What Do You Know About 'Mad Cow' Disease?

Twenty years ago, few people had heard of Creutzfeldt-Jakob disease (CJD). Today, it has made headlines, mostly from its possible association with "mad cow disease." To help make sense of this puzzling disease, take this quiz, based on information from the Centers for Disease Control and Prevention and the National Institute of Neurological Disorders and Stroke.

1. CJD is a rare, degenerative, fatal brain disorder.

True

False

Answer: True. It was named after two German psychiatrists, Hans Gerhard Creutzfeldt and Alfons Maria Jakob. CJD is classified as a transmissible spongiform encephalitis (TSE). Spongiform refers to the description of the infected brain, which becomes filled with so many holes that it resembles a sponge. There are four forms of CJD: sporadic, which arises spontaneously; familial, or inherited; infective (very rare), which is passed on by pituitary growth hormone obtained from cadavers or through contaminated surgical instruments; and a new variant of CJD (v-CJD), associated with "mad cow disease." Besides CJD, there are four other TSEs that affect people: kuru, which was found in an isolated tribe in Papua New Guinea; Gerstmann-Sträussler-Scheinker syndrome (an inherited condition); fatal familial insomnia (an inherited condition); and sporadic fatal insomnia. These diseases are very rare.

2. CJD usually appears in childhood.

True

False

Answer: False. Symptoms of classic CJD typically appear about age 60. Symptoms of new variant CJD (v-CJD) or of CJD caused by contaminated pituitary growth hormone can first appear in the early 20s to early 40s. In all cases, about 90 percent of patients die within a year of symptoms.

3. A failing memory and lack of coordination are early symptoms of classic CJD.

True

False

Answer: True. But these symptoms are identical to other forms of dementia or illness, which makes it difficult to diagnose. Other symptoms of CJD include behavioral changes and visual disturbances. As the disease progresses, symptoms include mental deterioration, involuntary movements, blindness, weakness of limbs and coma.

4. A virus causes CJD.

True

False

Answer: False. It is caused by an abnormal prion, which is a particular kind of protein. Normal prions are harmless and found in every cell in the body. Abnormal prions take a slightly different shape and clump together in fibers and plaques. Researchers aren't sure what role these fibers and plaques play in CJD. About five to 15 percent of CDJ cases, the abnormal prion has been inherited.

5. CJD can be passed on through sexual contact.

True

False

Answer: False. CJD is not a sexually transmitted disease, nor is it a contagious one. It cannot be passed from one person to another. People in the same household as a person with CJD will not get the disease. The Food and Drug Administration (FDA) now bans blood donations from people who have spent an extended time (6 months or more) in England or Europe because of concerns that CJD may be passed through their blood products. To date, however, there is no documented case in which prions have been passed through blood products. The only proven manner in which CDJ has been passed on from an infected person is through contaminated tissue (a cornea, for example) or contaminated surgical instruments. Normal sterilization procedures such as cooking or boiling do not destroy prions. Contaminated material (such as infected cows or surgical material from people with CJD) is generally destroyed by incineration.

6. A biopsy is the only way to confirm a diagnosis of CJD.

True

False

Answer: True. In a brain biopsy, a neurosurgeon removes a small piece of the brain to be examined. There are several drawbacks to a biopsy, however. The procedure may be dangerous for the patient, and the brain sample removed may not be a part that's affected by CJD. Researchers have developed a safer test, which looks for a particular protein in a patient's cerebrospinal fluid, but this test is not yet commercially available. An autopsy after death also can confirm the illness.

7. CJD can be treated with antiviral medication.

True

False

Answer: False. Currently, there is no treatment for CJD. Medication is given to relieve symptoms, but does not alter the course of the disease. It is always fatal.

8. CJD is the same disease as bovine spongiform encephalopathy (BSE), also known as "mad cow disease."

True

False

Answer: False. BSE and CJD are similar but not identical. BSE is a progressive neurological disorder in cattle similar to a disease in sheep called scrapie. BSE has been found primarily in cattle in the United Kingdom, but also in other areas of Europe. It also recently has been found in U.S. and Canadian cattle. Researchers believe that BSE may be caused by feeding scrapie-infected sheep meat-and-bone meal to cattle. They also believe that a new form of CJD in people called v-CJD, which first showed up in England in the early 1990s, is caused by eating beef contaminated by BSE. (Cooking the meat does not destroy the prions believed to cause the disease.) The new variant CJD differs from CJD in that patients are typically much younger (30 versus 60) and that symptoms are more psychiatric and sensory than neurological.

9. Childhood vaccines given for other illnesses may pose a risk for contracting the new variant CJD.

True

False

Answer: False. The Food and Drug Administration and several advisory committees have determined that the risk of contracting v-CJD through any vaccine (for polio or hepatitis, for example) is remote. The concern about vaccines surfaced because some vaccines are manufactured using substances derived from cattle. Some of the bovine components have come from countries where BSE is found. There is no evidence in Europe that any vaccines have caused v-CJD, however.

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