most severe condition, chronic bladder ulcers and bladder carcinoma develop. treatment the drug of choice is praziquantel, a quinolone derivative. but it has low cure rate (only 82-88%). epidemiology s. hematobium is found in africa and the middle east, where infants and young children are most infected. infection is most prevalent in both the nile delta and the nile valley south of cairo. the first epidemiological survey in 1937 indicated that infection rate was as high as 85% among people in the northern and eastern parts of the delta. following construction of the aswan dam, basin irrigation is converted to perennial irrigation system, and this has significantly reduced the infection.