Mad Cow Disease In Humans

By Ashley Henshaw. May 7th 2016

In recent years, outbreaks and cases of mad cow disease have caused some individuals to become alarmed about possible risks to their health and safety. However, mad cow disease is often misunderstood, particularly in regards to whether it can be linked to health problems in humans. Here’s a simple guide to understanding mad cow disease in humans, and how it can affect you and your family.


Mad cow disease is the colloquial name given to bovine spongiform encephalopathy (BSE). BSE is a chronic degenerative disease in cows that affects the nervous system. It results in the brain taking on a spongy appearance. Changes in temperament (especially nervousness or aggression), lack of coordination, abnormal posture and decreased milk production are also associated with BSE. Mad cow disease can only be detected after a cow’s death because the brain tissue needs to be examined in order to procure a diagnosis. Meat from a cow with mad cow disease can be contaminated with BSE – however, this is usually restricted to certain tissues that are not included in cuts of meat intended for human consumption.

The most important fact to keep in mind is that BSE only affects cattle and not humans – people cannot get mad cow disease.

Effects On Beef And Dairy Products

Meat from a cow with mad cow disease may be contaminated with BSE. Fortunately, the government has put numerous standards, policies and safety practices into place to ensure that no meat available to consumers is infected with BSE. This includes a regulation regarding beef, which is mechanically separated with automatic deboning systems, powered knives or advanced lean meat recovery as well as a ban on meat procured from an animal that is too sick or injured to walk.

According to UDSA rules and regulations, all meat must be inspected before it is considered safe, and any meats that are suspected to possibly contain BSE are immediately recalled. However, these recalls are made out of extreme caution – it is unlikely that meats sold in the U.S. that have been approved by the USDA were contaminated with BSE since the tissues that carry the BSE agent are typically not used in meat cuts or products meant for consumption by humans.

The BSE agent cannot be removed by cooking, microwaving or applying irradiation to a cut of meat. BSE cannot be transmitted through cow’s milk, so milk and dairy products pose no risk.

Variant Creutzfeldt-Jakob Disease

Although humans cannot contract mad cow disease, there is strong data from epidemiologic and laboratory studies that links the consumption of BSE-contaminated meat with a degenerative brain disorder in humans called variant Creutzfeldt-Jakob Disease (vCJD). This disease, though extremely rare, is fatal and tends to affect younger individuals (the median age is 28).

The symptoms of vCJD are psychiatric in nature, such as depression, apathy and anxiety. As the illness progresses, patients display neurological symptoms as well, such as difficulty walking, involuntary movements and general unsteadiness. Like BSE, vCJD can only be diagnosed after death through the examination of brain tissue. However, the incubation period for this disease is quite long – researchers indicate that the disease likely develops a decade or more after the person consumes BSE-contaminated meat.

As of 2003, only 153 cases of vCJD had been reported world-wide. Only one of those cases occurred in the United States, and researchers strongly suspect that the disease was contracted while that patient was living in the United Kingdom. Additionally, it’s important to note that the connection between BSE-contaminated meat and vCJD is not considered scientifically proven yet.

Recent Cases

A recent case of mad cow disease in the United States was confirmed on April 24, 2012. This case affected a single cow in California and was described as posing no risk to humans as the cow had been used solely for dairy purposes.

Before that, the first U.S. case of BSE was detected in 2003, followed by two more cases in 2005 and 2006. Each incidence was considered rare and occurred as a result of the cow spontaneously contracting the disease rather than through its feed supply. The vast majority of BSE cases worldwide have occurred in Britain and Europe. In addition, cases of the disease continue to drop year after year – only 29 cases were diagnosed in 2011, down from around 200 in 2007.

Mad cow disease is fatal in cows, but it cannot be contracted by humans. However, there is a very small risk of humans developing a fatal disease called vCJD when eating BSE-contaminated meat. Fortunately, the U.S. government has put very strict regulations into place to ensure that meat products intended for human consumption will not contain BSE. In short, increased awareness of mad cow disease and its affects has nearly eliminated any chance of individuals in the U.S. developing a disease as a result of mad cow disease.


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