Characterization of Influenza A Outbreaks in Minnesota Swine Herds and Measures Taken to Reduce the Risk of Zoonotic Transmission

Amanda L Beaudoin, S. Johnson, Peter R Davies, Jeff B Bender, Marie R Culhane

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Influenza A virus infections commonly cause respiratory disease in swine and can be transmitted between people and pigs, with potentially novel strains introduced into herds and spilling back into the human population. The goals of this study were to characterize influenza infections in Minnesota pigs and assess biosecurity measures used by swine workers. Veterinarians submitting influenza-positive swine samples to the University of Minnesota Veterinary Diagnostic Laboratory between October 2007 and April 2009 were surveyed regarding disease-related information and biosecurity procedures at each farm. Influenza-positive samples were submitted year-round, peaking in spring and fall. H1N1 was the most commonly detected subtype (56%), followed by H3N2 (14%) and H1N2 (12%). Most positive submissions were associated with illness in growing pigs (median age 8.8weeks, IQR 5-15). Median morbidity and mortality were 25% (IQR 10-48) and 2% (IQR 0.5-3.5), respectively. Vaccination of sows and growing pigs was conducted at 71% and 7.9% of the swine farms, respectively. Specialized footwear was reported as the most common form of protective equipment used by workers. Employee vaccination for seasonal influenza was 19%. The sow vaccination rate in this study is consistent with national data, although growing pig vaccination is lower than the national average. Seasonal and age trends identified here may provide diagnostic guidance when growing pigs experience respiratory disease. Inconsistent use of protective equipment and employee vaccination at swine farms indicates the need for further discussion and research of approaches to minimize interspecies influenza transmission on swine farms.

Original languageEnglish (US)
Pages (from-to)96-106
Number of pages11
JournalZoonoses and Public Health
Issue number2
StatePublished - Mar 2012


  • Influenza
  • Surveillance
  • Swine
  • Zoonoses


Dive into the research topics of 'Characterization of Influenza A Outbreaks in Minnesota Swine Herds and Measures Taken to Reduce the Risk of Zoonotic Transmission'. Together they form a unique fingerprint.

Cite this