The development process of leaflet disease is divided into three periods of incubation, onset and recovery, usually only the onset of the corresponding clinical symptoms. 1. incubation period: leaflet disease is mainly caused by EBV infection, an acute infectious disease, the virus infects the human body will have a few days to a few weeks of incubation period, this period of time patients often have no obvious clinical symptoms. 2. Morbidity: after the incubation period of viral infection, fever, malaise, headache and other symptoms, the disease continues to develop for about a week some patients will appear lymph node swelling, sore throat and other symptoms of pharyngitis, the need for active treatment. During this period, light, high-calorie, high-protein, high-vitamin fluids or semi-fluids should be given, and adequate water supply should be ensured. 3. Recovery period: after active clinical treatment, clinical symptoms such as fever, malaise, swollen lymph nodes and sore throat will be relieved one after another until they finally disappear. The prognosis of the disease is good, and there is usually no after-effects after cure. It is recommended that if the above symptoms occur, to go to the hospital in time, under the guidance of the physician to actively cooperate with the relevant examination and treatment, so as to avoid delaying the condition.