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Epidemiologic Notes and Reports Prevalence of Cytomegalovirus Excretion from Children in Five Day-Care Centers -- Alabama

Recent studies have been done in Birmingham, Alabama, to determine the prevalence of cytomegalovirus (CMV) infection among attendees of day-care centers. Samples of urine and saliva from children attending five day-care centers were tested for CMV by viral isolation between March and June 1984 (Table 1). A culture was obtained from each child on a single occasion at both sites in almost all cases. Prevalence of serum antibody to CMV among parents and day-care center workers was determined using a commercial enzyme immunoassay. Centers A, B, and C served mainly middle-income families; centers D and E served primarily low-income families. Although excretion rates varied among the centers, each center had children who were shedding virus. Centers A, B, and C had at least one age cohort with greater than 50% excretion. A small number of children under 3 years of age had CMV in saliva and not in urine. Thus, the percentage of children with excretion from either site for the respective centers was 49% (A), 40% (B), 32% (C), 9% (D), and 13% (E). Frequency of viral excretion was lower in both urine and saliva specimens from children in the lower socioeconomic centers. Questionnaires completed by parents provided past medical histories and histories of recent illness. One 3-year-old in center B had congenital CMV infection proven by viral isolation at birth. No children had histories of mononucleosis-like illness, and there was no association between any specific acute illness during the preceding 6 months and CMV excretion at the time of the study. Previous CMV studies have found infection rates for preschool-aged children in the United States to range from approximately 5% to 30% (1). Serologic results revealed that 50%-100% of workers from each day-care center had antibody to CMV, as did 56%-88% of parents (Table 2). These data indicate that CMV infection is common among young children in day-care centers. Reported by C Hutto, MD, RE Ricks, RF Pass, MD, Dept of Pediatrics, University of Alabama School of Medicine, Birmingham; Div of Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: Public awareness that maternal primary CMV infection during pregnancy can result in damaging fetal infections has increased in recent years. Although little is known about how CMV is transmitted in the community, it does not appear to be highly contagious. Acquisition appears to require close or intimate contact with persons who are excreting CMV in their urine, saliva, or other secretions. CMV can also be transmitted via blood transfusions, breast milk, sexual intercourse, and transplanted organs (2-6).

Studies have shown that infants and children acquire CMV infection from other children or from their mothers either in utero, at birth, or during the perinatal period (7,8). Intrauterine CMV infection is the most common of all recognized intrauterine infections, occurring in an estimated 0.4%-2.3% of all live births, and it can have a variable outcome. It may result from either primary maternal infection acquired during pregnancy or from a recurrent infection (reactivation) or reinfection in a seropositive woman (9). Current evidence indicates that most but not all symptomatic congenital CMV infections result from primary infection of the mother. In the United States, 35%-90% of women (depending on race and socioeconomic status) entering their childbearing years are seropositive, and thus, they are not susceptible to primary CMV infection (9).

CMV infection is endemic in the community, and infection in childhood is common and usually asymptomatic. Previously published results from a longitudinal study of children in a day-care center indicate that the majority of children acquired CMV after joining the center and that the estimated cumulative infection rate may reach as high as 80% for children during their second year of life (1). Excretion of CMV has persisted for months to years in most of the children studied at that center, as it does in congenital CMV-infected children. Another study comparing point prevalence rates of CMV excretion in urine and saliva of children attending infant development centers for the developmentally delayed and those in day-care centers demonstrated that urinary excretion occurred in 22% of children in both types of centers (10). Since CMV infection appears to be endemic in the day-care setting, there is very little justification for excluding a child from these settings because the child is known to be excreting CMV (11-13).

Unfortunately, concern over the risk of acquiring CMV infection from children known to have congenital infection has led to placement of unwarranted restrictions in some communities on the participation of these children in public programs, such as day care, schools, and even intervention programs for the developmentally disabled. The risk of exposure from a child with congenital CMV infection is minimal, compared to the unavoidable exposures to the many healthy children in the general population who are unrecognized excretors of CMV. The risk of spread of CMV infection to child-care personnel, particularly women of childbearing age, is not fully known. Until more data are available on occupational infections and the potential risk of exposure to pregnant workers, female employees in their reproductive years should be informed that a significant percentage of infected children may be present in any child-care setting, and that care for any infants and children should include hygienic measures, such as washing hands after each contact with urine and respiratory-tract or other potentially infectious secretions and careful handling and disposal of diapers and other articles known to be contaminated with urine or other secretions (2, 11-14).

Routine serologic testing of pregnant women who take care of children in institutions is not currently indicated because: the extent of risk is not currently established; testing facilities are not readily available; and the significance of antibody titer in a single test is difficult to interpret (2, 12-14). Also, it is not known whether the risk of primary CMV infection would be appreciably reduced by identifying seronegative women and transferring them to areas where there is less contact with infants and children (11,14). Until further data are available, the most practical means by which pregnant women or women planning pregnancy can prevent acquiring CMV is rigorous, good personal hygiene throughout pregnancy, particularly in any setting where frequent, close contact with infants and children occur.


  1. Pass RF, Hutto SC, Reynolds DW, Polhill RB. Increased frequency of cytomegalovirus infection in children in group day care. Pediatrics 1984;74:121-6.

  2. Onorato IM, Morens DM, Martone WJ, Stansfield SK. The epidemiology of cytomegalovirus infections: recommendations for prevention and control. Rev Infect Dis (in press).

  3. Prince AM, Szmuness W, Millian SJ, David DS. A serologic study of cytomegalovirus infections associated with blood transfusions. N Engl J Med 1971;284:1125-31.

  4. Nakervis GA. Cytomegalovirus infections in the blood recipient. Yale J Biol Med 1976;49:13-5.

  5. Dworsky M, Yow M, Stagno S, Pass RF, Alford CA. Cytomegalovirus infection of breast milk and transmission in infancy. Pediatrics 1983;72:295-9.

  6. Ho M, Suwansirikul S, Dowling JN, Youngblood LA, Armstrong JA. The transplanted kidney as a source of cytomegalovirus infection. N Engl J Med 1975;293:1109-12.

  7. Alford CA, Stagno S, Pass RF. Natural history of perinatal cytomegalovirus infections. In: Perinatal infections. The Netherlands: Excerpta Med, 1980:125-47.

  8. Gold E, Nakervis G. Cytomegalovirus. In: Evans AS, ed. Viral infections of humans. New York: Plenum Medical Books, 1982:167-86.

  9. Stagno S, Pass RF, Dworsky ME, Alford CA Jr. Maternal cytomegalovirus infection and perinatal transmission. Clin Obstet Gynecol 1982;25:563-76.

  10. Jones LA, Duke-Duncan PM, Yeager AS. Cytomegalovirus infections in infant-toddler centers: centers for developmental delay versus regular day care. J Infect Dis (in press).

  11. CDC. Day-care center study group. Public health considerations of infectious diseases in day care centers. J Pediatr 1984;105:683-701.

  12. Exposure of women to cytomegalovirus infections in medical and educational facilities. California Morbidity Supplement #7, February 25, 1983.

  13. Pass RF, Kinney JS. Child care workers and children with congenital cytomegalovirus infection. Pediatrics (in press).

  14. Williams WW. Guideline for infection control in hospital personnel. Infection Control 1983;4:326-49.

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