PCR检测蜱中查菲埃立克体DNA及其序列分析

应用从查菲埃立克体１６ＳｒＲＮＡ基因序列高变区构建的特异引物，进行ＰＣＲ，检测蜱标本中病原体ＤＮＡ。结果从云南采集的龟形花蜱、从福建采集的越原血蜱和卵形硬蜱扩增出３８９ｂｐ的特异ＤＮＡ片段。收集龟形花蜱和越原血蜱的特异ＰＣＲ产物，通过与Ｔ载体连接，进行克隆和序列测定。其ＤＮＡ序列与美国查菲埃立克体分离株对应位置相差一个核苷酸，与其它种埃立克体的同源性为８０．７％～９６．１％。这是首次在我国发现埃立克体存在的病原线索，表明在我国南方可能存在人单核细胞埃立克体感染的自然疫源地

DETECTION AND SEQUENCE ANALYSIS OF EHRLICHIA CHAFFEENSIS DNA IN TICKS

Specific primers derived from a variable region of the 16S rRNA gene sequence were used to amplify DNA of Ehrlichia chaffeensis (EC)from ticks by polymerase chain reaction(PCR).The characteristic 389 bp product was observed after amplification of extracts from Amblyomma testudinarium obtained from Yunnan province, Haemaphysalis yeni and Ixodes ovatus collected from Fujian province.The specific EC DNA fragments amplified from A.testudinarium and H.yeni were cloned,and DNA sequence was analyzed.The nucleotide sequence of the fragment differs in one position compared with American strains.The homology with other ehrlichiae ranges from 80.7% to 96.1%.This is the first time to find the pathogenic evidence for existence of EC in China.The findings indicate that there may be natural foci of human monocytic ehrlichiosis in southern China.