American Fancy Rat & Mouse Association

This article is from the Spring 2002 AFRMA Rat & Mouse Tales news-magazine.


By Karen Robbins & Carmen Jane Booth, D.V.M.


* Have you brought
in any new rats or
mice in the last 2
months (from a pet
shop, friend,
breeder, school,
out-of-state, or
rescue source)?

* Did they show any
signs of respiratory
disease (sneezing,
wheezing, rattling,
eye/nose discharge)?

* Did you medicate
any of them?

* Have you had any
rats or mice show
any signs of
respiratory disease,
lethargy, diarrhea,
or other problem in
the last 2 months?

* Have you had any
rats or mice die in
the last 2 months?

* If you answered
YES to any of the
above, you need to
quarantine, seek
expert medical
advice, and
medicate your
animals before
going to shows/
events or placing
your animals into
other homes *

Quarantine is a process by which you try to eliminate or minimize the risk of introduction of specific viruses, bacteria, or parasites into an existing colony of animals. In the case of our rodents, quarantine is used before new animals are introduced or when animals have been away for breeding or showing. When done properly, the virus, bacteria, or parasite should remain with the quarantined/ infected animals and not be spread into the resident colony of rodents. When a problem is found in the animals being quarantined, you then have the choice of trying to treat the specific problem or to eliminate the affected animals rather than to place the resident animals at risk.

When bringing in new animals or after a show, it is best to quarantine animals for a minimum of two weeks before reintroducing them to your other animals [Update: we now require a 12-week quarantine period before entering new animals in a show and a 4–12-week after-show quarantine, effective September 15, 2018]. This means you keep them in a separate building that doesn’t have the same air flow as your other animals (e.g., garage, shed, friends’ house, etc.). If you don’t have the facilities to keep them in a separate area, then it is best to keep them in a room at opposite ends of the house from where your other rodents are located. It is important to remember that some disease causing viruses and bacteria are transmitted in the air and by you (clothing, equipment). In either case, they should be cared for after the other animals. Specifically, this includes feeding, watering, cleaning cages, playing with them, etc. You will want to have separate watering containers, cleaning buckets, bedding, and cleaning disinfectants for the animals in quarantine. It is also a good idea to get in the habit of changing your clothes and showering after you care for the quarantined animals and before you take care of your existing colony when returning from a show or other event where you handled or were in contact with other rats or mice.

If during the two-week quarantine period you notice signs of respiratory (i.e., sneezing, rattling/wheezing, eye/nose discharge) or other symptoms (i.e. lethargy, lack of appetite/water consumption, swellings, death, etc.), then you should immediately consult with your veterinarian as to the specific treatment indicated. Depending upon what disease is suspected, then blood and tissue samples may need to be submitted to determine if the problem is viral, bacterial, etc. If an animal dies a few hours before you can get it to the veterinarian for a necropsy (collection of tissues for histopathology), place the animal in the refrigerator rather than the freezer. Freezing the animal will destroy the tissues and make it impossible to get a proper diagnosis. Once you know the results, then you can decide what treatment if any is possible or indicated for your animals. This will also determine the quarantine period (if any) based on the disease.

If any of the quarantined animals become sick or die, then you should immediately put your entire colony in quarantine, especially if you are unable to keep the new/infected animals in a separate location. You have an increased risk of having your entire colony infected by use of the same air space, chance of accidental contamination from handling, or infected bedding or cages being used on the resident animals. The new quarantine period will be determined by what the results are that come back from the veterinarian/pathologist as to what you are dealing with. Severe cases of disease such as Sialodacryoadenitis Virus (SDAV) [see the Nov./Dec. 1993 pg. 2, January– March 1994 pg. 38, January–March 1994 pg. 26, and the April–June 1994 pg. 25 issues for more on SDAV, Ed.] which can kill rats, will require a complete quarantine of your rodent colony for 2 months starting from the date of the last litter born. During the quarantine period for SDAV, there cannot be any new litters born nor entrance or exit of any rodents from the colony if SDAV is to be eliminated completely. Other diseases may just need to have the animals treated with medication for a specified period of time until the symptoms are gone. Unfortunately, for some viruses and bacteria, once the animals are exposed they still carry them but have no clinical signs. Some examples of this are Mycoplasma pulmonis and Mouse Hepatitis Virus (MHV). In the case of SDAV, once the animals have recovered from the virus, they are immune to it.

Also, many times you may be dealing with more than one pathogen in the infected animals and you will need to treat all the different diseases accordingly. There are many viruses that by themselves just show mild symptoms, but when combined with several other viruses and bacteria, you end up with a deadly outbreak and loss of numerous animals. *

Breeders should be testing new stock brought in as some diseases have no symptoms.

Any new animals you bring into your rattery/mousery must go through a minimum 12-week quarantine period before being entered in a show. [Effective September 15, 2018]

Go to Quarantine Form
Go to Quarantining Part 2
Go to Medical - Rodent Diseases Contagious to People

Updated October 11, 2018