Naegleria Infection

What is Naegleria?

Naegleria is an ameba (single-celled living organism) commonly found in warm freshwater (for example, lakes, rivers, and hot springs) and soil. Only one species (type) of Naegleria infects people: Naegleria fowleri.

How does infection with Naegleria fowleri occur?

Naegleria fowleri infects people by entering the body through the nose. This typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. The Naegleria fowleri ameba travels up the nose to the brain where it destroys the brain tissue.

You cannot be infected with Naegleria fowleri by drinking contaminated water. In very rare instances, Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or heated tap water <47°C) enters the nose, for example when people submerge their heads or cleanse during religious practices, and, possibly, when people irrigate their sinuses (nose).

Where is Naegleria fowleri found?

Naegleria fowleri is found around the world. In the United States, the majority of infections have been caused by Naegleria fowleri from freshwater located in southern-tier states . The ameba can be found in:

  • Bodies of warm freshwater, such as lakes and rivers
  • Geothermal (naturally hot) water, such as hot springs
  • Warm water discharge from industrial plants
  • Geothermal (naturally hot) drinking water sources
  • Soil
  • Swimming pools that are poorly maintained, minimally-chlorinated, and/or un-chlorinated
  • Water heaters with temperatures less than 47°C

Naegleria fowleri is not found in salt water, like the ocean.

Can I get a Naegleria fowleri infection from a disinfected swimming pool?

No. You cannot get a Naegleria fowleri infection from a properly cleaned, maintained, and disinfected swimming pool.

How common are Naegleria fowleri infections in the United States?

Naegleria fowleri infections are very rare. In the 10 years from 2001 to 2010, 32 infections were reported in the U.S. Of those cases, 30 people were infected by contaminated recreational water and two people were infected by water from a geothermal (naturally hot) drinking water supply.