Submitted to: Journal of Applied Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/27/2011
Publication Date: 8/20/2011
Citation: Cutler, T., Wang, C., Qin, Q., Zhou, F., Warren, K., Ridpath, J.F., Miller, C., Yoon, K.J., Hoff, S.J., Zimmerman, J. 2011. Kinetics of UV254 inactivation of selected viral pathogens in a static system. Journal of Applied Microbiology. 111(2):389-395. Interpretive Summary: Killing, also known as inactivation, of viruses by exposure to ultraviolet (UV) radiation has been an accepted method of disinfection since the 1930s. It has been assumed that all the viruses of the same type in the same sample were equally susceptible to inactivation. In this study, which used 4 different kinds of virus, it was demonstrated that this assumption is incorrect. It was shown that viruses in samples belong to two different groups. One group that is more easily killed with UV and one that is less easily killed with UV. This indicates that protocols for killing viruses with UV must be developed as two-stage protocols. This finding will be used to develop better guidelines for the the prevention and control of these viruses in the environment.
Technical Abstract: The objective of this study was to ascertain baseline inactivation constants for Influenza Type A, PRRSV, BVDV, and Reovirus at varying UV254 dosages. Viruses in culture medium were exposed to 9 different dosages of UV254. Following exposure, the viruses were harvested, stored at -80 C and titrated for infectious virus. UV254 viral inactivation was analyzed and described using the “Standard one-stage inactivation model” and a “Two-stage inactivation curve model” (Kolwaski et. al., 2000). Our results were best described by the “Two-stage inactivation curve” and showed large populations of UV254 susceptible RNA. With the exception of retrospective work of Kowalski et. al.,2000, this is the first time Two-Stage Inactivation model has been used to describe viral UV254 inactivation. This work provides a baseline for future work into the UV254 inactivation of RNA viruses and supports the concept the UV254 inactivation of viruses is dependent upon at least two populations of viruses.