Diagnosis of congenital cytomegalovirus (cCMV) infection by PCR in dried samples

Background – The ease of collection and handling of neonatal dried blood spots (DBS) can promote their use in the neonatal screening for congenital CMV(cCMV) infection.However the viral load in the blood can be lower than the threshold of some methods of detection.Since urine or saliva of infected babies usually have viral loads higher than those in the blood we compared the results of CMV-DNA detection in neonatal dried samples of urine (DUS), saliva (DSS) and blood in the aim of identifying alternative methods for cCMV diagnosis and screening. Methods - Viral DNA was searched by means of nested PCR (gB gene) in both dried and conventional urine and saliva samples collected from 115 unselected newborns (≤ 14 days).DBS samples were tested to assess the nature of the infection (Binda et al 2003). Results – On a whole fourteen newborns gave positive results in at least one dried sample. DBS test identified four of them as cCMV cases.As to the 111 DBS negative cases DUS positivity was confirmed on liquid samples in one instance and DSS positivity in two.Six babies were DSS positive only. Conclusions – Use of dried samples seems to be a reliable, fast and simple means for diagnosis and screening of cCMV infection.The highest positivity of DSS test can be due to the high sensitivity of the test observed in a preceding validation assay.The role, if any, of remnants of breast milk will be investigated.