Related Experiment Video
Updated: Feb 16, 2026
Diagnosis of Ecto- and Endoparasites in Laboratory Rats and Mice
Published on: September 6, 2011
PCR Testing of IVC Filter Tops as a Method for Detecting Murine Pinworms and Fur Mites
Philip M Gerwin1, Rodolfo J Ricart Arbona2, Elyn R Riedel3
1Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, Center for Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center and Weill Cornell Medicine, New York, New York, Comparative Medicine, Pfizer Worldwide Research and Development, Groton, Connecticut;,
Abstract:
We evaluated PCR testing of filter tops from cages maintained on an IVC system through which exhaust air is filtered at the cage level as a method for detecting parasite-infected and -infested cages. Cages containing 4 naïve Swiss Webster mice received 360 mL of uncontaminated aspen chip or α-cellulose bedding (n = 18 cages each) and 60 mL of the same type of bedding weekly from each of the following 4 groups of cages housing mice infected or infested with Syphacia obvelata (SO), Aspiculuris tetraptera (AT), Myocoptes musculinus (MC), or Myobia musculi (MB) and Radfordia affinis (RA; 240 mL bedding total). Detection rates were compared at 30, 60, and 90 d after initiating bedding exposure, by using PCR analysis of filter tops (media extract and swabs) and testing of mouse samples (fur swab [direct] PCR testing, fecal flotation, anal tape test, direct examination of intestinal contents, and skin scrape). PCR testing of filter media extract detected 100% of all parasites at 30 d (both bedding types) except for AT (α-cellulose bedding, 67% detection rate); identified more cages with fur mites (MB and MC) than direct PCR when cellulose bedding was used; and was better at detecting parasites than all nonmolecular methods evaluated. PCR analysis of filter media extract was superior to swab and direct PCR for all parasites cumulatively for each bedding type. Direct PCR more effectively detected MC and all parasites combined for aspen chip compared with cellulose bedding. PCR analysis of filter media extract for IVC systems in which exhaust air is filtered at the cage level was shown to be a highly effective environmental testing method.
Insights
PCR testing of filter media extract effectively detects parasites in individually ventilated cages (IVC). This environmental testing method surpasses traditional diagnostics for identifying parasite-infected and -infested mouse cages.
Area of Science:
- Laboratory Animal Science
- Parasitology
- Molecular Diagnostics
Background:
- Accurate detection of parasitic infections in laboratory animals is crucial for research integrity.
- Traditional diagnostic methods may have limitations in sensitivity and scope.
- Individually Ventilated Cage (IVC) systems with cage-level filtration require effective environmental monitoring.
Purpose of the Study:
- To evaluate the efficacy of PCR testing of filter tops from IVC systems for detecting parasite-infected and -infested mouse cages.
- To compare PCR-based environmental testing with conventional mouse sample analysis methods.
- To assess the impact of bedding type (aspen chip vs. α-cellulose) on detection rates.
Main Methods:
- PCR analysis of filter media extract and swabs from IVC cage filter tops.
- Comparison with mouse sample testing: direct PCR (fur swab), fecal flotation, anal tape test, direct examination, and skin scrape.
- Exposure of naïve mice to bedding from cages infected with specific parasites: Syphacia obvelata, Aspiculuris tetraptera, Myocoptes musculinus, Myobia musculi, and Radfordia affinis.
- Detection rate assessment at 30, 60, and 90 days.
Main Results:
- PCR testing of filter media extract achieved 100% detection of most parasites at 30 days, outperforming non-molecular methods.
- This method identified more cages with fur mites (Myobia musculi, Myocoptes musculinus) than direct PCR when using cellulose bedding.
- PCR analysis of filter media extract was superior to swab and direct PCR for cumulative parasite detection across both bedding types.
Conclusions:
- PCR analysis of filter media extract from IVC systems is a highly effective environmental testing method for detecting parasitic infections.
- This molecular approach offers superior sensitivity and broader detection capabilities compared to traditional diagnostic techniques.
- Environmental monitoring via filter top PCR is a valuable tool for maintaining parasite-free laboratory animal colonies.
