Palaeopathological evidence of infectious disease in a skeletal population from late medieval Riga, Latvia (15^th-17^th centuries AD)

The aim of this study was to evaluate the presence of infectious disease in the Dome Church (Riga Cathedral) Cemetery population, dating from the late medieval period (15^th-17^th centuries AD). A total of 274 individuals were macroscopically observed for evidence of infectious disease, and seven individuals with lesions possibly associated with a bacterial infection affecting the skeleton were selected for further analysis. Pathological changes on the outer table of the skull and in the long bones of legs characteristic of venereal syphilis were observed in four female and one male individual. Likewise, changes possibly related to late congenital syphilis were observed in a 14-15-year-old non-adult individual. All these individuals were buried in a small area adjacent to the northern wall of the Dome Church, which possibly belonged to a hospital or a shelter. The evidence for venereal syphilis from the cemetery complements historical data about the spread of the disease in Riga during the 16^th-17^th centuries AD. One adult male individual had destructive changes in the lower spine, which could be associated with tuberculosis (TB). So far, this is the first individual with possible TB from the archaeological populations of Riga. This research provides unique evidence about infectious disease in skeletal populations from the late medieval period in Latvia, and the results will be used as the basis for future research in the subject, including extraction of ancient pathogen DNA.