Epidemic characteristics of plague in the plague foci of Spermophilus dauricus in Inner Mongolia Autonomous Region,China,2013-2022
Objective To analyze the species composition and dencity of host animals and vector fleas and the epidemiological characteristics of animal plague in the plague foci of Spermophilus dauricus in Inner Mongolia Autonomous Region (Inner Mongolia),China,so as to provide scientific evidence for plague prevention and control.Methods Descriptive epidemiology methods were used to analyze the surveillance and epidemic data in the plague foci of S.dauricus in Inner Mongolia from 2013 to 2022.Excel 2019 software was used for data collation and calculation,and SPSS 19.0 software for statistical analysis.The flea infestation rates were compared by the Chi-square test;the rodent density and the index of rodent body fleas were compared by the t test;the index of burrow fleas and nest fleas were compared by the Wilcoxon rank sum test.Results In Songliao Plain,a total of 61756 individuals from 20 species of host animals were captured,with 44299 individuals from 12 species of fleas obtained;the mean density of S.dauricus was 0.45 inds/hm2.In Qahar Hills,14096 individuals from 19 species of host animals were captured,with 42713 individuals from 15 species of fleas obtained;the mean density of S.dauricus was 2.26 inds/hm2.No outbreaks occurred in Songliao Plain.Animal plague outbreaks occurred in two banners (districts) in Qahar Hills over the four years,with four strains of Yersinia pestis from Meriones unguiculatus isolated and two positive serum samples of S.dauricus detected.Conclusions The epizootic plague in Songliao Plain remains in a resting state at present,while that in Qahar Hills is active.M.unguiculatus plague and S.dauricus plague are prevalent simultaneously.The epidemic situation is complex.