Courtney Nash, 16, fell ill and died of the rare disease after swimming in a river that harbored the infectious microbes, the CDC confirmed on Monday. The girl's family says she died Saturday afternoon.
Officials say the girl had been swimming last week in a small tributary of the St. Johns River in Florida's Volusia County. She was later hospitalized with what Brevard County health officials identified as an amoebic infection.
The amoeba - which can attack the brain after entering through the swimmer's nose - are most commonly found in the mud bottoms of lakes and ponds. They are also found in rivers, although less frequently.
Symptoms of the infection - which doctors call amoebic meningoencephalitis - include headaches, vomiting, and neck stiffness, according to the website of the Oklahoma Department of Environmental Quality. The website cautions against swimming in stagnant water, especially water that doesn't feel cool upon entering. In addition, it's best to avoid underwater swimming except in swimming pools and to hold your nose or use nose plugs when diving into water except swimming pools.
Amoebic meningoencephalitis is rare, with fewer than 100 cases reported in the U.S. since 1975, according to the website. But it's often fatal.