The relative sensitivity of four intradermal and five serologic procedures was determined on patients with an unequivocal diagnosis of Schistosoma mansoni infection. Cercarial antigen proved to give the highest sensitivity (75%) of the intradermal antigens. At this laboratory, sensitivity of all intradermal tests was considerably less than that obtained with the serological procedures. Sensitivity of the complement fixation test was 97% with adult antigen and 96% with cercarial antigen. Comparable results were obtained in the cercarial slide flocculation (98%) and the cercarial agglutination (98%) tests. However, a relatively large number (21%) of weak reactions were obtained in the agglutination test. The circumoval precipitin procedure showed a sensitivity of 88%.
All schistosome infections in the group of 355 patients, on whom all tests were performed, could have been detected serologically. A combination of either complement fixation test with the slide flocculation or agglutination test would have sufficed. In a like manner a combination of the slide flocculation procedure and the agglutination test would have detected all of the infections. The complement fixation tests and the slide flocculation test showed the greatest sensitivity.
Present address: Department of Medical Zoology, Walter Reed Army Institute of Research, Washington 12, D. C.
Present address: Office of the Surgeon, Headquarters Fourth U. S. Army, Fort Sam Houston, Texas.