Comparison of Plenum and Cage-level Filter Exhaust Dust PCR Testing to Soiled Bedding Sentinel Mice (Mus musculus) on an IVC Rack.

The use of soiled-bedded sentinels (SBSs) has historically been the standard for colony health surveillance monitoring at our institution. With the advent of newer technologies in which dust collected from filters is tested by PCR, we compared traditional SBS with PCR testing of both exhaust air dust collected from a filter in the downstream vertical plenum (exhaust dust test [EDT]) and the SBS cage-level exhaust filter (SCEF). Our hypothesis was that both methods of filter testing would identify more pathogens than SBS testing. Twenty-five individually ventilated mouse racks that used disposable caging were sanitized and placed into rotation. Rack plenums were tested by PCR to verify negative results before the study start. Exhaust dust collection media were placed in the exhaust plenum (n = 25). SBS cages were placed on each side of the rack with 2 mice per cage (n = 42 mice), with the remaining cage slots occupied by research animals. At each triweekly cage change, the exhaust air filters were carefully removed from the cage top, placed in sterile 50-mL conical tubes, and pooled for submission. After 3mo, the SBS mice were tested via serology for bacterial and viral agents and by PCR for Helicobacter species, pinworms, and ectoparasites. In addition, the EDT filter and SCEF were collected for PCR to evaluate for the same agents. Our results indicate that the SCEF consistently detected agents more frequently than the EDT filter placed in the plenum and that the EDT filter media detected agents more frequently than did the SBS mice. Our data suggest that both PCR methods of detection are superior to SBS for individually ventilated disposable rodent cages and that the SCEF is superior to EDT. These data supported our movement of institution toward environmental monitoring as a method of rodent colony health surveillance.

Evaluation of a Novel Battery-Operated Tumbler Device for Use in the Detection of Mouse Pathogens for Rodent Health Monitoring.

The search for alternatives to live animal sentinels in rodent health monitoring programs is fundamental to the 3Rs (Reduction, Replacement, and Refinement) of animal research. We evaluated the efficacy of a novel battery-operated tumbler device that rotates soiled bedding in direct contact with sample media against the use of exhaust sample media and soiled bedding sentinel (SBS) mice. Four rodent racks were used, each with 3 test cages: a cage with a tumbler device that rotated for 10min twice a week (TUM10), a cage with a tumbler device that rotated for 60min twice a week (TUM60), and a cage housing 2 female Crl:CD1(ICR) mice. Every 2 wk, each test cage received soiled bedding collected from all cages on each respective rack. In addition to soiled bedding, the tumbler device contained various sample collection media: a contact Reemay filter (3mo-cRF) that remained in the tumbler for the duration of the study, a contact Reemay filter (1mo-cRF) that was replaced monthly, adhesive swabs (AS) that were added at every biweekly cage change, and an exhaust Reemay filter located at the exhaust outlet of the cage. All analyses were performed by direct PCR for both sample media in the animal-free methods, and fecal pellet, body swab, and oral swabs were collected from sentinel mice. Out of 16 total pathogens detected, assessment of 1mo-Crf from both TUM10 and TUM60 cages detected 84% and 79% of pathogens, respectively, while SBS samples detected only 47% of pathogens. AS in TUM60 and TUM10 cages detected the fewest pathogens (24% and 13%, respectively). These results indicate that the novel tumbler device is an effective and reliable tool for rodent health monitoring programs and a suitable replacement for live animal sentinels. In this study, 1mo-cRF in TUM10 cages detected the highest number of pathogens.

Campylobacter species abortion in sheep.

This focus article was prepared by Jasmine Smith of the APHA Small Ruminant Species Expert Group. Data extraction and analysis was done by Anna Brzozowska of the APHA Surveillance Intelligence Unit and Leanne Dempsey from APHA Thirsk.

Laboratory diagnosis of gastrointestinal nematodes in first-grazing-season cattle.

This focus article has been prepared by Natalie Jewell of the APHA Cattle Expert Group with the assistance of Vanessa Swinson (veterinary lead of the APHA Cattle Expert Group), Claire Hayman, Lucy Martindale and Anna Brzozowska (Surveillance Intelligence Unit), and Siân Mitchell (formerly the APHA's parasitology discipline champion).