Cytomegalovirus (CMV) infection

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 27, 2016
StartDiseasesCytomegalovirus (CMV) infection

Cytomegalovirus (CMV) infection is a common viral infection affecting 50 to 80 percent of adults by the age of 40. In most instances, CMV infections are harmless, causing few, if any, symptoms. Once a person is infected with CMV, the virus remains in the body for the rest of the individual’s life, but it typically remains dormant as long as the individual remains healthy.

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Definition & Facts

Cytomegalovirus is a form of herpes virus. This is the same family of viruses that includes varicella zoster virus, Epstein-Barr virus, and herpes simplex 1 and 2 viruses. In otherwise healthy individuals, a CMV infection is not typically problematic. The disease can be potentially life-threatening to people with weakened immune systems, including bone marrow or organ transplant patients, HIV and AIDS patients, and individuals taking immunosuppressive drugs.

Immunocompromised individuals can experience a variety of complications, including pneumonia, hepatitis, colitis, encephalitis, and retinitis. Women who develop CMV infections during pregnancy can pass the infection along to their unborn child. This can result in the baby being born with congenital CMV, which can cause permanent disabilities, such as vision loss, hearing loss, microcephaly, and mental disability.

Symptoms & Complaints

The incubation period for CMV is estimated to be between three and 12 weeks. In most cases, individuals infected with CMV do not experience any symptoms or even realize that they have been infected. If the person does experience symptoms during an acute infection, they are typically mild and include:

In patients with compromised immune systems, CMV can attack various organs, which can cause the following symptoms:

Babies infected with CMV at birth may initially appear healthy but develop symptoms months or even years later. Infants who are sick at birth typically exhibit the following symptoms:

Causes

CMV is transmitted through close contact with the bodily fluids of the infected individual. The virus can be found in saliva, blood, urine, semen, vaginal fluids, tears, and breast milk. The most common method of transmission is when a person touches their eyes, nose, or mouth after coming into contact with the bodily fluids of an infected individual or through sexual contact.

In rare cases, the virus can be spread through blood transfusions or organ transplants. The virus can pass through the placenta to infect unborn babies. Infants may also become infected through the breast milk of an infected mother. It is possible for the virus to be shed in bodily fluids for months following the initial infection. Since the virus remains in the body for life, it is possible to shed the virus intermittently throughout life without experiencing any symptoms.

Diagnosis & Tests

Since CMV is normally benign, there is little need for routine screening for the condition. If an individual is symptomatic, the doctor can use a simple blood test that checks for the antibodies created by the immune system in response to the virus. Cultures of blood or other bodily fluids, as well as tissue biopsies, can also be used to test for the condition. If a new infection is suspected during pregnancy, the doctor may recommend performing an amniocentesis to determine if the fetus has been infected.

If a parent or doctor suspects that a child has been born with congenital CMV, it is important to perform testing within three weeks of birth. After that time, it is possible that the infection could have been contracted through nursing or other infected family members. Babies born with CMV should be monitored closely for vision and hearing problems as well as developmental delays.

Individuals with HIV, AIDS, or other immunosuppressive conditions should be tested whether or not they currently have symptoms of an active infection. Even if they are currently asymptomatic, immunocompromised individuals should be regularly monitored for complications, including hearing and vision problems.

Treatment & Therapy

There is currently no cure for CMV. Treatment is not normally recommended or needed in otherwise healthy individuals. Self-care steps, including rest, are generally enough to alleviate any symptoms. In most cases, it isn’t even necessary to see the doctor. Newborns and individuals with weakened immune systems should seek treatment if they experience symptoms or if the physician suspects congenital CMV.

The specific treatment varies depending on the type and severity of the symptoms. In most cases, treatment involves antiviral drugs designed to slow the rate of virus reproduction. The antivirals most often used to treat CMV include ganciclovir and valganciclovir. Foscarnet may be used in patients who cannot tolerate or who have a CMV infection that is resistant to ganciclovir. Foscarnet is a second line treatment since it can be toxic to the kidneys.

Cidofovir is used in limited circumstances in patients who have not responded to other treatments. It is primarily used in AIDS patients who have developed CMV-related retinitis. Transplant patients who are at high risk of developing CMV infection may be placed on prophylactic antiviral medications and CMV immunoglobulin to reduce the risk of CMV infection. Research is underway to develop vaccines and new drugs designed to prevent and treat CMV.

Prevention & Prophylaxis

The best way to prevent CMV infection is to practice good hand hygiene. The following steps can limit the risk of CMV infection:

  • Wash hands frequently with soap and water for a least 20 seconds.
  • Don’t eat or drink after others.
  • Avoid coming in contact with a child’s tears or saliva.
  • Thoroughly clean toys, countertops, and any other surfaces that may be contaminated by a child’s urine or saliva.
  • Dispose of diapers and any other items contaminated with bodily fluids very carefully and wash hands thoroughly afterward.
  • Condoms can prevent the transmission of CMV through semen or vaginal fluids.