Risk factors

Millions of people are exposed to the amoeba that causes naegleria infection each year, but only a few people get sick from it. Between 2010 and 2019, 34 infections were reported in the United States.

Some factors that might increase your risk of naegleria infection include:

• Freshwater swimming. Most people who become ill have been swimming in a freshwater lake within the previous two weeks.
• Heat waves. The amoeba thrives in warm or hot water. Infections are more likely to occur in the summer months and in southern states, but can also occur in more northern states.
• Age. Children and young adults are the most likely age groups to be affected, possibly because they are likely to stay in the water longer and are more active in the water.
• Nasal cleansing or irrigation. Very rarely, infections have occurred in people who used contaminated tap water to irrigate their sinuses or to cleanse their nose during religious practices. To ensure that your water is safe for sinus rinsing or ritual cleansing, don't use water straight from the faucet. Use boiled or distilled water instead.