Variant Creutzfeldt-Jakob disease (vCJD) is a prion disease, a rare and severe disorder that damages the brain. The emerging disease is linked to infections of humans by bovine spongiform encephalopathy (BSE), or mad cow disease.
Since first reported in Great Britain in 1996, about 177 cases occurred in Great Britain through 2014. There were 27 cases in France, and others in Europe and North America. Variant CJD usually affects younger people, averaging 28 years old. The classic form of CJD usually affects people around 68 years old. The age range of people affected by vCJD is from about 14 years old to 74 years old. The number of U.K. cases of vCJD peaked in 2000 at 28 for the year, but then lowered each year through 2008 to only two cases per year. The National CJD Research and Surveillance Unit in Edinburgh, United Kingdom, reported in 2017 that 178 people around the world had died from confirmed or probable vCJD.
Only four cases of the disease had been reported in the United States as of mid-2017. According to the Centers for Disease Control and Prevention (CDC), the most recent case reported (as of spring 2017) was confirmed in October 2014 in Texas. The infected person died of the disease. However, investigation of the disease determined that the person most likely acquired vCJD abroad, as is true of the other three U.S. cases of the disease.
People get vCJD from eating meat that is contaminated with BSE. The time lapse between exposure to BSE and development of vCJD symptoms (or incubation period) is estimated to be 11 or 12 years.
The condition labeled mad cow disease affects the central nervous system of cattle. Research has shown that BSE does not transmit from one cow to another by contact or proximity. Instead, BSE occurs when a cow eats feed containing protein supplements made from infected cows. This is possible because parts of slaughtered cows can go into human food and other parts into animal feed. Nerve tissue from an infected cow can make its way into animal feed, and rarely into beef products eaten by people. The first case in the United States occurred in late 2003, when BSE was found in a dairy cow in Washington. However, the cow had been imported from Canada.
The U.S. Food and Drug Administration banned the use of cattle feed containing protein supplements from ruminant animals (cows, sheep, goats, and deer) in 1997. This move broke the cycle of the disease in domestic cattle. Because BSE attacks the central nervous systems of cattle, the U.S. Department of Agriculture (USDA) introduced a ban in 2003 in the food supply to eliminate the spread of BSE to people. The USDA also bans the sale of cattle that show possible signs of BSE such as inability to walk. BSE is not present in steaks or ground beef, but only in foods containing tissue from the brain and spinal cord.
The illness and symptoms caused by vCJD last a long time, on average 12 to 14 months. As of 2017, vCJD is not curable and is fatal. The disease causes troubling and severe symptoms, including psychiatric ones. Most people die from vCJD because they become bedridden and then develop pneumonia.
The CDC tracks reported deaths from vCJD and looks for other deaths in state listings that could be from the disease. The CDC and the American Association of Neuropathologists created a database in 1997 at Case Western Reserve University, where staff also can perform special testing for vCJD, including postmortem tests. Although states do not require autopsy on people who die of suspected vCJD, the disease is reportable, so the CDC strongly encourages postmortem examination of these patients. The CDC also coordinates with local and other federal agencies. For example, the U.S. Department of Agriculture (USDA) oversees farming and ranching practices.
The United Kingdom made BSE a reportable disease in 1988 and the European Union has added measures to control and contain BSE. Other efforts in the United Kingdom and around the world aim to protect the human blood supply to lower risk of vCJD spread by blood transfusion. The WHO recommends that all countries ban use of ruminant tissues in cattle feed and further cautions pharmaceutical companies to avoid use of materials from cows in any animal species in which BSE occurs.
The variant form of CJD tends to affect people in their late twenties more than any other age group. Studies continue on how genetics might play a role in vCJD. There is a genetic mutation that leads to classic CJD, and it is possible that inheriting identical copies of some variants of the gene increases risk of vCJD after eating contaminated food. The risk of beef contamination in the United States and other counties that have implemented measures to protect cattle and people is almost nonexistent, but people should use caution when eating beef from countries without those protections. This includes the United Kingdom, where risk was higher for people who ate beef early in the BSE epidemic and before regulations were put in place. Transmission from blood transfusions is extremely rare (fewer than four cases ever reported), but a possibility.
Eating contaminated meat is the primary method of transmitting vCJD. Once the prion, or abnormal protein, is in the body, it causes damage to normal processes of the brain.
The primary symptoms of vCJD involve psychiatric problems, and they usually are the first sign of infection, although it can be difficult to assign the cause of symptoms as vCJD. People with vCJD become withdrawn, anxious, irritable, depressed, or lose interest in activities once of interest. Insomnia also occurs. Signs of decline in thinking or memory begin within about five months, and by about seven months, signs of neurological deficits, such as disorientation, involuntary movement, or trouble walking, become apparent. Symptoms can vary because vCJD can affect any part of the central nervous system. About one-third of people with vCJD develop unusual and persistent pain.
The symptoms of vCJD help with diagnosis but can easily occur in other conditions or diseases. Young age at onset of symptoms is a clue that the cause could be vCJD, as is the progressive nature of the symptoms. The CDC lists criteria for diagnosis of definite vCJD or suspected vCJD. Criteria for definitive vCJD are:
Diagnosis of vCJD is difficult before a patient dies, but doctors can determine whether a person has suspected vDJD with the following criteria and others:
Doctors can examine patients for signs of dementia or other neurological symptoms. It also helps to discuss patient history, such as travel previous travel to a country that does not ban ruminant feed for cattle.
In patients with vCJD, tests might not be reliable indicators of the disease if conducted before clinical symptoms begin and no definitive tests can confirm the disease while the patient is alive. Still, several tests can be combined with the diagnostic criteria to determine the best supportive treatment. Results of an electroencephalogram (EEG) can be normal or abnormal, but are not the same as the kinds of changes seen in classic CJD.
Magnetic resonance imaging (MRI) uses powerful magnets and radio waves to capture images through special software. MRI is a useful and highly sensitive tool for imaging brain tissue. Radiologists specially trained to interpret the images generated can detect specific signs in the brain that indicate vCJD. The MRI findings are part of the WHO's criteria for diagnosing vCJD.
A tonsil biopsy can show the presence of the abnormal prions associated with vCJD. Tonsils, like lymph nodes, are part of the immune system. By taking a small sample of tonsil tissue out, doctors can send the tissue for examination in a laboratory. It can be very effective at detecting vCJD early in the disease, soon after symptoms appear. Doctors also can remove a sample of the fluid that lines the brain and spinal cord (called cerebrospinal fluid) for study. Doctors use a needle to extract a small amount from near the spinal cord, in a procedure called a lumbar puncture.
The only way to confirm diagnosis of vCJD is after the patient has died, when brain tissues are evaluated with a brain biopsy or the brain is observed in a postmortem examination (autopsy). The autopsy requires removal of the entire brain for analysis. Doctors might suggest that the autopsy be performed at the closest regional center that is part of a national network.
There is no cure for vCJD, although several existing drugs have been tried. Instead, treatment is designed to slow the progression of the disease and support patients in dealing with the symptoms it causes.
Drugs called interleukins, which are related to immune system substances, have shown some success in slowing the progression of vCJD. To treat symptoms, doctors might try drugs called antiepileptics, which help manage seizures and also can be used to suppress violent outbursts from patients. Examples of antiepileptic drugs are carbamazepine (Carbatrol, Epitol, Tegretol, others) and gabapentin (Horizant, Neurontin). A drug called clonazepam (Klonopin) can help control involuntary movements.
Several drugs are available to help manage or slow progression of dementia in patients with vCJD. These can include donepezil (Aricept), a combination donepezil and memantine (Naamzaric), galantamine (Razadyne), and rivastigmine (Exelon).
Experimental treatments are being studied that could help control prion protein production. Other ideas include the use of drugs that work on the immune system.
Because vCJD is fatal regardless of medical treatment, patients who prefer alternative therapies for easing symptoms should discuss ideas with their diagnosing physician. Further, patients should be aware that alternative remedies, including vitamins or herbal supplements, can interfere with some prescription medications.
Like similar prion diseases, infection with vCJD is severe, progressive, and inevitably fatal. The illness can last more than a year, with symptoms becoming progressively worse before the patient dies, typically from pneumonia.
The risk of vCJD is extremely low in the United States. Much of prevention is in the hands of ranchers and laws governing safe feed practices and in healthcare workers, who must follow recommended infection control procedures. Restrictions also are in place for beef imported to the United States. Blood donation centers will not take blood from people who have spent at least three months in areas known for high levels of BSE. In addition, laboratory and healthcare workers, undertakers, and those involved in performing autopsies must use care when handling material from patients with vCJD. The WHO has developed specific protocols for safe handling of tissues and disinfection procedures. The CDC maintains information for travelers regarding prevention of vCJD and other infectious disease when traveling outside the United States.
See also Epidemiology: Monitoring outbreaks and the spread of infectious disease ; Prion diseases.
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Teresa G. Odle, BA, ELS