MONITORING THE EFFICACY OF DIFFERENT DOSES OF PRAZIQUANTEL BY QUANTIFICATION OF CIRCULATING ANTIGENS IN SERUM AND URINE OF SCHISTOSOMIASIS PATIENTS

We evaluated the quantitation of two schistosome circulating antigens in serum and urine as a tool for the assessment of the efficacy of pra ziquantel dosage regimens (40 versus 60 mg/kgbw). In addition we compa red the efficacy of two different brands of praziquantel (Biltricide(R ) and Distocide(R)), given at the same dosage (40 mg/kgbw). Thirty fiv e Egyptian hospitalized schistosomiasis mansoni patients participated in this study. Thirteen patients (Group 1) received 60 mg/kgbw Biltric ide(R), administered in 3 oral doses of 20 mg in one day; 22 individua ls (Group 2) were treated with 40 mg/kgbw (12 Biltricide(R), 10 Distoc ide(R)), given in one oral dose. Circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were quantitated by monoclonal anti body-based ELISA's before, and 1, 3 and 6 weeks after chemotherapy. Be fore treatment, all patients were positive for at least one of the cir culating antigen assays. Three to six weeks after treatment significan tly more patients were found to be negative in Group 1 compared to Gro up 2 (X(2) = 7.13, P = 0.008, n = 35). Also the levels of CCA and CAA in serum and of CCA in urine were found to be significantly higher in Group 2 (Mann-Whitney U < 85, P < 0.05, n = 35). These results were co nfirmed by parasitological data. No differences were found between tre atment with Biltricide(R) or Distocide(R). Our results indicate that p raziquantel treatment of schistosomiasis with 60 mg/kgbw divided in 3 doses results in a higher cure rate compared to 40 mg/kgbw as a single dose, and provide further evidence for the use of the CAA and CCA ass ays as a sensitive method to monitor the efficacy of chemotherapy, par ticularly when circulating antigen assays are combined by parallel tes ting.