The viral etiology of an influenza-like illness during the 2009 pandemic

Authors

  • S.D. Thiberville,

    1. UMR 190 (Aix-Marseille Univ IRD EHESP), “Emergence des Pathologies Virales,” Marseille, France
    2. Infectious Disease and Tropical Medicine, AP-HM CHU Nord, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • L. Ninove,

    1. UMR 190 (Aix-Marseille Univ IRD EHESP), “Emergence des Pathologies Virales,” Marseille, France
    2. Laboratory of Clinical Microbiology, AP-HM Timone, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • V. Vu. Hai,

    1. Department of Infectious and Tropical Diseases, Viet Tiep Hospital, Nha Thuong Road, Le Chan, Haiphong, Vietnam
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  • E. Botelho-Nevers,

    1. Infectious Disease and Tropical Medicine, AP-HM CHU Nord, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • C. Gazin,

    1. Laboratory of Clinical Microbiology, AP-HM Timone, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • L. Thirion,

    1. UMR 190 (Aix-Marseille Univ IRD EHESP), “Emergence des Pathologies Virales,” Marseille, France
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  • N. Salez,

    1. UMR 190 (Aix-Marseille Univ IRD EHESP), “Emergence des Pathologies Virales,” Marseille, France
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  • X. de Lamballerie,

    1. UMR 190 (Aix-Marseille Univ IRD EHESP), “Emergence des Pathologies Virales,” Marseille, France
    2. Laboratory of Clinical Microbiology, AP-HM Timone, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • R. Charrel,

    Corresponding author
    1. UMR 190 (Aix-Marseille Univ IRD EHESP), “Emergence des Pathologies Virales,” Marseille, France
    2. Laboratory of Clinical Microbiology, AP-HM Timone, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
    • Federation de Microbiologie Clinique, AP-HM Timone, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • P. Brouqui

    1. Infectious Disease and Tropical Medicine, AP-HM CHU Nord, University Hospital Institute for Infectious Disease and Tropical Medicine, Marseille, France
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  • Conflicts of interest: None.

Abstract

Many viruses are known to cause influenza-like illness (ILI); however, in nearly 50% of patients, the etiologic agent remains unknown. The distribution of viruses in patients with ILI was investigated during the 2009 A/H1N1 influenza pandemic (A/H1N1p). From June 2009 to January 2010, 660 patients with suspected influenza were questioned and examined, and nasal swabs were collected. All patient samples were tested for influenza virus, and 286 negative nasal swabs were tested further for 18 other respiratory viruses using real-time RT-PCR. Two waves of ILI were observed in the epidemic curve (weeks 35–42 and 42–49). At least eight viruses co-circulated during this period: human rhinovirus (HRV) (58), parainfluenza 1–4 viruses (PIV) (9), human Coronavirus (hCoV) OC43 (9), enterovirus (5), adenovirus (AdV) (4), and human metapneumovirus (hMPV) (2); however, 204 samples remained negative for all viruses tested. ILI symptoms, according to the Centers for Disease Control and Prevention criteria for ILI definition, were reported in 75% of cases. These patients had positive swabs for A/H1N1p, HRV, hCoV-OC43, PIV, AdV, and hMPV without significant difference with non-ILI patients. This study found that many respiratory viruses circulated during this period and that the A/H1N1p did not impact on the kinetics of other respiratory viruses. The proportion of non-documented cases remains high. ILI could not distinguish A/H1N1p infection from that due to other respiratory viruses. However, in multivariate anlaysis, cough, chills, hyperemia, and dyspnea were associated significantly with influenza virus versus other respiratory viruses. J. Med. Virol. 84: 1071–1079, 2012. © 2012 Wiley Periodicals, Inc.

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