What causes cytomegalovirus infection? CMV infection can cause a decrease in immune function, especially cellular immunity. CMV infection has a significant effect on thymus development and the function of splenocytes, mononuclear phagocytes, NK cells and CTL cells. What are the manifestations of cytomegalovirus infection and how is it diagnosed? Clinical manifestations vary depending on the route of infection. Twenty percent of congenital cytomegalovirus infections are asymptomatic at birth, but some develop lethargy, respiratory distress and convulsions shortly after birth and die within a few days or weeks. Other symptoms include impaired consciousness and movement, mental retardation, hepatosplenomegaly, deafness, and central nervous system symptoms. The vast majority of infants infected perinatally are asymptomatic, with only a few developing intermittent fever, pneumonia, and mononucleosis in the first 3 months of life. Cytomegalovirus mononucleosis is more common in adults than in children and manifests mainly as fever and fatigue. After 1-2 weeks of fever, there is an increase in the absolute value of lymphocytes in the blood with anisocytic changes, splenomegaly and lymphadenitis. Cytomegalovirus mononucleosis due to blood transfusion mostly occurs 3-4 weeks after transfusion and has the same symptoms as general cytomegalovirus mononucleosis. Occasionally, interstitial pneumonia, hepatitis, meningitis, myocarditis, hemolytic anemia and thrombocytopenia may occur. Cytomegalovirus infection occurs in almost all renal transplant patients within 2 months after surgery, with 50-60% asymptomatic and 40%-50% of patients presenting with a self-limiting, non-specific syndrome. Patients with AIDS almost always have cytomegalovirus infection with extensive visceral damage. How should cytomegalovirus infection be treated? Cytomegalovirus infection can be treated with various antiviral agents such as GCV, anti-cytomegalovirus immunoglobulin agents, interferon and transfer factor. However, these drugs do not solve the fundamental problem, and often the virus rises again latently after stopping the drugs. In view of the fact that this virus may be one of the causes of AIDS, scholars from various countries are working on the research of controlling its infection. Recently, American scholars have developed two live vaccines, which have been effective after initial trials. One was developed from the AD169 strain; the other was made from the TOWN strain, which has clearly demonstrated anti-cytomegalovirus efficacy and elevated CMV antibodies after non-intestinal administration, leading to enhanced immune function.