In 2005, the American Association of Swine Veterinarians declared the big hairy audatious goal of achieving North American PRRS Eradication by 2025. Some 15 years later we have made some significant progress on PRRS control but elimination has been thus far elusive for a number of reasons. Other countries have declared similar goals. In 2014, the Pig Strategy of the Government of Hungary prioritized the eradication of PRRSV. A National PRRS Eradication Program was introduced in order to reach a more efficient, economical and competitive international market position. In 2015, 188 out of 307 large-scale fattening farms (61.2%) kept PRRS-positive animals. The main source of infection of these farms was the import of PRRS-infected fattening pigs.
The following methods were used during the eradication of PRRS from Hungarian finishers from 2017:
- Only pigs coming from PRRS-free farms were allowed to be used for fattening in Hungary
- Quarantine of all herds for 60 days
- PCR test for PRRS 48 hours after the arrival of the prefattening animals
- Serological test for PRRS at the end of the quarantine period. If any diagnostic test gave even one positive result and the result was confirmed by another test, the stock had to be sold for slaughter within 15 days or placed outside Hungary, so that the infected stock would not compromise the PRRS status of that area.
PRRSV eradication on large-scale fattening units applying all-in/all-out operation was relatively simple, using the depopulation-repopulation method. On permanently operating farms, the infected herd was sold from time to time, without having to be repopulated until the last delivery. After cleaning, disinfection and restocking, the repopulation was done with PRRS-free animals. As the eradication progressed over the years, a ban on the import of infected fattening pigs was imposed.
Although its significance has decreased in recent decades, 20% of the Hungarian pig population is still kept on small-scale (backyard) farms (< 100 animals). The prevalence of PRRSV in backyard farms was 3.9% at the beginning of the program.
The following methods were used during the eradication of PRRS from back yard farms :
- During all the phases of the program , serological testing of the breeding animals of the registered small-scale herds was performed, including the highest number of individual animals.
- Seropositive individuals were tested by PCR and were removed from the backyard farm within the framework of official measures.
- By sequencing the identified PRRS strains, the possible epidemic relationships between small-scale and large-scale farms were continuously monitored.
Take Home Messages:
- By the end of 2018, Hungarian large-scale fattening farms were free of PRRS.
- By the end of 2015, PRRS-free status of the small-scale herds was achieved and this status was maintained in 2016-2018.
- PRRS Elimination on a regional basis is possible and this is especially true when the goal of elimination becomes a government policy with regulatory support of that policy.
Ref: Szabó I, Molnár T, Nemes I, Abonyi T, Terjék Z, Bálint Á. PRRSV eradication on large-scale fattening pig farms in Hungary between 2014 and 2019. Acta Vet Hung. 2019 Dec;67(4):529-542. doi: 10.1556/004.2019.052.
Nemes I, Molnár T, Abonyi T, Terjék Z, Bálint Á, Szabó I. Eradication of PRRS from backyard swine herds in Hungary between 2012 and 2018. Acta Vet Hung. 2019 Dec;67(4):543-552. doi: 10.1556/004.2019.053.