Biology Reference
In-Depth Information
Congenital Infection
Congenital infection with HCMV is an important cause of cognitive and perceptual
disorders in children in North America and Western Europe (Yow et al. 1988;
Ahlfors et al. 1999, 2001; Stagno and Britt 2006). In the US it is estimated that
between 0.1% and 1% of all live births have an intrauterine infection with HCMV;
however, this number may reflect the results of epidemiological studies in geo-
graphically and in some cases racially restricted populations (Stagno and Britt
2006). Thus, the estimated incidence of this intrauterine infection may not reflect
that of the entire US population. Interestingly, in a limited number of studies from
the developing world, the incidence of congenitally infected newborns varied
between 0.5% and 2.0%, a finding suggesting that intrauterine transmission of this
virus is a frequent event in all populations (Alford and Pass 1981; Stagno et al.
1982b; Sohn et al. 1992; Yamamoto et al. 2001; Stagno and Britt 2006). In fact,
the rate of congenital HCMV infection increases as the prevalence of serological
reactivity to HCMV increases in the maternal population, suggesting that exposure
to this virus represents the most consistent risk factor for delivery of an infected
infant (Fig. 1). This is in contrast to descriptions of the relationship between rates
of maternal seroimmunity and the occurrence of other well-studied intrauterine
infections such as that described for congenital rubella syndrome, an infection that
100
90
80
70
60
50
40
30
20
10
0
0.24
0.4
0.6
1.2
1.4
1.7
2
2.1
2.2
% of live births with congenital HCMV infection
Fig. 1 Incidence of congenital CMV infection increases with maternal seroprevalence. The inci-
dence of congenital HCMV infection and maternal seroprevalence rates from published studies
carried out in North America, Europe, South America, and Africa were plotted as shown. Note
that as rate of maternal seroprevalence increases so does incidence of congenital CMV infection,
suggesting that a threshold level of immune individuals that will eliminate transmission within
these population may not be reached
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