The disease is caused primarily by parasite eggs, which are deposited by adult worms in the blood vessels surrounding the bladder or intestines.
The classical sign of urogenital schistosomiasis is haematuria (blood in urine). In women, urogenital schistosomiasis may present with a range of signs and symptoms including lesions of the cervix and vagina, vaginal bleeding, pain during sexual intercourse and nodules in the vulva. In areas endemic for urogenital schistosomiasis a large proportion of women may have female genital schistosomiasis (FGS). A recent WHO working group concluded that there is biological plausibility that female genital schistosomiasis is a risk factor HIV transmission to women. Genital schistosomiasis also affects men, inducing pathology of the seminal vesicles, prostate and other organs. This disease may also have other long-term irreversible consequences, including infertility. Bladder and ureteral fibrosis and hydronephrosis are common findings in advanced cases, and bladder cancer is also a possible late-stage complication.
Intestinal schistosomiasis has a nonspecific clinical picture of abdominal pain, diarrhoea, and blood in the stool. Liver enlargement is common in advanced cases, frequently associated with ascites and other signs of increased portal pressure. In such cases there may also be splenomegaly.
The Scientific Working Group (SWG) on Schistosomiasis held in 2005 characterized the clinical pathology due to the disease.