Schistosomiasis

This article is about the disease. For the organism, see Schistosoma.

Schistosomiasis, also known as snail fever and bilharzia,^[9] is a disease caused by parasitic flatworms called schistosomes.^[5] The urinary tract or the intestines may be infected.^[5]

Schistosomiasis
Other names	Bilharzia, snail fever, Katayama fever[1][2]
11-year-old boy with abdominal fluid and portal hypertension due to schistosomiasis (Agusan del Sur, Philippines)
Pronunciation	/ˌʃɪstəsəˈmaɪəsɪs, -toʊ-, -soʊ-/[3][4]
Medical specialty	Infectious disease
Symptoms	Abdominal pain, diarrhea, bloody stool, blood in the urine[5]
Complications	Liver damage, kidney failure, infertility, bladder cancer[5]
Causes	Schistosomes from freshwater snails[5]
Diagnostic method	Finding eggs of the parasite in urine or stool, antibodies in blood[5]
Prevention	Access to clean water[5]
Medication	Praziquantel[5]
Frequency	252 million (2015)[6]
Deaths	4,400–200,000[7][8]

Symptoms include abdominal pain, diarrhea, bloody stool, or blood in the urine.^[5] Those who have been infected for a long time (chronic infection) may experience liver damage, kidney failure, infertility, or bladder cancer.^[5] In children, it may cause poor growth and learning difficulty.^[5]

Cause

The disease is caused by contact with fresh water containing the parasites (schistosomes).^[5] These parasites are from infected freshwater snails.^[5] The disease is very common among children in developing countries, as they are more likely to play in infected water.^[5] Other high-risk groups include farmers, fishermen, and people using unclean water.^[5] It is a helminth infections.^[10] Eggs of the parasite may be found in urine or stool.^[5] Antibodies may also be found in the blood.^[5]

Prevention and treatment

To prevent the disease use clean water and reduce snails.^[5] The medicine praziquantel may be given once a year to everybody in some places.^[5] This will decrease the number of people infected.^[5] Praziquantel is also the treatment recommended by the World Health Organization for those who are known to be infected.^[5]

Epidemiology

Schistosomiasis affected about 252 million people in 2015.^[6] An estimated 4,400 to 200,000 people die from it each year.^[7][8] The disease is mainly found in Africa, Asia, and South America.^[5] About 700 million people, in more than 70 countries, live where the disease is common.^[7][11] In tropical countries, schistosomiasis is a great economic problem.^[12] Schistosomiasis is listed as a neglected tropical disease.^[13]