Naegleria fowleri

Naegleria fowleri is a species of the genus Naegleria, belonging to the phylum Percolozoa. It is a free-living, bacteria-feeding amoeba that can be pathogenic, causing a fulminant brain infection called naegleriasis, also known as primary amoebic meningoencephalitis (PAM). This microorganism is typically found in bodies of warm freshwater, such as ponds, lakes, rivers, and hot springs. It is also found in the soil near warm-water discharges of industrial plants, and in unchlorinated or minimally-chlorinated swimming pools. It can be seen in either an amoeboid or temporary flagellate stage.

Lifecycle

Naegleria fowleri is a thermophilic, free-living amoeba. It is found in warm freshwater ponds, lakes and rivers, and in the very warm water of hot springs. As the water temperature rises, its numbers increase. It was first discovered in 1965, and first identified in Australia.N. fowleri occurs in three forms – as a cyst, a trophozoite (ameboid), and a biflagellate. It does not form a cyst in human tissue, where only the amoeboid trophozoite stage exists. The flagellate form can exist in the cerebrospinal fluid.

Naegleriasis

Naegleriasis, also known as primary amoebic meningoencephalitis (PAM), amebic encephalitis, and naegleria infection, is an infection of the brain by the free-living protist Naegleria fowleri, also known as the "brain-eating amoeba". The term "brain-eating amoeba" has also been applied to Balamuthia mandrillaris, causing some confusion between the two, however Balamuthia mandrillaris is unrelated to Naegleria fowleri, and causes a different disease called granulomatous amoebic encephalitis, and unlike Naegleriasis, which is usually seen in people with normal immune function, granulomatous amoebic encephalitis is usually seen in people with poor immune function such as those with HIV/AIDS or leukemia.

N. fowleri is typically found in warm bodies of fresh water, such as ponds, lakes, rivers, and hot springs. It is also found in soil, poorly maintained municipal water supplies, hot water heaters, near warm-water discharges of industrial plants, and in poorly chlorinated, or unchlorinated swimming pools, in an amoeboid or temporary flagellate stage. There is no evidence of it living in salt water.