It’s normal to have many questions and concerns before switching a facility to environmental health monitoring. Below are answers to the most commonly asked questions our group encounters.
Yes, EHM as a whole is compatible with both static and individually ventilated cage (IVC) systems. However, the specific method of EHM depends on filtration style.
For IVC systems that filter at the rack level (i.e., Allentown Inc., TecniplastTM , Alternative Design), you can perform EHM with “exhaust dust testing” via plenum swabbing and collar-mounted media.
For all systems, you can perform EHM with “sentinel free soiled bedding” (SFSB) by using collection media (e.g., filter paper or swabs) in a cage that holds soiled bedding without the use of sentinel animals.
Although sentinel free soiled bedding (SFSB) is still reliant on soiled bedding transfer to a collection media, scientific evidence demonstrates it is superior at detecting pathogens compared to soiled bedding sentinels. It also is a cost-effective replacement and thereby an essential strategy for implementing the 3Rs of animal research. Finally, it may even help improve compassion fatigue.
For more information view our Overview Page or Publication Page.
Yes. A recent systematic review of environmental health monitoring demonstrates that environmental health monitoring is more effective than soiled bedding sentinels. There have been over 42 publications supporting environmental health monitoring for over a decade. Systematic reviews are considered among the highest levels of evidence. For more information, read the systematic review yourself by clicking here.
Typically not, although it is possible. In most cases, it is less expensive to use environmental health monitoring instead of soiled bedding sentinels (Luchins, 2020). Review our Cost Analysis Resource Page for more information and instructions on calculating cost-savings of switching.
Regardless, cost alone should not prevent replacing live soiled bedding sentinel animals with the non-animal replacement of environmental health monitoring as this method is aligned with the 3Rs of animal research.
The 3RsC has many resources to decrease initial time investment of switching such as our editable SOPs. We also have an EHM mentorship program that can help you reach your goals. Finally, in the long run there is typically time savings once you have switched to environmental health monitoring (Luchins, 2020).
This is a possibility. However it was also a possibility with the use of sentinel animals. Always investigate unexpected results further.
Typically, yes. Our surveys indicate that nearly all institutions will accept rodents from institutions using only environmental health monitoring. In fact, some institutions feel more comfortable accepting rodents from those institutions due to the greater sensitivity of EHM.
Potentially. There may be some for Helicobacter spp. or MNV though may not (Mailhot, 2019). If seen, you may need to wash racks more than once or even scrub plenums to remove residual nucleic acids. This is highly dependent on your sanitation procedures. For guidelines on sanitation best practices, please refer to our sanitation resource page.
Though EHM replaces the need for using animals in routine health monitoring, it does NOT eliminate the need for other diagnostics in the event of a new or emerging pathogen. Sampling from ill animals, either through direct colony sampling (DCS) for survival sample collection (e.g. serology or direct PCR) or terminal sampling (e.g. necropsy and histopathology or blood culture/organ culture) is still the gold standard for detecting new and emerging pathogens. It is best to work in conjunction with the facility veterinarian in the event of unexpected morbidity or deaths that may be due to new or emerging agents.
It depends on the pathogen and situation. Ask your diagnostic laboratory and/or your facility veterinarian what they recommend. They may recommend testing colony animals by cage perimeter swabs, direct fur swabs, blood, or feces to narrow down positive cages. Alternatively, they may suggest pooled plenum swabbing for confirmatory testing.
If you suspect a false positive or residual nucleic acid, move cages to a clean rack and collect follow-up samples in 2-4 weeks.
You may also consider submitting your samples to a different diagnostic lab for confirmatory testing.
There are plenty of areas of EHM that can still be explored, ranging from prevalence of excluded agents needed to detect a positive to ability of EHM to detect new and/or emerging agents. Investigation into the use of EHM in other species (such as wild rodents, rabbits, guinea pigs, aquatics, etc.) can also be an area of promising research for publication. To discuss a potential EHM project with one of the members of the 3RsC team, you can request mentorship on our Call for Research page.
There are some groups that are looking into the possibility of using SFSB in a quarantine setting (as compared to DCS). Thus far the results look promising. Keep your eyes out for publications!
Yes, SFSB is fully compatible with standard quarterly testing frequencies, which allow sufficient time for pathogen accumulation and detection. Some studies indicate that pathogen detection can occur within a week dependent on pathogen involved, but more frequent testing may not significantly enhance results and could increase workload.
While no universal standards exist, common recommendations include:
Exposure duration: Up to 90 days (about 3 months) for optimal pathogen detection.
Bedding agitation: Regular shaking or mixing of bedding during cage changes enhances exposure and improves detection sensitivity.
Institutions should establish detailed protocols and provide staff training to ensure consistency.
Consulting with the diagnostic laboratory is recommended when developing standardized protocols to ensure practices meet current acceptable criteria, templates for SOPs can be found at: https://3rc.org/health-monitoring/sops/
SFSB testing using PCR-based diagnostics has been shown to effectively detect fur mites in rodent colonies in multiple publications. Unlike traditional sentinel-based methods, which rely on mite transmission through bedding (often ineffective), SFSB directly detects mite DNA in the environment. Research supports SFSB’s ability to improve detection rates when paired with PCR analysis. For more information see our systematic review.
Several diagnostic laboratories in the U.S.A offer PCR-based SFSB testing. The below companies are current members of the 3RsC-Environmental Health Monitoring Initiative.