The brain infection is called primary amebic meningoencephalitis. It destroys brain tissue and is usually fatal.
Infections from the amoeba are rare. Florida officials cited federal statistics showing that 28 infections were reported in the U.S. from 2003 to 2012, mostly from exposure to contaminated recreational water. A person cannot be infected with the amoeba by drinking contaminated water, state officials said, and the amoeba is not found in salt water.
Victims typically are exposed while swimming or doing water sports in warm ponds, lakes, rivers and canals during the hot summer months, mostly in the South.