Humans cannot get mad cow disease, but they can get a variant of the disease if they eat food contaminated with the diseased tissue of sick cattle.
Mad cow disease is the common name for a disease affecting cattle that slowly destroys the brain and spinal cord.
The human form, called variant Creutzfeldt-Jakob disease (vCJD), is a rare and fatal degenerative disorder that destroys the brain and spinal cord over time.
Keep reading to learn more about mad cow disease in humans, including the transmission and symptoms, as well as when to see a doctor.
Humans cannot get the same form of mad cow disease as cattle.
Mad cow disease, known medically as bovine spongiform encephalopathy (BSE), is a progressive neurological disorder in cattle. The disease gets worse over time, slowly eating away at the brain and spinal cord.
The exact cause is still unclear, though according to the Food and Drug Administration (FDA), most scientists believe that BSE results from an abnormal change in specific proteins called prions within the brain and nervous tissue of cattle.
Cattle get the disease by eating animal feed that includes the remains of infected cattle. Humans cannot get this form of the disease. However, people can get a human variant of the disease, called vCJD.
The Centers for Disease Control and Prevention (CDC) note that there is strong evidence to link vCJD and mad cow disease. The evidence suggests that similar to BSE in cows, vCJD comes from eating food contaminated with the brain or spinal cord tissue of sick cattle.
Other possible causes are outliers, such as a 2020 case featuring in the New England Journal of Medicine of a technician who contracted the disease after cutting their thumb while handling diseased brain tissue.
vCJD is just one type of Creutzfeldt-Jakob disease. Other forms of the disease may occur that have no connection to mad cow disease.
The three other types of CVD are:
- Hereditary CJD: This type occurs in people who have a family history of the disease or a genetic mutation associated with CJD.
- Acquired CJD: The acquired form transmits via exposure to brain or nerve tissue, generally during medical procedures.
- Sporadic CJD: This type appears when a person has no known risk factors.
These forms of CJD usually appear later in life and have a very fast disease course. The National Institute of Neurological Disorders and Stroke (NINDS) note that the onset of symptoms typically occurs around the age of 60 years and that about 70% of people die within 1 year.
vCJD follows a specific pattern that these other forms do not. The onset of the variant form of the disease tends to occur at a younger age, with the symptoms lasting longer than those of other forms of CJD.
The FDA note that neither BSE in cows nor vCJD in humans is commonly contagious. It is not possible for vCJD to transmit to others through everyday forms of contact, such as through breathable vapors, bodily fluids, or sexual contact.
Additionally, people cannot get the disease from drinking milk or eating dairy products. The only common way for both humans and cows to contract the disease is to eat food containing contaminated tissue from cows that have the disease.
The disease also has an incubation period, so the person is unlikely to feel sick immediately after consuming the contaminated food. It may take years for the disease to cause noticeable symptoms.
vCJD is a degenerative disease, meaning that it gets worse over time. The disease damages brain tissue, leading to symptoms such as:
- psychiatric problems
- psychotic episodes
- nerve issues, such as stinging, burning, or electric shock sensations in the extremities and face
- muscle jerks
- poor coordination
- problems with vision
- difficulty moving parts of the body
- inability to walk
vCJD is a fatal condition. As the disease affects more and more brain tissue, the symptoms will get worse over time before the person dies. According to the FDA, of the 232 people who had contracted vCJD worldwide by 2019, none survived.
There is no known cure for vCJD. Instead, treatment focuses on supporting the person and easing other symptoms they may feel as the disease progresses. For example, doctors may provide walking devices, drugs to ease pain, or other supportive care for the person.
vCJD is extremely rare. The NINDS note that about 1 in 1 million people receive a diagnosis of any form of CJD each year, and vCJD is even more rare.
In most cases, another underlying condition is likely causing similar symptoms. However, it is still important to speak with a doctor as soon as possible.
Anyone experiencing troubling symptoms, such as tingling or stinging sensations in their arms, legs, or face, should see a doctor. Many nerve-related conditions could cause these symptoms, and a prompt diagnosis may help give the person a better outlook.
Government agencies, such as the FDA and CDC, have taken steps in recent years to help prevent all forms of mad cow disease. The FDA note that since 1997, there has been a ban on feeding most parts of cows and other animals to cattle to help reduce the risk of BSE spreading. Additionally, it is no longer permitted to use high risk parts of the cow’s body to make other animal feed, such as dog or cat food.
These regulations help ensure that any food that a person comes into contact with is free from the abnormal proteins that may cause the disease.
The CDC also work with state health departments to monitor and test for abnormal proteins in dead cows and investigate reports from healthcare personnel if they suspect a case of vCJD. This monitoring helps ensure that they identify and reduce the likelihood of outbreaks.
Mad cow disease occurs when cattle consume damaged proteins in the brain or spinal tissue of other cattle in their feed.
A variant of this disease, called vCJD, may occur in humans who eat meat contaminated with proteins from the brain or spinal tissue of a sick cow.
Government programs and regulations have now banned the practices that could potentially allow contaminated proteins to enter the food supply in both humans and animals.
There is no known treatment for the equivalent of mad cow disease in humans. The disease progressively gets worse and is eventually fatal after several years.
Anyone noticing any of the symptoms of vCJD should see a doctor. Although various other issues may cause similar symptoms, a quick diagnosis is important in any case.