A 12-year-old boy has died from a brain-eating amoeba after swimming in a South Carolina lake over the July Fourth weekend. The amoeba enters the body through the nose and causes a fatal brain infection. Fewer than 10 cases are reported annually in the U.S., but almost all are deadly. More than 160 people are known to have died from the amoeba in the U.S. in the past 60 years. The boy’s parents were unaware of the amoeba when they let their son swim in Lake Murray. The amoeba is common, even if the infections caused by it are rare. Other dangers in lakes include E.coli and harmful algae, which can cause severe health issues.