It is possible for the eb virus to recur and the condition to recur after it has gotten better. EB virus, also known as human herpesvirus type 4, mainly transmitted by saliva, respiratory tract, can proliferate in the epithelial cells of the human oropharynx, infected B lymphocytes, and then through the blood to cause systemic infection, and can be long latent in lymphocytes, when the body’s resistance to decline, latent EB viruses may be activated, resulting in recurrent infection. Diseases caused by EBV infection include: infectious mononucleosis, chronic active EBV infection, EBV-associated hemophagocytic lymphohistiocytosis, X-chain lymphohistiocytosis syndrome, and even with nasopharyngeal carcinoma, Burkitts lymphoma, and other oncological diseases have a certain relationship. Therefore, it is important to prevent EBV infection, and it is especially necessary to avoid mouth-to-mouth kissing with infants and young children.