Differential diagnosis of rib lesions: a case study from Middle Woodland southern Ontario circa 230 A.D.

The right ribs of an adult male (#18) from the LeVesconte Burial Mound in southern Ontario show extensive osteolytic and/or osteobastic lesions, some with bone thickening, interpreted herein as evidence of a chronic actinomycotic infection. In the alveolus, the presence of periapical abscesses and periodonitis with secondary inflammation may be associated with the pathogenesis of this bacterial disease by providing the normally commensurate Actinomyces israelii with the necessary conditions for their reproduction. This presumptive diagnosis, if correct, appears to represent the first case of actinomycosis in human palaeopathology. Recent literature reviews suggest that actinomycosis was not uncommon in preantibiotic populations, and that it has a high predilection for bone. Though actinomycosis can be associated with any subsistence strategy, such as, in this case, hunting and gathering, hypothetically it is most likely to occur in agricultural populations where general disease stress and age-adjusted dental pathology are highest. It is argued that in the differential diagnosis of archaeological specimens, as much attention should be given to the documentation of the natural range of variation of lesions produced by less well-known diseases, such as actinomycosis, since the disease ecology of pre-western populations differed significantly from our own.