Burket C T, Vann C N, Pinger R R, Chatot C L, Steiner F E
Department of Biology, Ball State University, Muncie, IN 47306, USA.
J Med Entomol. 1998 Sep;35(5):653-9. doi: 10.1093/jmedent/35.5.653.
In 1994 and 1995, 8 cases of human monocytic ehrlichiosis were confirmed. These cases originated from southern counties where the putative tick vector Ambylomma americanum (L.) is well established. To confirm the presence of Ehrlichia chaffeensis in ticks in southern Indiana and to determine the minimum infection rate, specimens of A. americanum were collected from 5 counties (7 sites). Nucleic acid was isolated from 88 pools of ticks (430 individuals) using an optimized phenol/CTAB (cetyltrimethylammonium bromide) extraction procedure and subjected to polymerase chain reaction analysis using species-specific 16S rRNA gene bacterial primers. Twenty-one of 88 pools (a minimum of 21 of 430 individuals) were positive for the presence of E. Chaffeensis, yielding an average minimum infection rate of 4.9%. Minimum infection rates at individual sites ranged from 0 to 9.4%. These data extend the known distribution of the bacterium to 3 southern counties of Indiana and suggest a higher prevalence of E. chaffeensis than previously reported for Missouri, North Carolina, or Kentucky.
1994年和1995年，共确诊8例人单核细胞埃立克体病病例。这些病例来自南部各县，当地假定的蜱传播媒介美洲钝缘蜱（Ambylomma americanum (L.)）分布广泛。为了确认印第安纳州南部蜱中查菲埃立克体（Ehrlichia chaffeensis）的存在并确定最低感染率，从5个县（7个地点）采集了美洲钝缘蜱标本。使用优化的苯酚/十六烷基三甲基溴化铵（CTAB）提取程序从88组蜱（430只个体）中分离核酸，并使用物种特异性16S rRNA基因细菌引物进行聚合酶链反应分析。88组中有21组（430只个体中至少21只）查菲埃立克体呈阳性，平均最低感染率为4.9%。各个地点的最低感染率在0至9.4%之间。这些数据将该细菌的已知分布范围扩展到印第安纳州的3个南部县，并表明查菲埃立克体的患病率高于此前密苏里州、北卡罗来纳州或肯塔基州的报道。
