Naegleria fowleri is a microscopic, single-celled organism that causes primary amebic meningoencephalitis (PAM), a severe brain infection. While infections are rare, PAM is almost always fatal. This amoeba infects humans when water containing it enters the nose, typically leading to a rapid and devastating illness. It is not spread from person to person, nor can it be contracted by swallowing contaminated water.
Where Naegleria Fowleri Resides
Naegleria fowleri naturally exists in various warm freshwater environments, including lakes, rivers, ponds, and hot springs. The amoeba thrives in warmer temperatures, ideally up to 115°F (46°C), which explains why infections are more common during summer months when water temperatures are higher and water levels might be lower.
It can also be found in poorly maintained swimming pools, splash pads, and other recreational water venues with insufficient chlorination. It has been detected in tap water systems, particularly in warm water discharge areas from industrial plants and within water heaters. However, it cannot survive in saltwater or in properly treated and disinfected swimming pools.
Key Prevention Strategies in Recreational Waters
Preventing Naegleria fowleri infection in recreational freshwater environments focuses on minimizing water entry into the nose. Avoid swimming, diving, or jumping into warm freshwater during periods of high water temperature and low water levels, as these conditions favor the amoeba’s growth. Assuming Naegleria fowleri is present in warm freshwater bodies is a prudent approach.
When engaging in activities in warm freshwater, use nose clips or hold the nose shut to prevent water from entering the nasal passages. Also, avoid activities that stir up sediment in shallow, warm freshwater areas, as Naegleria fowleri is more likely to reside in the bottom sediment.
Preventing Exposure in Other Settings
Beyond recreational waters, precautions are important for preventing Naegleria fowleri exposure. When using nasal rinsing devices like neti pots or sinus rinses, use only distilled, sterile, or previously boiled and cooled water. Untreated tap water can harbor the amoeba, and its use for nasal irrigation has been linked to fatal infections. Boiling tap water for at least one minute and allowing it to cool is an effective way to sterilize it for nasal rinsing.
Maintaining home water systems also helps reduce risk. Private swimming pools and hot tubs should be properly disinfected with adequate chlorine levels, as Naegleria fowleri cannot survive in appropriately treated water. Flush garden hoses or outdoor spigots before use, especially if water has been sitting in the heat, to clear out any stagnant water where the amoeba might grow. Avoiding water entering the nose during showers or baths is a sensible precaution, particularly in areas where the amoeba is known to be present.