Procedures for Veterinary Outbreaks

Unit for Laboratory Animal Medicine
Aug 16, 2017 12:00 am

To outline the appropriate procedures after an outbreak is detected and reported to the clinical veterinarian.

  • Responsibilities

    1. ULAM Veterinary Staff, ULAM Husbandry and the Rodent Health Surveillance Team: Responsible for coordinating eradication of detected pathogens and initiating replacement and testing of new surveillance animals once eradication is complete (see Appendix A).
    2. TST or the Laboratory: Additional responsibilities are outlined in Procedures section 3, please refer to this section for further instructions.
  • Glossary Definitions

    Principal Investigator (PI)

    The researcher who has received protocol approval to conduct the study.


    This method of eradication is an option for most viral outbreaks in SPF barrier rodent rooms (i.e. rodents housed in microisolator cages). Because microisolator cages are individual biologic units, if appropriate technique is used, there should be minimal risk of viral spread from cage to cage. Eradication is directed at testing one or all mice in each cage and euthanizing any positive cages. This definition may change in unique circumstances.

    Appropriate Blood Collection Age and Size

    Animals must be > 6 weeks of age AND > 15 grams for blood collection. This is due to the fact that animals need to be at least 6 weeks of age to appropriately develop antibodies to exposed pathogens; in addition, at least 25µg of blood is needed for dried blood spot technology. Alternatively, PCR test on environmental swabs, tissues, or feces can be performed.

  • Procedures

    1. Rodent Health Monitoring Overview

    1. ULAM Managed Areas
      1. Surveillance on all SPF barrier mouse rooms is performed on a quarterly basis. Surveillance on most SPF barrier rat, guinea pig and other rodent rooms is done semi-annually, unless otherwise indicated and approved by the faculty veterinarians. For other rodent species, final decision will be determined by faculty veterinarians.
        1. Mouse Pathogens Tested
          1. Quarterly: EDIM (Rota), MHV, MPV, MVM, Pinworms
          2. Semi-annually: Quarterly tests plus ECTRO, GDVII (TMEV), LCMV, MAV, MPUL, NS-1, POLY, PVM, REO, Sendai, Pinworms
          3. Semi-annually: Fur Mites
          4. ULAM-Quarantine: All test above plus HANTA
        2. Rat Pathogens Tested
          1. Semi-annually (unless otherwise indicated): GDVII, H-1, KRV, LCMV, MAV, MPUL, NS-1, PVM, REO, RPV, RVM, SDAV/RCV, Sendai, Pinworms
        3. Guinea Pig Pathogens Tested
          1. Semi-annually: GAV, LCMV, PVM, REO, Sendai
        4. Hamster Pathogens Tested
          1. Semi-annually: CRL Assessment Profile for Hamsters that includes SEND, PIV-5, PVM, REO, LCMV, ECUN, CPIL
        5. Other Rodents Pathogens Tested
          1. Surveillance varies based on rodent species
      2. Surveillance on most conventionally housed rodents is performed annually. These rodents are tested using the more inclusive panels as described above for the corresponding species.
    2. For more information on rodent pathogen surveillance at U-M refer to:
      1. RHST document Procedures for Rodent Health Surveillance
      2. ULAM Seminar Series "Clinical Pathology in Laboratory Animal Medicine - Diagnostic Serology (Applied) in Rodents"
      3. Charles River Laboratories and

    2. Veterinary responsibilities - Ancillary information to flow chart (see Appendix A), numbering corresponds to flow chart item number.

    1. Step 4a. Resident: Contact PI of Infected colonies
      1. Contact area faculty veterinarian for confirmations of sending the letter and other action items.
      2. Contact researchers. This should be in the form of a professional letter that is emailed directly to the PI and any additional laboratory contacts giving a response deadline of one week. See ULAM SOP Packet "Standard Outbreak Letters" (ULAM Network Share Drive: ULAM_SOP → Veterinary → Veterinary SOPs and Policies → Rodent-specific → Veterinary Outbreak Documents → Positive Letters or Negative Letters) if there is not a corresponding stock letter for a particular pathogen, appropriately fill out the "template outbreak format".
      3. CC the appropriate faculty veterinarian, husbandry supervisors, veterinary technician and surveillance coordinator to the initial email. Forward or CC all responses or communication to and from the PI to the faculty veterinarian.
      4. Email addresses can be obtained through the husbandry supervisors for the animal housing area of the outbreak or the approved protocol for these animals.
      5. Tracking outbreaks - Resident is to meet with the faculty veterinarian to review the answers to all questions from the PI asked on the outbreak letter sent and assess possible causes for the outbreak. After reviewing these questions with the veterinary faculty, a meeting with the laboratory may be necessary.
      6. If responses are not received by the date indicated the following steps should be taken:
        1. Resident sends high priority reminder email with original email attached and gives an additional week to respond.
        2. If still no response, faculty sends email giving final week for responses and treatment selection if applicable, and indicates in the email that treatment will be initiated regardless on X date if no response is given.
    2. Step 4b. Resident: Contact ALL other PIs of Non-Infected Colonies in the room
      1. Contact should be in the form of a professional letter that is emailed directly and individually to the PI's of non-infected colonies and any additional laboratory contacts in the outbreak room (See ULAM Network Share Drive: ULAM_SOP → Veterinary → Veterinary SOPs and Policies → Rodent-Specific → Veterinary Outbreak Documents → Positive Letters or Negative Letters. If there is not a corresponding stock letter for a particular pathogen, appropriately fill out the "template outbreak format")
      2. CC the appropriate faculty veterinarian, husbandry supervisors, and RHST to the initial email. Forward or CC all responses or communication to and from the PI to the faculty veterinarian.
      3. It is important to contact ALL PI's and other relevant laboratory contact in the room as some eradication procedures may affect their animals and subsequently their experiments. A complete list of PI's currently in the room should be obtained through the husbandry supervisor for the animal housing area of the outbreak.
      4. Email addresses can be obtained through the husbandry supervisors for the animal housing area of the outbreak or the approved protocol for these animals
      5. If the outbreak letter includes questions, resident reviews the PI's answers to these questions with faculty veterinarian.
      6. For outbreaks requiring negative PI's to respond to questions or choose a treatment option, follow the same contact procedures for timelines given in Procedures section 3 below.
      7. NOTE: Meet with veterinary faculty prior to sending email if:
        1. The PI or room has >1 pathogen detected.
        2. There is history of recent contamination in this room with the same pathogen
        3. The pathogen does not have a standard outbreak letter
        4. The outbreak is in a conventionally housed area.
        5. There are any questions, doubts or concerns regarding the outbreak.
    3. Step 6. Resident continuously update RHST
      1. In order to timely place new sentinels after all eradication procedures are compete it is necessary to constantly update the RHST with anticipated timelines as the eradication timelines change through-out the outbreak process.
    4. Step 7a. Viral outbreak plan for blood collection
      1. Appropriate plan may depend on several factors. The final decision is made by the area faculty veterinarian.
      2. If the "test-and-cull" method for eradication is chosen, Technical Service Team (TST) will be contacted to collect blood and/or PCR samples from animal in cages that have been identified by the lab and/or faculty veterinarian. This is outlined in the letter sent to the infected PI. TST will use ULAM Outbreak/Treatment and Tracking Form for their record.
      3. Sample collection is typically at no additional cost to the laboratory; however, some exceptions may occur in which the PI would be responsible for cost incurred. For example if the researcher requests that additional cages are sampled and tested that are not considered part of the outbreak in the contaminated room. If ULAM's TST is to sample collection an email should be sent to with the appropriate outbreak information and sample collection plan.
      4. The laboratory has the option to perform the blood collection procedures on their own animals; however, because TST can perform this procedure at no cost to the laboratory, this option should be discouraged. If a laboratory chooses to perform the sample collection, a plan should be made in consultation with, or by the faculty veterinarian and resident. The plan should specifically outline how the sampled cages will be uniquely identified, how the samples will be collected, the site of collection and type of sample (for serology, identify blood collection site; for PCR, identify samples to be collected), cages/animals from which to be collected, sample storage/submission plan and a time-line. In addition the laboratory must follow the instructions outlined in Procedures section 3 below.
    5. Step 9. Serology and/or PCR results and culling
      1. Once serology and/or PCR results are finalized and available, a depopulation or eradication plan, which may include culling of affected animals and room decontamination, should be reviewed with the faculty veterinarian and coordinated with the laboratory. Be sure to include animals that were too small to bleed or sample, and potential weaned animals into this plan (see Procedures section 3 below). Some viral pathogens (MHV, MPV, MMV, RPV) should follow the Room Sanitization SOP for decontamination procedures (Consult with husbandry supervisor for additional information on these husbandry documents).
      2. Culling of affected animals can be performed by the laboratory, ULAM's TST or husbandry. Regardless of who performs the euthanasias, the husbandry supervisor for the area should be continuously updated on the plan so flowchart items 10 (Husbandry confirms animals were depopulated and emails resident and RHST) and 11 (appropriate decontamination) can be performed.

    3. Special Circumstances for neonatal and/or weanlings

    Considerations include pathogen, strain/stock of the animals, and veterinary professional judgment (serology and/or PCR should be considered to track weanlings). Final determination will be made by the faculty veterinarian.

    1. Viral outbreaks may require tracking of any neonatal or weanling animals until serology results are available. During blood collection some animals may be too small to collect blood safely and may need to have serology performed at a later date. In addition, some animals may be weaned from cages during/after the sample collection - depopulation phase of eradication and tracking to the parent cage is essential for eradication. PCR may be considered as a viable alternative.
    2. The outbreak letter shall indicate unweaned pups shall be considered positive if their dam is tested positive. If their dam is tested negative, neonatal pups still need to be tested again at appropriate size after weaning.
    3. If serology is to be performed, follow the procedures below for animals too small to collect blood safely during initial sample collection (see Definitions section 5 above for Appropriate blood collection age and/or size of mice)
      1. These animals should be given a unique identification on the cage card at the time of blood collection by ULAM's TST or the laboratory.
      2. ULAM's TST or the laboratory should send a list of these animals to the veterinary resident.
    4. If these animals can be tracked back to their parent cage and were not co-mingled, they should be incorporated into the eradication plan and assumed to have the same viral status as their parent, and thus treated as such during culling.
    5. If animals cannot be tracked back to their parent cage or were co-mingled with other animals, the laboratory should be encouraged to euthanize these animals. If euthanasia is not an option, samples should be collected on these animals as soon as possible and tested at the research laboratory's expense. The depopulation plan should be started with the first round of test results but clean-up and placement of new sentinels should NOT be performed until ALL appropriate procedures are completed.

    4. Tracking Outbreaks

    1. Update the outbreak information in the "ULAM Outbreak Testing/Treatment and Tracking Form" maintained in M+Box. After the outbreak is cleared, notify RHST to place a new sentinel animal in the room.

    5. Outbreak Letters

    This is a current list of all available outbreak letters for certain pathogens. See ULAM Network Share Drive: ULAM_SOP → Veterinary → Veterinary SOPs and Policies → Rodent-specific → Veterinary Outbreak Documents → Positive Letters or Negative Letters.  Please refer to SOP Packet "Standard Outbreak Letters" for the complete letter.

    1. Mice
      1. MPV
      2. MHV
      3. MVM
      4. Pinworm
      5. Fur mites
      6. EDIM
    2. Rats
      1. RPV
      2. Pinworm
    3. Guinea Pig
      1. GAV
    4. Build your own "template outbreak format" letter
  • Additional Resources

    1. Fur Mite Outbreak and Treatment Procedures for Rats and Mice <-- link needed
    2. Surveillance of Mice and Rats Ectoparasites (external link)
    3. ULAM Outbreak Testing/Treatment and Tracking Form (maintained on M+Box) <-- link or specific location needed
  • Appendix A: Rodent Health Surveillance Results Flowchart


Questions or concerns about the content of this document should be directed to the Unit for Laboratory Animal Medicine (ULAM) at (734) 764-0277 or