Acanthamoeba is a microscopic, free-living ameba that is relatively common in the environment. This ameba has been isolated from water (including natural and treated water in pools or hot tubs), soil, air associated with cooling towers, heating, ventilation and air conditioner systems, sewage systems, and drinking water systems (shower heads, taps). Most people will be exposed to Acanthamoeba during their lifetime and will not get sick. However, Acanthamoeba is capable of causing several infections in humans.
Acanthamoeba keratitis is an infection of the eye that occurs in healthy persons and can result in permanent visual impairment or blindness. The infection is caused when a microscopic, free-living ameba called Acanthamoeba invades the transparent outer covering of the eye called the cornea.