Fig 1. Diagrammatical representation of core mammalian vasculature showing (white arrows) possible routes of migration of a schistosome juvenile to the portal vasculature, where the parasites mature.

A cercaria (depicted at bottom) has penetrated the skin of the lower body and invaded the vasculature, as suggested by the black arrow. White arrows track the parasite travelling via the inferior vena cava to the heart, then to the left lung before returning to the heart and entering the abdominal aorta. From the aorta, pathway “A” indicates parasites entering the celiac trunk to the gastroduodenal, hepatic, or splenic arteries to the liver. Pathway “B” indicates parasites entering the superior or inferior mesenteric arteries and moving through the hepatic portal vessels to the liver. Pathway “C” depicts parasites entering the internal iliac artery to the vessels of the bladder, from where they could reach the liver via the superior rectal and hepatic portal vasculature. Arteries are depicted in red, most veins in blue; hepatic portal veins in purple. Fig 1 was created with Biorender.com.