Two weeks after Jaysen Carr spent the Fourth of July swimming and riding on a boat on one of South Carolina’s most popular lakes, he was dead from an amoeba that lives in the warm water and entered his brain through his nose.

COLUMBIA, S.C. (AP) — A 12-year-old boy died from a brain-eating amoeba two weeks after a holiday weekend on a popular South Carolina lake. The brain-eating amoeba enters the body when water is forced up the nose, like when someone jumps or dives in the water.

Most people who come into contact with Naegleria fowleri never get sick. The amoeba can only infect a person when contaminated water goes up the nose, often during swimming or diving. It then travels to the brain, where it destroys brain tissue.