Cytomegalovirus
Cytomegalovirus (Cytomegalovirus, CMV) is a genus of viruses belonging to the subfamily Betaherpesvirinae of the herpes viruses family Herpesviridae. Although the CMV species, which is an infectious agent in humans, is known as human herpesvirus 5 (Human herpesvirus 5, HHV-5), the name “cytomegalovirus” is used more often for this species.
Cytomegalovirus (Cytomegalovirus, CMV) is a genus of viruses belonging to the subfamily Betaherpesvirinae of the herpes viruses family Herpesviridae. Although the CMV species, which is an infectious agent in humans, is known as human herpesvirus 5 (Human herpesvirus 5, HHV-5), the name “cytomegalovirus” is used more often for this species.
What is cytomegalovirus infection?
Cytomegalovirus infection is an infection caused by a virus known as mei. It is quite common and one of the most common neonatal infections. When adequate diagnostic methods are used, this virus can be detected in approximately 1% of cases.
How is it found?
CMV can be transmitted to people by breathing in the common air, as well as by contact with body secretions such as saliva, urine, feces, breast milk, vaginal secretions, semen-semen. Other modes of transmission are blood transfusions. Another transmission route that is clinically important is the transmission to the unborn baby – fetus during pregnancy.
The infection is often passed in childhood, and adults who have not yet had the infection are also passed on from their children who have the virus in public places such as nurseries or schools. Due to the prevalence of transmission routes, at least 50% of the population has had this infection before. This rate can go up to 80% in the low socioeconomic level.
What are the symptoms?
It is usually asymptomatic. Non-specific signs and symptoms such as fever, sore throat, lymphadenopathy (swelling of the lymph nodes), and joint pain are observed in 15% of the cases.
Infections are more common and cause serious symptoms, especially in people whose immune system is suppressed for various reasons (such as AIDS patients, those who have to use immunosuppressant drugs due to organ transplantation).
What is the importance of infection during pregnancy?
Infection during pregnancy can pass to the baby through the placenta. Infection transmitted to the baby may cause signs and symptoms such as intrauterine growth retardation, microcephaly, calcification areas in the brain tissue, chorioretinitis eye findings, mental retardation, motor development retardation-late walking, hearing loss, enlargement of the liver and spleen, jaundice and anemia.
While some of these conditions, which are caused by virus infection, are obvious immediately after birth (such as jaundice, small head, low birth weight), some may occur as the baby grows (such as deafness, delayed walking, mental retardation).
The majority of expectant mothers have had this infection before they became pregnant. It occurs during pregnancy in 1-4% of those who have never had this infection before. In this case, the risk of transmission of the infection to the baby is high, as there is no immunity in the body. However, when a baby is infected, this does not necessarily mean that it will cause an abnormal condition. Approximately 90% of these expectant mothers have a normal baby at birth. A small number of these normal babies may develop the effects of infection at a later time.
In the 10% of infants with signs of infection at birth, the probability of serious symptoms and sequelae due to infection is high.
How is it diagnosed?
A four-fold increase in cytomegalovirus-specific IgG antibody in the blood in two separate measurements or detection of IgM antibody in a single sample is diagnostic of infection. IgG elevation alone (IgM should not be elevated) in patients with previously determined IgG diagnoses recurrent infection. However, erroneous results are also relatively common, as CMV can cross-react with other viruses.
In some cases, this infection is suspected by detecting early growth retardation, microcephaly and/or calcifications in the brain tissue.
Is the diagnosis possible for the fetus during pregnancy?
Although the probability of transmission to the baby in the womb is 25-30% in cytomegalovirus infection during pregnancy and especially in the first months of pregnancy, the probability of serious damage to the baby if transmitted to the baby is around 75-80%. Therefore, it is an option not to continue the pregnancy in cases where it is certain that they had cytomegalovirus in the first months of pregnancy.
If the gestational week is between 15-22 weeks, the antigen of cytomegalovirus virus can be searched in the amniotic fluid by amniocentesis. If the result is negative, the pregnancy can be continued. However, since there is a possibility of transmission from the mother to the baby after the date of amniocentesis, both IgM and virus antigen can be checked by taking blood from the baby’s umbilical cord at 22nd-23rd gestational week. If it is detected, termination of pregnancy should be an option, it is not always possible to say that it will absolutely protect the fetus, despite the fact that the mother has a therapeutic drug against this virus and is given to the mother.