Factual error: The type of book that Eli is protecting would actually be just a fragment. The complete Bible, in braille, occupies as many as 18 volumes.
Factual error: Eli uses an apparently moist KFC wetnap to clean himself in an early scene, yet it's been at least 30 years since the apocalyptic event happened. Unopened wipes only stay moist for months, even big packets of baby wipes only stay wet for 2-3 years.
Answer: Kuru, a disease caused by cannibalism, causes victims to shake.