Naegleria fowleri Infection (Brain-Eating Amoeba Infection)

  • Medical Author:

    Sandra Gonzalez Gompf, MD, FACP is a U.S. board-certified Infectious Disease subspecialist. Dr. Gompf received a Bachelor of Science from the University of Miami, and a Medical Degree from the University of South Florida. Dr. Gompf completed residency training in Internal Medicine at the University of South Florida followed by subspecialty fellowship training there in Infectious Diseases under the directorship of Dr. John T. Sinnott, IV.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Is it possible to prevent Naegleria fowleri infections?

PAM is entirely preventable. The risk can be eliminated by avoiding untreated freshwater recreation during hot periods of the year. Consistent use of nose clips is probably next best, by keeping freshwater out of the nose. Avoidance of jumping, diving, and submerging the head are basic precautions. While it is recommended to avoid stirring up the bottom of lakes, amoeba are present at all levels where water temperatures are between 76 F-115 F. This makes warm surface water in the middle of a lake a risk, as well as the shore.

While common sense suggests that signs will be posted if there is a risk, this is rarely the case, and safety is in the hands of the swimmer. Most untreated freshwater is not tested for microbes. Recreational lakes and rivers with beaches may be tested for bacteria that cause diarrheal illness but rarely for amoebae. Even testing of such waters is not reassuring, because it may be found one week and not the next. The CDC recommends that all swimmers assume there is a low risk of amoebic meningitis at all times in untreated freshwater during hot months and take precautions to keep water out of the nose.

It is not possible to eliminate the amoeba from untreated freshwater since, like fish, it is simply a part of the life cycle. Chlorination to a level of 1 part per million (ppm) of free chlorine is needed to eliminate amoebae and other waterborne pathogens from pools; 3 ppm is recommended for hot tubs.

In addition to untreated freshwater, chlorine levels may be low in plumbing systems the further they are from a treatment plant. Chlorine also may dissipate in unused water pipes in a home, and hot water heaters are excellent incubators at temperatures under 120 F. Hot water heaters should be kept at minimum 120 F (higher may pose a scalding risk to children and the elderly). All the faucets should be run regularly with very hot water. Children should be taught not to suck water up the nose in the tub or shower. Outdoor hoses should not be used for drinking as they are contaminated and may force water up the nose by accident. If a filter is attached to the end of a hose used to fill kiddie pools or water toys, it should be labeled as NSF-certified to filter "cysts", or filter particles down to 1 micron. Care should be taken to clean and dry water play items in between uses and keep them away from dirt.

Those who flush their sinuses or nose should never use water straight from the faucet to prepare irrigation solution. The water should be boiled for at least one minute (longer at higher altitudes above sea level) and then allowed to cool. It can be used for a day or so. Purified or distilled water may also be purchased for this use.

Public swimming pools may not always be well maintained, especially during heavy use or traveling, but anyone can use standard pool test strips to check the chlorine and pH of a public facility before going in. People can empower themselves and get free pool test strips at (

Medically Reviewed by a Doctor on 8/18/2016

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