Naegleria fowleri - Primary Amebic Meningoencephalitis (PAM)

Naegleria fowleri (commonly referred to as the "brain-eating ameba or brain-eating amoeba"), is a free-living microscopic ameba*, (single-celled living organism). It can cause a very rare, but severe, infection of the brain called primary amebic meningoencephalitis (PAM). The ameba is commonly found in warm freshwater (e.g. lakes, rivers, and hot springs) and soil. Naegleria fowleri usually infects people when contaminated water enters the body through the nose. Once the ameba enters the nose, it travels to the brain where it causes PAM, which is usually fatal. Infection typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. In very rare instances, Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or heated and contaminated tapwater) enters the nose ^{1, 2, 3}.

Left: EM image of Naegleria fowleri in its cyst stage. Center: EM image of Naegleria fowleri in its ameboid trophozoite stage. Right: EM image of Naegleria fowleri in its flagellated stage. Credit: DPDx and GS Visvesvara.