Life Cycle of
Naegleria fowleri
Naegleria fowleri is a the cause of primary amebic meningoencephalitis.
This is a brain disorder that is almost invariably fatal resulting from the
invasion of the brain by this facultative parasite. N. fowleri
exists as a free-living organism in freshwater ponds and lakes, and possibly
swimming pools and is quite common. It is believed that diving into
"swimming holes" in which amoebae are stirred up from the bottom and are
aspirated into the nasal passageways represent the principle epidemiological
factor. The organism exists in an amoeboid as well as a biflagellated
form. It is believed the biflagellated form is the invasive stage and
reverts to the amoeboid form when invading the cribiform plate through which the
olfactory nerves pass to the brain. The amoebae pass into the brain where
they lyse brain tissue. It is a rare disease usually only diagnosed during
an autopsy. Cooling pools of power plants are often inhabited by this
amoeba. Run-off from such plants may contaminate nearby waterways.