Naegleria fowleri: An emerging drinking water pathogen (PDF)

Naegleria fowleri (N. fowleri) is a free-living amoeba (FLA) that is nearly ubiquitous in the environment and potentially present in high numbers in warm waters. It causes primary amoebic meningoencephalitis (PAM), a rare but lethal disease. Although N. fowleri was isolated from drinking water supplies in Australia in the 1980s, it was not considered a drinking water threat in the United States until recent cases were associated with a ground-water system in Arizona and surface water systems in Louisiana. N. fowleri in drinking water distribution systems can be managed using disinfectant concentrations typical in the United States, although nitrification poses control challenges. The greatest N. fowleri challenge is premise plumbing systems in whch residuals might be low or nonexistent and water temperatures could support rapid growth of the amoebae. This article reviews studies describing the occurrence, survival, pathogenicity, and disinfection of N. fowleri.