Self-Mutilating Lesions Associated with Rabies in White-Tailed Deer (Odocoileus virginianus): Detection and Diagnosis.

Rabies is a universally fatal viral disease that affects a wide variety of mammalian species, including carnivores and herbivores. While testing and confirmed reports in wild carnivores are common, comparatively less is known about this disease in wild herbivores. Between 2022 and 2024, nine white-tailed deer (Odocoileus virginianus) in Pennsylvania, USA were diagnosed with rabies. Eight (89%) presented with erratic neurologic signs and one was found dead. Evidence of chronic self-mutilation characterized by hair loss and thickened, hardened, and hyperpigmented skin was present on the head in seven cases (78%) and/or body or legs in two cases (22%), while two (22%) did not have any evidence of external lesions. Microscopically, lesions were like those in other mammalian species, with variably severe inflammation and abundant cytoplasmic inclusion bodies with associated antigen immunoreactivity. This case series highlights a common and characteristic gross lesion that can prompt caution and testing for rabies in deer and further expands understanding of this disease in an uncommonly diagnosed species.