There has never been a case of vCJD that did not have a history of exposure within a country where the cattle disease, BSE, was occurring. It is believed that the persons who have developed vCJD became infected through their consumption of cattle products contaminated with the agent of BSE or in three cases, each reported from the United Kingdom, through receipt of blood from an asymptomatic, infected donor.
There is no known treatment of vCJD and it is invariably fatal. The current risk for infection with the BSE agent among travelers to Europe is extremely small, if it exists at all. The median age at death from vCJD in the United Kingdom has been 28 years and almost all cases have been in persons under age 55 years.
The reasons for this age distribution are not well understood but it suggests that through the oral route of exposure, older adults are much less susceptible to vCJD than children and young adults. By year of onset, the incidence of vCJD in the UK appears to have peaked in and to have been declining thereafter.
In contrast, the number of reported cases in France has been increasing since the beginning of However, the future pattern of these ongoing epidemics remains uncertain. In , a prevalence study of asymptomatic vCJD infections in the UK identified three positive appendices out of a sample of 12, surgically removed tonsils and appendices that were satisfactory for analysis.
Genetic studies completed on two of the appendices regarded as positive for vCJD revealed that both had a different polymorphism at codon of the prion protein gene than any of the patients with clinical vCJD tested to date, indicating that more people are genetically susceptible to vCJD infection, although not necessarily to the disease, than had been previously determined 4. From through , however, for the first time, Portugal rather than the United Kingdom reported the highest total country incidence of indigenous cases of BSE per million bovines aged over 24 months, reflecting the relatively more rapid decline of BSE cases in the United Kingdom.
As of July , the number of European countries that had ever reported an indigenous BSE case increased to The reported BSE incidence rates, by country and year, are available on the Internet website of the Office International des Epizooties External external icon and new information is being generated on a regular basis. Transfusion of blood contaminated with the vCJD agent is believed to be responsible for at least three vCJD infections reported in the UK, including two blood recipients with clinical vCJD and one infected recipient who died without signs of neurologic disease.
These three recipients indicate that the blood of asymptomatic, infected donors can contain infectivity 18 months to 3. Blood transfusion The possibility of transmission of CJD through blood transfusion or the use of blood products is sometimes suggested. There is no evidence to support the argument that blood products may cause sporadic or medically acquired CJD.
Variant CJD has been confirmed to be transmissible through blood transfusion. This has been supported in both the experimental laboratory setting and subsequently by the experience of variant CJD in the United Kingdom. In response to the recognised transmission of variant CJD by blood transfusion in the United Kingdom, Australian blood-banking guidelines defer donors who may have some risk for CJD.
Before donating blood, screening is performed to identify potential donors who may have CJD, those who may have been medically exposed and also some relatives from families where a CJD-related death has occurred. These people are routinely deferred and asked not to donate blood.
These people include: the first-degree relatives of those who have died from sporadic CJD families with genetic CJD recipients of human pituitary hormone extract anyone who received neurosurgery on the head, neck or spinal cord between and and who may have had dura grafts.
Blood donations in Australia In September , a ban was placed on blood donations from people who lived in the United Kingdom for six months or more from to or who have received blood transfusions in the UK since 1 January Early symptoms can be vague and there are no diagnostic tests to confirm exposure, or diagnose CJD, until symptoms are well advanced.
As the disease progresses, extensive investigations are necessary to exclude the possibility of other treatable diseases. A possible diagnosis is made only as the illness progresses. Examination of brain tissue after death is the only way to definitely confirm this disease. Symptoms may include: confusion or disorientation, which rapidly advances to a dementia personality changes behavioural changes weakness, loss of balance and muscle control causing difficulty walking muscle spasms visual symptoms such as double vision or blindness.
Normal prion protein is manufactured in the healthy brain. Although the function of normal prion protein is not understood, it is known that prion diseases are caused when the normal prion protein changes its physical structure or shape. This abnormal prion protein causes damage and cell death in the brain. Once present, it is believed the abnormal protein acts as a template, converting other normal prion protein into the abnormal, disease-causing form.
It is not known what causes the initial change to the prion protein structure. A viral connection remains unproven CJD is sometimes referred to as a slow virus. However, the viral theory has never been confirmed. It remains active outside the body and survives accepted and routine levels of hospital sterilisation for other disease-causing agents like viruses and bacteria. Recommended levels of sterilisation required for CJD exceed routine standards of sterilisation.
However, these cannot be performed routinely as the higher levels cause significant damage to medical instruments and equipment. CJD is not transmitted by casual contact CJD is not transmitted by casual contact like drinking from the same cup, kissing or close physical contact with an individual suffering from CJD. This means any newly diagnosed case must be reported to local health departments by their treating doctors. More information here. Give feedback about this page.
Since , all human growth hormone used in the United States has been synthesized by recombinant DNA procedures, which eliminates the risk of transmitting CJD by this route. Many people are concerned that it may be possible to transmit CJD through blood and related blood products such as plasma.
Some animal studies suggest that contaminated blood and related products may transmit the disease, although this has never been shown in humans. Recent studies suggest that while there may be prions in the blood of individuals with vCJD, this is not the case in individuals with sporadic CJD. Scientists do not know how many abnormal prions a person must receive before he or she develops CJD, so they do not know whether these fluids are potentially infectious or not.
They do know that, even though millions of people receive blood transfusions each year, there are no reported cases of someone contracting sporadic CJD from a transfusion.
Even among people with hemophilia a rare bleeding disorder in which the blood does not clot normally , who sometimes receive blood plasma concentrated from thousands of donors, there are no reported cases of CJD. While there is no evidence that blood from people with sporadic CJD is infectious, studies have found that infectious prions from BSE and vCJD accumulate in the lymph nodes which produce white blood cells , the spleen, and the tonsils.
At present, four cases of vCJD infection have been identified following transfusion of red blood cells from asymptomatic donors who subsequently died from vCJD. Recently, one case of likely transmission of vCJD infection by concentrates of blood-clotting protein has been reported in an elderly individual with hemophilia in the United Kingdom.
The possibility that blood from people with vCJD may be infectious has led to a policy preventing individuals in the United States from donating blood if they have resided for more than three months in a country or countries where BSE is common.
Both brain biopsy and autopsy pose a small, but definite, risk that the surgeon or others who handle the brain tissue may become accidentally infected by self-inoculation. Special surgical and disinfection procedures can markedly reduce this risk. The only way to confirm a diagnosis of CJD is by brain biopsy or autopsy. This procedure may be dangerous for the individual, and the operation does not always obtain tissue from the affected part of the brain. Because a correct diagnosis of CJD does not help the individual, a brain biopsy is discouraged unless it is needed to rule out a treatable disorder.
In an autopsy , the whole brain is examined after death. Currently, there is no treatment that can cure or control CJD, although studies of a variety of drugs are now in progress. Current treatment for CJD is aimed at easing symptoms and making the person as comfortable as possible. Opiate drugs can help relieve pain if it occurs, and the drugs clonazepam and sodium valproate may help relieve myoclonus. During later stages of the disease, intravenous fluids and artificial feeding also may be used.
To reduce the already very low risk of CJD transmission from one person to another, people should never donate blood, tissues, or organs if they have suspected or confirmed CJD, or if they are at increased risk because of a family history of the disease, a dura mater graft, or other factor.
Normal sterilization procedures such as cooking, washing, and boiling do not destroy prions. Although there is no evidence that caregivers, healthcare workers, and those who prepare bodies for funerals and cremation have increased risk of prion diseases when compared to general population, they should take the following precautions when they are working with a person with CJD:.
The mission of the National Institute of Neurological Disorders and Stroke NINDS is to seek fundamental knowledge of the brain and nervous system and to use that knowledge to reduce the burden of neurological disease. Researchers are examining and characterizing the prions associated with CJD and other human and animal prion diseases and trying to discover factors that influence prion infectivity and transmission, and how the disorder damages the brain.
For example, researchers are investigating the cellular mechanisms involved in abnormal prion formation and accumulation, as well as their replication by select cellular subsets in the brain. Other projects are examining how abnormal prions cross the protective blood-brain barrier and spread throughout the central nervous system, and tests that measure the biological activity of prions.
Findings may identify new therapeutic targets to treat prion diseases. Scientists are conducting biochemical analyses of brain tissue, blood, spinal fluid, urine, and serum in the hope of determining the nature of the transmissible agent or agents causing CJD.
To help with this research, they are seeking biopsy and autopsy tissue, blood, and cerebrospinal fluid from individuals with CJD and related diseases. The following investigators have expressed an interest in receiving such material:.
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