Submitted to: Pesquisa Veterinaria Brasileira
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2011
Publication Date: 9/1/2011
Citation: Schaefer, R., Zanella, J.R.C., Brentano, L., Vincent, A.L., Ritterbusch, G.A., Silveira, S., Caron, L., Mores, N. 2011. Isolation and characterization of pandemic H1N1 influenza viruses in pigs in Brazil. Pesquisa Veterinaria Brasileira. 31(9):761-767. Interpretive Summary: Influenza A virus typically causes a mild respiratory disease in pigs but is also a component of the multiple pathogen porcine respiratory disease complex in young pigs. When multiple pathogens simultaneously infect pigs, a more severe disease can occur. It is important to know the prevalence of the various pathogens circulating among swine in modern production systems in order to provide optimal herd health vaccination recommendations. Here we report the introduction and detection of the 2009 A/H1N1 pandemic virus in a swine research herd in Santa Catarina State, Brazil. Typical of this virus in pigs, a mild respiratory disease was observed in growing pigs with no mortality. Sequence analyses of the virus gene segments revealed that the virus was consistent with the 2009 A/H1N1 influenza pandemic virus strain that circulated in humans. Our previous studies with swine sera collected before and after 2009, did not detect the presence of antibodies against the pandemic influenza virus (H1N1) in pigs in Brazil before 2009. Therefore, this is the first report of an outbreak of the 2009 A/H1N1 influenza pandemic virus in pigs in Brazil. This report is entirely consistent with what occurred elsewhere in pig herds around the world that became infected with this virus after it circulated amongst the human population during the past 2 years.
Technical Abstract: Influenza A virus (IAV) infections are endemic diseases in pork producing countries around the world. The emergence of the pandemic 2009 human H1N1 influenza A virus (pH1N1) raised questions about the occurrence of this virus in Brazilian swine populations. During a 2009-2010 swine influenza virus research project at Embrapa Swine and Poultry, an outbreak of a highly transmissible H1N1 influenza A virus was detected in a pig herd in Santa Catarina State, Brazil. This virus caused a mild disease in growing pigs with no mortality. Sequence analyses of HA, M and NA genes revealed that the virus was consistent with the pandemic (A/H1N1) 2009 influenza virus strain that circulated in humans. This is the first report of an outbreak of pandemic A/H1N1 influenza virus in pigs in Brazil.