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Treatment and eradication of murine fur mites: III. Treatment of a large mouse colony with ivermectin-compounded feed
Rodolfo J Ricart Arbona1, Neil S Lipman, Felix R Wolf
1Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College and The Rockefeller University, New York, New York, USA. ricartr@pi.cpmc.columbia.edu
Abstract:
We determined the efficacy of ivermectin-compounded feed against fur mites in mice and describe its use to eradicate mites in vivaria holding approximately 30,000 cages. C57BL/6NCrl mice infested with Myobia musculi and Myocoptes musculinus were treated with ivermectin-compounded feed (approximate ingested dose, 1.3 mg/kg) for 1, 4, or 8 consecutive weeks. Regardless of treatment duration, all treated mice, as well as contact sentinels, remained free of fur mites for as long as 21 wk after treatment. No adverse effects were observed. Subsequently, facility-wide treatment was implemented in an attempt to eradicate fur mites from 3 vivaria housing approximately 120,000 mice. Medicated feed was provided for 8 wk to ensure that all cages and mice were treated. A single investigative group reported adverse effects in their colony 4 wk after treatment was initiated; mortality was attributed to ivermectin toxicity after an intracranial injection at 1 d of age. Naïve pups were unaffected. No other adverse effects were noted. Approximately 14,500 skin scrape samples were evaluated during the 12-mo posttreatment surveillance period. All samples were negative for mites. To our knowledge, this is the first report of successful eradication of fur mites from a mouse colony of this large size.
Insights
Ivermectin-compounded feed effectively eliminated fur mites in mice, even in large-scale vivarium settings. This treatment offers a safe and successful method for eradicating mites in mouse colonies.
Area of Science:
- Veterinary Medicine
- Parasitology
- Laboratory Animal Science
Background:
- Fur mites (Myobia musculi and Myocoptes musculinus) are common ectoparasites in laboratory mice.
- Mite infestations can compromise research integrity and animal welfare.
- Effective and scalable eradication strategies are crucial for maintaining healthy research animal populations.
Purpose of the Study:
- To determine the efficacy of ivermectin-compounded feed against fur mites in mice.
- To describe the use of ivermectin-compounded feed for facility-wide mite eradication in large vivaria.
- To assess the safety and long-term effectiveness of this treatment approach.
Main Methods:
- Mice were treated with ivermectin-compounded feed at an approximate dose of 1.3 mg/kg for 1, 4, or 8 weeks.
- Facility-wide treatment involved providing medicated feed for 8 weeks to approximately 120,000 mice across 3 vivaria.
- Post-treatment surveillance included approximately 14,500 skin scrapes over 12 months.
Main Results:
- All treated mice and contact sentinels remained mite-free for up to 21 weeks post-treatment, regardless of duration.
- Facility-wide eradication was achieved, with all post-treatment skin scrapes testing negative for mites.
- One adverse event of mortality in neonatal pups was reported, attributed to ivermectin toxicity from intracranial injection, but naive pups were unaffected. No other adverse effects were noted.
Conclusions:
- Ivermectin-compounded feed is a highly effective and safe treatment for fur mites in mice.
- This method facilitated the successful eradication of fur mites from a large-scale mouse colony (approx. 120,000 mice).
- The study presents the first report of successful, large-scale fur mite eradication in a mouse vivarium using ivermectin-compounded feed.
