Taconic Biosciences Implements Changes to its Animal Health Program

July 17, 2023

Pasteurella multocida now excluded at all health standards

Pasteurella multocida has been added to the exclusion list for the Murine Pathogen Free™ health standard. This means that P. multocida is now excluded from all Taconic health standards.

Update to virus name

TMEV has been added as a synonym for Mouse Encephalomyelitis Virus, so the entry for this agent on health reports has changed from "Mouse Encephalomyelitis Virus (GDVII)/Rat Theilovirus (RTV)" to "Mouse Encephalomyelitis Virus (TMEV/GDVII)/ Rat Theilovirus (RTV)".


Oct 21, 2022

Animal health program updates

aconic periodically reviews and updates our animal health program based on new scientific findings and feedback from customers. As a result of that assessment, we are retiring the Excluded Flora health standard, removing SFB from most health reports, adding several agents to our exclusion list and updating names for certain organisms on health reports. Read on for more details on what's changing.

Excluded Flora health standard retired

Taconic is eliminating the Excluded Flora (EF) health standard and transitioning all EF locations to the Opportunist Free™ (OF™) health standard as of January 1, 2023. The only difference between the two standards is how Segmented Filamentous Bacteria (SFB) is handled; the EF standard excluded it, whereas this normal commensal agent is accepted at OF™. All other agents excluded at EF are also excluded at OF™. Any existing commercial orders booked against EF inventory for delivery on or after Jan 1, 2023, will be automatically updated to reflect that they will source from an OF location. After today, all new commercial orders for 2023 delivery which request EF animals will be booked at OF. For Colony Management or Custom Model Generation projects at Taconic, all health reports will be updated for the respective locations on Jan 1, 2023, to reflect the conversion from EF to OF. This change does not require movement of animals to other locations, so your project will remain in its current location. Please contact Taconic Customer Service for any concerns regarding projects or booked orders.

SFB removed from health reports

SFB is not a rodent pathogen, but rather is a normal member of the gut commensal microbiome. Taconic previously reported SFB on all health reports as an aid to microbiome researchers, however there is insufficient market demand to continue this practice. This aligns Taconic with other major rodent vendors, none of which treat SFB as an organism on which to report or exclude. Taconic will cease SFB monitoring at all health standards except the legacy Excluded Flora (EF) health standard. This means that effective immediately, SFB will not appear on any non-EF health report. SFB will continue to be excluded at the Germ Free (GF) health standard, but it will not appear as a specific line item on those health reports. Note that the Defined Flora (DF) health standard accepts anaerobic spore-forming bacteria, so SFB will be tolerated at DF. Microbiome researchers who are interested in ordering animals based on SFB status should contact Taconic to discuss options.

Organisms added to Taconic's exclusion lists

Dermatophytes, Rat Polyomavirus 2 (RPyV2) and Rat Rotavirus, aka Infectious Diarrhea of Infant Rats or IDIR, have been added to the exclusion list for all Taconic health standards. Only rats will be tested for RPyV2 and IDIR. Corynebacterium bovis has been added to the exclusion list for the Murine Pathogen Free™ standard and is now excluded at all Taconic health standards. These changes will appear on health reports as of Oct 24, 2022.

Updates to organism names and other nomenclature

Taconic updates the names of organisms shown on health reports based on the latest taxonomic consensus. The following updates will be reflected on health reports as of Oct 24, 2022.


Previous name

New name


Polyoma Virus

Polyoma Virus (mouse)

Updated this virus name to distinguish it from newly added Rat Polyomavirus 2

Pasteurella pneumotropica

Rodentibacter pneumotropicus, Rodentibacter heylii

P. pneumotropica was reclassified in the Rodentibacter genus and the Jawetz and Heyl biotypes have been renamed as R. pneumotropicus and R. heylii, respectively.

Cilia Associated Respiratory Bacillus (CARB)

Filobacterium rodentium (CAR Bacillus)

Formally named by Ike et al. 2016

"16S bacterial RNA screening" will now appear as "Bacteria 16S rRNA gene screening" on health reports.

Sept 14, 2020

SARS-CoV-2 testing added for susceptible models

Taconic has added SARS-CoV-2 testing for models which are susceptible to SARS-CoV-2 infection. This applies to a small list of models in limited locations. Standard laboratory mice and rats are not susceptible to infection by SARS-CoV-2. For susceptible models, fecal samples are collected from line animal cages and tested by PCR on a biweekly basis. Additionally, quarterly testing of the exhaust air duct (EAD) filters from the IVC racks housing susceptible models will include SARS-CoV-2 testing. SARS-CoV-2 will not be added to Taconic health standard definitions as it is not considered a laboratory rodent pathogen. However, if SARS-CoV-2 is confirmed in a susceptible model, shipments will stop immediately, and customers who have received animals from the location since the last negative test result will be notified.

For more information on housing and husbandry for SARS-CoV-2 susceptible models, review our fact sheet.


June 1, 2019

Taconic now excludes MKPV from all health standards

Taconic has screened all commercial mouse production locations for the presence of mouse kidney parvovirus (MKPV) and is pleased to announce that all Taconic commercial mouse colonies and contract mouse breeding barriers are negative for MKPV. Taconic attributes this result to the strength of its biosecurity program, which includes practices and procedures designed to prevent entry or spread of viral contaminants.

As part of Taconic Biosciences' continued efforts to improve its animal health program, Taconic has added mouse kidney parvovirus (MKPV) to the exclusion list for all Taconic health standards. Regular testing will commence starting in July 2019, and MKPV test results will appear on health reports as of June 4, 2019.

Feb 27, 2018

Parasite updates

Taconic is rolling out changes to how parasites are reported on its animal health reports. Taconic continues to exclude all parasites at all health standards. That won't change. We will continue to exclude all parasites and test using a range of diagnostic methods, including microscopy, flotation, MFI and PCR. We are changing the way we report parasites on the health report. Taconic currently reports a defined listed of 16 parasites. This might falsely give the impression that we only exclude those parasites, when in fact Taconic excludes all parasites. We will now report parasites on our health reports under broad classes: endoparasites, ectoparasites and enteric helminths. We will continue to report one specifically named agent, Encephalitozoon cuniculi, which is of particular concern to those customers who also house rabbits. Below is an example of the relevant health report section, shown as before and after.

This change will take effect on February 28, 2018 for most production locations. It will take effect by April 1, 2018 for Isolator Breeding Solutions (IBS) locations.


Table of previous health standard


Interactive health selector tool

Taconic is also launching an interactive digital tool to help customers select the most appropriate health standard. Customers can select the agents their facility excludes and the tool will analyze and display which Taconic health standard(s) meet that exclusion list. We believe this tool will make choosing a health standard easier. Try the tool now!

Sept. 1, 2017

Taconic introduced a number of animal health updates and improvements as of Sept 1, 2017. A brief overview of the changes include:

  • Introduction of a new health standard, Opportunist Free™ (OF™)
  • Exclusion of an additional agent, Pasteurella multocida, at the Restricted Flora™ (RF™), Opportunist Free™ (OF™) and Excluded Flora (EF) health standards
  • Redesigned health testing in production locations using Individually Ventilated Cages (IVCs)
  • Addition of isolator microbial monitoring and bacterial 16S PCR testing results to health reports for Germ Free locations

Opportunist Free™ (OF™)

Taconic is adding the Opportunist Free™ (OF™) standard to the set of precisely defined health standards applied to its production of laboratory mice and rats. The OF™ standard applies to animals which are free of seven opportunistic pathogens, in addition to all agents excluded at the Murine Pathogen Free™ (MPF™) standard. Excluded organisms include:

  • Beta hemolytic Streptococcus (non Group D)
  • Klebsiella oxytoca
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa
  • Staphylococcus aureus
  • Proteus spp.
  • Pasteurella multocida

This standard will be initially applied to production of barrier-raised animals in the following European production locations: IVU102, IVU131, IVU150, and is designed to meet the needs of customers for animals free of confounding commensal organisms. Both immunocompetent and immunodeficient animals will be available at the OF™ standard.

Customers with pending orders from a location now designated as OF™ will be contacted with updated order confirmations.

P. multocida exclusion

Pasteurella multocida is a gram-negative coccobacillus that causes a range of health problems in some laboratory animal species. Pasteurella species including P. multocida are common commensal organisms in most livestock, domestic and wild animals, but P. multocida can be a primary pathogen associated with both acute and chronic disease under certain circumstances. It can also cause zoonotic infections in humans (Pasteurellosis) at low frequency, usually associated with animal bites or scratches or contact with domestic animal mucous secretions1. In laboratory animals, P. multocida is of most concern for rabbits, which can develop clinical illness, including rhinitis, conjunctivitis, pneumonia and otitis media2. It is not considered a pathogen in laboratory mice or rats.

P. multocida is not commonly found in most laboratory animal stocks at this time. This agent is unlikely to be introduced to production facilities from laboratory animal suppliers, does not form spores, and vegetative bacteria can be easily eliminated using typical laboratory disinfection protocols. However, once this agent has been introduced into laboratory rodents or rabbits, it is not possible to eliminate through test and cull, and depopulation would be required in order to eliminate it.

Taconic already excludes P. multocida from its Defined Flora and Germ Free health standards and tests for and reports on P. multocida status in all production locations. Taconic will now also exclude P. multocida from the Restricted Flora™, Opportunist Free™ and Excluded Flora health standards. P. multocida will continue to be tested for, reported and accepted at the Murine Pathogen Free™ health standard.

More complex health testing in IVC locations

Taconic is investing in upgrading animal production locations with individually ventilated cages (IVCs), which represents a more biosecure production method over static caging. Taconic is transitioning all commercial Opportunist Free™ and Excluded Flora animal production to IVCs. IVC production requires more complex health testing compared to static caging purely because it is more biosecure and transmission of infectious agents is limited. A multifaceted testing program in which agents of highest concern are screened using different methodologies to increase the likelihood of accurate and rapid detection is needed.

In static caging Restricted Flora™ (RF™), Opportunist Free™ (OF™) and Excluded Flora (EF) locations, core testing is performed monthly along with opportunist screening using cultures of fecal and oral samples. The redesigned testing program IVC locations includes four elements:

  • Core testing which includes serology, culture, PCR and necropsy
  • PCR testing of fecal samples from line animal IVC cages
  • IVC exhaust air duct PCR testing
  • Opportunist screening using culture testing of fecal and oral samples

The core testing, IVC PCR and exhaust air duct testing are each performed quarterly on a staggered schedule such that one element is performed each month. The opportunist screening is performed monthly.

Existing IVC exhaust air duct test results will begin appearing on select IVC location health reports in October, with additional IVC location test results becoming available throughout January 2018. New IVC locations will have exhaust air duct test results available approximately three months after opening.

More details on health testing in IVC locations can be found at the IHMS™ Testing Program.

Updated Germ Free health testing and reports

Taconic defines the Germ Free (GF) health standard as follows: no detectable organisms (viruses, parasites, bacteria, fungi) are present. The microbiological status of germ-free animals is verified through three separate methods. Each Germ Free isolator is tested via the IHMS™ core testing system for a list of defined viruses, bacteria, mycoplasma, fungi and parasites. Microbial monitoring of the isolator environment is designed to identify possible contamination of Germ Free isolators. Each isolator is tested weekly via culture for all aerobic and anaerobic organisms.

Taconic has added an additional level of screening to its Germ Free animals in the form of 16S generic bacterial PCR. This assay identifies any bacterial RNA which may be present. This added testing reinforces the integrity of Taconic's Germ Free animals.

The health reports for Germ Free animals previously only listed the core testing results, but will now also display the isolator monitoring results including both the culture testing and the 16S PCR. Look for these new test results on Germ Free health reports starting in mid-September.


1. Wilson, B. A.; Ho, M. Clinical Microbiology Reviews 2013, 26 (3), 631-655.

2. The Merck Veterinary Manual. Bacterial and Mycotic Diseases of Rabbits. Available at: http://www.merckvetmanual.com/exotic-and-laboratory-animals/rabbits/bacterial-and-mycotic-diseases-of-rabbits. Accessed July 7, 2017.

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