Schistosomes, commonly known as blood flukes, are a genus of trematodes known to cause schistosomiasis. These worms are transmitted to humans through contact with contaminated freshwater and can live in the blood vessels. Seven schistosome species can cause human infection, but three are much more common. They include two species responsible for intestinal tract diseases (S. mansoni and S. japonicum) and one responsible for genitourinary tract disease (S. haematobium). Symptoms depend on the species and involved organs, and may include abdominal pain, diarrhea, bloody urine, and fever. Treatment involves medications to kill the parasites, such as praziquantel and oxamniquine, as well as those to reduce inflammation, like steroids.