Parasite
Naegleria fowleri
Freshwater brain-eating free-living amoeba
nay-GLEER-ee-uh FOW-ler-eye
High-yield clue
Warm-freshwater exposure with nasal entry through the cribriform plate causing rapidly progressive PAM is the classic clue.
Overview
A thermophilic free-living amoeba found in warm freshwater that enters the nose and travels along the olfactory nerve to cause primary amebic meningoencephalitis (PAM). It matters as the classic warm-water, nasal-entry CNS amoeba.
Classification
- Protozoa
- Free-living amoeba
- Trophozoite / flagellate / cyst stages
- Thermophilic
Lab & identification clues
- Motile trophozoites in CSF wet mount
- Olfactory-nerve / cribriform-plate route vocabulary
- Flagellated form in distilled water
- PCR confirmation vocabulary
Associations
- Warm lakes, hot springs, poorly chlorinated water
- Nasal-rinse/tap-water exposure route
- Primary amebic meningoencephalitis (PAM)
- Rapid clinical course study framing
Commonly confused with
- Acanthamoeba species
- Bacterial meningitis presentation
Your notes
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.