Multicity Italian study of congenital cytomegalovirus infection.

Background: Cytomegalovirus (CMV) infection is the most frequent congenital infection in humans. Its prevalence and the frequency of disabling sequelae must be assessed in different populations to permit the formulation or assessment of preventive measures.

Objectives: To check the prevalence of congenital infection and seroprevalence in Italy; to verify the rate of sensorineural hearing loss (SNHL) in infected infants; and to assess the proportion of children with SNHL attributable to congenital CMV infection.

Methods: Diagnosis of congenital CMV infection was sought in 9032 children born between March 2002 and February 2003 by testing for viral DNA [CMV dried blood spot (DBS) test] in each newborn's Guthrie card and confirmation by isolation of CMV from urine collected in the first 3 weeks of life; CMV IgG testing in 1200 women of childbearing age; clinical and audiologic tests in the first 24 months for infected children; CMV DBS tests on the Guthrie cards collected from screening centers for 77 children (3 months-5 years) presenting SNHL of 40 dB or more.

Results: CMV infection was diagnosed in 14 asymptomatic and 2 symptomatic newborns (0.18%). CMV seroprevalence was 80%. In 2 infected infants, transient, unilateral SNHL was found. Nineteen of the 71 children with SNHL >70 dB were congenitally infected.

Conclusions: The prevalence of congenital CMV infection is low in Italy. Population characteristics limiting the circulation of CMV strains in adult women might explain this. The fact that CMV contributes to significant SNHL highlights the need for preventive measures.