What You Need to Know About Mad Cow Disease in Humans

A Rare, Deadly Brain Disorder

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Creutzfeldt-Jakob disease (CJD) is a rare, degenerative brain disease that causes dementia and death. Although its symptoms are similar to diseases like Alzheimer's, CJD progresses more rapidly. There is no cure for Creutzfeldt-Jakob disease.

This article will discuss Creutzfeldt-Jacob disease and how it affects the brain. Keep reading to learn how people get it and the symptoms people show when they have this serious disease.

Overview of CJD

Creutzfeldt-Jacob disease is caused by an abnormal type of protein called a prion. When prions are inside an animal or human's body, their immune system can't recognize them and fight the disease. CJD is the most common prion disease. Kuru is another prion disease seen in the past in New Guinea.

What Is a Prion?

A prion is a mis-folded protein that can cause other proteins to change their shape too. This sets off a chain-reaction effect. The prions build up in the brain cells, causing brain damage and, ultimately, death.

CJD progresses quickly. It is always fatal, and most people with the disease die within one year.

Creutzfeldt-Jacob disease made headlines throughout the world in the year 2000. During this time period, there was a rise in cases in the United Kingdom. Those cases were linked to food contaminated with bovine spongiform encephalopathy (BSE), a prion disease in cows that causes variant CJD (vCJD), also known as "mad cow" disease.

The cases of CJD in the United Kingdom were called "variant" CJD since typical "classic" CJD is not linked to eating beef. Fortunately, all forms of CJD, even the variant, are extremely rare. It affects about one person in every one million per year worldwide. In the United States, there are about 350 cases per year. 

Selection of fresh cuts of beef
istetiana / Getty Images

Types of CJD

There are four types of CJD:

  • Sporadic CJD is the most common form. It makes up about 85 % of all CJD cases. People who have this form of CJD have no known risk factors. This means doctors don't know why a specific person gets the disease.
  • Variant CJD occurs when a person eats contaminated beef.
  • Hereditary CJD occurs because of a family history of the disease. This form of CJD makes up 10% to 15 % of all cases.
  • Iatrogenic CJD is spread through specific kinds of medical procedures like corneal transplants or blood transfusions. It can also be transmitted through improperly sterilized surgical tools used on patients who have CJD.

How Mad Cow Disease Spreads

People get vCJD by eating contaminated beef. Cows can get BSE from eating feed containing ingredients made from another cow with BSE. When people eat beef from these cows, they can get vCJD.

The disease is not contagious, meaning you can't get it from standing near an infected person or cow. If an infected person coughs or sneezes on you, you won't get vCJD. You also can't get it from drinking milk that comes from an infected cow.


CJD causes the brain to deteriorate over time until the person slips into a coma and dies. Early signs of CJD may involve insomnia, depression, and confusion. As time goes by, other symptoms appear. The following symptoms are related to all forms of CJD:

  • Memory loss
  • Decrease in intellectual abilities
  • Slurred speech
  • Personality changes
  • Vision problems, including blindness
  • Walking difficulties
  • Balance problems
  • Uncontrollable jerking movements

Symptoms of vCJD can differ from other types of this disease. For example, people with vCJD have more mental health symptoms than people with the classic form of CJD.

In the final stage of the disease, the patient loses all mental and physical functions and eventually dies. The course of the disease usually takes one year.

Risk Factors

Some people have an increased risk of getting some form of CJD. They include:

  • People who are 50 years or older
  • People who had a surgical procedure that involved the brain or nervous system tissue
  • People who have a family history of CJD
  • People who consumed meat from an animal that had CJD

Classic CJD generally affects people between the ages of 50 to 75 years. But vCJD has affected people at a younger age—even teenagers. The ages of vCJD cases have ranged from 18 to 53 years old.


Some types of CJD cannot be prevented, but hospitals have procedures in place to prevent iatrogenic CJD. This is the kind of CJD that occurs when someone is exposed to infected tissue.

Hospitals follow strict procedures and regulations in order to prevent the spread of iatrogenic CJD while giving blood transfusions or using medical equipment. Hospitals destroy surgical instruments that were used on patients suspected of having CJD. They also do not accept organ donations from people who may have CJD.

Preventing vCJD

There are very few reports of people getting vCJD by eating meat from infected animals. Chronic wasting disease (CWD) belongs to the same family of diseases as bovine spongiform encephalopathy (BSE). While BSE affects cows, chronic wasting disease can affect wildlife such as moose, deer, reindeer, and elk. Hunters need to be aware of this issue so they can help to prevent the spread of vCJD.

The Centers for Disease Control and Prevention (CDC) strongly recommend that hunters have deer and elk meat tested for CWD before eating it. They should also not eat deer or elk that appear sick or are found already dead. The CDC suggests hunters wear rubber or latex gloves while handling the meat of any animal they've shot.

Mad Cow Disease Regulations

The Food and Drug Administration (FDA) helps keep food safe for both people and cows. The FDA does this in various ways. For example, it does not allow cow parts or the parts of certain other animals to be added to food created for cows to eat. This regulation helps to prevent cows from eating food contaminated with BSE.

The FDA also does not allow certain cow parts to be used in pet food or any other type of animal feed. Spinal cords and brains from cows are prohibited for use in animal feed. These cow parts are more likely to be infected with the abnormal prion.

The FDA works with the United States Department of Agriculture (USDA) to ensure mad cow disease doesn't spread throughout the country. The USDA prevents high-risk cows and products made from these animals from entering the United States. The organization also makes sure high-risk cow products like the brains and spinal cords of cows never make it into the food that people eat.


The FDA has regulations in place to make sure food stays safe for both people, cows, and other animals. Cows are not allowed to eat food composed of other cows' parts. Pet food and food that people eat cannot contain cow brains or spinal cords.


Unfortunately, there is no treatment for any type of CJD. Doctors may prescribe painkillers called opiates to treat a patient's pain. Muscle relaxer medication, as well as anti-seizure medications, can be used to treat muscle stiffness and uncontrollable jerking movements, Despite these treatments, CJD is fatal.


Creutzfeldt-Jacob disease is a fatal disease that affects the brain. Mad cow disease, also known as vCJD, is a type of Creutzfeldt-Jacob disease. People get vCJD by eating contaminated beef. The disease is always fatal. Most people who get the disease die within one year.

If you have a family history of CJD or other neurological diseases, schedule an appointment with a genetic counselor to learn more about your specific risks.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. NHS Choices. Creutzfeldt-Jakob disease.

  2. U.S. Food and Drug Administration. All about BSE (mad cow disease).

  3. National Institute of Neurological Disorders and Stroke. Creutzfeldt-Jakob disease fact sheet.

  4. Centers for Disease Control and Prevention. Classic CJD versus variant CJD.

  5. The National Academy of Sciences. Creutzfeldt-Jakob Disease.

  6. Centers for Disease Control and Prevention. Prevention.

Additional Reading

By Mary Kugler, RN
Mary Kugler, RN, is a pediatric nurse whose specialty is caring for children with long-term or severe medical problems.