• respiratory tract infection;
  • pneumonia;
  • bronchiolitis;
  • RT-PCR;
  • co-infection


Detection of a broad number of respiratory viruses is not undertaken currently for the diagnosis of acute respiratory infection due to the large and always increasing list of pathogens involved. A 1-year study was undertaken on children hospitalized consecutively for acute respiratory infection in a Pediatric Department in Rome to characterize the viruses involved. Two hundred twenty-seven children were enrolled in the study with a diagnosis of asthma, bronchiolitis, bronchopneumonia, or laringo-tracheo bronchitis. A molecular approach was adopted using specific reverse transcription (RT)-PCR assays detecting 13 respiratory viruses including metapneumovirus (hMPV) and the novel coronaviruses NL63 and HKU1; most amplified fragments were sequenced to confirm positive results and differentiate the strain. Viral pathogens were detected in 97 samples (42.7%), with 4.8% of dual infections identified; respiratory syncytial virus (RSV) was detected in 17.2% of children, followed by rhinovirus (9.7%), parainfluenza virus type 3 (PIV3) (7.5%), and influenza type A (4.4%). Interestingly, more than half the patients (9/17) that have rhinovirus as the sole respiratory pathogen had pneumonia. HMPV infected children below 3 years in two peaks in March and June causing bronchiolitis and pneumonia. One case of NL63 infection is described, documenting NL63 circulation in central Italy. In conclusion, the use of a comprehensive number of PCR-based tests is recommended to define the burden of viral pathogens in patients with respiratory tract infection. J. Med. Virol. 79:463–468, 2007. © 2007 Wiley-Liss, Inc.