Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #389943

Research Project: Intervention Strategies to Control Endemic and New and Emerging Influenza A Virus Infections in Swine

Location: Virus and Prion Research

Title: Overview of recent USDA surveillance data

item Baker, Amy
item Anderson, Tavis
item ARENDSEE, ZEBULUN - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: American Association of Swine Veterinarians Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 2/26/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Swine influenza is an acute respiratory disease caused by influenza A virus (IAV) of the Orthomyxovirus family. IAV impacts the health and welfare of pigs and results in significant economic losses for the swine industry worldwide. IAV possess a single stranded RNA genome with eight gene segments. The segmented genome allows for reassortment when a host is infected with more than one strain, and this mixing of gene segments is a major contributor to the diversity of IAV in swine. The IAV polymerase is error prone, and mutation followed by selection is another driver of increases in genetic diversity. IAV are shared between pigs and people, with human seasonal IAV introductions into swine dramatically increasing the genetic diversity maintained in pig populations. Swine adapted IAV also cause zoonotic infections in humans, known as variants, and caused the first global pandemic of the twenty-first century. Zoonotic IAV ranked the number one priority during a One Health workshop for disease prioritization in the USA (, with swine being one of the animal hosts posing the greatest risk for zoonotic IAV. In 2009, USDA-APHIS Veterinary Services initiated a surveillance system with the goal of characterizing the genetic diversity of swine IAV in the USA. The vast majority of circulating IAV subtypes in swine are H1N1, H1N2, and H3N2, with rare H3N1 detections. However, tremendous diversity exists within the hemagglutinin (HA) and neuraminidase (NA) genes, and requires phylogenetic characterization into lineages and clades. We summarized and visualized the current trends in the USDA IAV-S surveillance data to provide input to evaluate national and regional virus evolution and epidemiologic patterns in swine and information for zoonotic events for public health.