Recent Speciation of the Plague Microbe Yersinia pestis in the Heterothermal (Heteroimmune) Environment Marmot-Flea (Marmota sibirica-Oropsylla silantiewi): Biogeocenotic Preconditions and Preadaptations
Molecular-genetic and ecological approaches to solving the problem on the origin of the causative agent of the plague microbe Yersinia pestis are considered. The initial conditions of conversing the clone of the sapro-zoobiont pseudotuberkulosis microbe Yersinia pseudotuberculosis O:1b to the population of the plague microbe Yersinia pestis are described. It is shown that the distant biogeocenotic precondition for the speciation was aridization of Central Asian landscapes, and as a result, the formation of the species- specific behavior of the Mongolian marmot-tarbagan (Marmota sibirica): the arrangement of plugs in wintering burrows using their own excrements. A recent biogeocenotic precondition, which served as a direct inducer of the speciation process, was the last maximal Sartan cooling covered areas of Central Asia 22-15 thousand years ago. The deep freezing of the ground has caused a shift in the behavior of one of the components of biocenosis - larvae of the marmot flea Oropsylla silantiewi: the transition from saprophagy to hematophagy in winter months. This phenomenon has led to a direct (traumatic) contact of excrements with blood in the oral cavity of marmots during hibernation. The traumatic penetration of pseudotuberculosis microbe in the blood of marmots of the whole population during hibernation created conditions for the realization of sustainable bacteremia and development of the original epizootic plague system M. sibirica-O. silantiewi-Y. pestis. Psychrophilic properties and virulence are considered as the necessary preadaptive properties of the pseudotuberculosis microbe to invade the host-parasite environment rodent-flea.