河北省野鼠立克次体感染调查

Investigation of Rickettsia infections in wild rodents in Hebei Province

目的调查河北省南部和东北部野鼠立克次体感染情况以及感染株的遗传进化特征。方法采用粘鼠板和鼠笼在河北南部邯郸市及北部承德市进行捕鼠,提取鼠脾脏DNA,采用半巢氏PCR扩增立克次体的16S rRNA、ompA、gltA基因,对扩增阳性产物进行测序,并对获得序列进行同源性比较和系统发生树分析。结果在邯郸市和承德市共捕获鼠100只,在这些鼠脾脏样本中有6份(6%)被PCR扩增阳性,其中邯郸市2份、承德市4份。PCR阳性产物测序后同源性分析,发现本研究中扩得的6株立克次体的3个目的基因序列均与劳氏立克次体相应基因序列的同源性最高,16S rRNA与gltA的同源性大于99.9%,ompA大于98.8%。基因序列系统发生树分析结果显示河北野鼠携带的立克次体菌株与我国其它地区检出的劳氏立克次体菌株有密切的亲源关系。结论河北省南部和东北部野鼠均存在劳氏立克次体的感染,野鼠生存地区可能为立克次体感染的自然疫源地,应加强当地人群立克次体感染的防控。

This study investigated Rickettsia infections and genetic characteristics in wild rats in southern and northeastern Hebei Province.Rodents were captured with sticky boards and cages in Handan and Chengde,Hebei.DNA was extracted from the mice spleens.The 16S rRNA,ompA and gltA genes of Rickettsia were amplified with semi-nested PCR.The PCR products were sequenced,the nucleotide identities were determined,and phylogenetic analysis was performed.A total of 100 rodents were captured in Handan City in southern Hebei Province and Chengde City in northern Hebei Province.Six rodents tested positive for the 16S rRNA gene in the spleen,with a positivity rate of 6%.Of them,two were detected in Handan City,and four were detected in Chengde City.In addition,the ompA gene and gltA gene sequences were obtained.Nucleotide identity analysis indicated that all six strains were closely related,and shared the highest nucleotide identity(more than 99.9%for 16S rRNA or gltA,and 99.9%for ompA)with R.raoultii.Phylogenetic analysis using MEGA 6.0 indicated that all six strains had the closest relationship with known R.raoultii strains from other parts of China.Rickettsia infections exist in wild rodents in southern and northeastern Hebei Province.Monitoring and prevention measures for Rickettsia disease should be strengthened to decrease the threats to animal and human health.