Figure 6. Strategy to detect the Y. pestis antigen in ancient specimens by ELISA and iPCR.

In total, 34 ancient teeth were collected from skeletons that were excavated at five archaeological sites covering a broad time span from the 5^th to 16^th centuries. Dental pulp was extracted from 34 historically positive teeth and 20 negative teeth, which included modern and ancient teeth. The cut-off values for ELISA and iPCR were determined based on the screening of 10 negative teeth. Finally blind screening of 46 coded teeth, including the 34 historically positive teeth, 10 negative teeth and 2 blank controls was performed.