Characteristics 1. Double-stranded DNA herpesvirus. 2.Widespread infection in the population, with an infection rate of more than 90 in children aged 3 to 5 years. 3, most young children infected with no obvious symptoms, or cause a mild infection upper respiratory tract infection. 4. The virus proliferates in the oropharynx and then infects lymphocytes. There are three main diseases caused by or associated with EBV infection: (a) Infectious mononucleosis The clinical manifestations are varied, but three typical symptoms are fever, pharyngitis, and enlarged cervical lymph nodes. As the disease progresses, the virus may disseminate to other lymph nodes. The liver and spleen are large, liver function is abnormal, and peripheral blood mononuclear cells are increased with the presence of heterogeneous lymphocytes. Occasionally, the central nervous system may be involved (e.g., encephalitis). Clinical features: 1. Prodromal symptoms, including headache and weakness 2. Infection phase, which can involve all organs of the body, usually with fever, loss of appetite, nausea, vomiting, diarrhea, generalized lymph node enlargement, hepatosplenomegaly, and skin rash 3. Fever may last for several days to weeks, with slow pulse early in the course of the disease 4. Pharyngitis: small hemorrhagic spots on the palate and diffuse membranous tonsillitis are seen 5. Upper eyelid swelling 6. Hepatosplenomegaly, 2/3 abnormal liver function, and jaundice. Almost all patients have splenomegaly, fragility of the liver and spleen, and occasionally rupture of the liver and spleen. 7. Various rashes are seen. (B) African childhood lymphoma (i.e. Burkitt’s lymphoma) Most commonly seen in children aged 5 to 12 years, it is endemic in Central and Central New Guinea and the temperate tropics of America. The prevalent sites are the face and palate. All patients have serum antibodies to HBV, of which more than 80% have higher titers than normal. The EBV genome was found in the tumor tissue, so it is believed that EBV is closely related to this disease. (3) Nasopharyngeal carcinoma The southern part of China (Guangdong, Guangxi) and Southeast Asia is a high incidence area for nasopharyngeal carcinoma, which mostly occurs in middle-aged and elderly people over 40 years old. (3) The presence of only a single viral strain in a case suggests that the virus has entered the cancer cells at the tumor initiation stage. Prognosis of EBV infection Infectious mononucleosis, the prognosis is mostly good, the course of the disease is usually 1 to 2 weeks, but can recur, some children with low fever, lymph node enlargement, weakness, and post-illness weakness can last for weeks, or months. In rare cases, the disease may persist for several years. The disease has a mortality rate of 1% to 2% due to splenic rupture, meningitis, and myocarditis. In patients with congenital immunodeficiency, the prognosis is poor, and the disease can deteriorate rapidly and lead to death. Treatment of EBV There is no specific treatment, and the disease is mostly curable. Treatment is supportive, and antiviral drugs can inhibit EBV virus replication, but, there are clinically considered ineffective. Hormones, used only in the presence of anemia, thrombocytopenia, etc.