The Brain-Eating Amoeba, aka Naegleria fowleri
Causes primary amebic meningoencephalitis (PAM).
The Parasite: The Naegleria fowleri parasite is an amoeba that is generally found in freshwater and soil. Its life cycle begins in cyst form at the bottom of bodies of freshwater. It emerges as an amoeba and begins to divide rapidly. It enters a human host when water is splashed or inhaled into the nose, usually when the host is swimming in freshwater lakes, river, hot springs of unchlorinated swimming pools. From the nose, the parasite travels up to the brain and spinal cord where it destroys brain tissue. It can form a protective coat or "cyst" to protect itself from the body's immune system defenses. When it sheds a cyst, the life cycle of the parasite repeats. This parasite is thermophilic, meaning it prefers warm water. Infection from the brain eating amoeba can increase during the warm summer months.
The Infection: The Naegleria fowleri parasite causes a rare but very severe, usually fatal brain infection. It leads to primary amebic meningoencephalitis (PAM), a disease in which brain tissue is destroyed. Symptoms usually begin within two weeks of infection and include headache, fever, nausea, vomiting and a stiff neck. As the infection progresses, the infected individual may become confused, unable to focus on their surroundings and unable to balance properly. They may also experience seizures and hallucinations. The infection progresses rapidly and generally causes death within 3 to 7 days.
Treatment: There is no clear treatment for this infection. Although several drugs have proved effective against Naegleria in a laboratory setting, most infections in people are fatal even when treated.
Prevention: The only way to prevent the infection is to avoid water-related activities, particularly in bodies of warm freshwater, hot springs or thermally-polluted water near power plants (where the amoeba may be more abundant). Otherwise, holding the nose shut or using nose clips during water activities may help prevent this infection. Also, avoid stirring up the sediment while engaging in freshwater activities.