All about cytomegalovirus

Cytomegalovirus is a microorganism spread throughout the world belonging to the herpes virus family, which owes its name to the fact that it causes an increase in the size of the cells it infects. This family also includes viruses that cause herpes of the genitals and mouth, chickenpox and mononucleosis.

It is a very common microorganism, which can infect anyone: 80% of adults living in Western countries have antibodies against this virus.

Once the infection is contracted, the virus remains “quiet” within the body for life, but can be reactivated in case of lowering of the immune system, the body’s natural defense system.

In most cases these are asymptomatic infections because the immune system is able to keep them under control. Sometimes, however, in immunosuppressed people it can cause serious complications, especially to the eyes, liver, gastrointestinal system and nervous system.

Precisely for this reason, despite the frequent asymptomatic manifestation, it is important to know and evaluate all the possible consequences of a primary infection by cytomegalovirus, so as to limit the risk of even serious complications.

Congenital infections cause the greatest dangers. An infection contracted during pregnancy and then transmitted to the fetus, in fact, can also have serious and permanent repercussions on the unborn child.

Transmission and symptoms

Man is the only reservoir of cytomegalovirus infection, which is transmitted from person to person through body fluids, such as blood, saliva, urine, seminal fluid, vaginal secretions and breast milk.

Infection can occur by direct person-to-person contact (e.g. through sexual intercourse, kissing on the mouth, contact of the mouth with hands soiled with urine or saliva), by transmission from mother to foetus during pregnancy or from mother to child during breastfeeding, as well as by transfusions and transplantation of infected organs.

In this regard, to implement a first form of prevention, it is important to take due precautions, especially in contact with infected and contagious people. For example, kissing and coming into contact with a person’s salivary fluids can pose a risk of infection. Even consuming unprotected sex could expose you to the same risk of contagion.

The periods of life in which it is easier to contract the infection are mainly two: childhood and puberty, periods in which environmental promiscuity between individuals, due in the first case to the attendance of kindergartens and kindergartens, favors the transmission of the infectious agent.

The virus can be excreted from the infected organism even months or years after the first infection, especially in the youngest, while children can spread it for 5-6 years after birth.

Most healthy individuals, adults or children, who contract the infection do not experience symptoms and do not notice the infection, while other people may experience a mild form of the disease, characterized by fever, sore throat and headache, fatigue, muscle and bone pain, swollen lymph nodes and spleen. In more rare cases, petechiae may occur: red patches on the skin, which can cause itching and consequent malaise.

Congenital infections

Congenital cytomegalovirus infections occur by transmission from infected mother to fetus. Maternal infection is defined:

• primary when it is first contracted during pregnancy in a woman who was previously healthy;
• secondary when there is a reactivation of the virus already present within the body or by reinfection by a new strain in a woman who had already contracted the infection;

The risk of transmitting the disease to the fetus does not seem to be linked to the period of gestation during which the infection is contracted. However, experts believe that there may be a greater risk of seriousness of the disease if transmission occurs during the first three months of pregnancy.

The risk of transmission to the fetus varies between 30 and 40% in the primary form and between 0.5 and 2% in the secondary form. 85-90% of newborns with congenital infection do not complain of symptoms, although a small percentage may experience late manifestations, such as hearing problems of varying severity. About 10-15% of newborns, on the other hand, have symptoms already at birth, which can be temporary or permanent. The latter can also be very serious and cause different forms of disability, up to death.

A serious disorder that can occur due to a congenital infection is acute cytomegalovirus pneumonia, which may require antiviral drug therapy. In other cases, disorders of the child’s central nervous system and cognitive functions, including microcephaly, may occur.

In some children, finally, the symptoms appear months or years after birth, and in these cases the most common disorders are the loss of hearing and vision. The possibility of permanent disorders, on the other hand, is greater in children who show symptoms from birth. Some neurological implications may be visible in the period of language development and greater evolution of the child.

The most fragile categories

If cytomegalovirus is harmless in healthy people, it can be very dangerous in individuals with health problems, especially in the immunosuppressed, ie those who have a low level of immune defenses for example because they have undergone major operations (such as transplants), because they are on dialysis or because they are suffering from cancer. People infected with HIV are also at risk, because they do not have enough defenses to fight the germ.

Particular attention must be paid to patients who are undergoing chemotherapy treatment, known to be responsible for lowering the immune system, but also to subjects suffering from liver diseases of viral origin.

In these cases, the infection can compromise the health of the gastrointestinal system and the pulmonary system, causing hepatitis and pneumonia.

If specific symptoms occur, it is important to go immediately to your doctor, who through a complete visit will be able to indicate the best therapy to deal with the disorder.

Healthy children and elderly are safe

Cytomegalovirus is not dangerous if it affects young children or the elderly, two categories generally considered weak. If they are in good health, these individuals can also cope with the situation without problems. In general, despite having a still immature defense system that makes them more vulnerable to external aggressions, the children’s body is able to resist the virus. In the worst case, few lines of fever, fatigue, restlessness can be observed.

Even older people do not run particular risks and almost never present serious symptoms, although they have a less efficient defense system, so they can contract the virus more easily and remain contagious for a long time.

In case of more acute symptoms, a blood test can be performed to detect the presence of the virus in the body, or to detect strong white blood cell activity. In this case, it will be possible to undertake treatment immediately, through a consultation with the specialist. Immunoglobulins may also be present in the blood, proof of a past infection.

Yes to prevention

There is currently no vaccine on the market that can prevent cytomegalovirus infection. The best way to reduce the chances of being infected is through careful personal hygiene, especially for the categories of people most susceptible to the disease, such as pregnant women, immunocompromised people, young children or newborns.

For pregnant women, it is possible to perform checks both in view of childbirth and in the neonatal phase, to verify the onset of malformations and disorders in the unborn child. Among the most suitable examinations we find ultrasound and amniocentesis, for example.

In addition, it is always a good idea to wash your hands with warm soapy water before eating or preparing food, after changing children or going to the bathroom, and after any type of contact with body fluids. In addition, it is good to avoid exchanging cutlery or other utensils during meals, especially with the little ones.

Finally, it is advisable to clean the house well, especially surfaces that can be smeared by body fluids (such as saliva, urine, feces, seminal fluids and blood), in order to prevent the possibility of contagion. Dirt, in fact, is frequently a vector of contagion, through which cytomegalovirus can be transmitted.

Diagnosis and treatment

To diagnose cytomegalovirus infection, your doctor has several tests at your disposal. Among the most important are:

• the search for IgG antibodies against cytomegalovirus to be performed on a blood sample, which shows whether contact with the virus has occurred. However, this test is not able to indicate neither the period of infection (ie if the infection is in progress or has occurred in the past, very useful in case of pregnancy), nor the possible transmission of the virus to the fetus. In the event that this test is negative before pregnancy, it is important that the woman takes great care in following all the necessary precautions to avoid contagion;
• the search for IgM antibodies against cytomegalovirus to be performed on a blood sample, useful to know if the infection is recent. Unfortunately, this test often provides false positives and, consequently, the result is not to be considered reliable without having performed other types of tests;
• the IgG avidity test, used to trace the period of infection;

To know if there has been the passage of the virus to the fetus, other more invasive tests are used, such as amniocentesis or fetal blood test.

To detect a congenital cytomegalovirus infection in a newborn during the first three weeks of life, the presence of the virus is directly searched, while in the case of congenital infection no type of prognostic marker of the prenatal period has yet been identified that can predict whether the newborn will develop symptoms.

If, on the other hand, you have already suffered from an infection by cytomegalovirus, your doctor may provide specific indications, advising you to perform blood tests periodically, for a certain period of time. In particular, the virus could remain latent and manifest itself in moments of strong weakness, when there is a lowering of the immune defenses. Unfortunately, there are currently no vaccines that can prevent the appearance or reactivation of the virus, even in mild form.

How to fight

When the disease is silent or the cytomegalovirus infects a healthy subject, no treatment is needed, because the virus does not cause consequences and does not compromise the health of the person.

Even when it causes mild symptoms it is not necessary to intervene, because generally the situation tends to resolve spontaneously with a little rest. At most, the doctor can prescribe symptomatic drugs, such as antifebrile or painkillers, or recommend a cure with restorative supplements.

When, on the other hand, cytomegalovirus affects people with reduced immune defenses, endangering the health of some organs, it may be necessary to resort to antiviral drugs, which block the replication of the virus, thus limiting damage and helping to control the infection. It will be up to the doctor to establish methods and times of treatment based on each patient.

With regard to pregnant women in particular, there are currently no known effective and safe prenatal treatments to prevent the transmission of the infection from mother to fetus, nor to reduce the consequences of a congenital infection. The drugs available are in fact quite harmful to the fetus.