Naegleria fowleri

A) Computed tomographic scan: note the right fronto-basal collection (arrow) with a midline shift right to left. B) Brain histology: three large clusters of amebic vegetative forms are seen (H-E stain, x 250). Inset: Positive indirect immunofluorescent analysis on tissue section with anti– Naegleria fowleri serum.

A free living unicellular eukaryote protist. Typically found in warm fresh water sources such as rivers, lakes, and ponds. The life cycle includes three forms: Flagellate, trophozoite (infectious and reproductive stage), and cyst. Naegleria infects people by entering the body through the nose. Generally, this occurs when people use warm freshwater for activities like swimming or diving. The ameba travels up the nose to the brain and spinal cord where it destroys the brain tissue. Infections do not occur as a result of drinking contaminated water.Naegleria fowleri is found around the world. In the United States, it has caused infections in 15 southern tier states (AR, AZ, CA, FL, GA, LA, MO, MS, NC, NM, NV, OK, SC, TX, and VA). The ameba grows best in warm or hot water.Several drugs are effective against Naegleria in the laboratory. However, their effectiveness is unclear since almost all infections have been fatal even when people were treated.

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