What it is (overview)

Bilharzia Ag-s-cca is a diagnostic laboratory test used to help detect an active schistosomiasis (Bilharzia) infection, a waterborne parasitic infection caused by Schistosoma species. The name “Ag” refers to antigen—a substance released by the parasite. “s-cca” commonly refers to circulating cathodic antigen (CCA), which can be found in body fluids when adult worms are present.

This test looks for evidence that the parasite is currently in the body (ongoing infection), rather than only showing past exposure. It is often used as a screening or confirmatory test in people who have had contact with freshwater sources (lakes, rivers, canals) in areas where schistosomiasis is common.

What results may mean (plain language):

Positive (antigen detected): This suggests an active schistosomiasis infection—the parasite is likely present and producing antigen. Your clinician may recommend treatment (often praziquantel) and may consider other tests depending on symptoms and the suspected species (such as S. mansoni or S. haematobium).

Negative (antigen not detected): This makes an active infection less likely, but it does not always rule it out—especially if exposure was recent, parasite levels are low, or symptoms strongly suggest infection. In some situations, repeat testing or additional tests (stool/urine microscopy for eggs, serology, imaging, or blood counts) may be advised.

Borderline/indeterminate: Sometimes results are not clearly positive or negative. Your clinician may interpret this alongside your symptoms, travel or water exposure history, and may repeat the test or use a different diagnostic test.

When & why it's usually done

This schistosomiasis diagnostic test is commonly ordered when a person may have been exposed to contaminated freshwater and has symptoms or lab findings that raise concern for Bilharzia. Risk is higher after swimming, bathing, wading, fishing, or working in freshwater in endemic regions (parts of Africa, the Middle East, South America, and some areas of Asia).

Typical reasons a doctor may order Bilharzia Ag-s-cca include:

Symptoms after freshwater exposure that may fit schistosomiasis, such as:

• Itchy rash soon after water contact (“swimmer’s itch” can occur early in some cases)

• Fever, fatigue, body aches, cough, or diarrhea in the weeks after exposure (acute schistosomiasis/Katayama syndrome in some people)

• Ongoing abdominal pain, diarrhea, blood in stool, or enlarged liver/spleen (more typical of intestinal schistosomiasis, often linked to S. mansoni)

• Urinary symptoms such as blood in urine, painful urination, frequent urination, or pelvic discomfort (more typical of urogenital schistosomiasis, often linked to S. haematobium)

Unexplained lab findings that can occur with parasitic infection, such as elevated eosinophils (eosinophilia) or signs of inflammation, especially in someone with relevant travel or migration history.

Health screening for people at risk, including travelers returning from endemic areas, immigrants/refugees from endemic regions, or individuals with repeated freshwater exposure due to work or living conditions.

Supporting treatment decisions and follow-up: Because this test targets antigen associated with active infection, it may help clinicians decide whether treatment is appropriate and, in some settings, help assess response alongside symptoms and other tests.

Common diseases related to it

• Schistosomiasis (Bilharzia) due to Schistosoma species
• Intestinal schistosomiasis (often associated with S. mansoni)
• Hepatosplenic schistosomiasis (chronic liver/spleen involvement that can lead to portal hypertension)
• Urogenital schistosomiasis (often associated with S. haematobium)
• Hematuria related to parasitic infection (blood in urine due to urinary tract involvement)
• Katayama syndrome (acute schistosomiasis) in newly exposed individuals

Health goals where it may help

• Detecting a waterborne disease early after freshwater exposure in an endemic region
• Diagnosing a parasitic infection in people with persistent gastrointestinal or urinary symptoms
• Guiding timely treatment (e.g., deciding when antiparasitic therapy is appropriate)
• Targeted health screening for travelers, migrants, or communities with ongoing exposure risk
• Reducing risk of long-term complications such as chronic liver disease, anemia, urinary tract damage, and inflammation-related complications
• Supporting follow-up care by helping clinicians evaluate suspected ongoing infection alongside symptoms and other laboratory tests