Effect of Far-ultraviolet C irradiation on infection risk by airborne porcine reproductive and respiratory syndrome virus 1

Porcine reproductive and respiratory syndrome virus (PRRSV) is a significant porcine pathogen as it impairs reproduction and is a part of the porcine respiratory disease complex in pigs. PRRSV transmits through direct-contact but may also be transmitted over longer distances. Far-ultraviolet C (Far-UVC) radiation inactivates airborne microbes, including viruses, without causing harm to humans or animals. In this pilot study, several experiments were performed to establish an experimental model for airborne PRRSV-1 infection in pigs, and to assess the ability of Far-UVC radiation to reduce PRRSV-1 infections in pigs. In total, 48 pigs were exposed to varying doses of mesh-nebulized PRRSV-1 in different experimental setups. PRRSV-1 viremia was evaluated, and environmental contamination as well as air samples were assessed to investigate the presence of PRRSV-1 RNA. In the final setup of three replicate case-control trials, none of the case-pigs became infected with PRRSV-1, whereas two, one and zero of the controls were infected. These results indicate that Far-UVC exposure can reduce infection of airborne PRRSV-1 in an experimental inoculation model. The infection model does not consistently infect pigs - even with the highest dose of PRRSV-1, but mimics natural settings well, and therefore studies with similar setups are needed to confirm the ability of Far-UVC to reduce infection risk. This experimental setup, albeit it is not perfect, can also be used to investigate the potential effect on Far-UVC to prevent infection of other airborne viruses.