Brain-Eating Amoeba Naegleria fowleri: Global Epidemiology, Diagnosis, Therapeutic Challenges, and Strategies to Combat Primary Amoebic Meningoencephalitis

Naegleria fowleri, colloquially known as the “brain-eating amoeba,” is a free-living protozoan that causes the fulminant and often fatal disease primary amoebic meningoencephalitis (PAM). Although considered rare, the global case fatality rate exceeds 95%, making it one of the deadliest human infections. Traditionally associated with warm freshwater environments in tropical and subtropical regions, recent cases from temperate areas suggest climate change and water resource mismanagement are contributing to an expanding epidemiological footprint. Despite advances in molecular biology and phylogenetics, timely diagnosis remains elusive, as early clinical manifestations mimic bacterial or viral meningitis, often leading to misdiagnosis and delayed treatment. Current therapeutic regimens, largely based on amphotericin B, azoles, rifampin, and miltefosine, demonstrate limited success, and no standardized treatment protocol has been universally adopted. This review synthesizes the latest insights into the biology and pathogenicity of N. fowleri, outlines the global epidemiological trends and phylogenetic diversity, and discusses diagnostic challenges and therapeutic interventions. Furthermore, it highlights the pathogen’s emerging public health threat in the context of climate change and globalization, and proposes multi-pronged strategies for prevention, early detection, and therapeutic innovation. Strengthening surveillance systems, integrating genomic tools, and fostering international collaborations are essential to mitigate the devastating burden of PAM and to prepare for the potential global spread of this lethal pathogen. Keywords: Brain-eating amoeba, emerging infections, global health, Naegleria fowleri, primary amoebic meningoencephalitis.