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.


Porcine Reproductive and Respiratory Syndrome virus (PRRSv)



The Porcine Reproductive and Respiratory Syndrome virus (PRRSv) is present in most swine-producing countries and is the viral infection with the highest economic impact of any porcine disease in North America and many European countries.


  • PRRSv causes reproductive problems (abortions, mummified piglets) and affects the respiratory system (pneumonia, susceptibility to concurrent viral infections)
    • Can also contribute to susceptibility to concurrent infections
    • Symptoms can range from reduced appetite and fever to death
  • PRRSv is highly infectious and is easily spread following direct contact of uninfected animals with infected animals and/or their excretions (blood, saliva, feces, urine, semen, mammary secretions, nasal secretions) and poor biosecurity
    • Airborne spread has also been documented
    • Virus can be transferred from sow to litter in utero
    • Carrier animals with no symptoms can be a risk for persistence within a herd (shedding in groups can occur up to 100 days after infection)
  • PRRSv can be detected in saliva, urine, milk, colostrum, processing fluids and feces and is diagnosed using serology or PCR testing


  • Stillbirths/mummies can increase by 25% or more, abortions by 10% or more, pre-weaning mortality by 30% or more and weaned pig mortality by 10% or more


  • PRRSv is most commonly controlled by vaccine use in breeding and finishing units, which help to control and reduce virus shedding, to initiate exposure, build/homogenize immunity in a population and/or create immune memory in at risk populations
    • Full depopulation of barns followed by cleaning and disinfection may be required for eradication of some strains
  • No effective treatments; cleaning and disinfection is essential
  • Depopulation, of affected facilities may be recommended depending on severity

Risk to Human Health/Food Safety?

  • PRRSv is only infectious to swine and poses no threat to humans
  • Pork products from PRRSv affected herds are safe to eat

Federally Reportable?


PRRSv is monitored by SHO under the Swine Health Area Regional Control (SHARC) program. All producers should enroll in the program to facilitate traceability of PRRSv in Ontario. Visit www.swinehealtharc.ca for more information.

Porcine Reproductive and Respiratory Syndrome virus (PRRSv)

Additional Resources





Last Updated: 3/12/2024 9:40 AM