Schistosomiasis is a parasitic disease caused by various species of blood flukes, specifically those belonging to the genus Schistosoma. It is predominantly found in tropical and subtropical regions of Africa, South America, the Caribbean, the Middle East, and Asia. The disease is commonly transmitted through contact with fresh water contaminated with the parasite's larvae, known as cercariae.
Once the cercariae penetrate the skin during direct contact with infested water, they develop into adult worms and primarily dwell in the blood vessels surrounding the intestine or bladder. The worms produce eggs that are either excreted through urine or feces, leading to contamination of water bodies and perpetuating the cycle of infection.
Schistosomiasis can manifest as various clinical forms depending on the species involved, the number of parasites, and the duration of infection. Symptoms can range from mild, such as an itchy rash ("swimmers itch"), to more severe, including fever, fatigue, abdominal pain, liver enlargement, blood in stool or urine, and complications affecting organs such as the liver, intestines, bladder, or kidneys.
Prevention and control of schistosomiasis typically involve health education, access to safe water and sanitation facilities, snail control programs (as freshwater snails serve as intermediate hosts for the parasite), and periodic mass drug administration to at-risk populations. Treatment primarily relies on antiparasitic drugs, especially praziquantel, to kill the adult worms and reduce the impact of disease.
