Associations between the presence of Cytomegalovirus and wheezing infants with lower respiratory tract infection: an observational study

BACKGROUND: The aim of this study is to investigate the significance of various types of specimens for detection CMV in infants with lower respiratory tract (LRT) infection, to explore the easiest and most efficient specimens and tests reflecting CMV related infant lower respiratory tract infections, to study the role of CMV in infants with lower respiratory tract infection and wheezing, and to discuss the relationship between various indicators of recent active CMV infection.METHODS: A total of 166 infants younger than 24 months with a confirmed lower respiratory tract infection were included in this study, including 104 infants with wheezing and 62 without. All hospitalized patients were tested for CMV-DNA in sputum, saliva, plasma and urine, as well as CMV-IgG and CMV-IgM in serum.RESULTS: The positive rate of sputum in the wheezing group was significantly higher than that in the non-wheezing group (P=0.003). However, the detection of CMV in other specimens could not yield the same result (P>0.05). When excluded all infants who had RSV infection, and compared only two groups (CMV-RSV- and CMV+RSV-), the incidence of wheezing was still significantly increased when only CMV was detected in sputum. The detection of both CMV and RSV in sputum of lower respiratory tract infection infants did not result in a higher incidence of wheezing than the detection of CMV alone. The positive rates of plasma CMV-DNA and serum CMV-IgM were significantly different, and the two were not consistent (P=0.033).CONCLUSIONS: If an infant with wheezing from a lower respiratory tract infection is highly suspected to be associated with CMV, using PCR to detect CMV-DNA in sputum may be the simplest and most effective method. This study showed that CMV may be a factor leading to lower respiratory tract infection with wheezing in infants, and it is independent of RSV.