What is Naegleria?

Naegleria is a free-living ameba commonly found in the environment in water and soil. Only one species of Naegleria has been found to infect humans, Naegleria fowleri.

Where is Naegleria found?

Naegleria fowleri is found worldwide. Most commonly, the ameba is found in:

• Warm bodies of freshwater, such as lakes, rivers
• Geothermal water such as hot springs
• Warm water discharge from industrial plants
• Poorly maintained and minimally chlorinated swimming pools
• Soil

How common is Naegleria infection?

Although Naegleria is commonly found in the environment, infection occurs rarely. Only 23 infections were documented in the U.S. between 1995 and 2004.

When is Naegleria most common?

Infection with Naegleria is very rare. However, when it does occur, infection is most common during the dry, summer months, when the air temperature is hot, the water is warm, and water levels are low. The number of infections increase during years characterized by heat waves.

How does infection with Naegleria occur?

Infection with Naegleria occurs when the ameba enters the body through the nose. Generally this occurs when people are participating in water-related activities such as swimming underwater, diving, or other water sports that result in water going up the nose. The ameba then travels to the brain and spinal cord where it destroys the brain tissue.