Congenital and acquired cytomegalovirus infections. Virological and clinical studies on a Swedish infant population.

The study included two clinical materials. First, the frequency of cytomegalovirus and its clinical significance were studied among 661 Swedish children under one year of age admitted to a paediatric hospital. Before the age of one week 4/326 (1%) children excreted virus. At one month the frequency had risen to 6/52 (12%) and after this age the frequency was constant around 20--25%. Sixty per cent of infants born to immigrants were infected after one month of age. One of the four congenitally infected children had symptoms at birth followed by neurological sequelae. The majority of the infections acquired at birth or in early infancy seemed to be subclinical and without sequelae. Second, a retrospective investigation of 18 695 children born during a six-year period was performed. Two cases of virologically confirmed congenital cytomegalic inclusion disease was found. Regarding seven microcephalic patients in the retrospective study congenital CMV-infection could be excluded in four cases. In the remaining three cases the data did not permit any conclusions regarding the etiology.