Effective Eradication of Pinworm Infection (Syphacia muris, Syphacia obvelata) from a Large Rodent Breeding Center

Abstract

In the routine health monitoring of laboratory animals in our breeding and research center, rat pinworm, Syphacia muris, was detected in the research rat colony (10/16) and mice pinworm, Syphacia obvelata, in barrier SPF mice( 1/28). A combination anthelmintic regimen was designed to eradicate this infection. At first, 0.1% ivermectin solution was sprayed in both mice and rat cages on days 0, 14 and 28, while piperrazine citrate was administered twice weekly at a rate of 3 g/L in the drinking water on days 7, 10, 21, 24, 35 and 38. Ivermectin was then added to the drinking water (0.007 mg/mL) on days 42 and 49 in both rats and mice, followed by oral administration of fenbendazole-medicated chow in rats (150 ppm) and 0.2% thiobendazolemedicated chow in mice weekly for 6 weeks. Other measures to facilitate eradication in contaminated animal rooms were conducted simultaneously and included the use of filter-top cages, environmental decontamination by flame, research colony depopulation, breeding cessation and decrease in colony size. The colony was monitored for 24 months during and after treatments. Findings from examination of 4862 cellophane-tape impressions of the anus, 1109 cecal examinations from euthanized rats and mice, as well as 347 MIF concentration stool smears confirmed the efficacy of the treatment. This is the first report for the successful eradication of pinworms in large scale breeding colonies including both rats and mice.