Boundary Changes of Natural Plague Foci in the North-Western Pre-Caspian

Abstract

Objective of the study is to specify present-day locations and sizes of natural plague foci in the North-Western Pre-Caspian.

Materials and methods. Based on the results of field and office mapping of Pre-Caspian sandy and North-Western steppe plague foci, conducted in 2013–2014, designed have been electronic maps of the sectors, situated in the periphery of the foci.

Results and conclusions. Detected has been marked reduction in sizes of natural foci owing to plowing of arid pastures. Over a significant distance, new natural focal boundaries are represented by linear elements of hydrography. Wherein such elements are absent, sector frames, in which evidence of enzooty remains, are accepted as formalized external boundaries. The process of deep and irreversible anthropogenic transformation of landscapes has resulted in the reduction of enzootic as regards plague territories: the steppe focus area has decreased by 22 %, being 51152 sq. km, the sandy one – by 13 %, amounting to 62510 sq. km. Farming on the extensive territories as a means of radical alterations of the landscapes has made the lands unsuitable for habitation of the little souslik, midday and tamarisk gerbils, which is an evidence of a complete loss of plague enzooty factors in the territory. The survey of actual position and sizes of natural plague foci within the rigid bonds, plotted on topographic maps and easily identifiable afield, provides for substantiated planning and complex prophylactic plague-control measures. Novel spatial parameters of the natural foci are suggested for the inclusion into official regulatory-methodological documents, guiding performance of epidemiological surveillance over plague.