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Demodectic Mange, Dermatophilosis, and Other Parasitic and Bacterial Dermatologic Diseases in Free-Ranging White-tailed Deer (Odocoileus virginianus) in the United States From 1975 to 2012

Nemeth, N. M., Ruder, M. G., Gerhold, R. W., Brown, J. D., Munk, B. A., Oesterle, P. T., Kubiski, S. V., Keel, M. K.
Demodex, Dermatophilus congolensis, Nematoda, Odocoileus virginianus, alopecia, animal pathology, autumn, bacteria, chiggers, deer, demodicosis, demography, ears, erythema, face, fungi, game animals, hunters, inflammation, lice, males, mange, neck, ticks, wildlife diseases, zoonoses, Southeastern United States
The white-tailed deer (Odocoileus virginianus) is a common and widespread North American game species. To evaluate the incidence, clinical manifestations, demography, and pathology of bacterial and parasitic dermatologic diseases in white-tailed deer in the southeastern United States, we retrospectively evaluated white-tailed deer cases submitted to the Southeastern Cooperative Wildlife Disease Study from 1975 to 2012. Among 2569 deer examined, bacterial or parasitic dermatologic disease was diagnosed in 88 (3.4%) individuals, with Demodex spp (n = 37; 42.0%) and Dermatophilus congolensis (n = 19; 21.6%) as the most common causes. Demodicosis was significantly more common in deer older than 2 years and was most often detected in the fall; no statistically significant sex predilection was identified. Affected animals had patchy to generalized alopecia, often distributed over the head, neck, limbs, and trunk; microscopic lesions included epidermal crusts and cutaneous nodules with mild perifollicular, lymphoplasmacytic inflammation. Dermatophilosis was most common in males younger than 1 year that were often found dead. Crusting, erythema, and alopecia occurred on the face, ears, and distal extremities. Less commonly, infectious dermatologic diseases were associated with other bacteria (n = 13; 14.8%), fungi (n = 5; 5.7%), ectoparasites (chiggers, lice, mites, and ticks; n = 11; 12.5%), and larval nematodes (n = 7; 8.0%). Population-level effects of these diseases in white-tailed deer are likely minimal; however, due to their dramatic presentation, demodicosis, dermatophilosis, and other infectious skin diseases can be of concern to hunters and, in some cases, may have zoonotic potential.