Cytomegalovirus (CMV) infection
Filed under: Infectious Diseases
Cytomegalovirus (CMV) is a common and widespread virus that can infect almost anyone. Most people with CMV don't even know they have it, because it rarely causes symptoms. The greatest concern is if you're pregnant or have a weak immune system.
Once you're infected with CMV, the virus is in your body for life. CMV spreads through body fluids, such as blood, saliva, urine, semen and breast milk. People with weak immune systems have a greater risk of becoming ill from CMV. If you're pregnant and have never been exposed to the virus but develop an active infection, the virus can cause disabilities in your unborn baby.
There's no cure for CMV, but drugs can help newborns and people with weak immune systems.
Most people infected with CMV who are otherwise healthy experience few if any symptoms. In fact, many people never know they have the virus. The type and seriousness of a CMV infection usually depend on your overall health.
When first infected (primary CMV), some adults may have symptoms similar to mononucleosis. Signs and symptoms of primary CMV include:
* Night sweats
* Prolonged fever
* Swollen glands or sore throat or both
* Loss of appetite or weight loss or both
* Muscle aches or joint pain or stiffness
* General feeling of illness, discomfort or uneasiness
When the cause of these symptoms is CMV, you still may not know you have the virus, because the symptoms are usually mild and short-lived and are also common in other illnesses.
Signs and symptoms in adults with compromised immunity
If you're an adult with a weakened immune system (immunocompromised), CMV can attack specific organs. This can result in signs and symptoms in the:
* Eyes, including visual impairment and blindness
* Lungs, including pneumonia with low blood oxygen (hypoxemia)
* Gastrointestinal system, including diarrhea and ulcerations with bleeding
* Liver, including hepatitis, most often characterized by a prolonged, unexplained fever
* Brain, including inflammation of the brain (encephalitis), with behavioral changes, seizures and coma
Symptoms in children
If you're pregnant and become infected with CMV for the first time, you may not experience serious illness, but it's possible to pass CMV to your baby through the placenta. In most cases newborns don't show signs of infection at birth. Only about 1 newborn in 100 infected with CMV during pregnancy are ill at birth. Of this 1 percent, most will be very ill and have a significant risk of permanent disabilities.
Most babies who are infected before they're born appear healthy at birth, but a few can develop signs over time — sometimes not for months or years after birth. The most common of these late-occurring signs is hearing loss. A small number may develop vision impairment as well.
Most babies born with CMV (congenital CMV) never have any signs or symptoms.
Immediate signs of CMV in newborns include:
* Yellow skin and eyes (jaundice)
* Purple skin splotches or a rash or both
* Small size at birth (or low birth weight)
* Enlarged spleen
* Enlarged and poorly functioning liver
Disabilities arising from newborn CMV include:
* Hearing loss
* Eye abnormalities, including central vision loss, scarring of the retina, and swelling and irritation of the eye (uveitis)
* Mental disability
* Attention-deficit/hyperactivity disorder
* Lack of coordination
* Small head
When to see a doctor
If you have a weakened immune system and you're experiencing what may be signs or symptoms of CMV infection, see your doctor. CMV infection in people with compromised immunity can be fatal. People who are immunocompromised because they have undergone bone marrow or organ transplants seem to be at greatest risk. The mildness or severity of your infection depends on the strength or weakness of your immune system.
If you develop a mononucleosis-like illness while you're pregnant, see your doctor so that you can be evaluated for CMV infection. You'll also want to talk to your doctor about the possible risks to your unborn baby if you have contracted the virus.
If you have CMV but are otherwise healthy, and you're experiencing any mild, generalized illness, you could be in a reactivation period. Practical self-care steps, such as getting plenty of rest, should be enough for your body to control the infection. You likely don't need to see your doctor.
When your child should see a doctor
If you know you were infected with CMV during your pregnancy, let your baby's doctor know. Your baby should be followed closely to ensure there are no signs of vision or hearing problems. However, newborns who are well otherwise are unlikely to develop life-threatening disease later.
Cytomegalovirus is in the same family of viruses as those that cause chickenpox, herpes simplex and mononucleosis. Similar to other viruses in this family, CMV cycles through periods of dormancy and reactivation. If you're infected, your body sheds the virus in its fluids when the virus reactivates. This is when the virus can be passed to a noninfected person.
Infected body fluids that can spread CMV include blood, urine, saliva, breast milk, tears, semen and vaginal fluids. If you've been infected with CMV sometime in the past (CMV positive), you usually don't have the virus in these fluids unless you're experiencing reactivation. Transmission of the virus occurs, like HIV and hepatitis B, through exposure to these body fluids, and not by casual contact.
The virus can spread in a number of ways:
* Touching your eyes or the inside of your nose or mouth after coming into contact with the body fluids of an infected person. This is the most common way CMV is spread because it's absorbed through the mucous membranes.
* Through sexual contact with an infected person.
* Through the breast milk of an infected mother.
* Through organ transplantation or blood transfusions.
* By becoming infected during pregnancy — either for the first time or with recurrent CMV infection — when the virus is passed from mother's blood to the fetus through the placenta or during birth.
CMV is a widespread and common virus that can infect almost anyone. In fact, according to the National Institute of Neurological Disorders and Stroke, 50 to 80 percent of adults in the United States are infected by age 40.
Healthy children and adults who contract the infection usually have few if any symptoms. However, some babies born with CMV will develop long-term disabilities, so if you're pregnant and don't have CMV, be especially careful not to become exposed to the virus during pregnancy.
Some groups of children and adults are at greater risk of being severely affected if they contract CMV.
If you're pregnant and have never had CMV, you have the greatest risk that acquiring the disease could result in an affected child. If you acquire a primary infection during your pregnancy, your newborn has an approximately 1 percent chance of having the severe form of CMV at birth. If you acquire the disease during pregnancy but your baby is born healthy, there's still a 10 to 15 percent chance that your baby was infected while in the uterus. These babies are at risk of developing problems later with hearing or vision. All babies who acquire CMV infections during pregnancy should have regular vision and hearing tests.
Adults who have weakened immune systems may have more severe and longer lasting symptoms from a CMV infection. A variety of conditions can cause your immune system to become weakened:
* Having HIV or AIDS
* Receiving chemotherapy
* Taking anti-rejection drugs after an organ or bone marrow transplant
In the rare cases in which CMV causes a healthy person to become very sick, the infection may cause the following complications:
* CMV mononucleosis. This syndrome resembles infectious mononucleosis. Infectious, or classic, mononucleosis is caused by a different virus called Epstein-Barr virus (EBV). If you have symptoms that resemble mononucleosis — a sore throat, swollen glands, and tonsils, fatigue and nausea — your doctor will test you for the antibody your body makes to fight off EBV. If it's absent, there's a good chance CMV is causing your symptoms.
* Intestinal complications. CMV infection in your intestines can result in diarrhea, fever and abdominal pain; inflammation of your colon; and blood in your stool.
* Liver complications. CMV can cause abnormal functioning of your liver and an unexplained fever.
* Nervous system complications. A variety of neurological complications have been reported as a result of CMV infection in the nervous system. These may include inflammation of your brain (encephalitis).
* Lung complications. CMV can cause inflammation of your lung tissue (pneumonitis).
Preparing for your appointment
Because appointments can be brief, it's a good idea to be well prepared. Write down any symptoms you're experiencing — even if they seem minor, such as low-grade fever or fatigue. You should also write down any questions you have for your doctor.
What to expect from your doctor
Your doctor will ask you a number of questions, as well. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
* How long have you been experiencing your symptoms?
* Do you work or live with young children?
* Have you had a blood transfusion or organ transplant in recent months?
* Do you have a medical condition that compromises your immune system, such as HIV or AIDS?
* Are you currently receiving chemotherapy?
* Do you practice safe sex?
* Are you pregnant or breast-feeding?
In addition, if you think you have been exposed during pregnancy:
* When do you think you may have been exposed?
* Have you had any symptoms of the condition?
* Have you ever been tested for CMV before?
Tests and diagnosis
If you have symptoms of CMV, tests can determine whether you have the disease. Blood tests can indicate special proteins in your blood (antibodies) that are created by your immune system when you have CMV. The virus can also be detected by cultures or by a polymerase chain reaction (PCR) test from blood, other body fluids or a tissue biopsy.
Screening and testing for your baby
Testing to determine whether you've ever been infected can be important if you're pregnant. Pregnant women with antibodies have a very small chance of a reactivation infecting their unborn child.
When new infection is detected during pregnancy, you may wish to consider amniocentesis, in which your doctor obtains and examines a sample of amniotic fluid to determine whether the fetus has the infection. Occasionally the need for such testing arises when abnormalities that may be caused by CMV or other infectious diseases are seen on ultrasound.
If you or your doctor thinks your baby may have been born with CMV (congenital CMV), it's important that he or she be tested within the first three weeks of birth. If you wait longer, tests won't be conclusive for congenital CMV, because it's possible your baby could have contracted the infection by nursing or by exposure to siblings or others who may be shedding the virus.
Screening and testing if you're immunocompromised
Testing for CMV can also be important if you have a condition that weakens your immune system. For example, if you have HIV or AIDS, and even if you don't have an active CMV infection, the fact that you carry the CMV virus means you'll need regular monitoring for complications of CMV, such as vision and hearing problems.
Treatments and drugs
There's no cure for CMV, and treatment for the virus generally isn't necessary or recommended for normally healthy children and adults.
Newborns and people with compromised immune systems, however, do need treatment when they're experiencing symptoms of CMV infection. The kind of treatment depends on the symptoms and their severity.
If treatment is needed, it's most often in the form of antiviral drugs. Antiviral drugs slow down the virus by preventing it from dividing and creating more of itself. However, these drugs don't cure CMV.
Treatment may also address the specific symptoms of CMV infection. Treatable signs in newborns are:
* Hearing loss
* Retinitis, an inflammation of the light-sensing layer of the eye
Researchers are studying new medications and vaccines to treat and prevent CMV.
Careful hygiene is the best prevention against contracting CMV. Health care workers have the greatest opportunity for exposure, but, because of precautions used in the health care setting, their risk of acquiring the disease is very low.
You can take these precautions to help prevent CMV infection:
* Wash your hands often. Use soap and water for 15 to 20 seconds, especially if you have contact with young children or their diapers, drool or other oral secretions. This is especially important if the children attend child care.
* Avoid contact with tears and saliva when you kiss a young child. Instead of kissing a young child on the lips, for instance, give a kiss on the forehead. This is especially important if you're pregnant.
* Avoid sharing food or drinking out of the same glass as others. Sharing glasses and kitchen utensils can spread the CMV virus.
* Be careful with disposable items. When disposing of diapers, tissues and other items that have been contaminated with bodily fluids, be careful not to touch your hands to your face until after thoroughly washing your hands.
* Practice safe sex. Wear a condom during sexual contact to prevent spreading the CMV virus through semen and vaginal fluids.
Experimental vaccines are being tested for women of childbearing age. These vaccines may be useful in preventing CMV infection in mothers and infants, and reducing the chance that babies born to women who are infected while pregnant will develop disabilities. If you have a compromised immune system, you may benefit from taking antiviral medication to prevent CMV disease.