Schistosomiasis is a neglected tropical disease caused by Schistosoma blood flukes. Intestinal schistosomiasis is primarily due to Schistosoma mansoni, transmitted by Biomphalaria snails. In mammalian hosts, paired adult parasites reside in the mesenteric vasculature; females lay eggs that traverse the intestinal wall to be excreted by the host, but many become trapped in tissues, especially the liver, eliciting immunopathology. S. mansoni is the major laboratory model, and liver-derived eggs are typically used to maintain life cycles and study miracidia behaviors such as photosensation and chemosensation. However, eggs from liver and intestine differ morphometrically, transcriptomically, and antigenically, which may affect experimental outcomes. To test whether these differences endure after hatching to miracidia, the first larval stage, we compared miracidia hatched from mouse liver- versus intestine-derived eggs, sequencing their transcriptomes and quantifying behaviors using high-resolution tracking. Miracidia transcriptomes were distinguishable by egg source, though only a small subset of genes was differentially expressed. In contrast, basic behavior differed markedly. These distinct behavioral programs highlight egg source as a critical variable in experimental design and interpretation.
