滇西鼠疫疫源地野外鼠形动物感染贝氏柯克斯体的调查

目的调查滇西鼠疫疫源地野外鼠形动物贝氏柯克斯体感染情况。方法2015年12月至2016年10月，课题组以云南省玉龙县、剑川县和梁河县鼠疫疫源地为采样点，使用夹夜法在不同季节、不同海拔、不同生境捕获野外鼠形动物，收集到2 524份肝脾样本。采用巢氏PCR方法对Q热病原体贝氏柯克斯体(Coxiella burnetii,Cb)Com1基因的保守片段进行扩增。应用SPSS20.0软件，采用χ²检验或Fisher确切概率法分析不同疫源地、海拔梯度、生境、季节、性别间Cb在野外鼠形动物中的流行分布情况。结果检测2 524份样本，Cb阳性23份，阳性率为0.91%。检出Cb的鼠形动物包括齐氏姬鼠、中华姬鼠、黄胸鼠、社鼠、锡金小鼠、大绒鼠、臭鼩鼱和毛猬。不同生境、性别间野外鼠形动物Cb阳性率无差异(χ_生境²=6.514，χ_性别²=0.076,P>0.05)；季节间Cb阳性率春季(2.44%)高于秋季(0.37%)(χ²=11.550,P<0.008)；剑川鼠...

Coxiella burnetii infection of wild small mammals in the natural plague foci of western Yunnan

This study investigated the Coxiella burnetii (Cb) infection of wild small mammals in western Yunnan plague foci. From December 2015 to October 2016, the night trapping method was used to catch wild small mammals, and 2 524 liver and spleen samples were obtained in different seasons, at different elevation gradients, and geographical landscapes in Yulong, Jianchuan, and Lianghe. DNA was extracted from liver and spleen samples with magnetic beads, and nested PCR was used to amplify the conserved Com1 sequence of Cb. Chi-square tests and the exact probability method were used for statistical analysis. The positivity rate of Cb was 0.91% (23/2 524), and the wild small mammals testing positive for Cb included Apodemuschevrieri, Apodemusdraco, Rattus tanezumi, Niviventerconfucianus, Mus pahari, Eothenomysmiletus, Suncus murinus, and Hylomyssuillus. No statistical difference in Cb infection was observed among habitats and sexes (X²_habitats=6.514,X²_sex=0.076, P>0.05). The positivity rate of Cb was higher in spring than autumn (2.44% vs 0.37%, χ²=11.550, P<0.008). In addition, the positivity rate of Cbin Jianchuannatural plague foci was higher than that in Yulong (1.46% vs 0.34%, χ²=6.121, P<0.017), and the altitudinal gradient of more than 2 450 m was higher than that of below 2 450 m in Jianchuan (4.64% vs 0.13%, χ²=28.504, P<0.001). Homology and phylogenetic analyses indicated that the Com1 sequence of Cb in wild small mammals in western Yunnan plague foci was highly homologous to the related reference sequence in GenBank. In conclusion, a low Cb infection rate in wild small mammals in western Yunnan plague foci was observed, but Cb infection was widespread. The Cb Com1 fragment showed high conservation, prevalence, and distribution in wild small mammals.