Schistosomiasis, also known as bilharzia, is a disease caused by parasitic flatworms called schistosomes. Schistosomiasis is a disease caused by parasitic worms, transmitted through contact with contaminated freshwater. It can cause a range of chronic health problems, including damage to internal organs. Efforts to combat the disease include improving sanitation, reducing exposure to contaminated water, snail control, and mass drug administration of praziquantel.

Causative Agents: The main species causing schistosomiasis are Schistosoma mansoni, Schistosoma haematobium, and Schistosoma japonicum. These species vary geographically and cause different forms of the disease. In Africa, the two most prevalent species are S. mansoni and S. haematobium  

Transmission and Lifecycle: Schistosomiasis is transmitted through contact with freshwater contaminated with the larvae of the parasite, released by freshwater snails. When people swim, bathe, or wade in the water, the larvae penetrate the skin and migrate through the body to the veins around the liver or bladder, where they mature into adult worms.

Symptoms and Health Impact: Initial infection may cause a rash or itchy skin. Chronic infection can lead to various symptoms depending on the species of worm. Schistosoma mansoni and S. japonicum primarily affect the intestine and liver, causing abdominal pain, diarrhea, and liver damage. S. haematobium primarily affects the urinary system, leading to urinary tract infections, and bladder cancer, and can cause blood in the urine.

Epidemiology: Schistosomiasis is most prevalent in tropical and subtropical areas, especially in poor communities without access to safe drinking water and adequate sanitation. It's estimated to affect millions of people worldwide.

Prevention and Control: Prevention strategies focus on reducing exposure to contaminated water, snail control, and improving sanitation and access to safe drinking water. Health education plays a critical role in prevention efforts.

Treatment: The primary treatment for schistosomiasis is praziquantel, a medication that is effective against all forms of the disease. Mass drug administration campaigns are often conducted in endemic areas to reduce the prevalence of the disease.

Global Health Initiatives: Schistosomiasis is recognized as a significant public health problem and is targeted by various global health initiatives. The World Health Organization (WHO) and other agencies aim to control and eventually eliminate the disease through integrated approaches, including treatment, improved sanitation, and snail control.