Pinworm detection in mice with immunodeficient (NOD SCID) and immunocompetent (CD-1 and Swiss) soiled bedding sentinels in individually ventilated cage systems

Abstract

Sentinel exposure to soiled bedding is frequently used for health monitoring of mice housed in individually ventilated cage systems (IVCS). Despite its advantages, the use of soiled bedding sentinels (SBSs) is far for being a reliable method. Two studies were conducted to evaluate the sensitivity of immunodeficient SBSs NOD.CB17-Prkdcscid/NCrHsd (NOD SCID) against two immunocompetent outbred strains, Hsd:ICR (CD-1) and RjOr1:Swiss (Swiss) to pinworm detection in IVCS-housing. Four different diagnostic methods were used: perianal tape test, fecal flotation, plate method and histology. Positivity was considered if at least one of the techniques used was positive. In the first study NOD SCID were more sensitive than CD-1 SBSs (P 0.05), and except for the fecal flotation test performed at week 6, all the diagnostic methods were more sensitive with NOD SCID mice (P 0.05). In the second study differences between the Swiss and NOD SCID mice were less obvious (P=0.08). When compared separately, the different diagnostic methods, except for the fecal flotation test, were all more sensitive in the NOD SCID mice (P 0.05). In addition, the anal tape test in the Swiss SBSs was more sensitive at week 7 than at week 15 (P 0.05). In conclusion, combining various diagnostic techniques and samplings at week 7 post-exposure with non-invasive methods increases the rate of pinworm detection. Immunodeficient SBSs showed higher sensitivity than immunocompetent ones. Thus, use of immunodeficient SBSs is highly recommended in health control protocols.