Naegleria fowleri

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iNaegleria fowleri

Different stages of Naegleria fowleri

Scientific classification

Kingdom:	Protista
Phylum:	Percolozoa
Class:	Heterolobosea
Order:	Schizopyrenida
Family:	Vahlkampfiidae
Genus:	Naegleria
Species:	N. fowleri

Binomial name

Naegleria fowleri
Carter (1970)

Naegleria fowleri (pronounced nuh-GLEER-e-uh) is a free living amoeba typically found in warm fresh water, from 25-35 degrees Celsius in an amoeboid or temporary flagellate stage. It belongs among a group called the Percolozoa or Heterolobosea. In humans, N. fowleri can become pathogenic, causing primary amoebic meningoencephalitis (PAM or PAME), a syndrome affecting the central nervous system, characterized by changes in olfactory perception (taste and smell), followed by vomiting, nausea, fever, headache, and the rapid onset of coma and death.

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PAM usually occurs in healthy children or young adults with no prior history of immunocompromisation who have recently been exposed to bodies of fresh water. N. fowleri invades the central nervous system via penetration of the olfactory mucosa and nasal tissues, resulting in significant necrosis of and hemorrhaging in the olfactory bulbs. From there, amoebae climb along nerve fibers through the floor of the cranium and into the brain. Amphotericin B is currently the most effective known pharmacologic treatment for N. fowleri, but the prognosis remains bleak for those that contract PAM, as only eight patients have survived in a clinical setting. Amphotericin B devastates N. fowleri organisms in laboratory settings, and is the preferred choice in N. fowleri treatment, in addition to systemic rifampicin. A more aggressive antibody serum-based treatment is being pursued, and may eventually prove more effective than modern broad-spectrum antibiotic targeting. At this time, though, timely diagnosis remains a very significant impediment to the successful treatment of infection, as most cases have only been appreciated post-mortem.

N. fowleri can be grown in several kinds of liquid axenic media or on non-nutrient agar plates coated with bacteria. Detection in water is performed by centrifuging a water sample with Escherichia coli added, and then applying the pellet to a non-nutrient agar plate. After several days the plate is microscopically inspected and Naegleria cysts are identified by their morphology. Final confirmation of the species' identity can be performed by various molecular or biochemical methods.[1]

Naegleria fowleri was featured on the TV show House, on season 2, episodes 20-21.