[Several principles for epidemiologic evaluation of individual regions of the Trans-Caucasian plains-piedmont natural focus of plague].

The authors analyse many-year data concerning the epizootological study of seven landscape-geographical regions of the Eastern Transcaucasus differing by natural conditions and the enzootic intensity. Quantitative assessment of natural nidality determined by the level (norm) of many-year indices calculated for the years of 1955--1974 are presented for each region. Flea vectors were more numerous in localities of stable enzootic manifestation; also the numbers of Meriones erythrourus (carrier rodent) was more stable than in the regions of temporary occurrence of the causative agent and those free of plague. Many-year level of the flea (X. conformis) abundance index equal to one served as the threshold value determining the territory enzooticity.