Cytomegalovirus

However, CMV infection is important to certain high-risk groups. Major areas of concern are (1) the risk of infection to the unborn baby during pregnancy, (2) the risk of infection to people who work with children, and (3) the risk of infection to the immunocompromised person, such as organ transplant recipients and persons infected with human immunodeficiency virus (HIV).

Infectious CMV may be shed in the bodily fluids of any previously infected person, and thus may be found in urine, saliva, blood, tears, semen, and breast milk. The shedding of virus may take place intermittently, without any detectable signs, and without causing symptoms.

Although the virus is not highly contagious, it has been shown to spread in households and among young children in day care centers. Transmission of the virus is often preventable because it is most often transmitted through infected bodily fluids that come in contact with hands and then are absorbed through the nose or mouth of a susceptible person. Therefore, care should be taken when handling children and items like diapers. Simple hand washing with soap and water is effective in removing the virus from the hands.

CMV infection without symptoms is common in infants and young children; as a result, it is common to not exclude from school or an institution a child known to be infected. Similarly, hospitalized patients are not typically separated or isolated.

Pregnancy

1. Generalized infection may occur in the infant, and symptoms may range from moderate enlargement of the liver and spleen (with jaundice) to fatal illness. With supportive treatment most infants with CMV disease usually survive. However, from 80% to 90% will have complications within the first few years of life that may include hearing loss, vision impairment, and varying degrees of mental retardation.
   
   
2. Another 5% to 10% of infants who are infected but without symptoms at birth will subsequently have varying degrees of hearing and mental or coordination problems.

The virus can also be transmitted to the infant at delivery from contact with genital secretions or later in infancy through breast milk. However, these infections usually result in little or no clinical illness in the infant.

To summarize, during a pregnancy when a woman who has never had CMV infection becomes infected with CMV, there is a potential risk that after birth the infant may have CMV-related complications, the most common of which are associated with hearing loss, visual impairment, or diminished mental and motor capabilities. On the other hand, infants and children who acquire CMV after birth have few, if any, symptoms or complications.

Recommendations for pregnant women with regard to CMV infection:

1. Throughout the pregnancy, practice good personal hygiene, especially handwashing with soap and water, after contact with diapers or oral secretions (particularly with a child who is in day care).
   
   
2. Women who develop a mononucleosis-like illness during pregnancy should be evaluated for CMV infection and counseled about the possible risks to the unborn child.
   
   
3. Laboratory testing for antibody to CMV can be performed to determine if a women has already had CMV infection.
   
   
4. Recovery of CMV from the cervix or urine of women at or before the time of delivery does not warrant a cesarean section.
   
   
5. The demonstrated benefits of breast-feeding outweigh the minimal risk of acquiring CMV from the breast-breeding mother.
   
   
6. There is no need to either screen for CMV or exclude CMV-excreting children from schools or institutions because the virus is frequently found in many healthy children and adults.

People Who Work with Infants and Children

Recommendations for individuals providing care for infants and children:

1. Female employees should be educated concerning CMV, its transmission, and hygienic practices, such as handwashing, which minimize the risk of infection.
   
   
2. Susceptible nonpregnant women working with infants and children should not routinely be transferred to other work situations.
   
   
3. Pregnant women working with infants and children should be informed of the risk of acquiring CMV infection and the possible effects on the unborn child.
   
   
4. Routine laboratory testing for CMV antibody in female workers is not recommended, but can be performed to determine their immune status

Immunocompromised Patients

CMV should be suspected if a patient:

• has symptoms of infectious mononucleosis but has negative test results for mononucleosis and Epstein Barr virus, or,
• shows signs of hepatitis, but has negative test results for hepatitis A, B, and C.

Laboratory testing for antibody to CMV can be performed to determine if a woman has already had CMV infection. However, routine laboratory testing of all pregnant women is costly and the need for testing should therefore be evaluated on a case-by-case basis.

An ELISA technique for CMV-specific IgM is available, but may give false-positive results unless steps are taken to remove rheumatoid factor or most of the IgG antibody before the serum sample is tested. Because CMV-specific IgM may be produced in low levels in reactivated CMV infection, its presence is not always indicative of primary infection. Only virus recovered from a target organ, such as the lung, provides unequivocal evidence that the current illness is caused by acquired CMV infection. If serologic tests detect a positive or high titer of IgG, this result should not automatically be interpreted to mean that active CMV infection is present. However, if antibody tests of paired serum samples show a fourfold rise in IgG antibody and a significant level of IgM antibody, meaning equal to at least 30% of the IgG value, or virus is cultured from a urine or throat specimen, the findings indicate that an active CMV infection is present.