Chronic wasting disease was discovered in the 1950s when researchers observed deer in Colorado behaving like zombies, staggering around blindly as they starved to death.
The disease, caused by the spread of proteins called prions, has since been reported in Canada and some US states, including Michigan and Wisconsin.
No human has caught the disease, but a recent study suggests it could get into a person's brain if they were to eat meat from an infected animal.