Lamprey disease is a hoax, reports Snopes. Several disturbing photographs with apparently damaged fingers and eyes have been distributed on various websites with claims they are photographs of real medical conditions.
Snopes reports that the photographs are actually pictures of human body parts with photos of the mouths of lampreys edited into the picture, producing a disturbing appearance. The use of the lamprey's mouth in this fashion led to the name "lamprey disease."
Lampreys are a species of jawless fish, reports Animal Planet. They look a lot like eels, appearing long and snake-like with few evident fins. They grow from 12 to 20 inches in length. They have no jaws and instead have a round sucker-like mouth equipped with numerous teeth. They are parasites and live by clamping onto the sides of fish and chewing a hole into the side of the fish. They consume blood and body fluids from the fish, and may remain clamped onto the side of the fish for a few hours or weeks at a time. Smaller fish often die from infection and trauma after a lamprey attack, but larger fish may survive.