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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #284944
Title: Outbreak of influenza A (H3N2) in people and pigs at county fairs

Author
item SWENSON, SABRINA - Animal And Plant Health Inspection Service (APHIS)
item KILLIAN, MARY LEA - Animal And Plant Health Inspection Service (APHIS)
item POGRANICHNIY, ROMAN - Purdue University
item STRASSER, JENNIFER - Animal Health Service
item LINDSTROM, STEVE - Centers For Disease Control And Prevention (CDC) - United States
item Kitikoon, Pravina
item HOUSE, JENNIFER - Health & Human Services
item LENZ, STEVE - Purdue University
item KOSTER, LEO - Animal And Plant Health Inspection Service (APHIS)
item MARSH, BRET - Health & Human Services
item Baker, Amy

Submitted to: American Association of Swine Veterinarians Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/8/2012
Publication Date: 3/2/2013
Citation: Swenson, S.L., Killian, M., Pogranichniy, R.N., Strasser, J., Lindstrom, S., Kitikoon, P., House, J., Lenz, S., Koster, L., Marsh, B., Vincent, A.L. 2013. Outbreak of influenza A (H3N2) in people and pigs at county fairs. Proceedings of the 44th American Association of Swine Veterinarians Annual Meeting. p. 417.

Interpretive Summary:

Technical Abstract: On July 11, 2012 a fair veterinarian was requested to examine an ill pig in the show barn. The following day additional pigs were reported as listless, anorexic, and febrile (up to 107F). The Board of Animal Health was notified of the situation on July 12th. Approximately 280 pigs were in attendance at the fair which ran July 8th-14th. Nasal and oropharyngeal samples were randomly collected from 12 pigs dispersed throughout the swine barn. Each pig represented a different herd and was chosen to represent a range of clinical signs. Samples were sent to the State Animal Disease Diagnostic Laboratory (a participating National Animal Health Laboratory Network Laboratory) where they were tested by the matrix rRT-PCR for the presence of influenza A and by the H and N subtyping rRT-PCRs. All 12 were identified as H3N2. Samples were forwarded to the National Veterinary Services Laboratories (NVSL) where rRT-PCR testing determined that 12/12 samples contained the matrix gene from the 2009 pandemic H1N1 influenza virus. Samples with the strongest Ct’s were sequenced using the Ion Torrent whole genomic sequencer. Diagnostic specimens were collected from people reporting influenza-like illness that had been in contact with pigs at the fair. PCR testing at the State Department of Health Laboratory indicated a presumptive influenza A H3N2v. Samples were forwarded to the Centers for Disease Control and Prevention (CDC) for analysis. Sequence was obtained directly from the clinical specimens. Comparison of the sequence obtained by NVSL on the pig samples and CDC on the human specimens indicated virtually identical sequence, demonstrating virus transmission between people and pigs. Samples collected from sick pigs at additional fairs in which human illness has been reported is underway. Influenza H3N2 viruses with the pandemic matrix have been found in pigs in multiple states based on swine influenza surveillance testing by State veterinary diagnostic laboratories. Swine influenza is endemic in pig populations throughout the world. Transmission of influenza virus has been documented to occur from pigs to people and vice versa. This report demonstrates the importance of influenza surveillance in livestock and people and the need for strong ties between public health and animal agriculture at the local and Federal levels.