Figure 4: T.S of Biomphalaria alexandrina snails exposed to Schistosoma mansoni miracidia (SBSC): left panel (6hr post exposure), right panel (72hr post exposure). A&B: Ismailia snails, A: miracidium “Mi” (arrows) in head-foot region; note successful penetration of miracidia without tissue response at this time, B: hemocytes “H” infiltration around the abnormally developed sporocyst “Sp” in the head-foot region as an inward step of forming a capsule, C&D: Kafr El- Sheikh snails, C: three encapsulated miracidia “Mi” (arrows) in head-foot region; note obvious tissue reactions through hemocytes “H” aggregations around the miracidia, D: hemocytes “H” infiltration around the abnormally developed sporocysts “Sp” in the head-foot region forming a capsule, E&F: Damietta snails, E: two miracidia “Mi” (arrows) in tentacle; Note haemocytic response “H”, F: degraded sporocyst “Sp” and large capsule formation by several layers of hemocytes “H” in the head-foot region near the tentacle; germinal cell (GC); tegument (T) (h & e) (x 400).