Ecological aspects of evolution of the plague microbe Yersinia pestis and the genesis of natural foci

A new hypothesis of the origin of the plague microbe in the Mongolian bobak (Marmota sibirica Radde, 1862) populations in Central Asia during the Plei stocene is based on the ideas of its relative phylogenetic recency. The Lat e Pleistocene cooling; which induced a deep freezing of the grounds in sout hern Siberia, Mongolia,and Manchuria, is considered as an inducer of specia tion. The main ecological factors of the plague microbe evolution include t he species specific behavior of the Mongolian bobak during preparation to h ibernation related to its occurrence in arid petrophytic landscapes and the larval parasitism of the flea Oropsylla silantiewi-Wagn;, 1898 in winter. Genesis of the plague foci is divided into two periods: natural-historical and biosocial. During the first period, the primari natural foci in Eurasia were formed and, during the second period, synanthropic (rat) and secndary natural foci appeared, with the participation of humans, in Africa, The Ne w World, and-on some tropical islands.