Pathogenesis of pathogenic Naegleria amoeba
Chang, S.L.
Folia Parasitologica 26(3): 195-200
1979
ISSN/ISBN: 0015-5683 PMID: 120297 Document Number: 141854
Brain sections from autopsies of 14 cases of primary amoebic meningoencephalitis (originating from Australia, Belgium and the USA) were examined. Extensive demyelinization of the white matter, and severe histopathological changes and large clusters of trophozoites in the grey matter, were seen. The myelinoclasis appeared to be a result of a specific phospholipolytic effect, unlike that in post-viral encephalomyelitis, which has been attributed to vascular blockade, or haemorrhages. In monkey kidney cells cultured with Naegleria, a very early cytopathic effect was observed. Rat brain slices inoculated with Naegleria exhibited amoebic growth and demyelinization in 28 to 52 hours incubation at 35 deg C. In a chemically defined medium containing sphingomyelin, casein and glucose, Naegleria produced a limited growth parallelling the clearance of the lipid turbidity during a 72-hour incubation at 35 deg C. Chromatographic analysis of the turbidity-cleared cultures revealed decomposition of sphingomyelin with liberation of choline, sphingosine and fatty acids. It is concluded that the pathogenicity of pathogenic Naegleria can be attributed to the liberation of a phospholipolytic enzyme or factor during active growth.