Transmission dynamics of pandemic influenza A(H1N1)pdm09 virus in humans and swine in backyard farms in Tumbes, Peru

Yeny O. Tinoco, Joel M. Montgomery, Mathew R. Kasper, Martha I. Nelson, Hugo Razuri, Maria C. Guezala, Eduardo Azziz-Baumgartner, Marc Alain Widdowson, John Barnes, Robert H. Gilman, Daniel G. Bausch, Armando E. Gonzalez

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Objectives: We aimed to determine the frequency of pH1N1 transmission between humans and swine on backyard farms in Tumbes, Peru. Design: Two-year serial cross-sectional study comprising four sampling periods: March 2009 (pre-pandemic), October 2009 (peak of the pandemic in Peru), April 2010 (1st post-pandemic period), and October 2011 (2nd post-pandemic period). Sample: Backyard swine serum, tracheal swabs, and lung sample were collected during each sampling period. Main outcome measures: We assessed current and past pH1N1 infection in swine through serological testing, virus culture, and RT-PCR and compared the results with human incidence data from a population-based active surveillance cohort study in Peru. Results: Among 1303 swine sampled, the antibody prevalence to pH1N1 was 0% pre-pandemic, 8% at the peak of the human pandemic (October 2009), and 24% in April 2010 and 1% in October 2011 (post-pandemic sampling periods). Trends in swine seropositivity paralleled those seen in humans in Tumbes. The pH1N1 virus was isolated from three pigs during the peak of the pandemic. Phylogenetic analysis revealed that these viruses likely represent two separate human-to-swine transmission events in backyard farm settings. Conclusions: Our findings suggest that human-to-swine pH1N1 transmission occurred during the pandemic among backyard farms in Peru, emphasizing the importance of interspecies transmission in backyard pig populations. Continued surveillance for influenza viruses in backyard farms is warranted.

Original languageEnglish
Pages (from-to)47-56
Number of pages10
JournalInfluenza and other Respiratory Viruses
Volume10
Issue number1
DOIs
StatePublished - 1 Jan 2016

Bibliographical note

Funding Information:
We thank Hugo Garcia and Ayvar Viterbo from CEP in Peru and Maria Silva, Karen Segovia, and Bruno Ghersi from NAMRU-6, for their valuable assistance. Work performed in this study was supported by funding from the Bill and Melinda Gates Foundation (23981), the Centers for Disease Control and Prevention, the Armed Forces Health Surveillance Center Global Emerging Infections Surveillance and Response System, the NIH/NSF ‘Ecology and Evolution of Infectious Diseases’ award from the Fogarty International Center at the U.S. National Institutes of Health (3R01-TW005869), and a training grant from the Fogarty International Center (D43- TW001140)002E.

Funding Information:
We thank Hugo Garcia and Ayvar Viterbo from CEP in Peru and Maria Silva, Karen Segovia, and Bruno Ghersi from NAMRU-6, for their valuable assistance. Work performed in this study was supported by funding from the Bill and Melinda Gates Foundation (23981), the Centers for Disease Control and Prevention, the Armed Forces Health Surveillance Center Global Emerging Infections Surveillance and Response System, the NIH/NSF ?Ecology and Evolution of Infectious Diseases? award from the Fogarty International Center at the U.S. National Institutes of Health (3R01-TW005869), and a training grant from the Fogarty International Center (D43- TW001140)002E.

Publisher Copyright:
© 2016 John Wiley & Sons Ltd.

Keywords

  • Antibodies
  • Backyard pig farms
  • Human-animal transmission
  • Influenza

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