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Research Compliance

Why the need for a quarantine if mice are known to be healthy?

Reader Question: I am collaborating with an investigator at another university who wants to send me some mice that can be bred here at my university. They are free of diseases like my mice here, but I've learned they must go through a six-week quarantine. That will seriously delay our research. Why this quarantine if the mice are healthy?

Expert comments: The majority of rodents used for research are specific pathogen-free (SPF). Unfortunately, there is no written rule as to what the “specific” pathogens are to be, and thus they will vary from institution to institution. Although you understand these new mice to be “free of diseases,” they may not be free of the same diseases as the animals currently housed at your university.

Based on the chosen excluded pathogens, most institutions have an approved vendor and a non-approved vendor list from which investigators can order animals. Animals from the approved vendor are known to be free of all the institution’s excluded pathogens and can typically be ordered directly into the animal facility. But animals from a non-approved vendor either have an unknown health status or a known excluded pathogen and are required to go through a quarantine period.

It is quite common for the non-approved vendor list to include facilities that are composed of predominantly experimental units, such as universities. This is because the risk of introducing micro-organisms into experimental units is greater due to diverse populations of personnel, shared equipment, and, in general, increased movement of animals and people. It is much more challenging to control pathogen exposure and transmission in this setting.

Additionally, transgenic animals from academic institutions are an increased risk because they have the possibility of being immunodeficient due to their genetic manipulation. As such, they may shed a micro-organism longer than other animals or may be persistently infected where other animals would typically clear the infection.

With regard to quarantine, personnel access should be minimized. Some facilities do allow limited access to carry out minimal procedures, such as breeding and/or genotyping. Check with your institution regarding what can and cannot be done while your animals are in quarantine.

While it may seem inconvenient that these new animals must go through quarantine, remember that it is essentially a safety mechanism. The purpose of quarantine is to protect the health of the research animals at your institution, including your existing colony.

Expert comments by Laura Gallaugher, DVM, clinical laboratory-animal veterinarian, University Laboratory Animal Resources, and assistant professor of preventive medicine, The Ohio State University.