Causes and pathogenesis of cytomegalovirus infection

Cytomegalovirus infection is widespread in children, most people suffer from the latent, hidden or inapparent form of the disease at an early age. In 70-80% of adults, virus-neutralizing antibodies are found in the blood. In 4-5% of pregnant women, the virus is excreted in the urine, in scrapings from the cervix of 10% of women, in milk - in 5-15% of nursing women. Among newborns who died from various causes, cells containing cytomegalovirus in the salivary glands are found in 5-30% of cases, and signs of generalized infection are detected in 5-15%.

The source of cytomegalovirus infection is only a person, a sick person or a virus carrier. Transmission occurs mainly by contact, less often - by airborne droplets. In addition, infection can also occur parenterally during blood transfusion or its products. Newborns can be infected through mother's milk. The transplacental route of transmission of cytomegalovirus infection has been reliably proven. Infection of the fetus occurs from the mother - a carrier of the virus. In these cases, cytomegalovirus can be detected in the placenta, although clinical manifestations of the disease in the mother are not detected. Cytomegalovirus infection is transmitted directly through a damaged placenta or during the passage of the child through the mother's birth canal. However, not all those infected intrauterine are born with manifest signs of the disease. More often in newborns, the infection is latent with giant cell metamorphosis in the salivary glands. With age, the frequency of detection of cells containing cytomegalovirus decreases with a simultaneous increase in the number of people with antibodies to cytomegalovirus in the blood. Humoral immune response is also produced during latent infection - complement-binding and virus-neutralizing antibodies appear in the serum.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ]

Pathogenesis of cytomegalovirus infection

In case of intrauterine infection, cytomegalovirus easily penetrates the placenta and can cause premature birth, stillbirth, congenital malformations and deformities. In case of infection during the passage through the birth canal or immediately after birth, cytomegalovirus infection manifests itself in the postnatal period as a localized lesion of the salivary glands or in a generalized form, with damage to the brain and spinal cord, liver, spleen, lungs, kidneys and other organs. In this case, the epitheliotropism of the virus is of the utmost importance, especially to the epithelium of glandular organs. In response to intracellular parasitism of the virus, a pronounced infiltrative-proliferative process occurs with dysfunction of the affected organ. In the pathogenesis of generalized forms, the general toxic effect of the virus, as well as DIC syndrome and functional insufficiency of the adrenal cortex, may also be important.

The nature of the developing pathological process (localized or generalized) depends solely on the degree of maturity of the fetus, concomitant diseases, immune reactivity, including residual anti-cytomegalovirus immunity in the mother and child.

In the genesis of chronic forms of infection, the ability of cytomegalovirus to persist for a long time and reproduce in leukocytes, the mononuclear phagocyte system and lymphoid organs is of great importance. With immunodepression, the virus can leave the cells and affect many organs.