cytomegalovirus

Cytomegalovirus: description

Cytomegalovirus is an infectious disease caused by cytomegalovirus (CMV). It belongs to the family of herpesviruses and is also called human herpesvirus-5 (HHV-5). After healing the infection, these viruses remain in the body for a lifetime. This time is called latency. If, for example, the immune system is severely weakened by another serious illness, the viruses can be reactivated from their latency. Then they trigger the clinical picture of cytomegalovirus again.

Cytomegaloviruses are distributed worldwide. There is a connection between the prevalence and the prosperity of the population. In Third World countries, over 90 percent of the population has antibodies to cytomegalovirus. In the industrialized countries of the western world, the prevalence rate in children up to the age of six lies between five and 30 percent, and increases from puberty with an increase in sexual contacts to up to 70 percent in adulthood.

The cytomegaloviruses are transmitted via saliva, tears, blood products, organ transplants, seminal fluid, cervical secretions, breast milk and the placenta. With 0.3 to 1.2 percent of affected newborns, cytomegalovirus is the most common congenital viral infection. Approximately 35 percent of infants of cytomegalovirus-positive mothers are infected by breastfeeding.

Cytomegalovirus: symptoms

In cytomegalovirus the symptoms can be individually very different. Above all, the defense strength of the body’s immune system is crucial. Immuno-infected people in most cases show no signs of disease at all. Congenital (congenital) cytomegalovirus infections can sometimes lead to severe disabilities. One differentiates thus depending upon time of the infection and age of the concerning:

Congenital (connatal) cytomegalovirus symptoms

If unborn children in the womb become infected with cytomegalovirus, 90 percent of them are symptomless at birth. During their lifetime, 10 to 15 percent are diagnosed with late damage such as hearing impairment. Five percent of infected newborns have nonspecific disease signs:

• low birth weight
• Jaundice (jaundice)

Another five percent of infected children have serious consequences:

• premature birth
• enlarged liver and spleen (hepatosplenomegaly)
• Coagulation disorders
• Hydrocephalus
• Retinal inflammation (retinitis)

Later, children often have mental and physical disabilities such as learning disabilities or hearing problems.

Cytomegalic symptoms in healthy children

In healthy children, CMV infection is usually asymptomatic. This means that usually no signs of disease occur.

Cytomegalic symptoms in healthy adults

In otherwise healthy adults, cytomegalovirus infection is symptomless in over 90% of cases, or patients complain of uncharacteristic, flu-like symptoms such as:

• Fatigue over weeks
• swollen lymph nodes (lymphadenopathy)
• mild liver inflammation (hepatitis)

Cytomegalic symptoms in immunocompromised patients

If patients have a weakened immune system due to a disease (such as cancer, AIDS, SCID = severe combined immunodeficiency) or immunosuppressive therapy after organ transplantation, cytomegalovirus infection is often severe. Among other things, the patients develop the following complaints:

• fever
• Muscle and joint pain
• severe pneumonia
• Liver inflammation (hepatitis)
• Brain inflammation (encephalitis)
• Retinal inflammation (retinitis)
• Colitis (Colitis)
• Renal inflammation (especially after transplants)

Cytomegalovirus: causes and risk factors

The cause of cytomegalovirus is the cytomegalovirus (CMV). It is a pathogen that consists solely of a shell with capsule and genetic material contained therein. If the virus enters the body via smear infections, sexual contacts or blood products, it penetrates into individual cells and proliferates in them. These cells are damaged and develop into giant cells. This gave rise to the name of the disease: The Greek word “cytos” means “cell,” and “megas” stands for “big.”

The cytomegalovirus can affect almost all organs, preferably the salivary glands. At what place in the body the viruses remain lifelong, is not yet clarified. Some of them probably survive in blood-forming stem cells.

The viruses can be excreted by all body fluids (including urine, saliva, seminal fluid) of infected people. Often this happens only during the first weeks of the primary infection, that is, when the patient has been infected with cytomegalovirus for the first time. However, it may happen that children who have become infected during pregnancy or shortly after birth, excrete the virus until the third year.

Risk factors for cytomegalovirus

Pregnancy is a special risk situation: if a woman becomes infected with the cytomegalovirus for the first time during pregnancy, the unborn child is infected in 40 percent of the cases. Although 90 percent of affected children are symptomless at birth. However, ten to 15 percent of these children develop late damage during their lifetime, such as hearing impairment. The remaining ten percent of the children born with cytomegalovirus show at birth half of them unspecific, mild symptoms, on the other half severe signs of disease.

Patients with immune deficiency, such as AIDS, cancer, congenital immunodeficiencies or organ transplants, are also at risk for cytomegalovirus. Such immune deficiency can not only favor a primary infection, but also the reactivation of the viruses from their latency after an earlier infection. The same applies to pregnant women. In about ten percent of women who have already been infected with CMV, cytomegalovy breaks out again during pregnancy.

Cytomegalovirus: examinations and diagnosis

In order to diagnose cytomegalovirus, your doctor will ask you in detail about your medical history (anamnesis). He asks you for example the following questions:

• Since when do you feel sick?
• Are you pregnant?
• Are you suffering from an underlying disease, such as cancer or AIDS?
• Do you get good air?
• Do you feel pressure in the upper abdomen?

During the subsequent physical examination, the doctor listens to your lungs and palpates the lymph nodes on the neck and your abdomen. In addition, your fundus is mirrored (fundoscopy / ophthalmoscopy) to detect a possible retinal inflammation.

A sample inspection

In addition, a sample of body fluid is taken, which is examined for the cytomegalovirus in the laboratory. Suitable for this are blood, urine, bronchial fluid, amniotic fluid or umbilical cord blood. It is examined whether there are genetic material or surface proteins of the cytomegalovirus or antibodies against them.

Here it is important to find out whether it is a first infection with the cytomegalovirus (primary infection) or whether an earlier and then dormant (latent) infection was reactivated. For this purpose, two samples are taken, which are obtained every two weeks. If no specific antibodies against CMV are present in the first sample (seronegative) and in the second sample both antibodies of class IgG and class IgM (seropositive), a primary infection has been proven. The switch from seronegative to seropositive sample material is called seroconversion.

Listening tests in children

Children who have been infected with cytomegalovirus during pregnancy should have their hearing tests performed at regular intervals, as the hearing impairment can sometimes be diagnosed late.

Cytomegalovirus: treatment

How cytomegalovirus is treated depends mainly on the strength of the immune system and the severity of the symptoms. Healthy adults with a well-functioning defense system and therefore usually only uncharacteristic symptoms such as fatigue are usually given no medication.

Patients with weakened immune systems get antivirals and hyperimmunoglobulins.

antivirals

Antivirals are drugs that prevent viruses from reproducing and spreading. They are often associated with severe side effects and are therefore given only in serious cases. Like all other herpes viruses CMV can not be completely removed. Part of the virus remains in the body for life despite antiviral therapy.

Cytomegalovirus is treated with the antiviral ganciclovir. It can cause severe side effects because it has a toxic effect on the kidneys and bone marrow. Depending on how well ganciclovir works, other antivirals may be used. These include valganciclovir, which is favored for the treatment of retinal inflammation, cidofovir, foscarnet and fomivirsen. Pregnant and nursing mothers should not be treated with these medicines. Newborns with cytomegalovirus should only be treated in specialized facilities that have experience with the condition.

hyperimmunoglobulins

A hyperimmune globulin consists of antibodies that are effective against a specific pathogen. In the case of cytomegalovirus, CMV hyperimmunoglobulin sera are used. These are used in immunocompromised patients as well as in pregnant women who are suspected to have been infected with CMV for the first time.

Cytomegalovirus: disease course and prognosis

The time between infection and the onset of cytomegalovirus (incubation period) is about four to eight weeks. Cytomegalovirus remains in the body for life after survival. Therefore, especially in case of weakening the immune system, the disease again and again erupt.

Patients with an intact defense system have a good prognosis, and cytomegalovirus usually heals without consequences. In all other patients, the outcome of the disease is dependent on the type and severity of symptoms. For example, cytomegalovirus can heal without consequences in newborns or can lead to blindness, hearing damage and mental disability. In immunocompromised patients, generalized infection (ie infection of many different organ systems) can be fatal. In particular, the pneumonia in the context of cytomegalovirus infection is dangerous: It ends in about half of the cases with death.

Cytomegalovirus: prevention

Cytomegalovirus is distributed worldwide. When it comes to prevention, it is therefore important to protect at-risk groups. These include pregnant women who were previously uninfected and people at risk of immunosuppression (such as those with underlying diseases or after organ transplants).

Organ Transplantation:

There is a great risk of transmission of cytomegalovirus during organ transplantation. In order not to repel the organ obtained, the immune system of the organ recipient is weakened by means of drugs (immunosuppressed). As a result, infections such as cytomegalovirus can be more severe because the body’s own defense system can not fight it. In order to prevent such an infection, as far as possible seronegative organ donors are selected. When blood is transferred, the blood can be filtered so that cells that may contain cytomegalovirus are not transmitted.

In addition, the organ recipients can receive hyperimmunoglobulin sera against CMV prior to transplantation. As a result, there are antibodies against the cytomegalovirus in their blood, which invade invaded viruses.

Pregnant women:

Women can have their CMV status tested at the beginning of a pregnancy or in advance. The blood is tested for specific antibodies against cytomegalovirus. According to the maternity guidelines, this examination is not provided and therefore corresponds to an individual health service (IGeL), which is not paid by all health insurances. If seroconversion is diagnosed during pregnancy, action can be taken accordingly.

Pregnant women who have not previously had cytomegalovirus should be aware of strict hand hygiene when in contact with infants. Children excrete cytomegalovirus viruses with urine or saliva, often without signs of disease. By washing hands with soap or alcoholic hand disinfection, the risk of infection can be minimized. In addition, seronegative pregnant mothers of infected infants should heed the following tips:

• Do not kiss your kids on the mouth.
• Do not use the same cutlery or dishes as your children.
• Do not use the same towels or washcloths.
• Disinfect your hands after cleaning your child’s nose or touching toys the children had in their mouths before.

These measures reduce the risk of cytomegalovirus infection for pregnant women.

Prohibition of employment:

For pregnant women who, for example, look after children up to the age of three as educators and, according to the blood test, do not have sufficient immunity cytomegalovirus a prohibition of employment applies for the entire duration of the pregnancy. This is for the protection of the unborn child.