From nose to neurons: The lethal journey of the brain-eating amoeba Naegleria fowleri

Naegleria fowleri , a thermophilic, free-living amoeba, is the causative agent of primary amebic meningoencephalitis (PAM), a rapidly progressing and often fatal infection of the central nervous system. During exposure to contaminated warm freshwater, the parasite enters the human host via the nasal cavity, migrates along the olfactory nerves, and induces severe inflammation in the brain. Despite its high fatality rate (>95 %), effective treatment remains elusive due to delayed diagnosis and limited therapeutic efficacy. Current diagnostic approaches include microscopy, PCR, and imaging techniques, but these are seldom applied promptly to alter outcomes. Therapeutic regimens typically involve amphotericin B, miltefosine, and combination antimicrobials, although survival is rare. Recent advances in drug repurposing, nanotechnology-based delivery systems, and immunotherapeutic strategies show potential but require further validation and assessment of effectiveness. Preventive measures, including public awareness initiatives and improved water treatment, are currently the most effective means of reducing the risk of PAM. This review provides an updated synthesis of the literature focusing on the causative agent, pathogenesis, diagnostic modalities, treatment options, and prevention strategies for N. fowleri infection. • Naegleria fowleri causes primary amebic meningoencephalitis (PAM), a rare but deadly brain infection that is usually fatal. • Naegleria fowleri thrives in warm freshwater; cases rise with global warming, poor sanitation, and water activities. • Rapid diagnosis and early treatment with amphotericin B and miltefosine slightly improve survival; research offers hope.