AP BIOLOGY

Detailed explanation-1: -A variant form is acquired by eating contaminated beef. Creutzfeldt-Jakob disease usually occurs spontaneously but may result from eating contaminated beef or from inheriting an abnormal gene.

Detailed explanation-2: -About 10 to 15 percent of cases of CJD in the United States are hereditary. In acquired CJD, the disease is transmitted by exposure to brain or nervous system tissue, usually through certain medical procedures. There is no evidence that CJD is contagious through casual contact with someone who has CJD.

Detailed explanation-3: -CJD patients usually die within one year following the onset of symptoms. An autopsy is very important in the diagnosis of CJD because it is the best way to confirm presence of the disease. CJD is not transmissible from person-to-person by normal contact or through environmental contamination.

Detailed explanation-4: -What causes CJD? CJD appears to be caused by an abnormal infectious protein called a prion. These prions accumulate at high levels in the brain and cause irreversible damage to nerve cells. While the abnormal prions are technically infectious, they’re very different from viruses and bacteria.

Detailed explanation-5: -Most reported vCJD cases appear to have been infected through the consumption of bovine meat products contaminated with the agent of BSE. In three cases, reported by the UK, the mode of transmission is thought to be through receipt of blood from an asymptomatic, infected donor.