Overview of Y. pestis subspecies, biovar, genotype, and natural foci as suggested by different authors [4], [5], [6], [7], [18], and as deduced in this study.

*abbreviations as defined by Achtman et al. [7] and Morelli et al. [6]: PE – pestoides (microtus), ANT – Antiqua, IN – Intermedium, ORI – Orientalis, and MED – Medievalis; Intermedium in Morelli et al. [6] has not the same meaning as intermedium defined by Li et al. [5] which refers to Rhamnose positive Y. pestis pestis isolates.# prefix refers to foci as described by Anisimov et al. [4]. Numbers without # refer to Mongolian foci as shown in Figure 4.