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close this bookFact sheet No 180: Variant Creutzfeldt-Jakob disease (vCJD) - Revised December 2000 (WHO, 2000, 4 p.)
View the document(introduction...)
View the documentTotal Cases
View the documentEpidemiology
View the documentClinical Features
View the documentDiagnosis
View the documentProbable Cause
View the documentEvidence of vCJD-BSE Link
View the documentOther Human TSEs
View the documentMeasures Taken to Protect Public Health
View the documentWorld Health Organization (WHO) Involvement
View the documentWHO Recommendations

Probable Cause

· vCJD is strongly linked with exposure to the BSE agent. BSE is a transmissible spongiform encephalopathy (TSE) affecting cattle and was first reported in the UK in 1986. Since that year, about 180,000 cases have been reported in the UK. The number of reports of BSE in the UK began to decline in 1992 and has continuously declined year by year since then.

· The most likely route of exposure was through bovine-based food, although infectivity is mainly found in the brain and spinal cord of clinically ill animals over two years of age.

· Since 1989 when the first BSE case was reported outside the UK, relatively small numbers of BSE cases (in total approximately 1500) have also been reported in native cattle in Belgium, Denmark, France, Germany, the Republic of Ireland, Liechtenstein, Luxembourg, Netherlands, Portugal, Spain and Switzerland. However, all but a couple of dozen cases have been reported in four countries - France, the Republic of Ireland, Portugal and Switzerland. Small numbers of cases have also been reported in Canada, the Falkland Islands (Islas Malvinas), Italy and Oman, but solely in animals imported from the UK. The International Office for Epizootic Diseases (OIE) reports these cases on their web site: http://www.oie.int

· The nature of the TSE agent is being investigated and is still a matter of debate. According to the prion theory, the agent is composed largely, if not entirely, of a self-replicating protein, referred to as a prion. Another theory argues that the agent is virus-like and possesses nucleic acids which carry genetic information. Although strong evidence collected over the past decade supports the prion theory, the ability of the TSE agent to form multiple strains is more easily explained by a virus-like agent.