N. fowleri is a widespread, free-living amoeba that resides in warm fresh water and moist soil. It generally infects humans when it is inhaled and then travels through the nasal passages to the brain and spinal cord.
While exposure to the organism rarely causes disease, when it does infect a human it produces one of the deadliest illnesses known, primary amebic meningoencephalitis.The protozoa digests tissue and cells in the brian, causing severe headaches, high fever, nausea, vomiting, coma, and eventual death. The disease has a fatality rate above 95%
Since it was first described in 1965, about 300 cases of PAM been reported. It is typically seen in young, healthy individuals who were infected by swimming or diving in warm fresh water.
Courtesy of Markell and Voge's Medical Parasitology