Cytomegalovirus (CMV) infections can cause symptoms such as fever, tiredness and a sore throat. But most healthy people who are infected with CMV have no symptoms.

People who are more likely to have symptoms of a CMV infection include:

• Newborns who became infected with CMV before they were born. This condition is called congenital CMV.
• Infants who become infected during birth or shortly afterward, also called perinatal CMV. This group includes babies infected through breast milk.
• People who have weakened immune systems. This includes people who've had an organ, bone marrow, or stem cell transplant, or those who have HIV.

CMV infection can cause illness when you're first infected. This is called a primary infection. The risk of a baby being born with CMV is higher when the pregnant parent gets a primary infection. If you're healthy, CMV mainly stays dormant. That means the virus doesn't become active and make copies of itself. But in people with weakened immune systems, CMV can become active again when the body's defenses can't keep it dormant.

Babies

Most babies who have congenital CMV appear healthy at birth.

A few babies with congenital CMV who appear healthy at birth get symptoms over time. Sometimes, the symptoms start months or years after birth. The most common of these late symptoms are hearing loss and delays in development. A small number of babies also may develop vision loss.

Babies with congenital CMV who are sick at birth can have symptoms or conditions that include:

• Low birth weight.
• Yellow skin and eyes, called jaundice — this may be harder to see on darker skin.
• Damage to the retina of the eye, called retinitis.
• Rash or pinpoint round spots on the skin.
• A head that is smaller than is typical, also called microcephaly.
• Enlarged spleen.
• Pneumonia.
• Seizures.
• Development and motor delays.

Babies with congenital CMV who have symptoms also might be more likely to be born premature.

People who have weakened immune systems

In people with weakened immune systems, CMV can lead to conditions that affect the:

• Eyes.
• Lungs.
• Liver.
• Esophagus.
• Stomach.
• Intestines.
• Brain.

Healthy adults

Most healthy people who are infected with CMV have few if any symptoms. When first infected, some adults may have symptoms such as:

• Fatigue.
• Fever.
• Sore throat.
• Headache.
• Swollen glands.

See your healthcare professional if:

• You have a weakened immune system and you get symptoms of a CMV infection. Without treatment, CMV infection can be serious or even fatal for some people who have weakened immune systems. Those who've gotten stem cell or organ transplants seem to be at greatest risk.
• You are pregnant and you become ill with symptoms such as fever, fatigue, sore throat or swollen glands.

If you have mild symptoms of a CMV infection but are healthy, you likely won't need treatment. Your healthcare professional might simply tell you get plenty of rest.

When your baby or young child should see a doctor

If you know you were infected with CMV during your pregnancy, tell your child's healthcare professional. Your child likely will be tested for hearing or vision problems.

A cytomegalovirus (CMV) infection is caused by a virus of the same name. When CMV is active in your body, you can pass the virus to other people. The virus is spread through body fluids. These include blood, urine, saliva, breast milk, tears, semen and vaginal fluids. Casual contact doesn't spread CMV.

Ways the virus can be spread include:

• Hand to face contact. For example, touching your eyes or the inside of your nose or mouth after touching the body fluids of an infected person.
• Sexual contact with an infected person.
• The breast milk of an infected mother.
• Organ, bone marrow or stem cell transplants or blood transfusions.
• Birth. A pregnant person with CMV can pass the virus to the baby before or during birth. The risk is higher if you get CMV for the first time during pregnancy.

There are no key risk factors for cytomegalovirus (CMV) infections. CMV is a widespread and common virus that can infect almost anyone. For instance, 1 in 3 children in the United States get the infection by age 5. More than half of adults become infected by age 40.

Medical conditions called complications that are linked with cytomegalovirus (CMV) infection vary. The possible complications depend on your overall health and when in life you were infected.

Healthy adults

It's common for CMV to cause healthy adults to get another illness that spreads from person to person called mononucleosis. Less often, CMV can cause healthy adults to get an enlarged spleen, inflamed liver or certain blood conditions. Rare complications include conditions that affect the brain, lungs, nerves and heart muscle.

People who have weakened immune systems

Health conditions that stem from CMV infections can include:

• Vision loss due to swelling called inflammation in the light-sensing layer of the eye. This condition is called retinitis.
• Digestive system conditions. These include swelling of the colon called colitis, swelling of the esophagus called esophagitis and swelling of the liver called hepatitis.
• Nervous system problems, including brain inflammation called encephalitis.
• An infection in one or both lungs called pneumonia.

Infants who have congenital CMV

An infant whose mother first became infected with CMV during pregnancy is more likely to experience complications. Complications for the baby can include:

• Hearing loss.
• Delays in development or skills related to movement.
• Vision loss.
• Seizures.
• Lack of coordination.
• Weakness or problems using muscles.

Careful hygiene is the best way to help prevent cytomegalovirus (CMV) infections in people who haven't already been infected. You can take these steps:

• Wash your hands often. Scrub with soap and water for 20 seconds. Wash after you change a diaper, help a child use the toilet or handle toys. Also wash if your child's saliva gets on your hands. These steps are very important if your child goes to daycare.
• Stay away from tears and saliva when you kiss your child. Instead of kissing your child on the lips, for instance, kiss on the forehead. This is very important if you're pregnant.
• Do not share food or drink out of the same glass as other people. Sharing glasses and kitchen utensils can spread CMV.
• Be careful with disposable items. Don't touch your face right after you throw out diapers, tissues and other items with bodily fluids on them. Wash your hands well before you touch your face.
• Clean toys and countertops. Clean any surfaces that come in contact with children's urine or saliva.
• Have safe sex. Use a new condom each time you and your partner have sex. This helps prevent the spread of CMV through semen and vaginal fluids.

If you have a weakened immune system, your healthcare professional may recommend antiviral medicine to prevent a CMV infection. Often, this medicine is prescribed to people who get stem cell transplants.

Vaccines for CMV aren't yet available. But they're being tested for young women. Someday, vaccines may help prevent CMV infection in pregnant people and infants. They also might lower the chances that babies born to pregnant people with CMV will develop long-term health conditions.

Lab tests can detect a cytomegalovirus (CMV) infection. These include tests of blood, saliva and urine. Sometimes, tests of tissue samples are done.

During pregnancy and after delivery

Most often, pregnant people aren't tested for CMV. But if you're pregnant, testing may be recommended for reasons such as:

• You're exposed to someone who is ill from CMV.
• You get symptoms such as a fever, headache, fatigue, sore throat and swollen glands.
• An ultrasound imaging test suggests that your unborn baby might have a CMV infection.
• You have a weakened immune system.

If you're pregnant, testing also can find out whether you've ever been infected with CMV. Blood tests can find proteins called antibodies that the immune system makes in response to a CMV infection. These proteins can linger in the blood for months to years after an infection.

If testing spots antibodies that suggest you've had a recent CMV infection, more testing is recommended. A new recent infection with CMV in pregnancy raises the risk of having your baby infected with CMV. Pregnant women who already developed CMV antibodies in the past have a very small chance of the virus becoming active again. But if this happens, it could infect the unborn child.

If your healthcare professional finds a new CMV infection while you're pregnant, a prenatal test called amniocentesis may be recommended. The test can find out whether the unborn baby has been infected. A sample of the fluid that surrounds your baby in the womb, called amniotic fluid, is removed with a needle and checked. In general, amniocentesis is recommended when an imaging test shows certain signs that might be caused by CMV.

If your healthcare professional thinks that your baby has congenital CMV, the baby is tested for it within three weeks of birth. If your baby has CMV, more tests likely will be needed. These tests check the health of the baby's organs, such as the liver and kidneys.

In people who have weakened immune systems

Testing for CMV also can be important if you have a weakened immune system. Regular testing may be recommended if you have HIV or AIDS, or if you've had a transplant.

Treatment for a cytomegalovirus (CMV) infection can include medicines and other therapies. But most often, healthy adults and children with CMV infections don't need treatment. Healthy adults who get CMV mononucleosis tend to get well without medicine.

Medications

Newborns and people who have weakened immune systems need treatment when they have symptoms of CMV infection. The type of treatment depends on the symptoms and how severe they are.

Medicines that treat infections caused by viruses are the most common type of treatment. They can slow the virus from making copies of itself. But they don't get rid of the virus. Researchers are studying new medicines and experimental vaccines to treat and prevent CMV.

Therapies

Various types of therapy can help children with hearing loss due to CMV infections. For example, speech therapy can improve speaking, listening, language and social skills. Occupational therapy can help children do everyday tasks affected by hearing loss.

Assistive devices such as hearing aids can make it easier to hear as well.

The sooner children get treatment for hearing loss, the better they might adjust to living with the condition.

Here's some information to help you get ready for your appointment.

What you can do

Before your appointment, take these steps:

• Write down any symptoms you or your child has. Include symptoms even if they seem minor, such as low-grade fever or fatigue.
• Write down questions to ask your healthcare team. Your time with your healthcare professional is limited, so it can help to make a list of questions.

For CMV, questions to ask your healthcare team include:

• What is likely causing my symptoms?
• What tests do I need?
• Is my condition likely short term or long term?
• What is the best course of action?
• How can I lower the chances of infecting others?
• Are there any restrictions I need to follow?
• I have other health conditions. How can I best manage them together?

What to expect from your doctor

Your healthcare professional likely will ask you questions such as:

• How long have you had your symptoms?
• Do you work or live with young children?
• Have you had a blood transfusion or organ, bone marrow or stem cell transplant recently?
• Do you have a medical condition that might weaken your immune system, such as HIV or AIDS?
• Are you receiving chemotherapy?
• Do you practice safe sex?
• Are you pregnant or breastfeeding?

If you think you have been exposed to CMV during pregnancy, your healthcare professional may ask:

• When do you think you may have been exposed?
• Have you had symptoms of the condition?
• Have you been tested for CMV before?