Immunohistochemical characterization of the initial stages of Naegleria fowleri meningoencephalitis in mice
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The initial stages of Naegleria fowleri meningoencephalitis in mice were immunohistochemically characterized following the first 8 h post-intranasal inoculation. The events found after 8 h were: (1) amebas in contact with the mucous layer of the olfactory epithelium, (2) numerous parasites eliminated by extensive shedding of the mucous layer, and (3) many organisms reaching the nasal epithelium. In contrast to other works, we observed that after 24 h, amebas invaded the epithelium, without evidence of the disruption of the nasal mucosa. In addition some trophozoites invading through the respiratory epithelium were observed, suggesting an additional invasion route. The inflammatory response detected was scarce until 30 h post-inoculation. After 96 h, the inflammatory response was severe in the olfactory bulb and brain, and the tissue damage great. Consequently, an inflammatory reaction may enhance tissue damage but apparently does not destroy amebas which seem to proliferate in the olfactory bulb.
KeywordsOlfactory Bulb Lamina Propria Alcian Blue Olfactory Epithelium Mucous Layer
This work was supported by COFAA, IPN, CONACyT 34834 and 43102 and UNAM DGAPA PAPIIT IN207800 and IN213903 grants. Saul Rojas Hernandez was supported by a doctoral fellowship from the Consejo Nacional de Ciencia y Tecnología (CONACyT) and Consejo Mexiquense de Ciencia y Tecnología. (COMECYT).
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