A Cross-sectional Survey on Rodent Environmental Health Monitoring Practices: Benchmarking, Associations, and Barriers.

Tens of thousands of rodents are used each year in Rodent Health Monitoring programs. However, Environment Health Monitoring (EHM) could replace sentinel rodent use while maintaining or even improving diagnostic quality. Despite its advantages, widespread implementation of EHM appears to be relatively low. To better understand EHM's prevalence and factors influencing its use, we surveyed research animal professionals. Our hypotheses were (1) EHM prevalence would be low and (2) EHM use would be associated with beliefs and knowledge about EHM. Participants were recruited via online promotion. A total of 158 individuals completed a mixed-methods survey about current practices, beliefs, and knowledge about EHM. Qualitative data were coded using thematic analysis and analyzed using generalized linear models. Results showed that current EHM implementation was low; only 11% of institutions used EHM exclusively. Across the 111 institutions surveyed, over 20,000 soiled bedding sentinels were used each year. However, most participants believed EHM to be advantageous in replacing sentinel animals (78% of participants). Some participants believed EHM could save time (31%), cost less (27%), and be highly accurate (15%). Conversely, some participants believed EHM would be difficult to use due to their current caging type (40%), higher costs (21%), lower accuracy (16%), and personnel attitudes/expertise (14%). Overall, respondents with higher planned EHM use also had more positive attitudes, norms, and control of EHM. We also identified several factors that could promote the implementation of EHM. Communication efforts should emphasize that EHM is compatible with various types of caging, can provide cost savings, has high accuracy, and is consistent with the 3Rs as a replacement. Efforts should also focus on improving attitudes, encouraging peers, and providing resources to facilitate implementation. Implementation in just the surveyed institutions could eliminate the need for well over 20,000 rodents each year, consistent with 3Rs goals.

PCR Testing of Media Placed in Soiled Bedding as a Method for Mouse Colony Health Surveillance.

Rodent colony health surveillance has traditionally been accomplished by testing sentinel animals that have been exposed to soiled bedding from colony animals. Collecting samples from exhaust plenums on ventilated caging systems, followed by PCR analysis, has emerged as another promising method for health surveillance. However, environmental testing at the rack level is not effective for all ventilated rack designs. In this study, we tested whether media placed in soiled bedding is effective in detecting 3 adventitious agents: mouse norovirus (MNV), Helicobacter spp., and fur mites. Soiled bedding was collected from pathogen-positive colony mice and distributed to traditional sentinel mouse cages and mouse-free experimental cages every 1 to 2 wk for static and ventilated cages, respectively. Experimental cages contained 10 flocked swabs ('passive swabs') and 1 piece of filter media. After 90 d, fresh feces, pelage swabs, and blood were collected from the sentinel cages, and the passive swabs and filter media were collected from the experimental cages. Concurrently, 10 additional flocked swabs ('active swabs') were stirred through the cumulated soiled bedding of each experimental cage. Sentinel mice were positive for MNV and Helicobacter spp., but negative for fur mites by pelage swab PCR. All samples from experimental cages were positive for Helicobacter spp. and fur mites in both caging types. For MNV, passive swabs were most effective at detection (100%), followed by active swabs (80% to 100%) and filter media (60% to 80%). These findings suggest that testing media in pooled soiled bedding samples is more effective than traditional sentinel methods for colony health surveillance and is a viable option when sampling at the rack level is ineffective.