Schistosoma mansoni Maintenance and Harvest

A Puerto Rican isolate of Schistosoma mansoni was maintained by passage through albino Biomphalaria glabrata snails and infection of 3–5 week-old, female Mesocricetus auratus Golden Syrian hamsters [54 (link), 55 (link)]. Cercariae (infectious larvae) were obtained from infected snails and mechanically transformed into somules as previously described [20 (link), 56 (link), 57 (link)]. To obtain adult schistosomes, hamsters were euthanized 42–45 days post-infection using an intra-peritoneal injection of 50 mg/kg sodium pentobarbital containing 50 U/ml heparin (as an anti-coagulant) in a total of 100 μL PBS. Worms were harvested by reverse perfusion of the hepatic portal system [54 (link), 55 (link), 58 (link)] in RPMI 1640 medium supplemented with 100 U/ml penicillin and 100 mg/ml streptomycin [54 (link), 55 (link)]. Adults were transferred into Basch medium 169 [59 (link)] supplemented with 100 U/ml penicillin and 100 mg/ml streptomycin. In this medium, parasites were washed three times, allowed to stand for 30–60 min in the presence of 2X amphotericin B (fungizone) and then washed another three times in medium minus fungizone prior to phenotypic screening.