"An unidentified 12-year-old died Friday after being infected with an amoeba while swimming in a Florida lake. The boy had meningeal encephalitis - a combination of meningitis and encephalitis, which causes the brain to swell. Cases of illness from amoebas are rare. There have been 20 to 30 cases in the United States, with the majority of cases reported in Florida. The environmental conditions in Florida lakes - especially in the hot summer months - are ideal for amoebas to thrive and proliferate."