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,  people are infected worldwide. In terms of impact this disease is second only to malaria as the most devastating parasitic disease. Schistosomiasis is considered one of the neglected tropical diseases (NTDs).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 into the water. You can become infected when your skin comes in contact with contaminated freshwater. The disease is spread by contact with fresh water contaminated with the parasites. These parasites are released from infected freshwater snails.The disease is especially common among children in developing countries, as they are more likely to play in contaminated water.Other high-risk groups include farmers, fishermen, and people using unclean water during daily living.It belongs to the group of helminth infections.Diagnosis is by finding eggs of the parasite in a person's urine or stool.It can also be confirmed by finding antibodies against the disease in the blood.Methods to prevent the disease include improving access to clean water and reducing the number of snails.In areas where the disease is common, the medication praziquantel may be given once a year to the entire group.This is done to decrease the number of people infected, and consequently, the spread of the disease. Praziquantel is also the treatment recommended by the World Health Organization for those who are known to be infected.