Toxoplasmosis is a zoonotic parasitic disease that is widespread around the world. Children infected with toxoplasmosis have different clinical manifetations according to the degree of mild and sever disease. Mild children infected with toxoplasmosis, sympotoms may be similar to a cold, only manifested as low-grade fever, loss of appetite, fatigue and other conditions. For critically ill children or typical cases, the following hazaards may be caused: 1. Typical discomfort: the child may have fever with body temperature up to 38-39℃, and may also have cervical lymphadenopathy. Accompanied by nausea, vomiting, headache and other symptoms; 2. Affect growth and development: some children may have short stature and slow weight gain due to toxoplasmosis infection; 3. Eye lesions: Toxoplasma gondii is mainly transmitted through pets, and some children develop eye lesions after infection with toxoplasmosis. Parents should try to avoid healthy children from contacting kittens, puppies and other pets to avoid infection with toxoplasmosis. Toxoplasma gondii tachyzoite surface membrane is the main target of host immune defense system to recognize and kill parasites, containing five major surface antigens: P30, P22, P35, P23, P43. Because of its high immunogenicity, P30 (SAG1) antigen can induce strong immune protection and has no strain specificity, and is currently the most widely expressed and studied parasite component by genetic engineering methods. P30 stimulates the body to produce IgG, IgM, IgA and other antibodies, and can induce the production of interferon-gamma and cytotoxic lymphocytes. P22 antigen is another important antigen on the surface of tachyzoite membrane, which is closely related to the invasion of Toxoplasma gondii into host cells. P22 (SAG2) protein can fix Toxoplasma gondii on the surface of nucleated cells and assist Toxoplasma gondii to enter nucleated cells and mediate the invasion process of Toxoplasma gondii tachyzoites.