Schistosoma

Schistosomiasis (bilharzia) is an infection with Schistosoma parasitic worms. People catch it through skin contact with fresh water, such as lakes and rivers, in parts of Africa, the Middle East, Asia and South America. A few weeks after exposure, some people develop fever, cough, rash and muscle aches (acute schistosomiasis). Long-term infection can cause blood in the urine and bladder damage, or abdominal pain, diarrhea and liver scarring, depending on the species.

Lab tests linked to schistosomiasis:

• No results are listed on this page yet.
• Doctors use Schistosoma antibody blood tests, microscopy of urine or stool for eggs, an eosinophil count, and a urine test for blood. Imaging may check the bladder or liver.

How results are read:

• Antibody tests usually turn positive several weeks to a few months after exposure, so testing travelers too early can miss infection.
• A positive antibody test shows exposure. It can stay positive after successful treatment, so it can't confirm a cure.
• Finding characteristic eggs confirms schistosomal infection, although light infections can be missed. After treatment, eggs can still be passed for a while, so persistent eggs need careful interpretation. Repeat samples help.
• A raised eosinophil count is common, especially early on.

When to see a doctor:

• If you swam, bathed or waded in fresh water in an area where schistosomiasis occurs, ask a doctor about testing, ideally at least 6 to 12 weeks after the last exposure, even without symptoms.
• See a doctor about fever, rash or cough in the weeks after such exposure, or blood in the urine at any time.

Clinical takeaway: schistosomiasis is detected with antibody tests and egg microscopy after freshwater exposure in endemic areas, and is treatable with medicine.