Mad cow disease, formally known as bovine spongiform encephalopathy (BSE), is a fatal neurological disease that affects cattle and some other animals. The disease is caused by a prion, which is an abnormally folded protein. Unlike bacteria or viruses, prions do not contain genetic material. Instead, they cause damage by forcing normal proteins in the brain to fold incorrectly, leading to brain deterioration.
Animals infected with BSE may show changes in behavior such as nervousness, aggression, or depression. As the disease progresses, affected cattle often experience loss of coordination, difficulty standing or walking, and abnormal posture. Mad cow disease is usually confirmed through examination of brain tissue after death. There is no treatment or cure, and the disease is always fatal. Control efforts therefore focus on preventing exposure and properly disposing of infected animals.
Humans can develop a related condition known as variant Creutzfeldt-Jakob disease (vCJD) after consuming food products contaminated with the BSE prion. Although cases of vCJD are rare, the disease is extremely serious. Like BSE, vCJD affects the brain, progresses rapidly, and has no cure. Because of its severity, preventing exposure remains the primary public health strategy.
How Mad Cow Disease Is Transmitted
Cattle primarily contract mad cow disease by consuming feed that contains contaminated nervous system tissue from infected animals. This route of transmission led to major regulatory changes banning the use of certain animal by-products in cattle feed.
There is no strong evidence that BSE spreads through casual animal-to-animal contact. Instead, feed contamination has been identified as the main source of transmission in cattle populations.
Humans may develop vCJD by consuming meat or other products derived from infected animals. Importantly, there is no evidence that mad cow disease can be transmitted through milk or properly regulated dairy products.
As a precaution, consumers are advised to reduce risk by following these practices:
- Avoid eating meat that has not been properly cooked.
- Do not consume brain or spinal cord tissue from cows, sheep, or goats.
- Be cautious with meat products sourced from regions with a history of BSE.
- Understand and recognize symptoms of neurological disease in livestock.
