- Diseases, Disorders & Conditions
Mad Cow Disease and Creutzfeldt-Jakob Disease
According to the United States Department of Agriculture, there have only been four cases of mad cow disease in the United States. The Centers for Disease Control say that there have only been 19 cases in Canada. The most recent case occurred in April 2012, when a cow was found to have Mad Cow Disease in California. According to authorities, there is very little risk of infection to humans in this case.
What is Mad Cow Disease?
Mad Cow Disease is a prion disease called bovine spongiform encephalopathy (BSE). In 1985, farmers noticed that some cows acted strangely (i.e., mad); these cows developed spongy areas inside their brains, and they eventually died. Later, a similar disease appeared in humans who ate infected beef.
When BSE appears in humans, it can cause a rare disease called variant Creutzfeldt-Jakob disease (vCJD). This is disease of the nervous system; it causes the human brain to degenerate. Eventually, the brain will develop spongy areas. It can be fatal.
In the 1980s and 1990s, Mad Cow Disease was a huge concern in Britain. During that 10 year span, the human version of the disease was thought to have killed over 100 individuals.
Unlike most diseases, which are transmitted via viruses and bacteria, Mad Cow Disease is transmitted via a prion. A prion is a protein that is passed to humans from animals and causes disease. Unlike most bacteria and viruses, prions are very difficult to kill. Cooking and irradiation will not destroy them.
Symptoms of Variant Creutzfeldt-Jakob Disease
Bovine spongiform encephalopathy is an extremely rare disease, and it appears to be related to variant Creutzfeldt-Jakob disease. Upon exposure, the patient may show no signs or symptoms. The disease can incubate for years. Then, the initial signs are subtle. A patient may appear depressed, anxious, or show other unusual behavior. They may also experience some pain. An MRI may show some changes to the thalamus, and the disease will be apparent in testing of lymph tissue. As the disease progresses, the patient may have difficulty walking, speaking, or have other neurological impairment. Eventually, the disease may be fatal. Please note that this disease is extremely rare.
According to the World Health Organization, it is possible for humans to contract variant Creutzfeldt-Jakob disease from eating infected beef, especially if they consume nervous tissue, such as cow brains or bone marrow. However, it is possible for a person to eat infected cow meat and NOT become ill. The disease can also be passed from person to person in blood transfusions, so the U.S. has very strict standards regarding blood donations from people who have traveled to countries that experienced an outbreak.
Since there have been so few cases in the United States and Canada, there is a very low risk of contracting any form of the disease. In addition, you cannot get infected from drinking milk or consuming cheese.
Interestingly, a mother cow can pass the disease on to her calf while she is giving birth. However, many scientists believe that the Mad Cow Outbreak in Britain was probably caused by the feed that the animals were eating at the time. The outbreak in humans was terrifying, but public heath officials have since taken measures to prevent new incidences. They changed the cattle feed, destroyed any cattle that may have been infected, and frequently test for any possibility of infection.
The incident in April 2012 appeared through a random test of cattle that is frequently conducted in the United States. There seems to be little cause for concern.
Fortunately, variant Creutzfeldt-Jakob disease is a rare disease. Once a patient has been diagnosed, the doctor will discuss various medications that may alleviate the symptoms. However, the disease is progressive and sadly there is no cure.