Following H5 Influenza As It Moves Through North American Food Animals
  
Dr. Carol Cardona, DVM, PhD, discussed the evolution and spread of H5 influenza, focusing on its movement through North American food animals. She noted the initial incursion of goose Guangdong H5 in 2014, leading to widespread outbreaks in commercial poultry, which were controlled through mass depopulation. The virus returned in 2021, this time driven by wild waterfowl as primary reservoirs, with poultry now mostly victims rather than sources of transmission.

Cardona highlighted that stamping out poultry, while effective in halting farm-to-farm spread, does not control the virus in wild birds. Over 170 million birds have been depopulated due to outbreaks, including 150 million from wild bird infections and another 20 million related to bovine infections. H5 has expanded into more than 50 mammalian species and continues to adapt to new hosts, including cattle, goats, alpacas, and bears.

Control options for H5 include stamping out, vaccination (which faces economic and export barriers), and biosecurity, though each has limitations due to the virus’s evolving host range. Cardona stressed the lack of surveillance in wild mammals and called for improved prevention strategies. She addressed misconceptions about asymptomatic carriers and pointed to genetic resistance in some animals, although no mechanism is known in chickens. The presentation concluded by emphasizing the unpredictable nature of influenza and the need for adaptable control measures. Health Watch USA^sm Webinar Aug. 29, 2025.   View Presentation Video: https://youtu.be/SALHVe_aAJ4  
 
Health Watch USA^sm Webinar, Combating Infectious Disease Challenges. Have we gone twenty steps forward or backwards?  Aug. 29, 2025  Download Slides
   
Presentations from additional countries can be viewed at:  https://www.healthwatchusa.org/conference2025/index.html