Abstract: A method of detecting the presence of first antibodies against a chorionic gonadotropin-like substance in a first biological sample obtained from an organism other than domestic poultry. The first biological sample is contacted with a chorionic gonadotropin-like substance, preferably isolated from Progenitor cryptocides microorganism, which has been immobilized on a solid phase, under conditions permitting first antibody/chorionic gonadotropin-like substance binding. Unbound sample components are removed from the solid phase, and a plurality of second antibodies, each comprising an immunological conjugate of the first antibody, are contacted with the solid phase, under conditions permitting second antibody/first antibody binding. Unbound second antibodies are removed from the solid phase and the presence of chorionic gonadotropin-like substance/first antibody/second antibody complex, if any, is observed, as a measure of the presence of first antibodies in the first biological sample.