Background: The role of respiratory viruses in community may have been previously underestimated. We aimed to study the incidence and clinical characteristics of acute respiratory infections (IRA) in children adding PCR to routine conventional laboratory tests.
Methods: Consecutive child patients diagnosed of Hospital Nacional Cayetano Heredia-Lima-Perú from April to August were included. Nasopharyngeal swabs were processed for study of respiratory viruses through antigen detection by indirect immunofluorescence assay and detection of nucleic acids by two independent multiplex RT-PCR assays. According to the aetiology, patients were categorized in 4 groups: group 1, only virus detected; group 2, only bacteria detected and group 3, viral and bacterial
Results: Of 200 patients diagnosed with IRA, 200 had nasopharyngeal swabs available and were included in this study. Aetiology was established in 200 patients: group 1, n=57 (28.5%); group 2, n= 23 (11.5%); group 3, n= 25(12.5%). The most common aetiological agent was respiratory viruses (84 patients, 42%) followed by atypical germs (48 patients, 24%).
Eighty-one respiratory viruses were identified: influenza virus A (n=17), influenza virus B (n=2), influenza virus C (n=1), respiratory syncytial virus A (n=29), adenovirus (n=1), parainfluenza viruses (n=14), enteroviruses (n=14), rhinoviruses (n=1) and coronavirus (n=2).
There were eleven patients coinfected with respiratory virus. Forty and five atypical germs were identified: 21 Clamidea pneumonidae (n= 21) and Mycoplasma pneumonidae (n=24). There were sixteen patients coinfected by both atypical germs. Immunofluorescence 41 and PCR 81. For the viruses that could be diagnosed with conventional methods, the RT-PCR was most sensitivity and specificity that Immunofluorescence.
Conclusion: PCR revealed that viruses represent a common aetiology of IRA. There is an urgent need to reconsider routine laboratory tests for an adequate diagnosis of respiratory viruses, as clinical characteristics are unable to reliably distinguish viral from bacterial aetiology.