Magnified 125X, this 1973 Trichrome-stained photomicrograph revealed the presence of Naegleria gruberi, free-living amoebae in a human brain tissue specimen, in a case of primary amoebic meningoencephalitis (PAM). Free-living amoebae belonging to the genera Acanthamoeba, Balamuthia, and Naegleria, are important causes of disease in humans and animals.
What is Naegleria?
Naegleria is an amoeba commonly found in the environment, in water and soil. Only one species of Naegleria has been found to infect humans, Naegleria fowleri.
How does infection with Naegleria occur?
Infection with Naegleria occurs when the ameba enters the body through the nose while the person is swimming underwater or diving. The ameba then travels to the brain and spinal cord. See PHIL 10915 for a higher magnification of a region of this image.