Comparative neuropathology of granulomatous amoebic encephalitis caused by Acanthamoeba spp. across species

Abstract Acanthamoeba species are free-living amoebae that cause granulomatous amoebic encephalitis, a rare but frequently fatal infection of the central nervous system that predominantly affects immunocompromised individuals. The disease is characterized by a subacute to chronic course, diagnostic difficulty and marked heterogeneity in clinical presentation. Here, we describe a comparative analysis of the neuropathology of Acanthamoeba encephalitis across humans and animals, highlighting conserved features of haematogenous dissemination, perivascular tropism, granulomatous inflammation and chronic tissue destruction. Across species, both trophozoites and cysts persist within neural tissue, reflecting prolonged host–pathogen interaction rather than acute cytolysis. Despite variability in lesion distribution and disease kinetics, the fundamental pathological signature of Acanthamoeba encephalitis is remarkably conserved. These observations validate the use of animal models for mechanistic investigation and therapeutic development and clarify key processes underlying this devastating opportunistic infection.