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.
References
Pass RF, Hutto SC, Reynolds DW, Polhill RB. Increased
frequency
of cytomegalovirus infection in children in group day care.
Pediatrics 1984;74:121-6.
Onorato IM, Morens DM, Martone WJ, Stansfield SK. The
epidemiology of cytomegalovirus infections: recommendations
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Prince AM, Szmuness W, Millian SJ, David DS. A serologic study
of
cytomegalovirus infections associated with blood transfusions.
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Engl J Med 1971;284:1125-31.
Nakervis GA. Cytomegalovirus infections in the blood
recipient.
Yale J Biol Med 1976;49:13-5.
Dworsky M, Yow M, Stagno S, Pass RF, Alford CA.
Cytomegalovirus
infection of breast milk and transmission in infancy.
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1983;72:295-9.
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.
Alford CA, Stagno S, Pass RF. Natural history of perinatal
cytomegalovirus infections. In: Perinatal infections. The
Netherlands: Excerpta Med, 1980:125-47.
Gold E, Nakervis G. Cytomegalovirus. In: Evans AS, ed.
Viral
infections of humans. New York: Plenum Medical Books,
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Stagno S, Pass RF, Dworsky ME, Alford CA Jr. Maternal
cytomegalovirus infection and perinatal transmission. Clin
Obstet
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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).
CDC. Day-care center study group. Public health
considerations
of infectious diseases in day care centers. J Pediatr
1984;105:683-701.
Exposure of women to cytomegalovirus infections in medical and
educational facilities. California Morbidity Supplement #7,
February 25, 1983.
Pass RF, Kinney JS. Child care workers and children with
congenital cytomegalovirus infection. Pediatrics (in press).
Williams WW. Guideline for infection control in hospital
personnel. Infection Control 1983;4:326-49.
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