Naegleria fowleri (cont.)
What are risk factors for Naegleria fowleri infection?
The major risk factor for infection is recreational exposure to warm fresh water, especially if there is a history of aspiration of water into the nose. A review of cases in the U.S. by Yoder, et al. showed that there were 111 reported cases of primary amoebic encephalitis between 1962 and 2008. Living in the southern States is a risk factor for infection, because the water is warmer and more conducive to growth of the amoeba. A frequently asked question is when infections most commonly occur. The answer is that the organism is most active in summer months, even in the southern states. Most cases occur in previously healthy young males (median age of 12 years).