Fifteen individuals infected with Schistosoma mansoni received daily intramuscular injections of 5 cc. of Fuadin until toxic reactions to the drug made it necessary to give this amount on alternate days. The treatment was continued until a total of 100 cc. had been given. The sera from these patients were tested for circumoval precipitins before and at regular intervals after therapy. For comparison seven untreated cases were given similar tests. The circumoval test became negative in 13 of the sera tested between the 120th and 183rd days of observation. It is believed that the two cases that remained positive represented treatment failures. The sera of the seven untreated patients remained positive throughout the period of study.
The skin reactions to antigens prepared from schistosome eggs were negative before treatment but became positive in 11 of 14 patients tested 183 days after therapy. Positivity was first manifested on the 150th day after treatment. The observations indicate that the circumoval precipitin content of sera and the skin response to egg antigen are inversely altered as a consequence of treatment. The results of the former are believed to indicate that all but two patients were cured with Fuadin. The change from negative to positive skin reaction observed in 11 out of 14 patients is suggestive of some action by the drug which sets up skin sensitization but not necessarily that treatment was successful.
The most important toxic reactions caused by treatment were loss of weight, anorexia and vomiting. These reactions, however, did not warrant discontinuation of the drug.