Severity of Influenza A(H1N1) Illness and Emergence of D225G Variant, 2013–14 Influenza Season, Florida, USA - Volume 21, Number 4—April 2015 - Emerging Infectious Disease journal - CDC

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Severity of Influenza A(H1N1) Illness and Emergence of D225G Variant, 2013–14 Influenza Season, Florida, USA - Volume 21, Number 4—April 2015 - Emerging Infectious Disease journal - CDC

Volume 21, Number 4—April 2015

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Severity of Influenza A(H1N1) Illness and Emergence of D225G Variant, 2013–14 Influenza Season, Florida, USA

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• The Study
• Conclusions
• Suggested Citation

Figures

• Figure 1
• Figure 2

Tables

• Table

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Nicole M. Iovine , J. Glenn Morris, Kristianna Fredenburg, Kenneth Rand, Hassan Alnuaimat, Gloria Lipori, Joseph Brew, and John A. Lednicky

Author affiliations: University of Florida, Gainesville, Florida, USA (N.M. Iovine, J.G. Morris Jr., K. Fredenburg, K. Rand, H. Alnuaimat, G. Lipori, J.A. Lednicky); Florida Department of Health, Gainesville (J. Brew)

Suggested citation for this article

Abstract

Despite a regional decline in influenza A(H1N1)pdm09 virus infections during 2013–14, cases at a Florida hospital were more severe than those during 2009–10. Examined strains had a hemagglutinin polymorphism associated with enhanced binding to lower respiratory tract receptors. Genetic changes in this virus must be monitored to predict the effect of future pandemic viruses.

In 2009, a novel influenza virus, influenza A(H1N1)pdm09, emerged. The resulting pandemic disproportionately affected persons <65 years of age (1), but illness caused by the virus was similar in severity to that caused by seasonal influenza (2). As the 2013–14 influenza season progressed, physicians at a Florida hospital noted that patients <65 years of age were affected in numbers similar to those seen in 2009–10, but with increased severity. To investigate these observations, we obtained the number of influenza admissions during the 2013–14 season, characterized pathologic findings in deceased patients, sequenced subtype H1N1 viruses, and assessed receptor-specific characteristics.

Dr. Iovine is the hospital epidemiologist at the University of Florida Health in Gainesville, Florida. Her research interests include the epidemiology of novel respiratory viruses and innate defense against multidrug-resistant gram-negative organisms.

Acknowledgments

We thank Gregory Gray and Gary Heil for useful discussions regarding this work.

This work was supported by the University of Florida Emerging Pathogens Institute and UF Health.

References

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Figures

• Figure 1. Proportion of all emergency department visits attributable to influenza-like illness, 2009–10 versus 2013–14 influenza seasons, Florida Department of Health Region 3, Florida, USA. Emergency department visits for influenza-like illness...
• Figure 2. Results of autopsies for patients who died from influenza A(H1N1) virus infection during the 2013–14 influenza season in Florida Department of Health Region 3, Florida, USA. A) Marked intraalveolar...

Table

• Table. Characteristics of 15 patients who died from influenza virus infection, Florida, USA, 2013–14

Suggested citation for this article: Iovine NM, Morris JG Jr, Fredenburg K, Rand K, Alnuaimat H, Lipori G, et al. Increased severity of influenza A(H1N1) virus infection during the 2013–14 influenza season, Florida, USA. Emerg Infect Dis. 2015 Apr [date cited]. http://dx.doi.org/10.3201/eid2104.141375

DOI: 10.3201/eid2104.141375