moxidectin and Rodent-Diseases

To protect the biosecurity of research rodent colonies, research institutions frequently require a quarantine period for live animals transferred into their facilities. Quarantine practices often include antibiotic and antiparasitic treatment with drugs such as fenbendazole and macrolide lactones. The influence of these compounds on the resident gut microbiota of mice is unknown, and any effects might subsequently affect model reproducibility. To test the influence of standard quarantine procedures on the composition of the microbiota, C57BL/6 mice, purchased from 2 different commercial suppliers, were randomly assigned to treatment groups (n = 12) by vendor and treated with fenbendazole-supplemented feed, topical moxidectin, both treatments, or no treatment (control), according to our institution's standard treatment regimen and duration. Feces were collected on arrival, immediately after completing the 8-wk treatment, and at 2 and 4 wk after treatment. Fecal DNA was extracted, sequenced, and analyzed to compare the changes in the microbiota of treated and control groups. Although significant main effects of time and treatment and interactions between those variables were detected in comparisons of richness, α-diversity, and β-diversity, the effect sizes associated with any particular treatment were consistently much smaller than that associated with acclimation to a new facility in the absence of any quarantine treatments. This outcome, along with the visual evaluation of principal coordinate analysis based on multiple similarity indices, suggests that time or institution plays a larger role in alterations of the murine gut microbiota than do quarantine treatments on its composition.

Topics: Administration, Oral; Animal Feed; Animals; Antinematodal Agents; Feces; Fenbendazole; Food, Fortified; Gastrointestinal Microbiome; Laboratory Animal Science; Macrolides; Mice; Mice, Inbred C57BL; Microbiota; Quarantine; Random Allocation; Reproducibility of Results; Rodent Diseases

Demodex musculi is a prostigmatid follicular mite that has rarely been reported in laboratory mice. Although prevalence of this species has not been assessed formally, we have found that many imported mouse strains from noncommercial sources harbor Demodex mites. To assess whether an acaricide can be used to eradicate this mite, infested immunocompromised mice were provided ivermectin-compounded (12 ppm) feed without restriction for 8 wk (n = 10), were treated topically with moxidectin and imidacloprid (MI; 3 and 13 mg/kg, respectively) weekly for 8 wk (n = 10), or remained untreated (n = 10). Mice were confirmed to be mite-infested before treatment and were tested after treatment by using fur plucks (FP), deep skin scrapes (DSS), and PCR analysis of fur swabs. In addition, the presence of mites was confirmed through skin biopsies at 2 study endpoints (1 wk [n = 5] and 12 wk [ n = 5] after treatment). Samples collected before treatment and from untreated mice were positive for D. musculi at all time points and by all test modalities. After treatment, all ivermectin-treated animals remained infested, whereas mice treated with MI were repeatedly negative by all test modalities. An additional shortened treatment trial revealed that 4 wk of MI (n = 7) was insufficient to eradicate mites. Neither treatment produced any evidence of adverse effects according to hematology, serum chemistry parameters, behavior, body weight, and histopathology. Of the 70 PCR assays performed in treated mice, 14 were positive when FP+DSS was negative. In 6 cases where PCR results were negative, 5 were positive by FP+DSS and a single sample was positive on skin biopsy. Although PCR analysis has a high detection rate for D. musculi, FP+DSS can further enhance the detection rate. In conclusion, topical MI administered for 8 consecutive weeks can safely eradicate D. musculi from an immunocompromised mouse strain.

Topics: Administration, Oral; Administration, Topical; Animal Feed; Animals; Drug Combinations; Female; Insecticides; Ivermectin; Laboratory Animal Science; Macrolides; Male; Mice; Mite Infestations; Mites; Neonicotinoids; Nitro Compounds; Polymerase Chain Reaction; Rodent Diseases

A field trial was conducted to assess the safety and efficacy of oral administration of moxidectin in mice naturally infected with the fur mites Radfordia affinis. The natural infection was diagnosed in two colonies within a large academic institution by direct hair examination. Animals received moxidectin (1% Cydectin, FortDodge) at an oral dosage of approximately 2 mg/kg body weight by micropipette; administration was repeated after 15 days. Forty mice served as an untreated control group. Moxidectin treatment resulted in clinical improvement within a few days after initial treatment, and mites were eradicated from all infested animals at day 30. No side effects or signs of ill health were observed in any of the treated animals. To our knowledge, this is the first report of oral moxidectin for treatment of murine acariosis.

Topics: Administration, Oral; Animals; Drug-Related Side Effects and Adverse Reactions; Female; Insecticides; Macrolides; Male; Mice; Mice, Inbred Strains; Mite Infestations; Mites; Rodent Diseases; Time Factors

A breeding colony consisting of 250 different strains of mice was treated with the topical acaricide selamectin for the mouse fur mite Myocoptes musculinus, with no apparent ill effect, suggesting that this drug is safe for use in mice. To further evaluate their efficacy in treating Myocoptes spp., we compared selamectin with another acaricide, moxidectin, in a controlled manner. Infested mice were treated with selamectin or moxidectin at the time of cage change, and a subset of mice was retreated 10 d later. Mice underwent routine cellophane tape examination of the pelage for 1 y. Although no adult mites were found in any group at 1 mo after treatment, egg casings were found in the selamectin treatment group as late as 6 mo after treatment, prompting concern about its effectiveness. Moxidectin used in combination with cage changing was effective in eradicating mites, with mice negative for traces of mites on cellophane tape examination of the pelage from months 2 through 12 after treatment.

Topics: Animal Husbandry; Animals; Female; Insecticides; Ivermectin; Macrolides; Mice; Mice, Inbred Strains; Mite Infestations; Rodent Diseases; Treatment Outcome

Guinea pigs are susceptible to lice infestations. Ten guinea pigs infested with Gliricola porcelli were free of adult lice and eggs, and of adverse reactions, 30 days after treatment, with a single application of 0.05 mL of a solution containing 10% (w/v) imidacloprid and 1% (w/v) moxidectin indicating that this procedure is an effective treatment for lice infestations in guinea pigs.

Topics: Animals; Female; Guinea Pigs; Imidazoles; Insecticides; Lice Infestations; Macrolides; Male; Neonicotinoids; Nitro Compounds; Rodent Diseases; Treatment Outcome

Topics: Alopecia; Animals; Female; Guinea Pigs; Imidazoles; Insecticides; Keratosis; Macrolides; Male; Neonicotinoids; Nitro Compounds; Rodent Diseases; Sarcoptes scabiei; Scabies; Skin

Murine fur mites are reported to exist in over one-third of research institutions and can be problematic to eliminate. Current treatment strategies can be labor-intensive, toxic, and may confound research studies. The ideal method would be technically simple, safe, effective, and relatively inexpensive. When we found that mice from a noncommercial vendor were infested with Myocoptes musculinus, the animals were treated topically with Cydectin pour-on (containing moxidectin 0.5%) at 0.5 [corrected] mg/kg. After one treatment, mites were eradicated from all infested mice. No toxic effects or clinical signs of illness were observed in the mice. To the authors' knowledge, this is the first report of topical moxidectin as a treatment for murine acariasis.

Topics: Animal Husbandry; Animals; Female; Insecticides; Macrolides; Male; Mice; Mice, Inbred Strains; Mice, Knockout; Mite Infestations; Mites; Rodent Diseases

Thirty hamsters diagnosed with a Notoedres infestation on the basis of their clinical signs and skin scrapings were allocated to three matched groups. The hamsters in group 1 received ivermectin at 400 microg/kg subcutaneously once a week for eight weeks, those in group 2 were treated with moxidectin at 400 microg/kg orally once a week, and those in group 3 were treated with moxidectin at the same dosage, but twice a week. The hamsters' skin lesions were scored weekly on the basis of the severity of crusting, erythema, scaling and excoriations at various sites. In all three groups the lesion scores were significantly lower after four and eight weeks, and there was no significant difference between the efficacy of the treatments. However, at the end of the treatment, skin scrapings were negative in only 60 to 70 per cent of the animals in each group.

Topics: Administration, Oral; Animals; Anti-Bacterial Agents; Cricetinae; Injections, Subcutaneous; Insecticides; Ivermectin; Macrolides; Mite Infestations; Rodent Diseases; Treatment Outcome

In this study, the effect of doramectin, moxidectin and netobimin was investigated in naturally infected Syphacia muris in rats. The natural infection was determined by the use of cellophane tape method on the perianal region and by the technique of centrifugal flotation of feces. The infected rats were divided into three treated and one control group (N = 10). Doramectin and moxidectin at the dose of 0.2 mg/kg per day and netobimin at the dose of 7.5 mg/kg per day were given in the diet for 4 days. Cellophane tape preparations were performed in all groups on 4th and 7th day after the last treatment. The rats of treated groups were necropsied on 7th day after the last treatment together with that of control group. While doramectin and netobimin were highly effective against S. muris, moxidectin was not found to be effective for eradication of S. muris.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Cellophane; Female; Guanidines; Ivermectin; Macrolides; Male; Oxyuriasis; Oxyuroidea; Perianal Glands; Random Allocation; Rats; Rats, Sprague-Dawley; Rodent Diseases

Haemonchus contortus- and Trichostrongylus colubriformis-infected jirds (Meriones unguiculatus) are useful for anthelmintic studies. With concurrent infections of these parasites established in the jird, questions of not only anthelmintic activity, but to some extent spectrum, could be assessed in a single model system. This report outlines a model using immunosuppressed (0.02% hydrocortisone in feed) jirds concurrently infected with H. contortus and T. colubriformis. Immunosuppressed jirds were inoculated with approximately 1,000 exsheathed infective larvae of each species, treated per os on day 10 postinoculation (PI), and killed on day 13 PI. Stomachs and small intestines were removed, opened longitudinally, incubated in distilled water at 37 C for 5 hr, fixed in formaldehyde solution, and stored for subsequent examination. Contents of both organs were examined using a stereomicroscope (15-45 x). Various standard anthelmintics were evaluated in the model; modern broad-spectrum ruminant anthelmintics (benzimidazoles, febantel, ivermectin, levamisole hydrochloride, and milbemycin D) are active uniformly and in most cases at doses comparable to those required for efficacy against these parasites in ruminants. This model, using worms of 2 genera living in distinct sites, allows preliminary evaluation of anthelmintic activity and spectrum for experimental compounds in a single cost- and resource-efficient experiment.

Topics: Animals; Anthelmintics; Anti-Bacterial Agents; Benzimidazoles; Bithionol; Diethylcarbamazine; Gerbillinae; Guanidines; Haemonchiasis; Macrolides; Piperazine; Piperazines; Pyrantel Tartrate; Rodent Diseases; Trichostrongyloidiasis