Dates: 2016 – current
Those working in animal agriculture are at risk of airborne exposure to infectious viruses, such as zoonotic influenza viruses. Conventional wisdom suggests that most transmission of infectious viruses occurs by droplet transmission. However, recent research indicates that at least some viruses can be transmitted by the airborne route. To assess exposures to viral aerosols and manage them effectively, we must know the concentrations and sizes of particles with which infectious airborne viruses are associated. Remarkably, only a few studies have investigated airborne levels of viral RNA as a function of particle diameter, and almost no measurements exist of the sizes of particles that contain infectious viruses. Our prior research indicates that large volumes of air must be sampled for sufficient live virus to be recovered in workplaces for detection and quantification, and that sampling methods (filters, impingers, impactors, cyclones, electrostatic precipitators) have different strengths and weaknesses.
The objectives of the current research are to develop a high-volume, field-portable, size-differentiating viral aerosol sampler and to use it to measure worker exposures to live airborne influenza viruses in animal agriculture facilities. The first step to accomplishing these objectives is to comprehensively evaluate existing sampling approaches. We will test an array of samplers side-by-side to determine the optimal combination of sampler properties for airborne viruses in animal agriculture. Using the results from these comparisons, we will design and build an improved sampler for measuring concentrations, sizes, and infectivity of virus-containing particles. We will utilize computational fluid dynamics to design the sampler. Size-dependent particle sampling efficiency will be established in laboratory tests. We will compare the newly-fabricated improved sampler to existing samplers to verify that the improved sampler recovers live virus more effectively than the others. Finally, we will demonstrate the utility of the new sampler by measuring virus-containing particle concentrations, sizes, and infectivity in animal agriculture facilities. These tests will demonstrate how data from the new sampler will be used to assess and manage risks of airborne virus transmission in animal agriculture workplaces.
Previous publications relevant to this project:
- Alonso C, Raynor PC, Davies PR, and Torremorell M (2015). Concentration, size distribution, and infectivity of airborne particles carrying swine viruses, PLoS ONE, 10:e0135675.
- Appert J, Raynor PC, Abin M, Chander Y, Guarino H, Goyal SM, Zuo Z, Ge S, and Kuehn TH (2012). Influence of suspending liquid, impactor type, and substrate on size-selective sampling of MS2 and adenovirus aerosols. Aerosol Sci Tech 46:249-257.
- Ge S, Kuehn TH, Abin M, Verma H, Bekele A, Kumar S, Goyal SM, Appert J, Raynor PC, and Zuo Z (2014). Airborne virus survivability during long-term sampling using a non-viable Andersen cascade impactor in an environmental chamber, Aerosol Sci Tech, 48:1360-1368.
- Torremorell M, Alonso C, Davies PR, Raynor PC, Patnayak D, Torchetti M, and McCluskey B (2016). Investigation into the airborne dissemination of H5N2 highly pathogenic avian influenza virus during the 2015 spring outbreaks in the Midwestern United States, Avian Diseases, 60:637–643.
- Zuo Z, Kuehn TH, Verma H, Kumar S, Goyal SM, Appert J, Raynor PC, Ge S, and Pui DYH (2013). Association of airborne virus infectivity and survivability with its carrier particle size, Aerosol Sci Tech, 47:373-382.