Rapid diagnosis of cytomegalovirus infection in infants by electron microscopy

Electron microscopy was applied to the diagnosis of cytomegalovirus infection in infants; we used the pseudoreplica method, which permits detection of herpesvirus particles within 15 to 30 minutes. Viruses were most readily detectable in urines with infectivity titers greater than or equal to 10(4) per milliliter (95 per cent correlation with the tissue-culture method). Virus particles were detected in 18 of 20 urines obtained from symptomatic or asymptomatic, congenitally or postnatally acquired cytomegalovirus infections in infants younger than six months. Viruses were demonstrated in six of 14 infants older than six months, whose urines usually contained greater than 10(4) per milliliter. All five oral specimens examined by electron microscopy were also positive. Viruses were readily detectable in specimens stored or shipped at 4 degrees C for several days, thus permitting physicians anywhere to obtain confirmation of a herpesvirus infection (presumably cytomegalovirus) within one to two days.