Evaluation of Rapid Immunochromatographic Tests for Norovirus in Neonatal and Infant Faecal Specimens

Objectives: To compare the diagnostic performance of two norovirus rapid immunochromatographic kits (QuickNavi(®)-Norovirus [QN] and QuickNavi®-Norovirus 2 [QN2]; Denka Seiken, Niigata, Japan) for neonatal and infant faecal specimens. Methods: Monthly faecal samples were collected from infants from birth to 12 months of age, and tested for norovirus using QN and QN2. Real-time reverse transcription polymerase chain reaction (RT-PCR) was used as the gold standard for norovirus detection. The diagnostic performance of the kits was calculated. Results: A total of 343 specimens from 81 infants were analysed. In all samples, the specificity of QN and QN2 was 80% (275/343) and 99% (339/343), respectively. In infants aged Conclusions: QN2 offers improved performance and is more useful than QN for the diagnosis of norovirus infection in the neonatal and infant period

Increased Eosinophilic Cationic Protein in Nasal Fluid in Hospitalized Wheezy Infants with RSV Infection

Background: Respiratory syncytial virus (RSV) is a major respiratory pathogen which causes bronchiolitis with dyspnea and wheezing in children less than 2 years old. RSV bronchiolitis in infancy severe enough to cause hospitalization might be a risk factor for allergic sensitization and bronchial asthma in future. However, the pathophysiology behind this development has not been clearly characterized. To evaluate the existence of airway inflammation and characteristic of RSV bronchiolitis, we analyzed and compared the concentrations of eosinophilic cationic protein (ECP) in nasal fluid and plasma. Methods: From 69 infants (aged <2 years) hospitalized for possible lower respiratory tract infections including RSV infection, we collected nasal fluid and plasma and determined the ECP concentrations. Results: ECP concentrations in nasal fluid were significantly higher in patients with wheezing and/or bronchial rales than in patients without them (1733 ± 660 ng/mL vs 680 ± 450 ng/mL, p = 0.018), and those of the respiratory syncitial virus-infected group were significantly higher than those of the uninfected group (p = 0.04). Meanwhile, there was no significant difference in plasma ECP levels between patients with wheezing and patients without wheezing, and no significant difference between RSV-infected and other pathogen-infected patients. There were significant correlations between nasal fluid ECP concentrations and both neutrophil and eosinophil counts in the peripheral blood. Conclusions: Nasal fluid ECP concentrations are increased in infants with lower respiratory infections including RSV infection accompanied with wheezing. ECP probably originates from neutrophils as well as eosinophils migrated into airways. The monitoring of ECP concentration in nasal fluid may be useful for evaluating leukocyte (including eosinophils and neutrophils)-mediated airway inflammation during infancy and its severity