Acanthamoeba is a genus of amoebae, single-celled eukaryotes commonly recovered from soil, fresh water, and other habitats, and is classified into the eukaryote supergroup Amoebozoa. Acanthamoeba has two evolutive forms, the metabolically active trophozoite and a dormant, stress resistant cyst. Trophozoites are small, usually 15 to 35 μm in length and amoeboid in shape. In nature, Acanthamoeba species are free-living bacterivores, but in certain situations, they can cause infections (acanthamebiasis) in humans and other animals.