What Does Mad Cow Disease Do to Humans?

Mad cow disease is the popular term for bovine spongiform encephalopathy (BSE), which is a progressive neurological disorder in cattle caused by infection with a rare transmissible agent called prions (defective proteins). They accumulate in the brain cells and damage them.

Animals with mad cow disease may exhibit behavioral changes, nervousness, aggression, abnormal posture, and lack of coordination. They produce less milk than usual and lose weight despite no changes in appetite and eventually die.

In the United States, about 250 persons are infected with classic Creutzfeldt-Jakob Disease (CJD) each year. Eighty-five percent of cases develop spontaneously, 5 to 10 percent are inherited and fewer than one percent are acquired by exposure to contaminated nervous-system tissue during surgical operations.

A person with spontaneously occurring CJD generally develops symptoms in their 60s, followed by a fast deterioration. Even young adults (average age 28 years) may develop CJD, but the symptoms may slightly vary.

The symptoms are similar to and could be mistaken for Alzheimer's disease. People have dementia-like symptoms such as staggering, memory loss, and decreased eyesight. They eventually die.

The disease-causing prion, variant Creutzfeldt-Jakob Disease (vCJD), is caused by consuming beef. vCJD steadily deteriorates the brain and eventually leads to death.

The first symptoms of vCJD include:

• Confusion
• Sadness
• Behavioral abnormalities
• Reduced eyesight
• Lack of coordination
• Dementia

vCJD often leads to death within six to nine months following the onset of symptoms. 

Both vCJD and bovine spongiform encephalopathy belong to a family of diseases called transmissible spongiform encephalopathies, which has no cure, treatment, or vaccination.

Your doctor will analyze your symptoms, personal history, and food habits.

• Radiological imaging of the brain, such as CT and MRI, is done to rule out stroke.
• Analysis of spinal fluid could be ordered to detect the presence of prions that cause mad cow disease.

Because mad cow disease is rare, the primary diagnosis could be different, and the final diagnosis may not be done until the advanced stages.

There is currently no medication available to reduce or stop the course of mad cow disease or other prion-induced diseases. Various studies and trials of therapies are underway to make the condition treatable in the future.

The chance of contracting variant Creutzfeldt-Jakob Disease (vCJD) in the United States is extremely low. Certain cow tissues are not permitted to be used in human diets due to regulations.

The transmission of mad cow disease among cattle usually happens when infected animal meat is fed to the cattle. To reduce the incidence of mad cow disease in humans, the FDA has banned animal protein in cattle feed.

Import restrictions prohibit animals positive with bovine spongiform encephalopathy from entering the United States, and monitoring protocols are in place.

Other nations have BSE, but most have rigorous control systems to prevent the illness from entering the human food chain. However, milk and milk products are safe.