Infantile hepatitis is occasionally seen in apparently healthy children. In most cases, the etiology of the infection is uncertain. However, cytomegalovirus (CMV), Epstein‐Barr virus (EBV), human herpesvirus‐6 (HHV‐6), human herpesvirus‐7 (HHV‐7), human parvovirus B19, and TT virus (TTV) are considered to be associated with hepatitis in children. The objective of this study was to investigate the correlations between these viruses and infantile hepatitis. Twenty‐six children from 1 to 24 months old (median age, 7 months) who had liver dysfunction of unknown etiology were enrolled in this study. Plasma samples were examined by a real‐time PCR assay for CMV, EBV, HHV‐6, HHV‐7, parvovirus B19, and TTV DNA. The DNA of CMV was detected in the plasma of four patients (15.4%) and was detected significantly more often in the patient group than in the control group. The CMV‐infected patients were 1 to 3 months old, which was significantly younger than the remaining patients. The serological findings did not always correlate with the results of the real‐time PCR assay. The DNA of TTV was detected in four patients (15.4%), while human parvovirus B19 DNA was detected in three (11.5%). However, the detection frequencies of these viral DNAs were not significantly different from those in the control groups, and some of these patients had co‐infections. These results indicate that CMV might be one of the major pathogens responsible for infantile hepatitis; however, serological tests have limited utility for the diagnosis of CMV infection in young children.

BackgroundMicrobial colonization of the upper respiratory tract (URT) during the first years of life differs significantly according to environmental factors. We investigated the association between early nursery attendance, URT infection (URTI) and drugs used for its treatment and the differences in the URT microbiota.MethodsThis prospective study included 33 young children (11 and 22 with and without nursery attendance during their infancy, respectively). URT secretions were collected from the nasopharynx of these children at 2, 4, 6, 12, 18 and 24 months old. Clinical information after the latest sampling, including histories of URTI and the uses of antibiotics or cold medicines, was collected from all children. URT bacteria were identified by a clone library analysis of the 16S rRNA gene.ResultsIn the diversity of URT microbiota using the Shannon index, we did not detect any associations between variations in the URT microbiota and environmental factors (nursery attendance, development of URTIs, or the uses of antibiotics or cold medicines). However, in a clustering analysis, the proportion of the samples classified as Corynebacterium propinquum-dominant cluster was significantly lower in children ≥6 months old with nursery attendance than in those without nursery attendance. In addition, the URT microbiota was significantly different between samples from children ≥6 months old with and without a history of ≥3 URTI episodes after the first sampling. Furthermore, the URT microbiota was also significantly different between samples from these children with and without antibiotic use between the previous and present samplings.ConclusionEarly nursery attendance and its related factors, including the frequency of URTI and antibiotic treatment, may be associated with the differences in the URT flora in young children.