Evaluating the effectiveness of moxidectin treatment in mite-infested mice and development of an in-house PCR assay for detecting Myobia musculi DNA.

Detection and eradication of fur mite infestations in mouse colonies can present a challenge to a laboratory animal facility. In 2011, an outbreak of Myobia musculi occurred in the University of Texas M.D. Anderson Cancer Center, Science Park animal facility, and the current case study describes the treatment with moxidectin, its effectiveness in controlling the outbreak, and the subsequent development of a PCR-based detection protocol. Methods of DNA collection using sterile swabs and fecal pellets were also evaluated. Results from the first mite check after the treatment indicated that moxidectin was highly effective in killing mites, but evidence of the infestation (mite body parts and eggs) was clearly visible throughout the duration of the monitoring period. Results from the PCR assay on swab samples were directly correlated with those of the conventional hair pluck samples, indicating that swabbing could be added to routine QA hair pluck monitoring procedures to increase the chances of detecting mites in laboratory mice. However, it is essential to keep in mind that positive PCR results may not necessarily indicate an active infestation but only the presence of mite DNA in the hair coats of mice.