Zack Lear
- Nov 3, 2023
- 3 min read

Reducing the Fluency of Swine Influenza

The following steps are potentially useful measures to reduce transmission of influenza viruses between pigs and people in the swine industry!

🛡️ Worker biosecurity 🛡️

Provide clothing and boots for workers that are worn only within the pig housing units, thus eliminating the chance to carry IAV into housing units from external sources. No contact with swine from other sources or with poultry is recommended for at least a 24 hour period before entry, along with a full body shower in between.

🧼 Basic hygiene practices 🧼

Workers should change clothes prior to leaving swine barns for office facilities, food breaks or their homes. In addition, hand-to-face contact should be minimized and hand-washing stations should be available and used prior to leaving each room or area and before returning to office or break rooms. Influenza viruses are spread not just by inhalation of aerosolized virus, but also by eye and nose contact with droplets of respiratory secretions. During outbreaks of ILI in swine, proper use of respirators can mitigate risk of transmission from pigs to workers.

🤒 Sick-leave policies 🤒

To further reduce the chances for infection of pigs with human lineage influenza viruses, the farm owner should provide sick-leave policies for employees that encourage them to remain away from work when they are suffering from acute respiratory infections. People typically shed influenza viruses for approximately 3-7 days, with the period of peak shedding correlated with the time of most severe clinical illness. Influenza-like illness (ILI) is typically defined as fever, cough, congestion, sore throat, and muscle aches. Workers that exhibit ILI after working with ill swine should seek medical care and disclose the swine contact to the medical professionals.

😷 Pursue alternative employment 😷

People with medical conditions that predispose them to severe influenza illness are recommended to avoid contact with swine, whether at public venues or through occupational exposure.

🤢 Influenza virus vaccination of swine farm workers 🤢

The vaccines produced on a yearly basis for the human population contain only human, not swine, strains of influenza viruses. Nonetheless, vaccination of farm workers may reduce the amount of virus shed by infected people during human influenza outbreaks, and thereby limit the potential for human influenza virus infection of their pigs.

🌬️ Ventilation & environmental conditions 🌬️

Ventilation systems in containment production facilities should be designed to minimize re-circulation of air within animal housing rooms. This is important to reduce the exposure of pigs to viruses from other pigs, to reduce their exposure to human influenza viruses, and conversely, to reduce exposure of workers to swine influenza viruses. Stressful environmental conditions or too few air exchantges contribute to reoccurrence of disease outbreaks caused by endemic strains.

🐷 Influenza virus vaccination of pigs 🐷

While the IAV vaccines used in swine today may not induce sterilizing immunity, nor completely eliminate clinical signs of infection, vaccination of pigs can reduce the levels of virus shed by infected animals, and thus reduce the potential for human exposure and zoonotic infections.

🐔 Interspecies transmission among pigs and birds 🐔

The global reservoir of IAVs in waterfowl, the examples of infection of pigs with waterfowl-origin influenza viruses, the risks for reassortment of avian viruses with swine and/or human influenza viruses in pigs, and the risk for transmission of influenza viruses from pigs to domestic poultry (especially turkeys) all indicate that contact between pigs and both wild and domestic fowl should be minimized.