云南省剑川县野鼠感染莱姆病螺旋体状况的初步调查

目的调查云南省剑川县野鼠中伯氏疏螺旋体(莱姆病螺旋体)的感染状况,以评估其对人群的潜在威胁。方法 2017年1—4月在剑川县选取石龙、长乐、新松3个自然村作为调查点,用鼠笼法进行捕鼠;经鼠种鉴定后采集鼠肾脏及膀胱标本,用BSK-Ⅱ培养基对其进行分离培养;用实时定量PCR及巢式PCR分别检测伯氏疏螺旋体特异性recA基因及5S～23S rRNA基因间隔区。结果 (1)共捕获10种439只鼠,其中齐氏姬鼠219只、大绒鼠165只,其余鼠种55只(中华姬鼠24只、贝氏树鼩13只、斯氏家鼠7只、巢鼠3只、灰麝鼩3只、赤腹松鼠2只、社鼠2只及大足鼠1只);(2) 439份标本均未分离培养到伯氏疏螺旋体;(3)实时定量PCR检测,结果显示伯氏疏螺旋体总阳性率为2.51%(11/439),其中中华姬鼠4.17%(1/24)、齐氏姬鼠4.11%(9/219)和大绒鼠0.61%(1/165);(4)11份阳性标本皆来源于剑川县石龙村,其余2个村的鼠标本未检测到阳性;(5)11份实时定量PCR阳性标本的5S～23S r RNA基因间隔区的检测皆为阴性。结论云南省剑川县野鼠中存在莱姆病螺旋体的自然感染,但鼠中病原体的载量较低,其传播给人群的风险不大。

Primary investigation on the infection of Borrelia burgdorferi in rats of Jianchuan County,Yunnan

Objective To investigate the infection of Borrelia burgdorferi in rats of Jianchuan County in order to assess its potential threat to the population. Methods The cage-trap method was used to capture rats in the three villages of Shilong, Changle and Xinsong from January to April 2017. The kidney and bladder specimens of rats were collected and cultured in BSK-Ⅱ medium after the identification of rat species. Real-time PCR and nested PCR were used to detect Borrelia burgdorferi of recA gene and the 5S-23S rRNA gene spacer respectively. Results A total of 10 species of 439 rats were captured, including 219 of Apodemus chevrieri, 165 of Eothenomys miletus and 55 of others (24 of Apodemus draco, 13 of Tupaia belangeri, 7 of Rattus sladeni, 3 of Micromys minutus, 3 of Crocidura attenuata, 2 of Callosciurus erythraeus, 2 of Niviventer niviventer and 1 of Rattus nitidus). But no Borrelia burgdorferi strains were isolated from the samples. The total positive rate of Borrelia burgdorferi detected by real-time PCR was 2.51% (11/439), including 4.17% (1/24) of Apodemus draco, 4.11% (9/219) of Apodemus chevrieri, and 0.61%（1/165）of Eothenomys miletus. The 11 positive samples were all from Shilong village in Jianchuan County, and there was no positive rat samples for the other 2 villages. The detection of the 5S-23S rRNA gene spacer in 11 real-time PCR positive specimens were negative. Conclusion There is natural infection of Borrelia burgdorferi in rats of Jianchuan County, Yunnan Province, but the low levels of pathogens in rats are less likely to spread to humans.