This recent article published in Nature Scientific reports by the Torremorell lab describes the size of particles shedding by pigs experimentally infected by H1N1 influenza A virus, as well as their associated viral load.
Methods
- 24 influenza-naive nursery pigs were enrolled in this study.
- 4 replicates of the study were conducted, each with 6 pigs.
- 4 out of the 6 pigs were inoculated with H1N1 influenza A virus intranasally.
- 2 inoculated pigs were placed in isolator 1, 2 inoculated pigs were in isolator 2 and the 2 naive pigs were in isolator 3.
- Each of the isolators were connected by a pipe only allowing air to flow in one direction: from isolator 1 to isolator 2 and then to isolator 3.
- Nasal swabs were collected from each pig daily.
- Air samples were collected twice a day from isolator 2.
Results
- Particle size ranges from <0.22 μm to >8 μm.
- The highest viral load was measured at day 2 post inoculation with influenza A virus.
Abstract
Airborne influenza infections cause significant disease in animals and people. However, there is limited information on the dynamics of viral emissions and size distribution of airborne virus-laden particles generated by infected animals. In this study, we used pigs as a model for the airborne transmission of influenza A virus (IAV) and we quantified nasal shedding, viral RNA load of airborne particles emitted from pigs experimentally infected with a swine-origin H1N1 IAV, and characterized the size distribution of the virus-laden particles generated from infected pigs over the course of infection. We found that the peak of nasal shedding and airborne IAV-laden particles across multiple size ranges took place at 2 days post inoculation (DPI), with higher viral RNA load found in larger particles. The amount of airborne IAV emitted by infected pigs over the course of infection in particles > 8 μm was significantly higher than that in particles between 0.22 and 1.7 μm. These findings help understand the risk of airborne transmission of IAV in pigs and provide information to help control airborne infections more effectively.