Schistosoma
Schistosomiasis, also known as bilharzia, is a disease caused by parasitic worms. Although the worms that cause schistosomiasis are not found in the United States, more than 200 million people are infected worldwide. In terms of impact this disease is second only to malaria as the most devastating parasitic disease. The parasites that cause schistosomiasis live in certain types of freshwater snails. The infectious form of the parasite, known as cercariae, emerge from the snail, hence contaminating water. You can become infected when your skin comes in contact with contaminated freshwater. Most human infections are caused by Schistosoma mansoni, S. haematobium, or S. japonicum.
Above is a foreign video of the parasite under a microscope
The digestive system
The digestive tract of S. mansoni consists of the oral sucker, the esophagus, which is surrounded by the esophageal gland in its posterior portion and the blind-ended gut. Schistosome mouth is subapical and opens through the oral sucker, which is the beginning of the digestive tract in the anterior extremity of the worm. The oral sucker is a funnel-shaped vent covered by the tegument and bears thousands of spines, which extend up to the esophagus The esophagus immediately succeeds the mouth opening and connects the sucker to the gut. It is a short tube that is invested by longitudinal and circular muscle fibers and two stronger circular muscle act as sphincters that control the entrance of blood. The esophagus is covered by an extension of the syncytial tegument with higher specialized surface architecture, specially focused in blood processing, and also an enormous membrane expanded into plates.