This increase is attributed to the use of contact lenses and especially incomplete cleaning and disinfection. Acanthamoeba probably gains access to the corneal stroma through small breaks in the corneal epithelium produced as a result of minor trauma or abrasion. The ameba can then further destroy the corneal stroma or permit secondary bacterial infections. A mild to moderate corneal inflammation is also associated with Acanthamoeba invasion. Clinical manifestations of amebic keratitis include severe ocular pain and corneal lesions refractory to antiviral, antibacterial, and antimycotic drugs.
Diagnosis is confirmed by detecting the amebas in corneal scrapings or biopsies.
Surgery is often need to correct the loss of vision. Balamuthia Balamuthia mandrilaris is the most recently described free-living ameba causing human disease. It was first reported in a mandrill baboon in 1990 and subsequently shown to be associated with human pathology. Many cases of GAE originally ascribed to Acanthamoeba have retrospectively been assigned to Balamuthia . Balamuthia has not yet been identified in the environment, but presumably exhibits a similar ecology as Acanthamoeba and Naegleria .