The brain is destroyed by the prion protein that causes variant Creutzfeldt–Jakob disease.
ZEPHYR/SCIENCE PHOTO LIBRARY
A study1 in the British Medical Journal reveals that 1 in 2,000 people in the United Kingdom might harbour the infectious prion protein that causes variant Creutzfeldt–Jakob disease (vCJD). Nature explains what this means.

What is vCJD?

The usually fatal condition vCJD is the human form of bovine spongiform encephalopathy (BSE) — dubbed mad-cow disease in the United Kingdom after an outbreak in the 1980s. Both diseases are caused by misfolded proteins called prions, which induce other proteins in the brain to clump together, eventually destroying neurons. Humans are thought to contract the disease by consuming beef that contains infected bovine brain or other infected central-nervous-system tissue. It can also spread through blood transfusions, and some worry that prion diseases can be transmitted through contaminated surgical instruments.