Diagnosing congenital cytomegalovirus infections using archived dried blood spots: A 15-year observational study, Portugal

Abstract

Cytomegalovirus (CMV) is a leading cause of congenital infections. Dried blood spots (DBS) collected in the first week of life (Guthrie cards) have been used in the diagnosis of CMV infection outside the three-week window period following birth. The present work summarizes the results of a 15-year observational study in which DBS from 1388 children were used for a late diagnosis of congenital CMV infection. Three groups of children were studied: i) symptomatic (with symptoms at birth or late sequelae) (N=779); ii) born to mothers with serological profile of primary CMV infection (N=75); iii) without any information (N=534). A highly sensitive method of DNA extraction (heat-induced) from the DBS was used. CMV DNA was detected by a nested PCR. In total CMV DNA was detected in 7.5% (104/1388) of children. Symptomatic children showed a low rate of CMV DNA detection (6.7%) than children born to mothers with serological profile of primary CMV infection (13.3%) (p=0.034). Sensorial hearing loss and encephalopathy were the two clinical manifestations with the highest CMV detection rate (18.3% and 11.1%, respectively). Children whose mothers had a confirmed primary infection showed a higher rate of CMV detection (35.3%) when compared with children whose mothers had a not confirmed primary infection (6.9%) (p=0.007). The present work emphasises the importance of testing DBS in symptomatic children even a long time after symptoms onset and in children born to mothers with serologic diagnosis of maternal primary CMV infection when they miss the diagnosis during the three-week window following birth.