Ingelvac Provenza®: The Importance of Vaccination in Controlling Transmission of Influenza A Virus in Swine (IAV-S)

The Importance of Vaccination in Controlling Transmission of Influenza A Virus in Swine (IAV-S)

Understanding transmission for better control of IAV-S
To properly control IAV-S, we must understand the way in which it is transmitted—both directly and indirectly—and the risks it poses to all swine herds.

Pigs are born free of IAV-S.¹ But on farms where IAV-S is endemic, pigs are exposed to disease early on. As we know, maternal antibodies begin to wane as early as 8 weeks, and often pigs become infected prior to weaning. ^2,3 Here, transmission of IAV-S is direct, via pig-to-pig or droplet transmission route: Pigs infected with IAV-S begin to shed infectious viral particles through nasal secretions as early as 1 day after infection and can continue to shed for 7 days. ^4,5

IAV-S can spread by direct transmission through all production phases

It is important to remember that transmission of IAV-S is not limited to direct nose-to-nose contact. IAV-S may also be spread via airborne viral particles emitted by infected pigs.⁶ A recent study showed that it is possible for these viral particles to travel up to 1 mile downwind of the infected barn, extending the risk of infection beyond a single system.⁷

Reducing transmission within and between systems
The issue of transmission is compounded by the constant movement of pigs. In 2015, it was estimated that approximately 1 million pigs are transported every day, including weaned pigs moving to distant locations and replacement gilts traveling to new gilt development units.^8,9 If any of these pigs are infected with IAV-S, they may transmit disease to other pigs, directly or indirectly-even in the absence of clinical signs.¹⁰

In his presentation at World Pork Expo 2018, Clayton Johnson, DVM, emphasized the ever-present risk of IAV-S: Regardless of origin, the virus pushes its way through the supply chain as pigs are moved, transmitting to and infecting groups downstream.¹¹

So, what can be done to decrease the risk? Implementing healthy habits, such as limiting the movement of young pigs, can reduce the transmission of IAV-S within the herd.⁷ But, as we know, IAV-S is frequently transmitted in other indirect ways:

Transmission via fomites can be reduced by practicing good group-to-group hygiene^12-14
Regional transmission can be limited by appropriately managing new arrivals¹⁵
Aerosol transmission has been shown to be mitigated using air filtration systems¹⁶

Practicing biosecurity measures like these as part of a whole-herd approach (WHA) can help reduce direct and indirect transmission and minimize overall exposure to IAV-S.

Ingelvac Provenza® is proven to reduce shedding and transmission¹⁶
In addition to minimizing exposure, the objective of a WHA is to maximize immunity through vaccination. In fact, studies have shown that transmission of IAV-S can be significantly reduced by vaccination.¹¹ INGELVAC PROVENZA is not only proven to protect pigs against IAV-S infection, but it is also proven to decrease shedding, which reduces transmission in a population.¹⁷ In fact, in a recent study in 3- to 5-day-old pigs vaccinated with INGELVAC PROVENZA and later challenged with a heterologous H1N1, pigs vaccinated with INGELVAC PROVENZA (n=36) had a median of 2 shedding days versus 4 for controls (n=48).¹⁷ Additional heterologous challenge studies of H3N2 AND H1N2 demonstrated similar findings.¹⁷

Learn more about reducing transmission of IAV-S using a WHA that includes vaccination with INGELVAC PROVENZA. Talk to your Boehringer Ingelheim representative or visit IngelvacProvenza.com.

References: 1. Van Reeth K, Brown IH, Olsen CW. Influenza virus. In: Zimmerman JJ, Karriker LA, Ramirez A, et al, eds. Diseases of Swine. 10th ed. West Sussex, UK: Wiley-Blackwell; 2012:557-571. 2. Markowsa-Daniel I. Pomorska-Mòl M, Pejsak Z. The influence of age and maternal antibodies on the postvaccinal response against swine influenza viruses in pigs. Vet Immunol Immunopathol. 2011;142:81-86. 3. Allerson MW, Davies PR, Gramer MR, et al. Infection dynamics of pandemic 2009 H1N1 influenza virus in a two-site swine herd. Transbound Emerg Dis. 2014;61(6):490-499. 4. Brown IH. The epidemiology and evolution of influenza viruses in pigs. Vet Microbiol. 2000;74:29-46. 5. Corzo CA, Morrison RB, Fitzpatrick AM, et al. Risk factors for detecting influenza A virus in growing pigs. J Swine Health Prod. 2014;22(4):176-184. 6. Alonso C, Raynor PC, Goyal S, et al. Assessment of air sampling methods and size distribution of virus-laden aerosols in outbreaks in swine and poultry farms. J Vet Diagn Invest. 2017;29(3):298-304. 7. Corzo CA, Culhane M, Dee S, et al. Airborne detection and qualification of swine influenza a virus in air samples collected inside, outside and downwind from swine barns. PLoS One. 2013;8(8):e71444 8. Chamba Pardo FO, Alba-Casals A, Nerem JO, et al. Influenza herd-level prevalence and seasonality in breed-to-wean pig farms in the midwestern United States. Front Vet Sci. 2017;4:167. 9. Broderson R. President's message: one million pigs on the road every day. American Association of Swine Veterinarians website. https://www.aasv.org/shap/issues/v23n6pm.html. Accessed Jan. 6, 2020. 10. Romagosa A. Allerson M, Gramer M, et al. Vaccination of influenza a virus decreases transmission rates in pigs. Vet Research. 2011;42:120. 11. Johnson C. Business Seminar World Pork Expo, 2018. Des Moines, IA. 12. Rathkjen PH, Dall J. Control and eradication of porcine reproductive and respiratory syndrome virus type 2 using a modified live type 2 vaccine in combination with a load, close, homogenise model: an area elimination study. Acta Vet Scand. 2017;59(1):4. 13. Levis DG, Baker RB. Biosecurity of pigs and farm security. The Board of regents of the University of Nebraska. 2011. 14. Ramirez A. Swine pathogen transmission: recognition, monitoring, and prevention. Graduate Theses and Dissertations. Iowa State University; 2011:12056. 15. Diaz A, Perez, Sreevatsan S, et al. Association between influenza A virus infection and pigs subpopulations in endemically infected breeding herds. PLoS One. 2015;10(6):e0129213. 16. Alonso C, Murtaugh MP, Dee SA, et al. Epidemiological study of air filtration systems for preventing PRRSV infection in large sow herds. Prev Vet Med. 2013;112:109-17. 17. Boehringer Ingelheim Animal Health USA Inc. studies #2017103, 2013200, 2013232, and 2014001 published on http://productdata.aphis.usda.gov.