDJ lives on average for about one year after the onset of symptoms.

How is Variant CDJ Diagnosed?

Examination of brain tissue is the only means of establishing a final confirmation of infection by Mad Cow or CDJ. This can only be done after the person has died. Probable diagnoses in humans can be established through brain scans using magnetic resonance imaging (MRI) or through a tonsil biopsy.

Is There a Treatment for Variant CDJ?

At present, there is neither a cure for CDJ, nor a treatment to slow the progression of the diseases.

Next >>
Mad Cow Worldwide

© 2001-2006 Maple Leaf Web.
All Rights Reserved

This page was last modified: August 10, 2007