Aim To search for the pathologic evidence of human granulocytc hrlichia(HGE) infection in ticks. Method Specific primers derived from the 16S rRNA gene sequence were used to amplify ehrlichial DNA from ticks by hemi - nested polymerase chain reaction(PCR). The PCR products were cloned and sequenced. The sequence was compared with other ehrlichiae for homology.Results Specific DNA fragments were amplified from Ixodes persulcatus collected from Heilongjiang province. The minimum infection rate was 0.8%. The sequence of 919- bp PCR product was analyzed, and identified as part of ehrlichial 16S rRNA gene. It differed at four positions in comparison to American strains. Conclusion This is the first report of having HGE - like pathogen in China. These findings demonstrate that there may be natural foci of human granulocytic ehrlichiosis in northern forest area in China.%目的 寻找我国蜱中人粒细胞埃利希体感染存在的病原学证据。方法应用从人粒细胞埃利希体16S rRNA基因构建的特异引物进行半套式PCR，检测蜱标本中埃利希体DNA。然后对PCR扩增产物进行克隆和序列测定，与已知序列进行同源性比较。结果从黑龙江采集的全沟硬蜱(Ixodes persulcatus)中扩增出特异DNA片段，计算最小阳性率为0.8％。对919bp的扩增产物进行序列分析，证实为埃利希体DNA，与美国人粒细胞埃利希体分离株对应序列比较，相差4个核苷酸。结论这是首次证明我国有类似人粒细胞埃利希体的病原体存在。表明我国北方林区可能存在人粒细胞埃利希体感染的自然疫源地。
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