Deaths from the "brain eating amoeba" Naegleria fowleri are fairly rare but each is highlighted in the press, as headlines containing brain eating beget clicks.

While it's not yet understood why this fresh water amoeba is a pathogen and ends up in the brain specifically; molecules in neurons may be structurally similar to molecules the amoeba is sensitive to and moves towards (1, 2).

Are there any guidelines to help reduce risk of exposure to, or infection of Naegleria fowleri when dealing with exposure to fresh water ponds, lakes, or rivers for recreation or even just washing-up ones self?


Here is what the Centers for Disease Control and Prevention say

The only certain way to prevent a Naegleria fowleri infection due to swimming is to refrain from water-related activities in warm freshwater. Personal actions to reduce the risk of Naegleria fowleri infection should focus on limiting the amount of water going up the nose.


Also see their pages on

So short of staying out of the water and if in the water keeping it out of your nose, there is little you can do, but the CDC does point out that it is very rare.

There have been 34 reported infections in the U.S. in the 10 years from 2008 to 2017, despite hundreds of millions of recreational water exposures each year 10. By comparison, in the ten years from 2001 to 2010, there were more than 34,000 drowning deaths in the United States.


  • 1
    @uhoh That and keep the water out of your nose if you do swim. If its any comfort you are far far more likely to drown. Oct 2 '18 at 6:06
  • 1
    This will protect against many other parasites as well
    – user15958
    Oct 2 '18 at 11:09
  • 1
    Do they define "warm" in that context?
    – Chris H
    Oct 2 '18 at 12:13
  • 2
    @ChrisH I don't think so Oct 2 '18 at 14:46
  • 1
    Keeping the nose out of the water (or rather the water out of the nose) also helps against drowning.
    – Graipher
    Oct 3 '18 at 12:55

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