Free-living ameba infection

Infections caused by free-living amoebae include three forms: primary amoebic meningoencephalitis, primarily caused by Naegleria fowleri; granulomatous amoebic encephalitis and keratitis caused by Acanthamoeba species. In healthy individuals, ocular infections such as iritis and keratitis often occur due to contact lens use (especially when wearing lenses while swimming). Early symptoms are mainly tearing and a foreign body sensation, characterized by stromal infiltrates and dendritic lesions involving epithelial cells without obvious corneal ulcer formation. Late stages are characterized by ring-shaped corneal infiltration. Amoebae can be identified in corneal scrapings or biopsy specimens via pathological examination or culture. This disease has only been reported in isolated cases domestically, but attention should be paid to it.