Discovery

Variant Creutzfeldt-Jakob Disease (vCJD) was first documented in March of 1996 after 10 Britons under the age of 45 displayed symptoms similar to those associated with a TSE. CJD was initially suspected as the specific disease, but further scientific analysis showed symptomatic and pathological differences of affected brain tissues compared with CJD victims. It was certain, however, that the 10 victims suffered from a strain of a Transmissible Spongiform Encephalopathy, and researchers initiallytermed this condition new variant CJD (nvCJD), but now just use variant CJD (vCJD).

Incidence

The number of definite and probable variant CJD cases is 194 people (158 in the U.K.,²² 21 in France, four in Ireland [two contracted in the U.K.], three in the United States [two contracted in the U.K., one contracted in Saudi Arabia], two in the Netherlands, one in Canada [contracted from the U.K.], one in Italy, one in Japan [contracted from the U.K.], one in Portugal, one in Saudi Arabia and one in Spain). Scientists have concluded that the patients in the United States and Canada contracted vCJD in the U.K. and in Saudi Arabia.²³ To date, the disease has occurred predominately in people under the age of 55, a number of whom were teenagers.

Scientists do not believe it is possible to predict the number of anticipated vCJD cases with accuracy given the unknowns about the disease, including method and amount of exposure, route of transmission and incubation period. Steps taken to remove potential sources of exposure to the disease agent should help minimize potential future exposure to the agent and thereby limit the occurrence of vCJD cases.

Transmission

Recent research provides convincing evidence that the BSE agent causes vCJD.Variant CJD likely developed as a result of people consuming products contaminated with central nervous system tissue of BSE-infected cattle.

The BSE agent has not been found in bovine muscle.³⁹

Symptoms

Variant CJD differs markedly from CJD.

On average, the duration of the vCJD illness is 14, compared about six months for patients with sproadic CJD.

Patients afflicted with vCJD experience early psychiatric symptoms such as depression, earlier loss of coordination and later onset of dementia. In addition, vCJD has, to date, occurred predominately in people under the age of 55, a number of whom were teenagers, whereas CJD typically strikes older people.^{2, 8, 15, 18}

Diagnosis

Diagnostic procedures for variant CJD are similar to those of CJD, keeping in mind patients with vCJD lack periodic sharp-wave complexes typically found on EEG results of sporadic CJD patients. Perhaps the most striking and consistent neuropathological difference between CJD and vCJD is found in the amyloid plaques. Plaques in vCJD cases are extensively distributed throughout the cerebrum and cerebellum, compared with the absence of plaques in CJD cases. Plaques in vCJD victims typically also have a dense center and are surrounded by a zone of spongiform change which give the plaques a daisy-like floral pattern. This pattern is not found in CJD patients. ^{4, 6, 7, 9, 15, 20}

Prevention and Control

Prevention of vCJD rests first and foremost on preventing BSE in cattle. There has never been a case of vCJD where there has not been the potential for exposure to BSE.

Second, prevention of vCJD depends upon removing potential sources of exposure from the food supply, such as brains and spinal cord of affected cattle. Third, physicians must guard against spread of vCJD through tissue transplantation or contaminated instruments.

Precautionary steps to prevent vCJD in humans from occurring in this country began in 1989 and include:

• FDA recommending that animal tissues used in drug products should not come from a country with BSE.
• FDA protecting the blood supply by excluding donors from giving blood who have 1) spent three months or more cumulatively in the U.K. from the beginning of 1980 through the end of 1996, 2) spent five years or more cumulatively in France from 1980 to the present. 3) resided at U.S. military bases in Northern Europe (Germany, United Kingdom, Belgium, and the Netherlands) for 6 months or more, from 1980 through 1990 4) resided at U.S. military bases elsewhere in Europe (Greece, Turkey, Spain, Portugal, and Italy) for 6 months or more, from 1980 through 1996 5) received a transfusion of blood or blood components in the U.K. between 1980 and the present 6) lived cumulatively for 5 years or more in Europe from 1980 until the present, as well as other recommendations based on risk and exposure. (See a complete list of recommendations at http://www.fda.gov/cber/gdlns/cjdvcjd.pdf)
• Centers for Disease Control (CDC) established the National Prion Disease Pathology Surveillance Center (NPDPSC) to perform surveillance for cases of vCJD among humans.
• Research conducted by several laboratories in the U.S. and the NPDPSC on BSE, CJD, vCJD and related neurological diseases.²⁸

For more statistics on vCJD, visit the National Prion Disease Pathology Surveillance Center Web site.

Last Updated - March 2005