Cytomegalovirus (CMV) Infection

Cytomegalovirus, or CMV, is a common virus that infects most people worldwide. CMV infection is usually harmless and rarely causes illness. A healthy immune system can hold the virus in check. However, if a person's immune system is seriously weakened in any way, the virus can become active and cause CMV disease.

Infectious agent that causes cytomegalovirus infection :

Cytomegalovirus is a member of the herpesvirus family. Other members of the herpesvirus family cause chickenpox, infectious mononucleosis, fever blisters, and genital herpes. These viruses all share the ability to remain alive, but dormant, in the body for life.

A first infection with CMV usually causes no symptoms. The virus continues to live in the body silently without causing obvious damage or illness. It rarely becomes active for the first time or reactivates (causes illness again in the same person) unless the immune system weakens and is no longer able to hold the virus in check.

Where is cytomegalovirus found ?

CMV is found worldwide. The virus is carried by people and is not associated with food, water, or animals.

How do people get infected with cytomegalovirus ?

CMV is spread from person to person. Any person with a CMV infection, even without symptoms, can pass it to others. In an infected person, the virus is present in many body fluids, including urine, blood, saliva, semen, cervical secretions, and breast milk.

CMV can be spread by any close contact that allows infected body fluids to pass to another person. CMV can spread in households and child-care centers through hand-to-mouth contact with infected body fluids. CMV can spread by sexual contact, blood transfusions, organ transplants, and breastfeeding. CMV can also be passed from an infected pregnant woman to her fetus or newborn.

Who is at risk for cytomegalovirus ?

Anyone can become infected with CMV. Almost all people have been exposed to CMV by the time they are adults, but the virus usually does not make otherwise healthy people sick. However, some people are at increased risk for active infection and serious complications :

* Babies born to women who have a first-time CMV infection during pregnancy
* Pregnant women who work with infants and children
* Persons with weakened immune systems, including cancer patients on chemotherapy, organ transplant recipients, and persons with HIV infection

Signs and Symptoms of cytomegalovirus :

Active infection in otherwise healthy children and adults can cause prolonged high fever, chills, severe tiredness, a generally ill feeling, headache, and an enlarged spleen.

Most infected newborns have no symptoms at birth, but, in some cases, symptoms will appear over the next several years. These include mental and developmental problems and vision or hearing problems. In rare cases, a newborn can have a life-threatening infection at birth. Infants and children who get CMV infection after birth have few, if any, symptoms or complications. When symptoms do appear, they include lung problems, poor weight gain, swollen glands, rash, liver problems, and blood problems.

People with weakened immune systems can have more serious, potentially life-threatening illnesses, with fever, pneumonia, liver infection, and anemia. Illnesses can last for weeks or months and can be fatal. In persons with HIV infection, CMV can infect the retina of the eye (CMV retinitis) and cause blindness.

How soon after exposure do symptoms appear ?

Most exposed people never develop symptoms. In those who do, the time between exposure and symptoms is about 3 to 12 weeks.

How is cytomegalovirus diagnosed ?

There are special laboratory tests to culture the virus, but testing requires 2 to 3 weeks and is expensive. Blood tests can help diagnose infection or determine if a person has been exposed in the past.

How long does disease from CMV infection last ?

The duration of disease varies, depending on the type of infection and the age and health of the infected person. Serious CMV infections that were acquired before birth can cause developmental problems that can affect a child for a lifetime. CMV infections in transplant recipients, cancer patients, and persons with HIV infection can be life threatening and require many weeks of hospital treatment. On the other hand, infections in young adults might cause symptoms for only 2 to 3 weeks.

What is the treatment for cytomegalovirus ?

There is no specific treatment or cure for CMV infection. Anti-virus medicines can be helpful in treating CMV retinitis in persons with HIV infection.

How common is cytomegalovirus ?

CMV is common worldwide. An estimated 80% of adults in the United States are infected with CMV. CMV is also the virus most often transmitted to a developing fetus before birth.

Is cytomegalovirus an emerging infectious disease ?

Yes. Increasing numbers of persons are at risk for CMV infection. Expanding use of child-care centers is increasing the risk to children and staff. Also, the number of people with weakened immune systems is growing because of increases in HIV infection, organ transplantation, and cancer chemotherapy.

How can cytomegalovirus be prevented ?