Naegleria fowleri, Brain-eating ameba

Naegleria fowleri (commonly referred to as the "brain-eating ameba") is a warm-water-loving ameba (single-celled organism) found around the world, often in warm or hot freshwater lakes, rivers and hot springs. Naegleria fowleri is normally found in the natural environment and is well adapted to surviving in various habitats, particularly warm-water environments up to 115 F. The ameba becomes dormant in cold temperatures and can survive buried in the sediment of water bodies. There are no known ways to control the amount of natural Naegleria fowleri in lakes and rivers.

When water containing the Naegleria fowleri ameba enters the nose, the ameba can travel up the nose and into the brain. This causes the disease Primary Amebic Meningoencephalitis (PAM), which destroys brain tissue and causes brain swelling and death. Naegleria fowleri infections are very rare and usually fatal. Of 135 people infected in the United States since 1962, only 3 people survived.

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Last Revised: March 23, 2017