Molecular epidemiology of cytomegalovirus infection in kindergarten children.

This study was conducted to determine the source of cytomegalovirus (CMV) excretion in children who had persistent viruria. A total of 287 children, ages 3-5 years, enrolled in two kindergartens were followed for 9 months, and 28.8% of 139 CMV-infected children were found to have shed virus persistently in urine for > or = 3 months. A polymerase chain reaction (PCR)-based method provided direct evidence to demonstrate differences in CMV strains shed by 32 persistent shedders selected at random. The glycoprotein B (gB) nucleotide regions of CMV were amplified and analyzed by restriction enzyme digestion. The CMV strains shed by most of these children showed different restriction profiles compared with strains from their playmates. It is considered that persistent reactivation of endogenous CMV is the most plausible explanation.