Amebic meningitis/encephalitis infections are not spread from person to person.
Naegleria fowleri infects people when water containing the ameba enters the body through the nose. This typically occurs when people go swimming or diving in warm freshwater, like lakes and rivers. In very rare instances, Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or contaminated tap water) enters the nose, such as when people submerge their heads or cleanse their noses during religious practices, and when people irrigate their sinuses (nose) using contaminated tap water. The Naegleria fowleri ameba then travels up the nose to the brain where it destroys the brain tissue. Naegleria fowleri has not been shown to spread via water vapor or aerosol droplets (such as shower mist or vapor from a humidifier), and you cannot be infected with Naegleria fowleri by drinking contaminated water.
While infections with Naegleria fowleri are rare, they occur mainly during the summer months of July, August, and September. Infections are more likely to occur in southern-tier states. Infections usually occur when it is hot for prolonged periods of time, which results in higher water temperatures and lower water levels.