Molecular characterization of influenza A(H1N1)pdm09 virus circulating during the 2009 outbreak in Thua Thien Hue, Vietnam

Authors

  • Le Van An Department of Microbiology, Hue University of Medicine and Pharmacy, Thua Thien Hue, Vietnam
  • Le Thi Bao Chi Department of Microbiology, Hue University of Medicine and Pharmacy, Thua Thien Hue, Vietnam
  • Nguyen Hoang Bach Department of Microbiology, Hue University of Medicine and Pharmacy, Thua Thien Hue, Vietnam
  • Huynh Thi Hai Duong Department of Microbiology, Hue University of Medicine and Pharmacy, Thua Thien Hue, Vietnam
  • Massimo Deligios Department of Biomedical Sciences, University of Sassari, Italy Genomics Laboratory, Porto Conte Ricerche Srl, Tramariglio, Alghero, Italy
  • Alberto Alberti Department of Pathology and Veterinary Clinic, Faculty of Veterinary Medicine, University of Sassari, Sassari, Italy
  • Piero Cappuccinelli Department of Biomedical Sciences, University of Sassari, Sasssari, Italy

DOI:

https://doi.org/10.3855/jidc.2883

Keywords:

A(H1N1)pdm09, genetic characterization, viral isolation, RT-PCR, Thua Thien-Hue

Abstract

Introduction: The influenza A(H1N1)pdm09 virus arrived in Vietnam in May 2009 via the United States and rapidly spread throughout the country. This study provides data on the viral diagnosis and molecular epidemiology of influenza A(H1N1)pdm09 virus isolated in Thua Thien Hue Province, central Vietnam.

Methodology: Nasopharyngeal swabs and throat swabs from 53 clinically infected patients in the peak of the outbreak were processed for viral diagnosis by culture and RT-PCR. Sequencing of entire HA and NA genes of representative isolates and molecular epidemiological analysis were performed.

Results: A total of 32 patients were positive for influenza A virus by virus culture and/or RT-PCR; of these 22 were positive both by viral isolation and RT-PCR, 2 only by virus culture and 8 only by RT-PCR. The novel subtype of influenza A(H1N1)pdm09 was present in 93.4% of the isolates. Phylogenetic analysis of the HA and NA gene sequences showed identities higher than 99.50% in both genes. They were also similar to reference isolates in HA sequences (> 99% identity) and in NA sequences (>98.50% identity). Amino acid sequences predicted for the HA gene were highly identical to reference strains. The NA amino acid substitutions identified did not include the oseltamivir-resistant H275Y substitution.

Conclusion: viral isolation and RT-PCR together were useful for diagnosis of the influenza A(H1N1)pdm09 virus. Variations in HA and NA sequences are similar to those identified in worldwide reference isolates and no drug resistance was found.

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Published

2013-03-14

How to Cite

1.
An LV, Bao Chi LT, Bach NH, Hai Duong HT, Deligios M, Alberti A, Cappuccinelli P (2013) Molecular characterization of influenza A(H1N1)pdm09 virus circulating during the 2009 outbreak in Thua Thien Hue, Vietnam. J Infect Dev Ctries 7:235–242. doi: 10.3855/jidc.2883

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