COLUMBIA, South Carolina — Twelve-year-old Jaysen Carr died last week after contracting a rare but deadly organism known as Naegleria fowleri while swimming July 18 in Lake Murray in Columbia, South Carolina, People Magazine reported, marking the state’s first reported case since 2016.

Rare cases of Naegleria fowleri can result in a severe infection in the brain, with infection fatal in around 95% of cases.

The Naegleria fowleri is a free-living amoeba, which is a one-celled organism that thrives in warm fresh water like lakes, rivers and hot springs, the CDC states. It is usually called the brain-eating amoeba because it can infect and destroy brain tissue. Infections from the amoeba are rare but nearly always fatal.

While Vibrio vulnificus thrives in brackish water, freshwater presents a different but equally rare threat: Naegleria fowleri, a brain-eating amoeba.