DAY-TO-DAY VARIATION OF EGG OUTPUT AND SCHISTOSOME CIRCULATING ANTIGENS IN URINE OF SCHISTOSOMA HAEMATOBIUM-INFECTED SCHOOL-CHILDREN FROM GABON AND FOLLOW-UP AFTER CHEMOTHERAPY

A group of 31 school children from Gabon infected with Schistosoma hae matobium was examined before praziquantel therapy and followed on days 3, 9, 14, 21, 24, 28, 31 and 35 after therapy. The day-to-day variati on of schistosome circulating antigens, urinary egg output, and the re agent strip index (RSI, a pathologic marker) was studied in six consec utive pretreatment urine samples collected under standardized conditio ns. The geometric mean pretreatment for egg output ranged between 97 a nd 223 eggs per 10 mi of urine; for urine circulating anodic antigen ( CAA) levels this was 44-154 pg/ml and for circulating cathodic antigen (CCA) levels this was 180-601 pg/ml. On the day of treatment, 97% of the children had viable eggs in their urine, 87% had a positive RSI; p ositive CAA levels were detected in 61% of the children and positive C CA levels in 77%. A significant correlation was consistently found bet ween RSI and egg counts. Five weeks after chemotherapy egg output, lev els of CAA and CCA and the severity of pathologic findings in the lowe r renal tract, as indicated by the RSI, had decreased significantly in all cases. Our results indicate that egg output in urine is an accura te method for diagnosis of S. haematobium, and additionally show less day-to-day variation than detection by ELISA of schistosome circulatin g antigens in urine.