Pathogen and transmission
Creutzfeldt-Jakob Disease (CJD) is a disease of the human brain which is probably caused by an abnormal folding of certain proteins (into pathogenic prions). There are three classic forms and one new form of CJD:
- Sporadic Creutzfeldt-Jakob Disease (sCJD) can randomly occur. The risk of contracting it increases with age (up to about age 70).
- In familial Creutzfeldt-Jakob Disease (fCJD) the tendency to develop pathogenic prions is inherited. Cases of fCJD can manifest themselves from age 50 onwards.
- Iatrogenic (which means caused by medical intervention) Creutzfeldt-Jakob Disease (iCJD) is transmitted indirectly from person to person, e.g. as a result of an operation. In the past the causes for such transmission included dura mater transplants and cornea transplants, growth hormone treatments and insufficiently sterilized neurosurgical instruments.
- A fourth form of CJD was identified in 1995: variant Creutzfeldt-Jakob Disease (vCJD). This is likely to be caused by consuming meat from a cow that had bovine spongiform encephalopathy (BSE). vCJD can develop in young people, too, and can also be transmitted from human to human through blood transfusions.
Pathology
CJD produces a wide range of symptoms that will slowly and gradually worsen. Persons infected lose their mental capacities, develop movement disorders and, in the final stages, are no longer able to interact with their surroundings. There is no effective treatment for CJD to date, and the disease is invariably fatal.
Distribution and frequency of occurrence
The three classic forms of Creutzfeldt-Jakob Disease occur all over the world. But cases of vCJD are now extremely rare since various actions were taken on the animal health front.
The Federal Office of Public Health receives an average of 10 to 15 reports of CJD in Switzerland a year, which invariably involve classic forms of the disease. There has not been a single case of vCJD in Switzerland to date.
Prevention
There is neither a vaccine nor a medical or medicinal treatment yet for CJD in any of its various forms. But a range of specific instructions have been devised and adopted (on the recommendations of the Swissnoso specialist group) to prevent any cases of iCJD developing as a result of surgical, medical or medicinal interventions.
To prevent infections of the fourth type of CJD, variant vCJD, actions have been taken on the food and medicinal safety front. These have been focused primarily on consistently removing and risk material from cattle from the production chain for food and other human commodities. All the currently valid provisions for preventing CJD are also regularly reappraised and modified wherever necessary in the light of the latest scientific findings.