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Identification and Treatment of Fur Mites (Radfordia lemnina) in California Deer Mice (Peromyscus californicus) Using
Abstract:
Peromyscus species have been used in research for decades, yet there are no specific reports of mite infestations in the laboratory setting despite many reports of various mite species found in wild Peromyscus. This study documents P. californicus infestation with Radfordia lemnina in an academic research setting. During the colony quarantine period, deer mice tested positive on a general mite PCR but negative on all species-specific mite PCR assays. Tape tests were performed on a subset of cages, and 21% were positive for adult mites or viable eggs. Mites were sent for sequencing and identified as R. lemnina, for which the natural host is Microtus pennsylvanicus. The entire colony was treated with selamectin, applied topically to the nape of the neck, and repeated one month later. All deer mice were successfully treated using a novel method of restraint, and no gross adverse reactions to selamectin treatment were noted. Tape tests were performed weekly to biweekly on a subset of deer mice, and PCR was used to confirm negative tape test results. PCR was positive at 14 wk posttreatment, and tape tests were intermittently positive for egg casings for 27 wk, indicating continued presence of genetic material but not necessarily an active infection. Weaned offspring were tape test and/or PCR negative at 12 and 21 wk posttreatment, providing further support for successful treatment. At 31 wk, 2 rounds of tape tests and PCR were both negative. This report documents a safe and effective treatment method for mites in P. californicus.
Insights
This study details a Radfordia lemnina mite infestation in laboratory Peromyscus californicus mice. A novel topical selamectin treatment protocol proved safe and effective for eradicating mites in the research colony.
Area of Science:
- Veterinary Parasitology
- Laboratory Animal Science
- Rodent Health
Background:
- Peromyscus species are common research models, but laboratory mite infestations are rarely reported.
- Wild Peromyscus harbor various mite species, posing a potential risk to research colonies.
- This study addresses a specific mite infestation in a Peromyscus californicus colony.
Purpose of the Study:
- To document the first reported case of Radfordia lemnina mite infestation in a laboratory Peromyscus californicus colony.
- To identify the mite species and confirm its presence using molecular methods.
- To evaluate the efficacy and safety of a selamectin-based treatment protocol.
Main Methods:
- Mite identification using PCR and sequencing.
- Diagnosis confirmed via tape tests and PCR during quarantine.
- Colony-wide topical selamectin treatment administered twice, with novel restraint.
- Post-treatment monitoring using weekly/biweekly tape tests and PCR.
Main Results:
- Radfordia lemnina mites, typically found on Microtus pennsylvanicus, were identified in Peromyscus californicus.
- Topical selamectin treatment was successfully implemented using a new restraint method.
- No adverse reactions to selamectin were observed in the treated deer mice.
- Post-treatment monitoring confirmed eradication, with negative tape tests and PCR by 31 weeks.
Conclusions:
- This report establishes a safe and effective treatment strategy for R. lemnina mites in Peromyscus californicus.
- The findings highlight the importance of vigilant parasite screening in laboratory animal facilities.
- Successful treatment using selamectin provides a valuable method for maintaining research colony health.
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