Ivermectin Treatment of Demodicosis in 56 Hamsters.

Abstract

ABSTRACT. Fifty-six hamsters with demodicosis were treated with daily oral administration of ivermectin (0.3 mg/kg). Thirty-three cases (58.9%) were cured and 6 cases (10.7%) had improved clinically but needed to continue treatment. Of 5 cases (8.9%) who relapsed within 3 months and were retreated with ivermectin, 4 were cured and 1 needed further treatment. Five cases (8.9%) had improved clinically but died within 3 months. Seven cases (12.5%) had not improved and died within 3 months. Overall 49 (87.5%) hamsters had improved clinically. No significant differences in prognosis of demodicosis were detected according to sex, breed, age and clinical features, but the prognosis of demodicosis in hamsters with concurrent disease was poor. KEY WORDS: demodicosis, hamster, ivermectin.J. Vet. Med. Sci. 63(11): 1245-1247 In hamsters, demodex is thought to be a common parasite [7,8,11,13,15] and to cause demodicosis associated with immunosuppressive disorders [3,13,15,16], but this latter conclusion is drawn from single case reports or studies of hamsters kept under experimental conditions, and clinical confirmation of underlying disease is often deficient or lacking. In addition, there is little information regarding the response to treatment of demodicosis in hamsters [4]. Demodicosis in dogs is usually treated with amitraz [1], but most topical drugs may be unsuitable for the treatment of demodicosis as they fail to reach the deep-seated immature stages of the mites [8]. Ivermectin treatment has been evaluated in dogs with generalized demodicosis [6,9,10,12,14] and the efficacy of this drug has been reported [9,14]. Topical treatment with amitraz seems to be effective in hamsters with demodicosis [1,13,15], although the efficacy of amitraz varies from one animal to another and the duration of treatment is long for their life-span. The purpose of the present study was to evaluate the efficacy of ivermectin treatment in hamsters with demodicosis in Japan.The veterinary records of all hamsters with demodicosis diagnosed between January 1997 and December 1999 in Kyoto, Japan were reviewed. Demodicosis was diagnosed in hamsters with alopecia associated with a large number of demodex mites visible microscopically in skin scrapings. Careful physical examination of all hamsters and ultrasonography or X-ray of some hamsters was performed, but extensive work-ups such as a CBC, serum biochemical analyses, or serum hormone levels were not performed. Fiftysix hamsters were treated with daily oral administration of ivermectin (0.3 mg/kg). These hamsters were considered to be cured when all skin lesions caused by the demodex mites had resolved and the results of microscopic examination of skin scrapings remained negative for 3 months. The distribution of demodicosis in male and female hamsters was evaluated with the z-test. The influence of sex, breed, age, clinical features at initial presentation and concurrent disease on prognosis was evaluated with the Kruskal-Wallis test and/or Mann-Whitney U test. Differences at P<0.05 were co...

Atypical fibrosarcoma in the skin of a Roborovski hamster (Phodopus roborovskii)

“…The more commonly encountered neoplasms in these 2 species include epithelial papilloma, androgen‐dependent atypical fibroma, mammary gland adenoma, and plasmactyoma . Atypical fibroma (and its malignant variant, atypical fibrosarcoma) has rarely been reported in hamsters and, to the best of the authors' knowledge, has never been reported in a Roborovski hamster.…”

First description of demodicosis in 12 galagos (Galago senegalensis)

“…In contrast, ivermectin appeared to be very effective in the treatment of demodicosis in humans after only a single systemic dose of 200 μg/kg (combined with topical permethrin; the route of administration of ivermectin was not reported) 27 or oral 250 μg/kg alone 28 . Ivermectin has been reported to be an effective treatment of demodicosis in other species (dogs, 5,29 a koala 15 and hamsters 30 ). In this report, ivermectin was used at 600 μg/kg once daily.…”

Infestivity of Demodex canis to Hamster Skin Engrafted onto SCID Mice

“…Even under an immunosuppressive condition, the number of Demodex mites does not increase in humans [2]. In contrast, generalized demodicosis is frequently detected in dogs [18] and hamsters [19], indicating the relationship with immunodeficiency.Genetically immunodeficient mice have been used as a xenograft model as they fail to reject skin grafts. The absence of a functioning immune system allows xenogenic transplantation into severe combined immunodeficiency (SCID) mice without major graft rejection.…”

“…Even under an immunosuppressive condition, the number of Demodex mites does not increase in humans [2]. In contrast, generalized demodicosis is frequently detected in dogs [18] and hamsters [19], indicating the relationship with immunodeficiency.…”

“…They suggested host specificity of D. canis because they failed to infect murine skin with D. canis. However, demodicosis has been rarely reported in mice, and thus the host specificity of D. canis needs to be tested by using animals such as the hamster for which naturally occurring generalized demodicosis has been well recognized [19]. The purpose of the present study was to evaluate the infestivity of Demodex canis to hamster skin engrafted onto SCID mice.…”