Risk of fatal amebic meningoencephalitis from waterborneNaegleria fowleri

Primary amebic meningoencephalitis (PAM) is a fatal disease of the central nervous system caused primarily by the free-living ameba,Naegleria fowleri. PAM is primarily associated with swimming in various types of fresh water. World literature was reviewed in order to derive a risk analysis model that would be helpful in the management of PAM. The management of PAM risk is difficult, and the prevention of PAM is almost impossible. However, it is reassuring that the cases and risks estimated by the risk model are usually small, with individual annual risk on the order of 10^–6.