Schistosomiasis is a type of infection caused by parasites that live in fresh water, such as rivers or lakes, in subtropical and tropical regions worldwide.
Schistosomiasis is also known as bilharzia.
Symptoms can develop a few weeks after someone is infected by the parasite and include:
- a skin rash
- a high temperature (fever) above 38C (100.4F)
- muscle aches
Alternatively, more serious symptoms can develop months and possibly years after infection and include:
- bloody diarrhoea
- abdominal pain or cramps
- vomiting blood
Doctors refer to this as chronic schistosomiasis.
Contact your GP if you develop any of the symptoms of schistosomiasis and you have travelled in parts of the world where schistosomiasis is widespread.
How do you get schistosomiasis?
The parasites that cause schistosomiasis are called schistosomes. Schistosomes are small, white-grey worms that are 7–20mm long. They are capable of burying into human skin and can then move into other organs of the body, such as the liver or bladder, where they lay eggs.
They live in lakes, rivers, reservoirs and canals and can infect anyone who comes into contact with contaminated water.
Once a person is infected, the parasites then pass out eggs in their urine or faeces (stools), which can survive in water for up to seven days.
Schistosomiasis is a disease associated with poverty. Poor living conditions, overcrowding, and lack of sanitation, clean water and medical services increase the risk of schistosomiasis.
Read more about the causes of schistosomiasis.
Treating schistosomiasis
If schistosomiasis is diagnosed and treated promptly, it can usually be successfully treated with a medication called praziquantel. This kills the parasites, which are then passed out of the body.
Schistosomiasis is usually only a serious health problem for people who do not have access to effective medical treatment, particularly people who are already vulnerable because of malnutrition or dehydration.
Read more about treating schistosomiasis.
Who is affected?
All cases of schistosomiasis that have been reported in England developed in people who travelled abroad. There were 78 reported cases in England in 2010.
Popular tourist destinations that are known to have high levels of parasites include Lake Malawi in Africa and the Mekong River in Southeast Asia.
Globally, schistosomiasis is the second most common disease caused by parasites after malaria. An estimated 200 million people are infected worldwide, and 85% of cases occur in sub-Saharan Africa.
Prevention
There is currently no vaccine available for schistosomiasis so it is important to take precautions when travelling in parts of the world where the infection is widespread. This includes not swimming or wading in fresh water.
Read more about preventing schistosomiasis.
