Naegleria fowleri, colloquially known as the “brain-eating amoeba”, is a free-living, bacteria-eating microorganism that can be pathogenic. It causes an extremely rare fulminant and fatal brain infection called naegleriasis, also known as primary amoebic meningoencephalitis.
This microorganism is typically found in bodies of warm freshwater, such as ponds, lakes, rivers, almost exclusively in hot geographic areas, and hot springs. It is also found in the soil near warm-water discharges of industrial plants, and in unchlorinated or minimally-chlorinated (under 0.5 mcg/ltr residual) swimming pools. It cannot survive in sea water.