Snail infections
Schistosoma mansoni (NMRI strain) eggs were collected from infected Swiss-Webster mice provided by the NIAID Schistosomiasis Resource Center. Sixteen infected mice were euthanatized on each date of egg addition to tanks (27 July 2015, 10 August 2015, 24 August 2015 and 8 September 2015), and S. mansoni eggs were collected from the livers. Egg isolation, viability testing, and deployment to tanks within 2 h was performed as described above for experiment one. Average egg viability for the four egg harvests in experiment two was 48 percent (Table S3).
Experimental biosafety protocols were approved by USF Biosafety (IBC # 1334) to minimize the risk of human infection via personal protective gear and to minimize snail escape using methods fully described by Halstead et al. (2018).