PROBLEM TO BE SOLVED: To provide a discrimination method, for the infection with neosporosis, in which whether an animal as an object is infected with the neosporosis can be detected with good accuracy and whose operation is simple.
SOLUTION: This discrimination method the the infection with neosporosis contains the following processes (a) to (e). (a) A neosporosis antigen is immobilized to a solid phase, and a surplus neosporosis antigen is then removed. (b) An antibody which is derived from living things other than the mammals is added to a solid phase, and a surplus antibody is removed. (c) The serum of an animal as an object is added to a solid phase, and substances other than an antigen-antibody complex are then removed. (d) An antigen-antibody complex is detected by using a marker protein AG. (e) According to whether an antigen- antibody complex exists or not, whether the antibody with reference to a neosporosis antigen in the serum of an animal as an object exists or not is judged. Then, whether the animal as the object is infected with neosporosis or not is discriminated. Thereby, whether the animal as the object is infected with the neosporosis or not can be discriminated with good accuracy.