CLINICAL CHARACTERISTICS AND PROGNOSIS OF HUMAN INFECTION BY NAEGLERIA FOWLERI: AN INTEGRATIVE REVIEW

Abstract

Naegleria fowleri, known as the “brain-eating amoeba,” is a free-living thermophilic protozoan responsible for Primary Amebic Meningoencephalitis (PAM), a rare, acute, and highly lethal infection that affects the central nervous system. This article aimed to analyze the clinical characteristics, prognosis, and therapeutic advances related to human infection by N. fowleri. The methodology consisted of an integrative literature review conducted between August and October 2025 using the Virtual Health Library (VHL) databases, covering studies published from 2000 to 2025. The results indicate that excretion and secretion products, especially extracellular vesicles (EVs), play a central role in virulence by promoting cell adhesion, immune evasion, and brain necrosis. Reported clinical cases suggest that early identification and intensive multimodal treatment — including amphotericin B, miltefosine, and antibiotics — are decisive factors in the rare cases of survival. Furthermore, recent studies highlight emerging therapies based on drug repositioning, the use of nanoparticles, and experimental vaccines, including recombinant and messenger RNA (mRNA) formulations, which have shown promising immune responses in animal models. Ecological and epidemiological studies also reinforce the environmental and zoonotic presence of the protozoan, as well as its symbiotic association with bacteria, factors that may modulate its virulence. It is concluded that confronting N. fowleri infection requires the integration of rapid diagnosis, therapeutic innovation, and environmental surveillance, representing a growing biomedical challenge of significant relevance to global public health.