Abstract: 　Objective] To study the effect of anti-mosquito-midgut antibodies on the development of P.yoelii in A.stephensi . [Methods] Ookinetes and oocysts in midgut and sporozoites in the salivary glands of mosquitoes were examined respectively at 14 h and 9 d and 12 d after the mosquitoes ingested infected blood containing anti-midgut antiboides by membrane feeders. The effect of anti-midgut antibody level and repeated feedings on the development of the oocysts in the mosquitoes was also observed. [Results] The anti-midgut antibodies reduced evidently not only the infection rates of the oocysts and the number of the sporozoites in salivary gland but also infection degree of ookinetes and the index of oocysts in the mosquitoes compared with control group ( P <0 05). The higher the antibody level, the more the times for mosqitoes digested antibodies, and the fewer the number of oocysts. [Conclusion] The anti-mosquito-mindgut antibodies inhibited ookinetes and oocysts of P.yoelii in A.stephensi , with oocysts in particular.

Key words: anti-mosquito-midgut bodies, P.yoelii, ookinetes, oocysts, sporozoites