IVC - External Validation of Exhaust Air Dust Testing by Comparison With Traditional Soiled Bedding Sentinels

For the past 2 years, routinely monitoring rodent pathogenic agents using soiled bedding sentinels has been conducted at our newly constructed animal facility. Recently, we have started systematically validating alternative methods for our modern caging systems (both rat and mouse) using index animals as well as filters for catching the exhaust air dust (EAD) from the Individually Ventilated Cage (IVC) system. We have tested multiple sampling locations for racks connected to different blower models and have run rat and mouse pathogen panels to compare with results from serology, microbiological cultures, gross necropsy and index animal direct sampling PCR. Adding direct animal testing in addition, was shown to increase the sensitivity for certain pathogens (ex: Helicobacter spp.). EAD testing was performed at 3 month intervals and we identified MNV, Helicobacter spp., Pasteurella spp., Entamoeba muris and fur mites which were not detected consistently in our soiled bedding sentinels. We found the design of the IVC exhaust blower/filter holder may impact the sensitivity of EAD sampling. The outcome of this study will allow us to implement a more sensitive environmental health monitoring program to limit the need of sentinel testing. Furthermore, our findings will externally validate this method for other facilities with similar IVC caging systems