Swine Health Ontario - Disease Information Detail

 Disease Information

Animal diseases found in swine vary in virulence, ease of transmission, mode of transmission, and host affinity. Diseases of concern are highly contagious diseases that cause significant morbidity or mortality. Animal diseases of concern are commonly categorized in the following manner.


Swine Influenza Virus (SIV)




  • This illness is known for its rapid onset, and pigs usually show signs within the first 12-48 hours of being infected
  • Symptoms can include fever, eye/nasal discharge, weakness, coughing
  • Pigs of all ages can be affected
  • Transmission occurs via contact with affected pigs or nasal secretions from affected animals (i.e. in contaminated pens etc.); virus may be airborne over short distances
  • Various methods of diagnosis (PCR, fluorescent antibody technique, immunohistochemistry, enzyme immunoassays)
  • SIV has evolved from a seasonal disease to a year-round, endemic respiratory disease


  • The disease is characterized by nearly 100% morbidity but low mortality
  • Recovery typically occurs within 5-7 days
  • Antibodies developed can reduce severity over time in persistent herd infections


  • There are no direct treatments outside of preventing secondary infections with antimicrobials and anti-inflammatories to manage symptoms
  • Vaccination programs for controlling SIV are commonplace
  • Ensure biosecurity protocols are in place and followed at all times
  • SIV typically does not survive more than 2 weeks outside of a host and can be destroyed using disinfectants
  • Depopulation, cleaning and disinfection of affected facilities may be recommended

Risk to Human Health/Food Safety?

  • Although somewhat rare, transmission of influenza virus can occur both from humans to pigs and from pigs to humans
    • Can recombine and transmit to other species when housed together (i.e., when pigs are housed with poultry)
  • Pork products from SIV affected herds are safe to eat

Federally Reportable?


Swine Influenza Virus (SIV)

Additional Resources



Merck Vet Manual - Influenza A in Swine

Last Updated: 3/12/2024 9:46 AM