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Symptoms and Signs of Mad Cow Disease (Variant Creutzfeldt-Jakob) Symptoms, Treatment, Prognosis

Doctor's Notes on Mad Cow Disease and Variant Creutzfeldt-Jakob Disease

"Mad cow" disease and Creutzfeldt-Jakob disease (CJD) are types of infectious disease caused by proteins in the brain called prions that affect the brains of cattle. “Mad cow” disease occurs after people eat beef infected with the disease, but due to government oversight this form rarely occurs. Creutzfeldt-Jakob disease is more common and is due to genetics, infected surgical instruments or transplant tissues, and can also occur with no known cause.

Symptoms of “Mad cow" disease and Creutzfeldt-Jakob disease include changes in attitude and behavior, muscle spasms, lack of muscle control, gradual uncoordinated movements, trouble standing and walking, weight loss despite having an appetite, and worsening problems with memory. In the early stages, people may also experience psychiatric symptoms including depression, withdrawal, anxiety, and trouble sleeping (insomnia). These prion diseases eventually lead to death.

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Mad Cow Disease and Variant Creutzfeldt-Jakob Disease Symptoms

  • Infected adult cattle may develop signs of the disease slowly. It may take from two to eight years from the time an animal becomes infected until it first shows signs of disease.
  • Symptoms in the animal include a change in attitude and behavior, gradual uncoordinated movements, trouble standing and walking, weight loss despite having an appetite, and decreased milk production. Eventually, the animal dies.
  • From the onset of symptoms, the animal deteriorates until it either dies or is destroyed (cattle who cannot stand are called "downers"). This disease process may take from two weeks to six months.
  • Similar symptoms may develop in humans: muscle spasms, lack of muscle control, worsening problems with memory.

Researchers looked at the first 100 people to develop vCJD in the United Kingdom and found psychiatric symptoms in early stages of the disease. These included

  • depression,
  • withdrawal,
  • anxiety, and
  • trouble sleeping.
  • Within four months of the disease onset, those affected developed poor memory and an unsteady gait.

Mad Cow Disease and Variant Creutzfeldt-Jakob Disease Causes

Prion diseases are unique and can be transmitted in a variety of ways:

  • Some forms can be inherited such as familial CJD, Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia (FFI). The disease is caused by a mutation in the gene that codes for prions. Other inherited prion diseases are rarer.
    • Prion disease may develop sporadically, for no apparent reason and with no pattern, such as sporadic CJD. Cases can occur in men and women of all ages, but the average age is 62 years. The prevalence of sporadic CJD is about one case per million people each year throughout the world, even among vegetarians. Sporadic CJD is the most common type of human prion disease.
    • Sporadic prion disease may be introduced into a human through infected surgical instruments or transplant tissues.
  • Infectious prion disease such as variant CJD (vCJD or nvCJD) is likely caused by eating BSE-infected meat from cattle.
  • A few seemingly sporadic cases in young men in Michigan may point to transmission to hunters from deer or elk with chronic wasting disease (CWD), a form of animal prion disease. CWD is becoming common in this animal population in the U.S. Because hunters eat the meat of these animals, there is a potential for the prion disease to cross from hunted to hunter.

One additional form of human prion disease is called kuru. It was found among native peoples of New Guinea who practiced ritualistic cannibalism (eating of humans, and their brains, specifically). Probably the illness began when a person with sporadic CJD was eaten. Death from kuru takes about one year following the onset of symptoms; however, the average incubation period was about 12 years and can be as long as 40 years. With the end of such rituals, this disease has nearly disappeared in New Guinea.

The disease has been experimentally transmitted among cattle and from cattle to monkeys who eat infected tissue (particularly brain tissue) in lab tests.

But the question remains: How do cattle develop BSE? Feed is the major route for transmission among cattle, according to veterinary medicine experts. When ranchers and farmers feed cattle with products made from other cattle or sheep, such as ruminant feed, they are recycling diseased animal protein in feed containing meat and bone meal, thus causing the disease in cattle. This practice has since been outlawed after the association of BSE with vCJD.

Prions may be transmitted among laboratory animals also through broken skin, suggesting the possibility of similar transmission to humans who contact infected tissue or products and who have broken skin.

Dementia, Alzheimer's Disease, and Aging Brains Slideshow

Dementia, Alzheimer's Disease, and Aging Brains Slideshow

In 1906 Auguste Deter, a woman in her early 50s, became the first person diagnosed with Alzheimer's disease, a form of dementia. The disease is named after the doctor who first described it, Alois Alzheimer. The disease is characterized by odd behavior, memory problems, paranoia, disorientation, agitation, and delusions. After Deter’s death, Alzheimer performed a brain autopsy and discovered dramatic shrinkage and abnormal deposits in and around nerve cells.

In 1910 the term “Alzheimer’s Disease” was formally used. In 1974 Congress established the National Institute on Aging (NIA), the primary federal agency supporting Alzheimer’s research.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.