“Zombie deer disease” is spreading across the globe.
Known more formally as chronic wasting disease (CWD), the infection eats away at the brains of deer, elk, and moose. It causes the animals to show signs of dementia, manifesting as difficulty walking and eating, before they ultimately die — and experts are now warning that the disease could make the jump from animals to humans.
“Zombie deer disease” is spread by prions, pathogenic proteins that can’t be killed because they aren’t alive. They’re neither bacteria nor viruses, but once they infect an animal, they cause its cells to fold abnormally and clump together. Essentially, the prions “turn the brain into Swiss cheese,” evolutionary biologist Peter Larsen told VOX.