Cytomegalovirus (CMV) infection is the most frequent congenital infection in industrialized countries and in Del Paese it has an incidence of just under one infected out of a hundred live-born children. Although the virus itself is usually harmless, if contracted during pregnancy it can cause it very serious harm to the fetus. CMV infection is, in fact, the first cause of inborn deafness not hereditary and also represents an important risk factor for the development of visual, intellectual and motor deficits. In our country, there are currently no screening programs for congenital infection in newborns.
In this article
- the Cytomegalovirus
- how it is transmitted
- how to know if the fetus is infected
- the risks to the fetus
- diagnosis in the newborn
- transmission of the virus after birth
- Eat if you prevent Cytomegalovirus
What is Cytomegalovirus
Cytomegalovirus (CMV) is a very common virus, especially among school-age children, belonging to the herpes virus family (such as chicken pox, cold sores or mononucleosis virus). Once contracted, the virus persists in latent form in the body for life, but in many cases it remains dormant. If our immune systems are weakened, however, the virus could reactivate.
When a person first contracts the virus it is referred to as primary infection, on the other hand, when the subject undergoes a reactivation (or reinfection from a different viral strain) of the virus, we speak of secondary infection. According to the estimates of the Istituto Superiore di Sanità, 70-80% of the population in Del Paese test positive for anti-Cytomegalovirus antibodies.
"The virus itself is harmless enough, but if contracted in the early stages of pregnancy it can cause fetal infection and cause very serious damage, even abortion" explains the Dr. Francesca Ippolita Calò Carducci of the Infectious Diseases and Immunoinfectivology Unit of the Bambino Gesù Hospital in the city.Read also: Cytomegalovirus (CMV)
How cytomegalovirus infection is transmitted
The virus is found in saliva, blood, urine and other body fluids and is therefore easily transmitted in the home and at school with the person-to-person contact.
The problem, however, is when a woman passes it on to the fetus during pregnancy: the cytomegalovirusIn fact, can pass the placenta and infect the fetus. "The mother's infection during pregnancy can be a primary infection or the reactivation of a previous infection and the woman usually does not notice it because the cytomegalovirus is almost always asymptomatic" explains Dr. Calò Carducci.
Furthermore, Cytomegalovirus can be transmitted from the infected woman during childbirth or through breast milk, but, as we will see shortly, in these cases the risks for the newborn are decidedly lower.Read also: Cytomegalovirus (CMV) in pregnancy: symptoms, remedies and how it is contracted
Is it possible to know before birth whether CMV has been passed on to the fetus?
Let's make a small clarification - says Dr. Calò Carducci - the risk of maternal-fetal transmission varies depending on whether it is a first infection or a reinfection. In the first case, the risk of transmission is attested around 30-40%, while in case of reinfection the risk of transmitting the virus to the fetus is very low, around 1-2%. The virus, therefore, does not always pass to the child, but the problem cannot be ignored. Having said that, the only way to know for sure if the child has contracted the infection is to perform theamniocentesis looking for the viral genome in the amniotic fluid. Even some signs detected by ultrasound can make us suspect a Cytomegalovirus infection, but the certainty can only be obtained with amniocentesis. Fortunately, for about a year we have had a drug available, the valaciclovir, for women who contract the primary infection in early pregnancy. Valaciclovir is a drug that has been shown to be safe in pregnancy and is capable of reducing the rate of transmission of the infection to the fetus. It is offered to all pregnant women who contract the infection in the first trimester ", explains Dr. Calò Carducci of the Bambino Gesù Pediatric Hospital.
Read also: Cytomegalovirus and amniocentesis. Fortunately, my son is fine
What are the risks if the infection passes to the fetus during pregnancy?
If the mother transmits Cytomegalovirus during pregnancy, two scenarios are possible:
- Nell '85-90% of newborns with congenital infection cytomegalovirus is asymptomatic, although 10% of them will experience some symptoms later in age. Symptoms are neurological, in particular affecting hearing and sight. "Precisely because some children can manifest secondary symptoms after birth, children born with cytomegalovirus infection are followed up at least until the age of 6" explains Dr. Calò Carducci.
- About 10-15% of infants who contract the virus are born with asymptomatic infection which can have consequences both before birth and after, with a considerable percentage of abortions. "The risks in case of symptomatic infection are linked to a deficit of hearing function (congenital hearing loss) which can be both mild and severe, neuromotor and cognitive deficits, vision problems and a possible development of autism."
Infants with congenital cytomegalovirus infection may also experience:
- temporary symptoms such as enlarged liver or spleen, jaundice and pneumonia;
- small size at birth, due to growth retardation;
- smaller head (microcephaly);
- deficiency of platelets (thrombocytopenia);
- petechiae, that is, red spots on the skin.
The severity of fetal-neonatal damage depends on the gestational age in which transmission occurs. In particular, the most serious damage occur when the primary maternal infection is contracted in the first quarter of pregnancy. "Even if, as we said before, the virus itself is harmless for immunocompetent people, when it infects tissues that are forming it causes serious damage" explains Dr. Calò Carducci.Read also: Positive for cytomegalovirus. Luckily my son was born beautiful and healthy!
How is the diagnosis made in the newborn
After birth it is possible to check whether there has been transmission of cytomegalovirus during pregnancy through urine or saliva tests to be performed within 21 days of life. In case of positivity at birth some assessments must be performed including:
- CT or MRI or brain ultrasound;
- Level II hearing test, a level I screening is routinely performed on all newborns;
- Ophthalmological evaluation to check for any vision problems.
Infant positive for Cytomegalovirus: what the therapy involves
If the newborn is positive for Cytomegalovirus e if you have typical symptoms of the infection, then one initiates a antiviral therapy with valganciclovir. "It is a drug that can have side effects, which is why it is only given to children who show symptoms of the infection for reduce the damage caused by the virus, in particular the deterioration of the auditory and visual function "specifies Dr. Calò Carducci. If the newborn is positive, but does not present any clinical manifestations, then antiviral therapy is not used, as indicated by the Del Paesena Society of Neonatology (SIN) .
In both symptom-positive and symptom-free infants, it is important to plan a follow-up course.
Read also: Cytomegalovirus and congenital deafness
What if the virus is transmitted during or after birth?
As we have seen above, Cytomegalovirus can also be transmitted during childbirth or subsequently with the breast milk. "In this case, however, mothers can be more relaxed because the virus itself is rather benign and clearly there is no risk that the newborn will have hearing or neuromotor deficits like babies who contract the infection during pregnancy "explains Dr. Calò Carducci.
How cytomegalovirus infection is prevented
Currently there is no vaccine for the prevention of Cytomegalovirus, so prevention is based on a series of adroitness that the pregnant woman must have. It is always a good rule:
- wash your hands with warm soapy water before cooking and eating, but also after changing the babies and after going to the bathroom;
- do not exchange cutlery or other utensils during meals, especially with younger children;
- do not put your baby's pacifier in your mouth or taste his meals.
- Advice from Dr. Francesca Ippolita Calò Carducci of the Infectious Diseases and Immuno-Infectious Diseases Operating Unit of the Bambino Gesù Hospital in the city;
- Document "Infectious diseases in obstetrics-gynecology and neonatology" of the Del Paesena Society of Neonatology (SIN);
- Information material of the Meyer Hospital of the city.
- cytomegalovirus in pregnancy
- cytomegalovirus prevention