The short answer
Schistosoma haematobium is a parasite caught from contaminated fresh water. Long-term infection is linked to bladder cancer, mainly in parts of Africa and the Middle East. NCI says avoiding contaminated fresh water lowers risk, and antiparasitic medicines can treat the infection.
NCI says Schistosoma haematobium infection can cause bladder cancer.
People are mainly exposed by skin contact with parasite-contaminated fresh water.
It is most strongly linked to bladder cancer.
A carcinogen classification describes hazard — whether something can cause cancer — not your personal risk at a given exposure.
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The whole article, with every detail and caution.
The simple version
This page is for travelers, people from affected regions, and their families. It explains how one parasite infection is linked to bladder cancer.
Schistosoma haematobium is a parasitic worm. NCI says it is found in some fresh waters in Africa and the Middle East. People get infected when the parasite enters skin that touches contaminated fresh water. NCI says the infection can cause bladder cancer.
What Schistosoma haematobium is
Schistosoma haematobium causes urinary schistosomiasis, also called bilharzia. The larvae live in freshwater snails. CDC says they leave the snails and enter human skin in contaminated water.
How people are exposed
Common ways people come into contact with it:
- Skin contact with contaminated fresh water.
- Living in or traveling to endemic regions (places where the parasite is common), such as parts of Africa and the Middle East.
Your care team can tell you more about your own risk.
The cancer connection
NCI says Schistosoma haematobium infection can cause bladder cancer. Antiparasitic medicines are available to treat the infection. NCI says treating it may help prevent cancer.
We could not open the international agency list to confirm how this parasite is graded, so this page does not state a grade.
Hazard is not the same as risk
Hazard and risk are easy to confuse, and they answer different questions. Saying this parasite can cause cancer is a statement about hazard. It says the parasite can cause cancer under some conditions. It does not describe your personal risk. That depends on whether you are exposed at all, how often, for how long, and other factors. One person never enters fresh water in an endemic area. Another farms in it daily. Their risks are not remotely the same, even though the parasite carries one label.
How to lower your exposure
- Avoiding contact with fresh water that may be contaminated in endemic areas. CDC says to boil bathing water, or add chlorine and wait 30 minutes.
- Treating infection with medication (praziquantel). CDC says testing is done 6 to 8 weeks after exposure. Ask your care team about testing if you may have been exposed.
Bladder cancer risk also responds to other choices you make. To see where schistosomiasis sits among all the things that affect cancer risk, read our overview of cancer prevention and what raises cancer risk.
The bottom line
Schistosoma haematobium infection can cause bladder cancer, NCI says. The useful step is knowing which waters carry the parasite and staying out of them where you can. If you have spent time in fresh water in those regions, mention it to your doctor.
Common questions
Does schistosoma haematobium cause cancer?
NCI says infection with Schistosoma haematobium can lead to bladder cancer. How much any one person's risk rises depends on how much they are exposed to and for how long.
How are people exposed to schistosoma haematobium?
Most exposure happens by skin contact with parasite-contaminated fresh water.
Which cancers are linked to schistosoma haematobium?
It is most strongly linked to bladder cancer.
How can I reduce my exposure to schistosoma haematobium?
The main steps are avoiding contaminated fresh water and getting infection treated by your care team.
Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether schistosoma haematobium can cause cancer under some conditions — not a prediction that any one exposed person will develop cancer. Your actual risk depends on the amount and length of exposure and other factors.
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Last updated: 2026-10-16Next planned review: 2028-07-05
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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