Naegleria fowleri as an infectious agent of primary amebic meningoencephalitis: morpho-biological properties of the pathogen, pathophysiology of meningoencephalitis, and clinical-diagnostic features (a literature review)
DOI:
https://doi.org/10.14739/2310-1210.2025.5.333243Keywords:
Naegleria fowleri, meningoencephalitis, amoebae, central nervous system parasitic infections, epidemiologyAbstract
Aim. To provide a comprehensive analysis of the morphobiological characteristics of Naegleria fowleri and summarize current data on the epidemiology, clinical course, diagnostic approaches, and therapeutic strategies for primary amebic meningoencephalitis (PAM).
Materials and methods. The review is based on scientific publications indexed in Web of Science, PubMed, Scopus, and Google Scholar from 1993 to 2025 with a focus on the past decade. It includes in vitro, in vivo and ex vivo studies, clinical reports, and epidemiological data.
Results. Naegleria fowleri is a thermophilic, free-living amoeba responsible for fulminant primary amebic meningoencephalitis, with a case-fatality rate exceeding 97 %. The trophozoite stage is the primary invasive form, capable of entering the brain via the olfactory nerves. Pathogenic mechanisms involve adhesion to the nasal mucosa, phagocytosis of neural cells, and secretion of metalloproteinases, proteases, and pore-forming proteins, contributing to blood-brain barrier disruption. The amoeba is believed to express actin-associated and integrin-like proteins that facilitate tissue invasion. Diagnostic tools include CSF microscopy, conventional and real-time PCR, LAMP, culture on non-nutrient agar with E. coli, and immunostaining techniques. Imaging (CT/MRI) supports diagnosis in cases with elevated intracranial pressure. Clinical evidence supports the efficacy of combination therapy including amphotericin B, miltefosine, fluconazole, rifampin, and azithromycin. However, treatment is complicated by poor central nervous system drug penetration and drug toxicity. Advances in nanocarrier-based delivery systems may improve outcomes.
Conclusions. Naegleria fowleri is a highly neuroinvasive facultative parasite with limited treatment options and poor prognosis. Early detection combined with aggressive, multi-drug therapy significantly improves survival. Future research should focus on novel diagnostic markers, therapeutic targets, drug delivery methods, and preventive strategies.
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