Non-Thermal Plasma Inactivation of Porcine Reproductive and Respiratory Syndrome (PPRS) Virus Aerosols

PRRSv is a virulent, infectious swine disease with high mortality rates. Studies
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have found viable PRRSv aerosols up to 4 kilometers downwind of infected pigs. Consequently, protection against airborne transmission is a priority in the industry. Unlike conventional air filters that only address the transport of infectious aerosols, non-thermal plasmas (NTPs) can address both aerosol transport and aerosol infectivity3 by electrostatically removing larger aerosols and inactivating the remaining smaller aerosols including viral aerosols. Previous laboratory experiments at U niv. of Michigan ultrasonically aerosolized MS2 phage, producing aerosols that were then entrained in the air flow supplied to a packed bed DBD reactor operated between 12 and 30 kV AC (60 Hz). Using virus stocks and wind tunnel facilities provided by the Univ. of Minnesota, the same reactor was tested for effectiveness in inactivating PRRSv. An air-jet atomizer aerosolized solutions containing ~105 TCID50/ml of PRRS VR2332 strain, aerosols that were then entrained in the air flow supplied to the reactor. Twin impingers upstream and downstream of the reactor collected pre- and post-treatment samples followed by TCID50 assay and quantitative polymerase chain reaction (qPCR) analyses. Over the range of voltages applied, results showed that PRRSv was inactivated to an equal or greater degree as MS2 under the same conditions. The results do not suggest any protective effect of the additional lipid layer that surrounds enveloped viruses (such as PRRSv) as compared to nonenveloped viruses (such as MS2). The results also proved MS2 can serve as a conservative surrogate for PRRSv in assessing NTP performance.