March 29, 2010
March 29 - Naegleria fowleri
Naegleria fowleri is a protist that seems to be straight out of science fiction. Ranking at number five on the Science Channel’s "Top Ten Infectious Diseases", N. fowleri is a free-living amoeba capable of devouring your brain! This insidious creature makes its home as a flagellated amoeboid in characteristically warm freshwater sites such as lakes, rivers, geothermal hot springs, warm water discharge from industrial plants, poorly maintained and minimally-chlorinated or unchlorinated swimming pools and Jacuzzis. However, it has also been documented that it can be contracted by the inhalation of dust containing its cyst form, and has been isolated in places such as soil or air conditioning units. Although it prefers warm conditions that can reach up to 46°C, N. fowleri can endure winters by becoming cysts that settle into bottom-lying sediment. Capable of parasitizing a variety of mammals, including humans, the amoeba causes primary amebic meningoencephalitis (PAM), a fatal disease that has been recorded as the cause of death in over 150 worldwide cases reported. In all of these cases, the victim of this lethal microbe died within two to three days of infection. Infection occurs almost exclusively through the olfactory tract whereupon it migrates to the brain or spine of its host by traversing the olfactory nerve. It then feeds upon brain tissue and blood cells as an amoeboid trophozoite via phagocytosis and pinocytosis. Thankfully, it isn’t contagious between hosts.
Contributed by Jameson Clarke, Bucknell University.