Parasite
Acanthamoeba species
Contact-lens keratitis free-living amoeba
uh-KAN-thuh-MEE-buh
High-yield clue
Contact-lens wearer with painful keratitis, plus double-walled cysts and spiny (acanthopodia) trophozoites, is the key study clue.
Overview
A ubiquitous free-living amoeba of soil and water that causes contact-lens-associated keratitis and, in immunocompromised hosts, granulomatous amebic encephalitis (GAE). It matters as the classic contact-lens eye amoeba.
Classification
- Protozoa
- Free-living amoeba
- Trophozoite (acanthopodia) + double-walled cyst
- Ubiquitous soil/water organism
Lab & identification clues
- Corneal scraping wet-mount vocabulary
- Double-walled cyst morphology
- Spiny acanthopodia trophozoites
- Non-nutrient agar with E. coli overlay concept
Associations
- Contact-lens / poor lens hygiene risk vocabulary
- Keratitis eye-infection study link
- Granulomatous amebic encephalitis in immunocompromised
- Soil and freshwater environmental source
Commonly confused with
- Naegleria fowleri
- Herpes simplex keratitis
Frequently asked questions
What is Acanthamoeba species?
A ubiquitous free-living amoeba of soil and water that causes contact-lens-associated keratitis and, in immunocompromised hosts, granulomatous amebic encephalitis (GAE). It matters as the classic contact-lens eye amoeba.
What are the lab clues for Acanthamoeba species?
Lab clues for Acanthamoeba species include Corneal scraping wet-mount vocabulary, Double-walled cyst morphology, Spiny acanthopodia trophozoites, and Non-nutrient agar with E. coli overlay concept.
What is Acanthamoeba species commonly confused with?
Acanthamoeba species is commonly confused with Naegleria fowleri and Herpes simplex keratitis.
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.