The Swine Health Information Center, in partnership with the American Association of Swine Veterinarians, recently organized a webinar tackling the topic of influenza A viruses. The main objective was to assess the threat posed by highly pathogenic avian influenza H5N1 to domestic livestock species, while also providing guidance to producers on preventive measures for on-farm infection control.
Amy Baker, a research veterinary medical officer at the USDA National Animal Disease Center, commenced the discussion with an in-depth overview of influenza A virus in swine. She explained that influenza A, characterized by a negative strand RNA genome and enveloped structure, is equipped with two major surface glycoproteins: hemagglutinin and neuraminidase. Baker highlighted the virus’s susceptibility to rapid evolution via genetic mutation and reassortment, emphasizing how it circumvents population immunity through antigenic drift and shift. She emphasized the significance of wild waterfowl as natural hosts for influenza, pointing out the potential for cross-species transmission to swine and humans.
Furthermore, Baker shed light on the USDA’s ongoing surveillance efforts for influenza A viruses in swine, which have been operational since 2009. These surveillance activities involve initial PCR screening of viruses identified at veterinary diagnostic laboratories, followed by comprehensive genome sequencing of selected cases meeting specific criteria. The ultimate goal is to monitor the genetic evolution of endemic influenza A viruses in swine populations, facilitate research through the availability of influenza isolates, and enhance diagnostic capabilities for timely intervention strategies.
The surveillance system plays a crucial role in addressing the interface between human and swine influenza A, with human influenza exerting a significant influence on the virus’s diversity in swine through interspecies transmission. By adopting a One Health approach, the surveillance system contributes to our understanding of influenza A hemagglutinin and neuraminidase diversity, both nationally and globally. Baker underscored the collaborative efforts within the influenza community, emphasizing the importance of robust surveillance and disease investigation in improving intervention strategies for animal and public health.
Moving on to the discussion on H5N1, Bailey Arruda, a research veterinary medical officer at the USDA Agricultural Research Service, provided insights into the differences between highly pathogenic avian influenza (HPAI) H5N1 and low pathogenic avian influenza. She emphasized the need to understand the risk posed by HPAI, particularly in light of its potential adaptation to mammalian hosts. Arruda highlighted multiple introductions of HPAI in recent years and the growing concern over its detection in various mammalian species.
Drawing from her research, Arruda underscored the importance of assessing the risk of HPAI incursion into swine populations, particularly in settings where poultry and wild waterfowl coexist with pigs. She emphasized the need for heightened awareness and precautionary measures to mitigate the risk of HPAI transmission to swine, especially in outdoor or multi-species farming environments.
In conclusion, the webinar aimed to equip producers with the latest information on influenza A viruses and provide guidance on preventive measures to safeguard swine health and production. It emphasized the importance of targeted surveillance efforts, biosecurity measures, and collaboration within the industry to effectively manage the threat posed by emerging influenza strains.
