RESUMEN
Acanthamoeba culbertsoni isolated from a water sample of El-Mahmoudia canal in Alexandria, was orally inoculated into a mouse model [200-400 amoebae / mouse] under different conditions. One week postinfection [P.I.], 20% of infected normoacidic mice and all animals received cimetidine or tetracycline prior to infection passed the parasite in their stools. One month P.I. 70% of cimetidine and 100% of tetracycline pretreated mice showed marked erosion in the intestinal mucosa and areas of necrosis with congestion in the brains with trophozoites and cysts in both tissues. It is concluded that, normoacidic mice may be simply acting as paratenic hosts. In case of hypoacidity or altered normal flora, the intestinal tract was invaded by amoebae representing a new portal of entry for CNS infection