Fig. (7) A representative young erythrocyte infested with Plas-modium at trophozoite stage: study model “mice Plasmodium berghei ANKA” (100X). Females C57BL/6 mice 8 weeks old weighing 20 g were purchased from Charles River Laboratoires Saint-Aubin-lès-Elbeuf France. These mice were either exposed to the bites of female anopheles mosquitoes infected by Plasmodium berghei ANKA or injected intraperitoneally with RBC infected by Plasmodium berghei ANKA. Blood was enriched with young RBC by bleeding these mice. The fresh blood obtained 5 days after the infestation of mice was incubated with reagent Cresyl RAL which was purchased from Rhône Poulenc, to cause the ribosomes in the young blood cells to appear. Then the Giemsa reagent RAL 555 which was purchased from Prosciences France, was applied to visualize the parasite in the RBC. The yellow arrow shows youngest RBC, the blue arrow indicates medium age RBC parasitized by Plasmodium berghei ANKA, the green arrow shows advanced age RBC, and the red arrow indicates mature RBC [Moumaris et al., 1996].