Serological diagnosis of schistosomiasis. 1 Demonstration and significance of bilharzial antigenaemia.

Circulating bilharzial antigens were demonstrated in 39% out of 87 bilharzial patients via the IHA and CF techniques using hyperimmune rabbit anti - S.mansoni worm serum. Correlation between the percentage of positive cases and the age, duration of infection, clinical presentation, type of bilharzial infection, chemotherapeutic effect and the intradermal test (I.D.T.) were made. The percentage of positive cases was found to increase with age and with the duration of infection. More positivity was encountered in hepatosplenomegalic and in S.mansoni-infected cases. Most of the I.D positive cases were also IHA positive, but still some I.D. negative cases were IHA positive. Specific chemotherapy resulted in rise in the number of IHA positive cases which was followed by gradual fall in teh next six months until they became negative. On the other hand, using the CF technique, all cases turned negative after treatment with no phase of augmentation. However, antigenaemia reappeared in few cases. These cases relapsed later. Comparing the results of IHA and CF indicates that each test may be detecting a different group of antigens.