Further Observations on Skin Reactions to Antigens from Heterologous Cestodes in Echinococcus Disease.

Although the skin test is the most valuable single procedure for the diagnosis of echinococcus disease, its use for either the identification or the exclusion of possible infection is limited because the specific hydatid antigen is not easily obtained in many parts of the world in which suspected cases appear. In recent years, antigens derived from heterologous cestodes have been tried as substitutes for the specific hydatid substance in the immediate type of skin test and, in a number of instances, they have been found to serve the purpose about as well as those from the specific source (1). Several such skin-testing substances have been described previously by the authors (2) who have reported their diagnostic use in a small series of surgically proved, cases of echinococcus disease. In the present communication, further observations on skin tests in echinococcus disease are recorded which indicate that many different species of cestodes are a potential source of antigen suitable for eliciting an immediate reaction. Some of these tests were performed directly upon patients known to have the disease, while others were carried out on normal persons by the passive transfer method of Prausnitz and Kiistner (3).