Figure 2. Schistosoma mansoni life cycle.

(A) Sexually differentiated cercariae, swimming in fresh water, infect the human host, penetrating the skin. During host entry, cercariae lose their tails and mature into schistosomulae, then migrate to the portal vasculature where mature adult worms form mated pairs (B) and begin depositing eggs (C). Eggs are shed via the feces and, upon contact with fresh water, hatch into miracidia (D). Miracidia infect snails of the genus Biomphalaria (E), where they undergo asexual reproduction (mother sporocysts), producing the next generation of cercariae, which are shed again into fresh water. Life cycle stages, contacting the human host (A-C), are outlined in black. Bullet points outline selected immunomodulatory actions of cercariae/schistosomulae, adult worms, and eggs.