西藏自治区2014-2018年鼠疫监测结果分析

An analysis of surveillance results of plague in Tibet autonomous region,China,2014-2018

目的分析西藏自治区(西藏)喜马拉雅旱獭鼠疫自然疫源地2014-2018年的鼠疫监测资料,评价鼠疫疫情流行情况,为科学防控鼠疫提供依据。方法对2014-2018年拉萨、日喀则、山南、林芝、昌都、那曲、阿里7个市(地区)所辖的52个鼠疫自然疫源县的疫情监测资料和数据,应用Excel 2003软件建立数据库,SPSS 17.0软件用于统计分析,小型鼠和媒介蚤用构成比进行描述,不同市(地区)间的鼠疫菌阳性检出率差异采用χ^2检验,鼠疫菌检出数与旱獭密度的关系采用回归与相关分析。结果2014-2018年西藏无人间鼠疫疫情报告。动物间鼠疫监测显示,鼠疫主要宿主喜马拉雅旱獭,密度在0.02~0.06只/hm^2之间,时间分布呈逐年下降趋势;小型鼠捕获率为1.00%,黑唇鼠兔为优势种,占74.88%;媒介蚤以斧形盖蚤和谢氏山蚤为优势种,旱獭染蚤率为27.84%,蚤指数为0.52,旱獭洞干染蚤率为0.77%,蚤指数为0.01。检测各类动物材料2526份,分离出鼠疫耶尔森菌(鼠疫菌)106株,阳性率为4.20%,分布于6市(地区)21县(区)。各市(地区)间鼠疫菌阳性检出率差异有统计学意义(χ^2=293.646,P<0.001),其中阿里地区鼠疫菌阳性检出率最高,为37.14%,其次是拉萨市,为10.79%。检测动物血清29668份,阳性50份,阳性率为0.17%,其中野犬血清阳性39份,藏系绵羊11份,阳性血清分布于4市(地区)13县(区),拉萨市最多,为27份;鼠疫菌检出数会随着旱獭密度的变化而发生线性改变(F=10.751,P=0.046),并存在正相关(r=0.884,P=0.023)。结论2014-2018年西藏未发生人间鼠疫,动物间鼠疫虽呈下降趋势,但仍持续流行,鼠疫防控形势依然严峻,应继续提高鼠疫监测能力并长期坚持综合性防控措施,尤其需加大疫情活跃重点城市的防控力度。

Objective To evaluate the plague epidemic situation by analyzing the plague surveillance data of the natural plague focus of Marmot himalayan in Tibet autonomous region(Tibet),China,from 2014 to 2018,and to provide a basis for scientific prevention and control of plague in this area.Methods Based on the data of 52 plague natural foci and counties in Lhasa,Shigatse,Shannan,Linzhi,Changdu,Naqu,and Ali during 2014-2018,the database was established by Excel 2003 software,and the data were statistically analyzed by SPSS 17.0 software.Small mice and vector fleas were described by composition ratio,the difference of positive detection rate of Yersinia pestis between different cities(prefectures)was tested by χ^2 test.Regression and correlation analysis on the relationship between the number of Y.pestis and marmot density.Results No human plague was reported in Tibet from 2014 to 2018.The surveillance results of animal plague showed that the density of Himalayan marmots(main hosts of plague)was 0.02-0.06 inds/hm2.There was a year-by-year decreasing trend in marmot density distribution over time.The capture rate of small-sized rodents was 1.00%,with Ochotona curzoniae as the dominant species,accounting for 74.88%.Callopsylla dolabris and Oropsylla silantiewi were dominant species in vector fleas.The body flea infestation rate of marmots was 27.84%,with a flea index of 0.52.The burrow flea infestation rate was 0.77%,with a flea index of 0.01.A total of 2526 animal samples distributed in 6 cities(prefectures)and 21 counties(districts)were tested and 106 strains of Y.pestis were isolated with the positive rate was 4.20%.There was a significant difference in the positive rate of Y.pestis among the cities(prefectures)(χ^2=293.646,P<0.001).Among them,Ali was the highest,accounting for 37.14%,and followed by Lhasa,accounting for 10.79%.A total of 29668 animal serum samples were tested,with 50 samples(39 from wild dogs and 11 from Tibetan sheep)having positive results(positive rate:0.17%),which were distributed in 13 counties/districts in 4 cities/prefectures,especially in Lhasa which contributed the most to the number(27 samples).The number of Y.pestis detected changed linearly with the density of marmot(F=10.751,P=0.046),with a positive correlation(r=0.884,P=0.023).Conclusion No human plague occurred in Tibet from 2014 to 2018.Although animal plague shows a downward trend,it is still prevalent.Due to the grim plague situation,plague surveillance should be strengthened,and integrated and long-term prevention and control measures should be taken,especially in key cities with active epizoonotic situation.