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Updated: Oct 2, 2026
High-throughput Detection Method for Influenza Virus
Published on: February 4, 2012
Pathogenic analysis of the pandemic 2009 H1N1 influenza A viruses in ferrets
Yoshimi Tsuda1,2, Carla Weisend1, Cynthia Martellaro1
1Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, U.S.A.
Abstract:
The pandemic 2009 H1N1 influenza A virus emerged in humans and caused the first influenza pandemic of the 21st century. Mexican isolates, A/Mexico/4108/2009 (H1N1) (Mex4108) and A/Mexico/InDRE4478/2009 (H1N1) (Mex4487) derived from a mild case and from a cluster of severe cases, showed heterogeneity in virulence in a cynomolgus macaque model. To compare the more pathogenic differences, we generated recombinant viruses and compared their virulence in ferrets. Ferrets infected with recombinant Mex4487 displayed a slightly higher rate of viral replication and severe pneumonia in the early stage of infection. In contrast, prolonged lower virus shedding of recombinant Mex4108 than that of recombinant Mex4487 was detected in throat swabs. Thus, Mex4487 induces severe pneumonia in infected individuals, whereas Mex4108 might have wide-spreading potential with mild disease.
Insights
The 2009 H1N1 influenza virus showed varied virulence. Recombinant Mex4487 caused severe pneumonia, while Mex4108 exhibited prolonged shedding, suggesting wider spread potential with milder disease.
Area of Science:
- Virology
- Infectious Diseases
- Epidemiology
Background:
- The 2009 H1N1 influenza A virus pandemic highlighted the emergence of novel influenza strains.
- Virulence heterogeneity was observed in Mexican H1N1 isolates (Mex4108 and Mex4487) from mild and severe cases, respectively.
Purpose of the Study:
- To compare the pathogenic differences between two distinct 2009 H1N1 influenza A virus isolates.
- To characterize the virulence and transmission potential of recombinant Mex4108 and Mex4487 viruses.
Main Methods:
- Generation of recombinant viruses from Mex4108 and Mex4487 isolates.
- Virulence assessment in a ferret model, including viral replication, shedding, and pneumonia severity.
Main Results:
- Recombinant Mex4487 induced higher viral replication and severe pneumonia in ferrets during early infection.
- Recombinant Mex4108 showed prolonged, lower-level virus shedding in throat swabs compared to Mex4487.
- Mex4487 was associated with severe pneumonia, while Mex4108 suggested potential for wider spread with milder symptoms.
Conclusions:
- The study elucidates distinct pathogenic profiles of 2009 H1N1 influenza A virus isolates.
- Mex4487 is linked to severe pneumonia, whereas Mex4108 may possess greater transmissibility with less severe disease.
- Understanding these differences is crucial for pandemic preparedness and response strategies.
