Nucleic acid detection and quantitative analysis of influenza virus
using exhaled breath condensate
Abstract
Background: Influenza is a common respiratory infectious disease that
can be transmitted by respiratory droplets from person to person. There
were few researches on influenza virus in exhaled breath. This study
aimed to investigate the detection of influenza virus in exhaled breath
condensate (EBC) and conduct quantitative analysis to evaluate the
existence and content of influenza virus in breath. Methods: We
recruited 30 patients with respiratory tract infection in the 2019
influenza season. The clinical data and samples of nasal swabs were
collected and rapid influenza diagnostic (antigen) tests (RIDTs) and EBC
influenza virus nucleic acid detection were performed. Each sample was
assessed thrice for qualitative and quantitative analysis. The patients
were followed up after one month, and the EBC was assessed again.
Results: The 30 cases were assessed for the presence of influenza virus
nucleic acid in each EBC sample three times. The results showed that
seven cases were positive for influenza A/ three times, seven cases were
positive for influenza A twice, seven cases were positive for influenza
A once, two cases were positive for influenza B once, and seven cases
were negative for all three times. Furthermore, quantitative analysis
showed that the influenza viral load in the EBC ranged from 103 to 107
copy/ml. Conclusion: The influenza virus can be detected using EBC and
the concentration can be calculated. Thus, EBC can be used for molecular
diagnosis of influenza.