Experimental amebiasis. I. Pathogenicity of axenically cultured Entamoeba histolytica in the brain of the newborn mouse
Mattern, C.F.; Keister, D.B.
American Journal of Tropical Medicine and Hygiene 26(3): 393-401
1977
ISSN/ISBN: 0002-9637 PMID: 194491 Document Number: 114973
Axenically cultured Entamoeba histolytica inoculated intracerebrally into newborn Swiss mice invaded the cerebrum and produced multiple abscesses containing viable trophozoites. As few as 20 amebae of a virulent strain (HM-1:IMSS) occasionally produced fatal disease, 200 killed about 75% of animals and higher doses regularly killed all animals. In contrast, avirulent strains (HK-9 and HB-301:NIH) failed to produce acute brain disease in comparable time periods even when mice were inoculated with as many as 20,000 amebae. Two other strains (1295 and H-458:CDC) were of intermediate virulence. High doses of avirulent amebae often produced hydrocephalus as a late manifestation. In newborn, 3 week-old, and 6-week-old mice resistance to infection increased with age, and older animals often responded late to virulent strains by developing hydrocephalus.