| Mandibular lesions in two bison from the early Holocene of Nebraska were compared with a mandible from a modern cow diagnosed with actinomycosis, or lumpy jaw. Lesions were studied using radiographic analysis and various thin sectioning techniques, including both paraffin- and methyl methacrylate-embedding and ground sections, with appropriate stains. Two new techniques for producing stained sections from thinly ground material are discussed. The gross, radiographic and histologic appearances of the mandibular lesions were consistent with a moderately severe, locally extensive, chronic, mandibular osteomyelitis with intralesional fungal organisms, morphologically consistent with Coccidioides immitis. These can represent either primary cutaneous or disseminated respiratory infections. The modern distribution of the organism in North America is limited to the arid southwestern United States and parts of Mexico. Possible migration of bison herds from sites in Nebraska to endemic foci is postulated along with changes in paleoclimate. |
