云南省剑川县新发野鼠鼠疫疫点宿主媒介构成及其危险度分析

Composition and risk analysis of hosts and vectors in new wild plague foci of Jianchuan county, Yunnan province, China

目的调查云南省剑川县野鼠鼠疫流行且波及家鼠情况,分析其对人群的危害程度。方法对2017年剑川县鼠间鼠疫进行宿主动物、媒介及指示动物调查,并对采集的标本进行鼠疫血清学及细菌学检验,采用χ~2检验分析鼠及其寄生蚤的分布是否存在差异。结果 (1)共捕获宿主动物221只,室内、外鼠密度分别为7.00%和24.66%,差异有统计学意义(χ~2=73.730,P=0.000);(2)室内以黄胸鼠和褐家鼠为主,室外以大绒鼠和齐氏姬鼠为主,室内、外鼠种分布差异有统计学意义(χ~2=160.005,P=0.000);(3)齐氏姬鼠染蚤190匹,大绒鼠染蚤85匹,黄胸鼠染蚤43匹,褐家鼠染蚤9匹;(4)齐氏姬鼠和大绒鼠染蚤种类分别主要为棕形额蚤和方叶栉眼蚤,黄胸鼠和褐家鼠染蚤种类均主要为棕形额蚤,其主要染蚤种类差异有统计学意义(χ~2=244.272,P=0.000);(5)从自毙黄胸鼠及其寄生的棕形额蚤和1匹活鼠寄生的特新蚤指名亚种上各分离1株鼠疫耶尔森菌。结论剑川县野鼠鼠疫疫点的鼠密度及蚤指数较高,棕形额蚤是家鼠和野鼠寄生的优势蚤种,该地区鼠疫疫情风险度评估为高风险。

Objective To investigate the prevalence of wild rodent plague and commensal rodent infection in Jianchuan county, Yunnan province, China, and to analyze its risk to the population. Methods The host animals, vectors, and indicative animals of the plague among rodents in Jianchuan county in 2017 were investigated. Serological and bacteriological tests related to the plague were carried out on the collected specimens. The X^2 test was used to analyze the differences in the distribution of rodents and their parasitic fleas. Results (1) A total of 221 rodents were captured. The densities of indoor and outdoor rodents were 7.00% and 24.66%, respectively, with a significant difference(X^2 = 73.730, P = 0.000).(2) Rattus tanezumi and R. norvegicus were the dominant indoor species;Eothenomys m iletus and Apodemus chevrieri were the dominant outdoor species. There was a significant difference in the distribution of species between indoor and outdoor rodents(X^2=160.005, P = 0.000).(3) Apodemus chevrieri was infected with 190 fleas;E. miletus was infected with 85 fleas;R. tanezumi was infected with 43 fleas;R. norvegicus was infected with 9 fleas.(4) The major flea species on A. chevrieri was Frontopsylla spadix;the major flea species on E. miletus was Ctenophthalmus quadrarus;the major flea species on both R. tanezumi and R. norvegicus were F. spadix. There was a significant difference in the major flea species between the four species of rodents(X^2=244.272, P = 0.000).(5) One strain of Yersinia pestis each was isolated from the naturally dead R. tanezumi and the F. spadix on it, as well as Neopsylla specialis specialis on a living rodent. Conclusion The density of rodents and flea index were high in the wild plague foci of Jianchuan county. Frontopsylla spadix was the dominant species of parasitic fleas on both wild rodents and indoor rodents. The plague epidemic in this area was of high risk based on the assessment.