Detection and clearance of Syphacia obvelata infection in Swiss Webster and athymic nude mice.

Our routine health-surveillance program is based on use of the Swiss Webster mouse, with sentinels submitted for testing every 7 weeks. Athymic nude (nu/nu) mice are used as an adjunct method to detect pinworm infections. The premise for the use of the nude mouse was based on research that revealed the thymus as necessary to confer resistance to pinworm infections. In light of this finding, it was inferred that an athymic mouse would be more susceptible to pinworm infections than a euthymic mouse, and hence a better sentinel animal for pinworm detection. To test the validity of this assumption, the Syphacia obvelata detection ability of the athymic nude mouse was compared to that of the Swiss Webster. Our results indicate no significant temporal difference in the detection ability of the two genotypes of mice. A clearance study for the parasite was also performed, in which the majority of Swiss Webster mice cleared the infection whereas athymic nude mice did not. In light of our results, we conclude that use of the athymic nude mouse for Syphacia obvelata detection offered no significant advantage over the euthymic Swiss Webster mouse for our program.