Gross pathology and Erysipelothrix rhusiopathiae immunohistochemistry staining of skin lesions on the foot (A, a, C) and mouth (B, b, D) of two adult muskoxen (Ovibos moschatus) harvested (bull) and a found dead (cow) in 2014 and 2015, respectively, on Victoria Island (Nunavut, Canada). (A, a) Adult bull: tarsus, plantar aspect, crust, and hyperkeratosis surrounding an ulcerative lesion (7×3 cm) on the coronary band. (B, b) Adult cow: thick crusts with fissures (3.5×2 cm) on the lower lip (black arrows). (C) Superficial part of crusted skin proliferations from the coronary band with dark-brown staining of E. rhusiopathiae (black arrows). Immunohistochemistry using a polyclonal E. rhusiopathiae antiserum and hematoxylin counterstain. (D) Skin from the lower lip showing positive E. rhusiopathiae staining in the superficial crust (black arrows). Immunohistochemistry staining as above. s=surface; sc=stratum corneum; sg=stratum granulosum of the epidermis. Scale bars as shown.