Cytomegalovirus Infection

Cytomegalovirus Infection 

Definition

Cytomegalovirus (CMV) is a virus related to the group of herpes viruses. Infection with CMV can cause no symptoms, or can be the source of serious illness in people with weak immune systems. CMV infection is also an important cause of birth defects.

Description

CMV is an extremely common organism worldwide. It is believed that about 85% of the adults in the United States have been infected by CMV at some point in their lives. CMV is found in almost all of the body's organs. It is also found in body fluids, including semen, saliva, urine, feces, breast milk, blood, and secretions of the cervix (the narrow, lower section of the uterus).

CMV is also able to cross the placenta (the organ that provides oxygen and nutrients to the unborn baby in the uterus). Because CMV can cross the placental barrier, initial infection in a pregnant woman can lead to infection of the developing baby.

Causes and symptoms

CMV is passed between people through contact with body fluids. CMV also can be passed through sexual contact. Babies can be born infected with CMV, either becoming infected in the uterus (congenital infection) or during birth (from infected cervical secretions).

Like other herpes viruses, CMV remains inactive (dormant) within the body for life after the initial infection. Some of the more serious types of CMV infections occur in people who have been harboring the dormant virus, only to have it reactivate when their immune system is stressed. Immune systems may be weakened because of cancer chemotherapy, medications given after organ transplantation, or diseases that significantly lower immune resistance like acquired immunodeficiency syndrome (AIDS).

In a healthy person, initial CMV infection often occurs without symptoms and is rarely noticed. Occasionally, a first-time infection with CMV may cause a mild illness called mononucleosis. Symptoms include swollen glands, liver, and spleen; fever; increased white blood cells; headache; fatigue; and sore throat. About 8% of all mononucleosis cases are due to CMV infection. A similar infection, though slightly more serious, may occur two to four weeks after receiving a blood transfusion containing CMV.

In people with weakened immune systems, CMV infection can cause more serious and potentially life-threatening illnesses. These illnesses include pneumonia, and inflammations of the liver (hepatitis), brain (encephalitis), esophagus (esophagitis), large intestine (colitis), and retina of the eye (retinitis).

Babies who contract CMV from their mothers during birth rarely develop any illness from these infections. Infants born prematurely who become CMV infected during birth have a greater chance of complications, including pneumonia, hepatitis, decreased blood platelets.

However, an unborn baby is at great risk for serious problems when the mother becomes infected with CMV for the first time while pregnant. About 10% of these babies will be born with obvious problems, including prematurity, lung problems, an enlarged liver and spleen, jaundice, anemia, low birth weight, small head size, and inflammation of the retina. About 90% of these babies may appear perfectly normal at birth. Unfortunately, about 20% will later develop severe hearing impairments and mental retardation. A 2003 report found that pregnant women 25 years and older who are immune to CMV are much less likely to pass the virus to their babies than younger women who have never been exposed to CMV.

Diagnosis

Body fluids or tissues can be tested to reveal CMV infection. However, this information is not always particularly helpful because CMV stays dormant in the cells for life. Tests to look for special immune cells (antibodies) directed specifically against CMV are useful in proving that a person has been infected with CMV. However, these tests do not give any information regarding when the CMV infection first occurred.

Treatment

Ganciclovir and foscarnet are both antiviral medications that have been used to treat patients with weak immune systems who develop a serious illness from CMV (including retinitis). As of 1998, research was still being done to try to find useful drugs to treat newborn babies suffering from congenital infection with CMV. Antiviral drugs are not used to treat CMV infection in otherwise healthy patients because the drugs have significant side effects that outweigh their benefits. In 2003, researchers in Europe announced a new compound that appeared to be highly effective against CMV infections. The new drug acted earlier in the viral replication of the infection and showed promise, however, clinical trials were continuing.

Key terms

Cervix — The narrowed, lowest part of the uterus through which a baby must pass in order to enter the birth canal.

Congenital — A condition that exists before birth and at birth.

Placenta — The organ that provides oxygen and nutrition from the mother to the unborn baby during pregnancy. The placenta is attached to the wall of the uterus and leads to the unborn baby via the umbilical cord.

Prognosis

Prognosis in healthy people with CMV infection is excellent. About 0.1% of all newborn babies will have serious damage from CMV infection occurring while they were developing in the uterus. About 50% of all transplant patients will develop severe illnesses due to reactivation of dormant CMV infection. These illnesses have a high rate of serious complications and death.

Prevention

Prevention of CMV infection in the normal, healthy person involves good handwashing. Blood products can be screened or treated to insure that they do not contain CMV. In 2003, a new high-dose prophylactic (preventive) treatment was being tested to reduce CMV risk in stem cell transplant recipients.

Resources

Periodicals

Fowler, Karen B., Sergio Stagno, and Robert F. Pass. "Maternal Immunity and Prevention of Congenital Cytomegalovirus Infection." JAMA, The Journal of the American Medical Association February 26, 2003: 1008.

"High-Dose Acyclovir May Reduce Cytomegalovirus Infection Risk." Virus Weekly July 15, 2003: 16.

"Novel Compound Highly Effective Against Cytomegalovirus Infection." AIDS Weekly November 25, 2003: 17.

Organizations

Baylor College of Medicine. 1 Baylor Plaza, Houston, TX 77030. (713) 798-4951. http://public.bcm.tmc.edu.

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. http://www.cdc.gov.

March of Dimes Birth Defects Foundation. 1275 Mamaroneck Ave., White Plains, NY 10605. (914) 428-7100. resourcecenter@modimes.org. http://www.modimes.org.

---

Patient discussion about Cytomegalovirus Infection.

Q. What is it CMV during pregnancy ? can i infect with that?

A. CMV or cytomegalovirus (http://en.wikipedia.org/wiki/Cytomegalovirus) is a virus that can cause disease (i.e. infectious mononucleosis, http://en.wikipedia.org/wiki/Infectious_mononucleosis) in everyone, not only pregnant women. The problem is that when a pregnant woman is infected in CMV for the first time of her life during pregnancy, CMV can cause malformations and problems with the baby, including hearing impairment and others (see also TORCHES: http://en.wikipedia.org/wiki/TORCH_infections).

Q. What is it CMV during pregnancy? can i infect with that?

A. CMV is a virus. What you refer to is infection with CMV, either the initial infection, or re-activation of latent (dormant) virus that resides in the mother's body during pregnancy.

The dangers are that CMV will infect the fetus, which may cause malformations, particularly growth restriction and hearing impairment.

You may read more here:
www.nlm.nih.gov/medlineplus/cytomegalovirusinfections.html