High Burden of Non-Influenza Viruses in Influenza-Like Illness in the Early Weeks of H1N1v Epidemic in France

BACKGROUND: Influenza-like illness (ILI) may be caused by a variety of pathogens. Clinical observations are of little help to recognise myxovirus infection and implement appropriate prevention measures. The limited use of molecular tools underestimates the role of other common pathogens. OBJECTIVES: During the early weeks of the 2009-2010 flu pandemic, a clinical and virological survey was conducted in adult and paediatric patients with ILI referred to two French University hospitals in Paris and Tours. Aims were to investigate the different pathogens involved in ILI and describe the associated symptoms. METHODS: H1N1v pandemic influenza diagnosis was performed with real time RT-PCR assay. Other viral aetiologies were investigated by the molecular multiplex assay RespiFinder19®. Clinical data were collected prospectively by physicians using a standard questionnaire. RESULTS: From week 35 to 44, endonasal swabs were collected in 413 patients. Overall, 68 samples (16.5%) were positive for H1N1v. In 13 of them, other respiratory pathogens were also detected. Among H1N1v negative samples, 213 (61.9%) were positive for various respiratory agents, 190 in single infections and 23 in mixed infections. The most prevalent viruses in H1N1v negative single infections were rhinovirus (62.6%), followed by parainfluenza viruses (24.2%) and adenovirus (5.3%). 70.6% of H1N1v cases were identified in patients under 40 years and none after 65 years. There was no difference between clinical symptoms observed in patients infected with H1N1v or with other pathogens. CONCLUSION: Our results highlight the high frequency of non-influenza viruses involved in ILI during the pre-epidemic period of a flu alert and the lack of specific clinical signs associated with influenza infections. Rapid diagnostic screening of a large panel of respiratory pathogens may be critical to define and survey the epidemic situation and to provide critical information for patient management

Evaluation du potentiel de chirurgie ambulatoire de l Hôpital Bicêtre (comparaison 2000-2009)

PARIS7-Xavier Bichat (751182101) / SudocSudocFranceF

Association between age and respiratory viral infections.

<p>For each distribution, the horizontal lines represent the 10th, 25th, 50th (median), 75th, and 90th percentiles. Comparison used Wilcoxon's test. H1N1v: H1N1v pandemic influenza virus; PIV: parainfluenza virus; ADV: adenovirus; RHV: rhinovirus.</p

Clinical characteristics of patients with respiratory samples positive for H1N1v, positive for other respiratory pathogens or negative.

<p>*w/: presence of the clinical sign,</p>†<p>w/o: absence of the clinical sign,</p>‡<p>N/A: not available.</p>§<p>These data include the three patients whose respiratory samples could not be studied with the multiplex assay because of RT-PCR inhibitors.</p>∥<p>Comparison between the three groups of patients (with respiratory samples respectively positive for H1N1v, positive for other respiratory pathogens or negative). If p value is significant (<0.05), patients positive for H1N1v are compared with patients positive for other respiratory pathogens ^(¶) and with patients without any detection of respiratory pathogens ^(**).</p>††<p>Significant p values (<0.05) are indicated in bold.</p

Aetiologies of influenza-like illness.

<p>For each pathogen, the number of patients in whom this pathogen was detected (including single and multiple infections) is indicated in italic at top. The different patterns of single and multiple infections (1 line = 1 pattern) are depicted by the presence of plain black rectangles for relevant pathogens. The total of samples for each pattern is indicated in bold at the end of the line. InfA: influenza virus A; InfB: influenza virus B; RHV: rhinovirus; PIV-1 to PIV-4: parainfluenza virus 1 to 4; hMPV: human metapneumovirus; ADV: adenovirus; RSVA and B: respiratory syncytial virus A and B; Cor-229E, Cor-OC43, Cor-NL63: human coronaviruses 229E, OC43 and NL63; CP: <i>Chlamydophila pneumoniae</i>; MP: <i>Mycoplasma pneumoniae</i>; LP: <i>Legionella pneumophila</i>; BP: <i>Bordetella pertussis</i>.</p

Weekly rate of endonasal swabs positive for H1N1v pandemic influenza virus.

<p>Percentage of H1N1v positive endonasal swabs are indicated for each hospital (SLS: open circle, TRS: open square) and for both (plain black triangle and black dotted line). The national weekly rate from data provided by the GROG network is indicated by a grey dotted line and plain grey circles. The epidemic status of H1N1v was proclaimed in France by health authorities during the second week of September (black arrow).</p

Number of endonasal swabs sent to SLS and TRS laboratories for H1N1v detection during weeks 35 through 44.

<p>Number of endonasal swabs sent to SLS and TRS laboratories for H1N1v detection during weeks 35 through 44.</p

Age of patients with respiratory samples positive for H1N1v, positive for other respiratory pathogens or negative.

<p>*These data include the 3 patients whose respiratory samples could not be studied with the multiplex assay because of RT-PCR inhibitors.</p