title: Modification of resistance of mice to Naegleria fowleri infections.
abstract: Naegleria fowleri, which produces a fatal meningoencephalitis in humans, is also able to produce a progressive and fatal disease in mice. The course of the disease in DUB/ICR mice is dependent upon the infecting dose of organisms, whether administered intraperitoneally (i.p.) or intravenously (i.v.). All of the mice receiving 10(7) trophozoites/mouse i.v. or 4.85 X 10(7) trophozoites/mouse i.p. were killed within 10 days. Escherichia coli O26:B6 lipopolysaccharide, administered at a dose of 1 mg/kg 24 h prior to N. fowleri, afforded some protection for several days after challenge, but by day 8 there was no difference in survival of untreated and endotoxin-treated mice. No significant protection was afforded by a complex of lipid A with concanavalin A (ConA) or bovine serum albumin (BSA) or by dimethylmyristamide-BSA, dimethylmyristamide, BSA, beta-hydroxymyristic acid-ConA, beta-hydroxymyristic acid, ConA, myristic acid-BSA, or myristic acid. Mice surviving primary i.v. or i.p. challenge doses of N. fowleri, 5 X 10(6) and 10(7) trophozoites/mouse, respectively, were highly resistant to rechallenge with an i.v. dose of organisms (5 X 10(6) Naegleria/mouse) that produced uniformly fatal disease in untreated control mice.
mesh_terms: D000656:Amoeba / Q000472:pathogenicity*; D000818:Animals; D004195:Disease Models, Animal; D008590:Meningoencephalitis / Q000209:etiology* / Q000401:mortality / Q000517:prevention & control; D051379:Mice; D008813:Mice, Inbred ICR; D011528:Protozoan Infections