The origin of plague. Future perspectives of ecological and molecular-genetic synthesis

Abstract

Plague, infamous due to three devastating pandemics, remains one of the most dangerous human diseases. Its causative agent, the microbe Yersinia pestis, is a priority in the arsenal of possible biological weapons, which requires increased attention to the development of a system of biological (bacteriological) security. A deep knowledge of the natural processes that facilitate the development of the causative agent of plague may be useful for this. There are currently two alternative approaches to determining the origin of Y. pestis – molecular genetics (MG) and ecological. MG-data has led to the innovative idea of the saltation conversion of the psichrophilic saprozoonotic microbe Yersinia pseudotuberculosis O:1b into a population of the pathogenic plague microbe Y. pestis, by horizontal transfer of two specific plasmids pFra and pPst from the external environment, or from other bacteria and inactivated/deletions of genes that have lost their functions in a new habitat, probably in populations of voles (Microtinae) in Asia. The ecological scenario is based on the idea of Darwinian adaptations by way of a quick "quantum" formation of its properties in a parasitic system; the "marmot–flea" (Marmota sibirica – Oropsylla silantiewi), during the transition between the Pleistocene and Holocene periods. Three important factors of quantum speciation were found: heterothermia of marmot bodies during hibernation, the oxidative "burst" of macrophages in hibernating marmots, and stress-induced mutagenesis initiated by the oxidative "burst" of macrophages. This article asserts the complementarity of the ecological and MG approaches. The prospect of a solution to the problem of quantum speciation of the causative agent of the plague, and the development of methods for the treatment and prevention of disease, can be observed in the synthesis of ecological and MG approaches.