The term quarantine means: to separate and isolate to prevent the spread of disease. This includes bacterial infections, viruses, funguses, and parasites (both internal and external).

Quarantining at a separate mouse/rat-free location and maintaining a persistent quarantine environment is possibly the most efficient way to prevent illness and /or death from contagious disease in a colony. During the quarantine period strict attention is necessary to determine any signs of illness. It is advisable to familiarize yourself with signs of illness, basic diseases of the rat, and to find a veterinarian that treats rats in the event that you see illness during quarantine.

Those involved with rats use levels of quarantine ranging from none, to very lax, to stringent. The type of quarantine used will depend on the needs associated with the colony, and the preferences of the person that maintains the colony. Unfortunately, if the level of quarantine is not high enough for the particular scenario, it puts the rats at risk.

There are particular quarantine issues for anyone that breeds rats. Breeding through an illness can perpetuate disease indefinitely. The placement of babies magnifies the potential to spread illness and death at a much larger scale than the average fancier. There are also times when placements do not work out and babies are returned after they have been exposed to outside rodents.

Breeders need to be extremely serious about quarantine.

To help you with identifying certain symptoms, and to get more information about specific pathogens, please refer to the internal links found at the bottom of the page.

*Note: Mice and other rodents can also carry disease of the rat. Take care to factor them, as well as wild rats, in quarantine scenarios. Incoming supplies or equipment can also act as a potential source of disease transmission.

Quarantine Time Frames

New & Returning Rats: Quarantine Time Frame

The absolute minimum quarantining for bringing rats in is fourteen days. This covers the acquisition of new rats or the return of resident rats to the colony after exposure to other rats (shows, co-breeding, returned placements, etc.). When acquiring a new rat from a show, pet store, breeders, or rescue facilities, check it over for signs of illness first. This will help reduce the risk of exposure to your other rats.

This will be enough time to detect certain dangerous viruses (such as SDAV and Sendai), obvious bacterial infections, ectoparasites (such as mites, fleas, and lice), and possibly internal parasites.

Generally the quarantine time for external parasite infections is three weeks. Quarantine begins on the first day of treatment. Treatment must include the environment as well as the rat.

In general, a two-week quarantine will not alert one to asymptomatic viral infections such as parvovirus (including Kilham rat virus) or to persistent festering diseases such as CAR bacillus (Cilia Associated Respiratory, or, as of 2016, renamed Filobacterium rodentium). Nor will any amount of quarantine detect or eradicate persistent life-long infection from Seoul Virus (an orthohantavirus) in an infected rat testing positive for the virus. For further information on this virus and its impact on rat colonies and humans see the article on Seoul Virus.

If any health issues arise while in quarantine seek immediate treatment from a qualified veterinarian. The quarantine will start again after the rat has recovered and is off any medications that may mask signs of illness. If any rats are introduced into the group it also necessitates starting quarantine over.

Signs of illness may include, but are not limited to, any of the following:

  • Porphyrin secretions from eyes or nose
  • Sneezing
  • Wheezing
  • Rough coat
  • Labored breathing
  • Lethargy
  • Hunched posture
  • Swelling on neck or body
  • Abscesses
  • Scabs or itching
  • Diarrhea
  • Constipation
  • Lack of appetite
  • Eye ulcerations, bleeding, or swelling
  • Visual identification of parasites, including lice nits
  • Abnormal odor from the rat
  • Abnormal smelling feces or urine
  • Respiratory distress
  • Head tilt or abnormal gait
  • Thinness

*Note: Quarantine concerns may not be the same in different areas/countries depending on the prevalence and/or virulence of particular pathogens.

Outbreak and Post Infection-Quarantine Time Frame

During an active infection no rats must enter or leave the colony. All breeding must be stopped to prevent perpetuation of the illness. After a colony has been exposed to a contagious disease, it is essential to quarantine them so as not to spread the illness to others. The length of quarantine depends on the pathogen involved, the size of the colony, and whether or not there has been breeding. It will take longer to be sure that the illness has passed in a larger group.

Outbreaks in a colony often tend to be viral in nature. Although viruses cannot be treated, it is important to aggressively treat the secondary infections that inevitably accompany them. Viral outbreaks can be reported to the Viral Tracking Database.

*Note: Immunocompromised rats in the colony can stay persistently infected with certain diseases.

A postinfection quarantine is performed in the rats’ home colony and begins only after the following criteria has been met:

  • All of the rats have recovered
  • All rats off medications that may mask signs of illness
  • All breeding is ceased
  • Any rats born or conceived during exposure are weaned


Post Infection for Specific Pathogens (for more detail use the highlighted links):

  • SDAV (SDA)– The accepted minimal quarantine is 30 days (after all babies are weaned, all rats are recovered, and all rats have completed their full course of treatment), even though the virus is not usually shed for that long. In a large or breeding colony it is not unusual to see a two-month quarantine just to be sure that the virus is no longer present.
  • Kilham Rat Virus–┬áMinimum quarantine is 60-90 days and involves draconian methods of sanitization. Other factors can affect post infection time frame such as persistent infection in prenatal or postnatal rats.
  • Sendai Virus (SeV)–┬áThe accepted minimal quarantine is 30 days (after all babies are weaned, all rats are recovered, and all rats have completed their full course of treatment), even though the virus is not usually shed for that long. In a large or breeding colony it is not unusual to see a two-month quarantine just to be sure that the virus is no longer present.
  • CAR Bacillus (Filobacterium rodentium)– Persistent contagious infection that will not be resolved through quarantine.
  • Mycoplasma pulmonis Persistent contagious infection that will not be resolved through quarantine.
  • Seoul Virus– Persistent, contagious, life-long infection that will not be resolved through quarantine.


Methods of Quarantine

In-Home Quarantine

Often, rat owners will quarantine by putting any new rat(s) in a separate room. This method, along with stringent hand washing, can be useful for preventing the spread of certain bacteria or parasites. It is not effective for containing airborne viruses such as SDAV, Sendai, or Parvovirus.

Using a garage, separate room, basement, or porch connected to the colony’s living area is not considered a safe alternative. Such locations may reduce the risk of contagion, but as you pass from such areas into the main part of the colony’s living area, you will be allowing air that may be contaminated with airborne pathogens to enter with you. This puts the resident rats at risk for infection.

In-home quarantine is not recommended as an advisable method, particularly if one is bringing in rats from high-risk scenarios or if breeding.

Separate Location Quarantine

As the name implies, this method of quarantine involves isolating in a rat-free environment at either a separate location from the colony, or in an area where there is a totally separate air supply. This is the safest method of quarantine for a fancier or non-laboratory colony.

Some possible locations are: a friend’s home, the home of a family member, a neighbor, a climate-controlled out building, or at your workplace.

It is advisable to have someone else care for the quarantined rats rather than risk bringing diseases home that can be carried on your person or clothing. If there is no alternative, upon returning to your home, shed your clothes outside and immediately shower.

Persistent Quarantine

Once a colony is determined to be in good health a persistent quarantine scenario can help keep it that way. In addition to the standard new rat quarantine, there are additional recommendations that you can follow:

  • Avoid pet stores that sell rats.
  • Do not handle rats at pet stores or shelters.
  • Have fellow rat fanciers wash up before visiting.
  • If you are exposed to outside rats, clean up as soon as you return home, or wait awhile before going into your home. SDAV and Sendai will only remain contagious when away from the host for approximately three hours.
  • Avoid housing rats in areas where wild rats have access.
  • Avoid taking your rats to rat-inclusive events.
  • Avoid constantly adding to your colony. It is safer to get rats less often and quarantine them well.
  • If showing rats, quarantine them at a separate location before returning them to the colony.


Isolator Maintained & Full Barrier Quarantine

This is the method most often used where rats are being bred and/or kept for the purpose of research. Certain diseases can be catastrophic to research projects. Rats are quarantined using methods such as airflow units and isolator units. Sterilization of supplies and equipment, and periodic testing for pathogens are required to prevent research results from being contaminated. In some cases, SPF quarantined colonies are started by harvesting embryos and transferring them to a pathogen free or defined flora recipient mother. Not all rats in laboratories and research colonies are free of pathogens. Some are only SPF (Specific Pathogen Free) or DFD (Defined Flora Derivations), and others are specifically infected with certain diseases so that researchers may learn more about the disease and/or determine its impact on research.


The following links contain additional information:


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