Variant Creutzfeldt–Jakob disease (vCJD) is a zoonotic human prion disease linked to exposure to bovine spongiform encephalopathy (BSE) agents. It was first identified in the United Kingdom in 1996 and differs from classical CJD in age of onset, clinical presentation and tissue distribution of the abnormal prion protein. The etiologic agent is believed to be the same prion strain responsible for BSE in cattle. Infection occurs predominantly through consumption of contaminated beef products or, less commonly, via transfusion of blood from vCJD-infected donors. The disease affects younger individuals, with a median age at death of around 28 years, and has a longer clinical course (median 13–14 months).
Pathogenesis, Clinical Features and Diagnosis
After oral exposure, BSE prions replicate in lymphoreticular tissues such as the tonsils, appendix and spleen before spreading to the central nervous system. Variant CJD is associated with the “type 2B” PrP^Sc strain and is characterised neuropathologically by widespread spongiform change and florid amyloid plaques surrounded by vacuoles. Clinically, vCJD often begins with psychiatric or sensory symptoms—depression, anxiety, behavioural changes or painful dysaesthesias—followed by progressive ataxia, cognitive decline and involuntary movements. Diagnosis relies on the combination of clinical features, MRI findings of high signal in the pulvinar thalamus (“pulvinar sign”), detection of PrP^Sc in tonsil or appendix biopsies and confirmation by neuropathology. Most patients are methionine homozygous at codon 129 of PRNP. There is no effective treatment; care is supportive.
Incidence, Transmission Control and Public Health
As of 2024, 232 probable or confirmed vCJD cases have been reported worldwide, with 178 in the United Kingdom, 27 in France and smaller numbers in 10 other countries. The incidence peaked in 2000 and has since declined dramatically due to public health measures, including bans on feeding mammalian meat-and-bone meal to cattle, removal of specified risk materials (brain, spinal cord and intestine) from the food chain and rigorous surveillance. Four cases of transfusion-associated vCJD highlight the potential for blood-borne transmission; as a result, several countries instituted donor deferral policies for individuals exposed to BSE risk or who have received transfusions. Ongoing surveillance of appendectomy and tonsil tissues provides insight into asymptomatic infection prevalence, and strict infection-control protocols are applied to surgical instruments exposed to lymphoid tissue. Variant CJD underscores the ability of prion diseases to cross species barriers and the need for vigilance in food safety and transfusion practices. Related Terms: Sporadic Creutzfeldt–Jakob Disease, Familial Creutzfeldt–Jakob Disease, Iatrogenic Creutzfeldt–Jakob Disease, Bovine Spongiform Encephalopathy, Gerstmann–Sträussler–Scheinker Syndrome