蜱中人粒细胞埃立克体DNA的PCR检测及序列分析

Detection and sequence analysis of human granulocytic Ehrlichia DNA in ticks collected in Jilin province

目的了解吉林地区蜱种感染人粒细胞埃立克体的情况。方法采用16S rRNA基因特异引物进行半套式PCR,检测吉林省部分林区蜱中人粒细胞埃立克体DNA,并对扩增产物进行克隆和测序,与已知序列进行同源性比较。结果从采集于吉林地区的全沟硬蜱中检出人粒细胞埃立克体的特异性DNA片段,阳性率为1.98%。扩增产物经克隆、测序发现吉林地区人粒细胞埃立克体扩增片段与美国人粒细胞埃立克体分离株(GenBank注册号为U02521)16SrRNA基因序列相对应片段相差2个核苷酸,同源性为99.7%。结论吉林地区的全沟硬蜱携带人粒细胞埃立克体,提示吉林地区可能存在人粒细胞埃立克体病的自然疫源地。

To determine whether there exists the human granulocytic Ehrlichia （HGE） infection in ticks collected in Jilin province, the semi-nested PCR assay with the 16 S rRNA gene-specific primers was used to detect the presence of HGE in tick specimens. The PCR products were cloned and sequenced, and the homology of sequences was compared with other Ehrlichiae. It was found that the HGE-specific DNA fragments could be detected in lxodes persulcatus collected from Jilin province with a detection rate of 1.98 %. After cloning and sequenceing of the amplified product, the amplified DNA fragment of HGE collected in Jilin province was found to be very similar to that of the HGE isolate strain in America （GenBank U02521）, just only with difference of 2 nucleotides; accordingly,the homology between these two strains was 99.7%. It is evident that lxodes persulcatus in Jilin province harbors the pathogen HGE , suggesting the natural loci of infection with human granulocytic Ehrlichia may exist in Jilin province.