New Epizootic Territory in Gorno-Altai High-Mountain Natural Plague Focus on the Ukok Plateau

Abstract

The aim of the work – analysis of peculiarities of the plague epizooty found in the southern steppe part of the Ukok Plateau in 2020.Materials and methods. Epizootiological survey was conducted over the area of 1573 km2 in July and August, 2020. 141 mammals, 157 ectoparasites (including 152 fleas), 17 bone remains samples, and 50 regurgitates of predatory birds have been tested for plague.Results and discussion. The background species of mammals – natural hosts of Yersinia pestis in the southern steppe part of the Ukok plateau are gray marmot, long-tailed souslik, and Daurian pika. Abundance of the gray marmot was high and amounted to 1.7±0.18 inhabited burrows per 1 ha (n=30) with 90 % occupancy. Three strains of Yersinia pestis ssp. pestis have been isolated: from Oropsylla alaskensis fleas collected from long-tailed souslik, gray marmot carcass, and regurgitates of predatory birds. Yersinia pestis DNA have been detected in 14 objects. Eight positive results of serological tests have been obtained. The epizooty area that was confirmed by Yersinia pestis isolation totaled 252 km2 . As a result of the survey the circulation of Yersinia pestis ssp. pestis have been for the first time established on the Ukok Plateau. The target species – the gray marmot, as well as the long-tailed souslik, are actively involved into the epizooty.