A genus of free-living soil amoebae that produces no flagellate stage. Its organisms are pathogens for several infections in humans and have been found in the eye, bone, brain, and respiratory tract.

A genus of motile, unicellular eukaryotic amoebae within the family of Acanthamoebidae that are characterized with the presence of acanthopodia (spiny surface projections) and are commonly found in air, soil, and water environments. Members of the Acanthamoeba genus are opportunistic and nonopportunistic human pathogens, and may cause granulomatous amoebic encephalitis, cutaneous acanthamebiasis and amoebic keratitis.

Any amoebic organism that is not assigned to the species level but can be assigned to the Acanthamoeba genus level.

Facultative parasite of humans usually causes chronic infectin of the skin or central nervous system; causative agents of keratitis (corneal inflammation and opacity); most common ameba in fresh water and soil.

The free-living amoebae that cause human infections include Acanthamoeba, Naegleria, Balamuthia mandrillaris, and Sappinia diploidea. All 4 genera cause CNS infections that are frequently fatal.