Schistosomiasis is a parasitic infection which occurs in tropical and subtropical regions of Africa, Asia, and South America. While schistosomiasis rarely causes death, it can cause illness and may lead to a variety of debilitating symptoms. People are at increased risk of developing bladder cancer when they have this disease. Cases of schistosomiasis are also highly treatable with a single course of medication.
People develop schistosomiasis when they are exposed to the parasite through contact with contaminated freshwater. This can include drinking from contaminated sources as well as swimming or washing in unclean water. Parasitic flukes enter through the skin, travel into the body, and mature into adults which can start to produce eggs. The symptoms of schistosomiasis are caused by immune reactions to the eggs, rather than reactions to the parasite itself.
In the early stages of infection, people can experience symptoms like abdominal pain, nausea, fatigue, fever, sores, and skin irritation. If the schistosomiasis is not treated, the patient will develop chronic illness. The liver and spleen can become enlarged, eggs may travel to the nervous system and cause symptoms like seizures, and internal organs are damaged.
A diagnosis of schistosomiasis is often accomplished simply by examination of the patient and a discussion of medical and travel history. People in areas where this infection is common who exhibit symptoms like bloody diarrhea may be assumed to have schistosomiasis. It is also possible to test the stool for eggs, as some of the eggs are expressed by the body.
Treatment involves administering medication to kill the parasite. Unfortunately for many people in areas where this disease is endemic, the medication can be expensive and difficult to obtain. After malaria, schistosomiasis is one of the most common parasitic infections in many regions of the world. Charitable organizations have promoted more ready availability of appropriate medications, along with steps for prevention.
This condition is also known as bilharzia, after the physician who first described it in the mid-1800s, or snail fever, after a common host of the parasitic flukes which cause it. People can reduce their risk of contracting schistosomiasis by avoiding sources of contamination. Drinking and bathing water should be boiled before use, and people should avoid swimming in freshwater if they can. These measures are usually more feasible for travelers passing through areas where the flukes are common than they are for residents. Long term control measures include developing clean reservoirs of water for communities to use.