Mice
Through Q1 2025, all mouse colony surveillance was conducted quarterly in all BL-1N animal rooms in HCCM-managed rodent facilities via dirty-bedding sentinels. Outbred sentinel mice (4-6 weeks of age) were purchased from an approved vendor (Taconic Farms or Charles River Laboratories) each quarter and housed two animals per cage, one cage per rack. Cages were changed weekly or bi-weekly, depending on the cage type and facility management plan. Sentinels received soiled bedding from a pooled sample of bedding taken from colony cages on their rack. Fifty per cent of sentinels’ cage bedding was soiled bedding from the colony animals under surveillance. Surveillance diagnostics were initially carried out on one sentinel animal per rack.
Effective June 2025, all facilities transitioned from live dirty-bedding sentinels to a filter media sample exposed to dirty cage bedding collected from colony animals. The filter media is collected at the end of the surveillance period for PCR testing. One surveillance cage is seeded per rack. For each individual facility, cumulative health reports reflecting 18 months’ worth of surveillance testing will contain language documenting the date of the transition from live mice to filter-media sampling of dirty bedding.
For all surveillance methods, the testing schedule is as follows: Serologic examination (sentinel mice through Q1 2025) or PCR of filter media (June 2025 onwards) for Mycoplasma pulmonis, Sendai Virus, Mouse Hepatitis Virus, Minute Virus of Mice, GDVII, Reo3, Pneumonia Virus of Mice, Mouse parvovirus, and Mouse Rotavirus (EDIM); internal parasites, fur mites, and C. bovis by PCR.
In addition to the panel described above, a more expanded panel is run in the second trimester for mouse adenovirus 1 & 2, K virus, Polyoma virus, Lymphocytic Choriomeningitis virus (LCMV), and ectromelia virus.
Unexpected clinical conditions in colony mice may prompt evaluation for the presence of other agents as necessary, such as respiratory or enteric bacterial pathogens (e.g. Klebsiella pneumoniae, Streptococcus pyogenes, Pasteurella pneumotropica, Bordatella bronchiseptica; Salmonella enteriditis, Citrobacter freundii).
