Forty-nine recent or old cases of schistosome dermatitis which occurred mainly in the vicinity of Douglas Lake, Michigan, were tested intradermally with the worm antigen of S. japonicum and cercarial antigen of S. mansoni. At the same time the antigens were tested intradermally on 49 cases that had had no history of schistosome dermatitis; and the results were negative.
It is concluded that schistosome dermatitis cases, caused by the penetration of the cercariae of avian schistosomes, seldom give positive intradermal reactions to the antigens made from the human schistosomes, S. japonicum or S. mansoni, due probably to a limited antibody production. A differential diagnosis between schistosome dermatitis and seabather's eruption of non-schistosome origin can not be made adequately by an intradermal test with human schistosome antigen. The results of the present study also indicate that the use of intradermal antigens for diagnosis of human schistosomiasis is valid even in the areas where the people may well have been exposed to avian schistosome cercariae.