Abstract
Introduction: Respiratory viruses are recognised for their ability to cause flu like symptoms and as exacerbators of pre-existing respiratory disease. However the possible ability of viruses to exist symbiotically within the lung has not yet been explored.
Aim: To determine the incidence of asymptomatic viral carriage in clinically stable patients undergoing bronchoscopy
Methods: Asymptomatic patients (no recent or current viral symptoms) undergoing bronchoscopy were recruited. Exhaled breath (three forced expiratory maneuvers via a spirometry filter) and 10mL bronchoalveolar lavage (BAL) were collected. A panel of respiratory viruses (Rhinovirus (RV), Respiratory Syncytial Virus, Influenza A, Influenza B, Parainfluenza Virus 1, 2, 3 and Human Metapneumovirus) was assayed for using a sensitive RT-PCR in each matched sample. Virus detection was classified as positive following visualisation of weak or strong band.
Results: Fifty bronchoscopies have been performed (50 BAL, 50 exhaled breath samples). Twenty-eight paired samples have been fully analysed by RT-PCR. Forty six percent (13 of 28) had a detectable virus in either their exhaled breath (4) or BAL sample (4), or both samples (5) as determined by a discernible band appearing on the agarose gel. 21% had strongly positive detection. RV was the most commonly detected virus (13/13). One patient had 2 viruses detectable concurrently (RV and Influenza B) in both exhaled and BAL samples.
Conclusion: This preliminary analysis suggests that asymptomatic carriage of viruses may be more common that previously recognised and that respiratory viruses likely contribute to the microbiome of the lung. Appropriate assay limits need to be established for clinically relevant results.
- Copyright ©the authors 2016
