Reduction in chromosomal damage in schistosomiasis patients after treatment with praziquantel

Schistosoma haematobium infection is the most common health problem in Egypt. It is strongly associated with the development of urinary bladder carcinoma. The aim of this study was to determine whether infection with this parasite resulted in an increase of chromosomal breakage in the exfoliated urothelial cells. Urine samples were collected from 211 Egyptian male farmers and schoolchildren with Schistosoma haematobium ova in their urine. 66 samples were suitable for scoring. Accordingly, 66 non-infected males attending the same village clinic were included in the study as a control group. The urine was centrifuged and the urothelial cells present in the sediment were assayed for the presence of micronuclei, a quantitative indicator of chromosomal breakage. Micronucleus frequencies were significantly higher in the infected group (mean frequency, 0.84 +/- 0.69%) than among controls (mean frequency, 0.12 +/- 0.21%, p < 0.001). There was a trend towards an increase in micronucleus frequencies in infected individuals who smoked (17 of the 66 subjects) compared with those who were non-smokers, although this effect was not significant (p > 0.05). Bladder infection was associated with a 6.1-fold increase in micronucleus frequencies among non-smokers. In this study, patients were treated with praziquantel, an anti-schistosomal agent. Out of the 66 studied patients, only 37 gave scoreable samples after treatment. The mean micronucleus frequencies were reduced significantly (before treatment, 0.80 +/- 0.70%, after treatment, 0.19 +/- 0.23%, p < 0.001), thus supporting a direct involvement of the infection in increased chromosomal breakage in the urothelium.