EBV belongs to the herpes virus group, and the infection rate in the population is very high, especially children aged 3-6 years old are more commonly infected with EBV. The most common is infectious mononucleosis, which is caused by EBV infection. The main manifestations are fever, inflammation of the pharyngeal isthmus, enlarged liver and spleen, and enlarged lymph nodes. The prognosis for children with normal immune function, no immunodeficiency or genetic defects is very good after EBV infection. Since most of the EBV infections go into latent recessive infections, it can exist in the body for a long time without doing any harm to the human body. For patients with genetic defects, it can cause chronic active EBV infection, which is quite difficult to treat, but is relatively rare.