Abstract

Mange is a dermatopathy of captive and wild black bears (Ursus americanus) caused by Demodex spp., Sarcoptes spp., and Ursicoptes spp.^3,4 Ursicoptes americanus is an audycoptid mite that lives in hair follicles.^2,5 The morphology of U. americanus has been well described⁵; however, a limited number of clinical descriptions of ursicoptic mange exist in the literature. Reports of clinical presentation of ursicoptic mange have been variable and may include mild to severe facial alopecia² associated with chronic lesions of the muzzle and forehead,⁵ crusting,³ and pruritus^3,5. Distribution of alopecia has also been variable and may be limited to the head² or include the neck, thorax and limbs⁵.

A juvenile female black bear presented to The Wildlife Center of Virginia in November 2003. On physical examination the bear weighed 6.25 kg and was emaciated and dehydrated. A clean wound approximately 4 cm long with thickened skin edges was present in the left axilla. Moderate fecal staining was present around the hindquarters. Large areas of bilateral alopecia with a diffuse thinning of the hair were also noted. The alopecia was more significant on all limbs, particularly in the flank region of the hind limbs, the ventral thorax and abdomen, and ventral to the ears. There was minimal alopecia on the face and along the spine. Small crusty scabs with associated erythema were present throughout the skin. There was no evidence of hyperkeratosis. Initial therapy consisted of basic wound management, rehydration and antibiotic therapy with ceftiofur (Excenel®, Pharmacia & Upjohn, Kalamazoo, MI, USA; 2 mg/kg) administered intramuscularly.

Complete diagnostic investigation was staged over the next 3 days and included hematology, serum chemistry profile, direct and flotation fecal examinations, survey radiographs, skin scrapings and skin biopsies. Hematology showed a severe anemia and severe panleukopenia. Serum chemistry panel showed a mildly decreased creatinine and calcium. Fecal examination revealed moderate to heavy numbers of Coccidia, Strongyloides, pinworms and ascarids. Baylisascaris transfuga infection was confirmed based on egg measurement and morphology from fresh fecal samples submitted to the Southeastern Cooperative Wildlife Disease Study (SCWDS). Radiographs were within normal limits. Skin scraping revealed several audycoptid mites identified as Ursicoptes americanus.⁵ Multiple skin biopsies were submitted to SCWDS for histopathologic examination. Microscopic examination identified golden brown pigment, interpreted to be mite feces, within hair follicles and along the skin surface. Occasionally, partial profiles of mites were noted on the epithelial surface and within some hair follicles. These mites were generally round with cuticular spines. Mite legs were not observed. Large numbers of yeast and fewer mixed bacteria were also noted on the skin surface and in some follicles; however, no associated inflammation was reported.

Treatment of ursicoptic mange was initiated with ivermectin (Ivomec®, Merial, Iselin, NJ, USA; 0.3 mg/kg SQ). Repeat ivermectin treatments were administered at 2 weeks (0.3 mg/kg PO), 3 weeks (0.3 mg/kg SQ) and 6 weeks (0.3 mg/kg SQ) after initial therapy. Three weeks after initial therapy, dermatologic examination of the bear under anesthesia showed no improvement and a secondary pyoderma was observed. Skin scrapings showed one dead Ursicoptes americanus mite. The bear was treated with trimethoprim/sulfamethoxazole (sulfamethoxazole and trimethoprim tablets, USP, Mutual Pharmaceutical Co., Inc., Philadelphia, PA, USA; 32 mg/kg PO BID for 7 days. Six weeks after initial ivermectin therapy, the bear cub was again examined under anesthesia and dermatologic evaluation showed generalized fur growth with only occasional crusted areas. Skin scraping showed one dead Ursicoptes americanus mite. Visual examination of the bear over the next 4 months showed a continued improvement in the pelage with no signs of pruritis. Steady weight gain and a generalized improvement in body condition were also noted.

Few reports describe the successful treatment of ursicoptic mange in black bears.^1,2 Currently, the recommended therapy consists of multiple treatments with amitraz.^2,3 The use of ivermectin has been reported to be unsuccessful in treating ursicoptic mange.¹ However, this report describes the successful treatment of ursicoptic mange in a black bear using repeated high doses of ivermectin, which can now be considered as an alternative treatment.

While Ursicoptes americanus has been identified in free-ranging black bears in the nearby state of Pennsylvania (M. Ternent, personal communication), this is the first report of Ursicoptes americanus associated with clinical mange in a free-ranging black bear in Virginia (D. Martin, personal communication). Further surveillance is planned in order to determine the prevalence of this mite infestation in black bears in Virginia.

Acknowledgments

We thank the Virginia Department of Game and Inland Fisheries for their cooperation and the staff of The Wildlife Center of Virginia for their excellent animal care.

Literature Cited

1.  Fowler, M.E. 1986. Ursidae (Bears). In: Fowler, M.E., ed. Zoo and Wild Animal Medicine. 2nd ed. W.B. Saunders, Philadelphia, PA. Pp 811–816.

2.  Gillespie, D., Schmietzel, L., Fowler, M.E. 1984. Successful treatment of audycoptid mange in a black bear. J Am Vet Med Assoc. 185: 1433.

3.  Ramsay, E.C. 2003. Ursidae and Hyaenidae. In: Fowler, M.E. and Miller, R.E., eds. Zoo and Wild Animal Medicine. 5th ed. Saunders, St. Louis, MO. Pp 523–534.

4.  Schmitt, S.M., Cooley, T.M., and Friedrich, P.D. 1987. Clinical mange of the black bear (Ursus americanus) caused by Sarcoptes scabiei (Acarina, Sarcoptidae). J. Wildl. Dis. 23: 162–165.

5.  Yunker, C.E., Binninger, C.E., Keirans, J.E., Beecham, J. and Schlegel, M. 1980. Clinical mange of the black bear, Ursus americanus, associated with Ursicoptes americanus (Acari: Audycoptidae). Journal of Wildlife Diseases. 16(3): 347–356.