The dynamics of a soluble egg antigen of Schistosoma haematobium in relation to egg counts, circulating anodic and cathodic antigens and pathology markers before and after chemotherapy

A cohort of Schistosoma haematobium infected schoolchildren from Cameroon ( n=146) was studied for urine circulating soluble egg antigen (SEA), in comp arison to other urine infection parameters: the circulating adult worm-deri ved antigens, circulating anodic and cathodic antigens (CAA and CCA), egg c ounts and the reagent strip index (RSI). Before treatment, SEA prevalence w as 90%, while 89% and 65% of the children were positive for CCA and CAA res pectively. The children were treated with 2 doses of praziquantel (2x40 mg/ kg bodyweight) at an interval of 10 days and followed-up at 1, 2, 3, 5 and 12 months after treatment. Urine SEA correlated significantly with egg coun ts and RSI; levels of CAA and CCA were also significantly correlated with t hose of SEA. The levels of SEA showed a better correlation to both egg coun ts and RSI than did the levels of CAA and CCA. SEA levels dropped sharply 1 month after treatment, with few children excreting any SEA whereas egg cou nts decreased less rapidly. The prevalence and levels of SEA remained low d uring the whole post-treatment period whereas egg counts, RSI and CCA in ur ine rose progressively in the post-treatment period with a final egg count prevalence of 78%. The results of the present study indicate that for S. ha ematobium infections, measurement of SEA in urine is a valuable additional diagnostic parameter.