Epidemiological analysis of animal plague in the plague foci of Lasiopodomys brandtii in Inner Mongolia Autonomous Region,China,2013-2022
Objective To analyze the epidemiological characteristics of animal plague in the plague foci of Lasiopodomys brandtii in Inner Mongolia Autonomous Region (Inner Mongolia),China,so as to provide a scientific basis for the formulation of plague prevention and control strategies.Methods The surveillance data in the plague foci of L.brandtii in Inner Mongolia during 2013-2022 were collected.The density of L.brandtii,capture rate of nocturnal rodents,flea infestation rate of vectors,etiological and serological positive rates,and annual percentage change (APC) were calculated.The joinpoint regression analysis of Joinpoint regression program 3.4.3 software was used for trend analysis of density,capture rate,and flea infestation rate.Results During 2013-2022,the mean density of L.brandtii in the plague foci of L.brandtii in Inner Mongolia was 2.36 inds/hm2,and the density showed a decreasing trend and an APC of-21.69%,with a significant difference in annual densities as shown by the trend analysis (Z=-3.133,P=0.014).The mean capture rate of nocturnal rodents was 1.27%,and the capture rate showed a decreasing trend and an APC of-4.75%,with no significant annual difference (Z=-1.136,P=0.289).The mean flea infestation rate of L.brandtii was 33.96%,with a flea index of 0.86,and the flea infestation rate showed a decreasing trend and an APC of-5.48%,with no significant annual difference (Z=-1.292,P=0.233).A total of 19593 host animals were examined etiologically,and 6 animals tested positive for Yersinia pestis,all of whom were Meriones unguiculatus,showing a positive rate of 0.03%.Conclusions The number and distribution of L.brandtii showed a decreasing trend in the plague foci of L.brandtii,and the plague epidemic of M.unguiculatus was in an active stage.Routine surveillance should be strengthened to detect and control the animal epidemic in time and effectively reduce the epidemic strength of animal plague and the risk of human plague infection.