How to Prevent Naegleria fowleri Infection

Key points

  • Naegleria fowleri can cause a rare but almost always fatal infection if the ameba goes up the nose and to the brain.
  • These infections have occurred when people go swimming in warm fresh water or rinse their sinuses or nasal passages with water containing Naegleria fowleri.
  • There are steps you can take to help prevent a Naegleria fowleri infection.
Shallow river with rocks surrounded by trees


If Naegleria fowleri goes up the nose and to the brain, the ameba can cause an infection called primary amebic meningoencephalitis (PAM). These brain infections are rare―typically fewer than 10 occur in the United States every year. However, only a few people have ever survived PAM.

Most Naegleria fowleri infections occur when people swim, dive, or do other activities in warm fresh water. If you're going to a lake, hot spring, or other body of warm fresh water, take steps to reduce your risk of infection.

Naegleria fowleri infections can also happen when people use tap or faucet water that contains the ameba for sinus or nasal rinsing. If you rinse your sinuses or cleanse your nasal passages, make sure the water you use is safe.