NOVEL PCR ASSAYS FOR THREE FUR MITES IN NATURALLY INFECTED MICE WITHOUT ANIMAL SACRIFICE

Rodent fur mite infestation is a persistent and intractable problem in laboratory rodent colonies, due to insensitive diagnostics, unrepresentative samples for testing and improper sentinel system. Myocoptes musculinus (COP), Myobia musculi (MOB) and Radfordia affinis (RDA) have been reported in laboratory mouse colonies. To improve the sensitivity and efficiency of fur mite detection, COP-specific PCR and MOB/RDA-specific PCR assays were developed to detect and differentiate these fur mites, with the existence of a rodent housekeeping gene. The COP-specific PCR and the MOB/RDA-specific PCR could specifically detect COP and MOB/RDA at as low as 10 copies, respectively. In comparison of the specific PCRs with traditional methods (pluck test, tape test and pelt exam) for fur mite diagnosis, 31 rodents and 17 cage environment samples were evaluated. In screening for the infestation status of various fur mites on individual animals, the specific PCR assays showed distinctly higher sensitivity and accuracy (100% and 100%) than those of the traditional methods (sensitivity: 25–80%, accuracy: 83.9–96.8%). Interestingly, by using cage wipe environmental samples, the specific PCR assays exhibited 100% sensitivity and accuracy in the fur mite detection and differentiation. The COP-specific and MOB/RDA-specific PCR assays developed in this study could be reliable alternatives for routine pathogen monitoring of laboratory mice and environments of animal facilities without animal sacrifice. [Chou C-L, Cheng Y-C, Wang MH, Wan CH, Novel PCR assays for three fur mites in naturally infected mice without animal sacrifice, Taiwan Vet J 46(4):133–142, 2020.]