Amoebic meningo-encephalitis due to a free-living amoeba. A case report.

A 47-year-old man developed an undiagnosed encephalitic illness and died within 12 days. Autopsy showed focal granulomatous lesions associated with a necrotizing vasculitis. Light microscopy revealed the presence of free-living amoebae morphologically resembling Acanthamoeba species. The pathology of this form of meningo-encephalitis is contrasted with that caused by Naegleria fowleri infection, and attention is drawn to its existence within the RSA.