Effects of Growth in Vitro with Selected Microbial Associates and of Encystation and Excystation, on the Virulence of Endamoeba Histolytica for Guinea Pigs

Abstract

Summary E. histolytica derived from cultures with T. cruzi were inoculated intracecally into guinea pigs at various intervals following isolation of the ameba with the trypanosome associate. The results showed that prolonged cultivation of the ameba with T. cruzi resulted in a complete loss of its virulence. However, the virulence was restored by returning the ameba to culture with selected bacteria followed by reisolation with T. cruzi, or by initiating ameba-trypanosome cultures from cysts produced in culture with the N.R.S. mixed bacterial flora. Cultures having their virulence thus restored retained such virulence for periods of three to eight weeks.