Blackleg in a free-range brown brocket deer (Mazama gouazoubira)

A case of blackleg in a brown brocket deer (Mazamagouazoubira) associated with trauma from being hit by a car in southern Rio Grande do Sul is reported. The clinical signs included fever, dehydration and lethargy that worsened progressively until 36 hours after the accident, when the animal died. In the fore right limb, there was a comminuted closed fracture of the radius and ulna but no skin wounds were observed. Grossly, the musculature of the pelvic limbs presented hemorrhage, edema and emphysema. Microscopically, the muscles of both rear legs had necrosis, edema, hemorrhage and mild inflammatory infiltration of neutrophils. Clostridium chauvoei was cultured from affected skeletal muscles, and it was also detected by immunohistochemistry, confirming a diagnosis of blackleg. The overlapping habitat of cattle and brown brocket deer is proposed as a predisposing factor in this case and alerts to spillover cases maybe happening in this region. In addition, blackleg should be included as differential diagnoses of deer with post-traumatic myositis.