Safety and efficacy of topical lime sulfur in mice infested with Myocoptes musculinus

Current treatment options for murine fur mites have limitations in safety and efficacy. This study evaluated whether topical lime sulfur (LS) is an adjunct or alternative to traditional treatment options for Myocoptes musculinus. To evaluate the safety of topical LS, mice were dipped in a 3% LS solution at 34 and 41 d of age. Mice were observed daily for side effects and mortality, with blood work and necropsy at 42 d of age to evaluate for pathologic changes. To determine the efficacy of topical LS, postweanling mice infested with M. musculinus were treated with LS once weekly for 2 wk and then housed with uninfested sentinel mice for 4 wk. Weekly tape tests and postmortem tape tests and skin scrapings were performed on all mice. Treated postweanling mice had significantly lower Hgb levels and higher BUN levels than did control animals. In mite-infested mice, the number of positive cages at euthanasia was the same between treated and control animals. Although topical LS did not cause gross or microscopic changes to organ systems, it may cause clinicopathologic changes, and topical LS is not effective as a sole treatment for M. musculinus infestation of postweanling mice.