Schistosomiasis

Schistosomiasis
Other namesBilharzia, snail fever, Katayama fever
11-year-old boy with abdominal fluid and portal hypertension due to schistosomiasis (Agusan del Sur, Philippines)
Pronunciation
  • /ˌʃɪstəsəˈməsɪs, -t-, -s-/
SpecialtyInfectious disease
SymptomsAbdominal pain, diarrhea, bloody stool, blood in the urine
ComplicationsLiver damage, cirrhosis, kidney failure, infertility (both male and female), bladder calcification, urethral obstruction, nephrotic syndrome, bladder cancer
CausesSchistosomes from freshwater snails
Diagnostic methodFinding eggs of the parasite in urine or stool, antibodies in blood
PreventionAccess to clean water
MedicationPraziquantel
Frequency252 million (2015)
Deaths4,400–200,000

Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever is a neglected tropical disease caused by parasitic flatworms called schistosomes. It affects both humans and animals. It affects the urinary tract or the intestines. Symptoms include abdominal pain, diarrhea, bloody stool, or blood in the urine. Those who have been infected for a long time may experience liver damage, kidney failure, infertility, or bladder cancer. In children, schistosomiasis may cause poor growth and learning difficulties.

Schistosomiasis is spread by contact with fresh water contaminated with parasites. These parasites are released from infected freshwater snails. The disease is especially common among children in underdeveloped and developing countries because they are more likely to play in contaminated water. Schistosomiasis is also common among women, who may have greater exposure through daily chores that involve water, such as washing clothes and fetching water. Other high-risk groups include farmers, fishermen, and people using unclean water during daily living. Schistosomiasis belongs to the group of helminth infections. Diagnosis is made by finding the parasite’s eggs in a person's urine or stool. It can also be confirmed by finding antibodies against the disease in the blood.

Methods of preventing 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 (WHO) for those who are known to be infected.

In 2019, schistosomiasis impacted approximately 236.6 million individuals across the globe. Each year, it is estimated that between 4,400 and 200,000 individuals succumb to it. The illness predominantly occurs in regions of Africa, Asia, and South America. Approximately 700 million individuals across over 70 nations reside in regions where the disease is prevalent. In tropical regions, schistosomiasis ranks as the second most economically significant parasitic disease, following malaria. Schistosomiasis is classified as a neglected tropical disease.