长角血蜱、草原革蜱经期传播莱姆病螺旋体的实验研究

为了明确长角血蜱、草原革蜱在我国北方莱姆病传播中的地位和作用,以全沟硬蜱为对照,在实验室内对它们经期传播莱姆病螺旋体的可能性进行了研究.结果表明,全沟硬蜱可保持活的螺旋体到下一发育阶段,并且其体内的莱姆病螺旋体具备感染敏感KM鼠的能力.长角血蜱和草原革蜱虽然可以通过吸血获得莱姆病螺旋体,但它们对莱姆病螺旋体的保持期较短,不能跨越蜕皮阶段,因而不具备经期携带、传播的能力.所以它们作为莱姆病媒介的可能性不大.在长角血蜱或草原革蜱体内检测到的莱姆病螺旋体可能是它们与全沟硬蜱共同吸血的原因所致.     

不同气候模式下我国长角血蜱潜在适生区预测

［摘要］　目的　分析环境和气候因子对我国长角血蜱适生区分布的影响,并预测不同气候模式下长角血蜱的潜在分布区。方法　从文献中获取我国长角血蜱分布点信息,结合环境和气候因子数据,运用MaxEnt最大熵模型,分析年均温、昼夜温差日均值、等温性、温度季节性变化标准差、最暖月最高温、最冷月最低温、年均温变化范围、最湿季度平均温度、最干季度平均温度、最暖季度平均温度、最冷季度平均温度、年均降水量、最湿月降水量、最干月降水量、降水量变异系数、最湿季度降水量、最干季度降水量、最暖季度降水量、最冷季度降水量等19个气候因子及海拔、坡度、坡向、植被覆盖率等4个环境因子对长角血蜱潜在分布的影响,并预测当前和未来不同气候模式下（RCP 2.6和RCP 8.5）长角血蜱潜在地理分布区。结果　在影响我国长角血蜱地理分布的环境和气候因子中,贡献率均超过10%的因子主要包括最干月降水量（26.0%）、年均温（11.2%）、年均降水量（10.0%）和海拔（24.2%）。当前气候模式下,我国长角血蜱高、中、低适生区面积分别为123.19万、169.62万、185.44万km2。在RCP 2.6气候模式下,2050和2070年我国长角血蜱分布区面积分别增加33.61万km2和36.73万km2;在RCP 8.5气候模式下,2050年和2070年我国长角血蜱分布区面积分别增加38.10万km2 和35.80万km2。结论　降水、温度和海拔等气候和环境因子对我国长角血蜱分布区影响较大;在未来不同气候模式下,我国长角血蜱适生区面积均可能增加。     

Heterogeneity in the effect of different ixodid tick species on human natural killer cell activity

Tick saliva plays a vital role in blood-feeding, including manipulation of the host response to tick infestation. Furthermore, a diverse number of tick-borne pathogens are transmitted to vertebrate hosts via tick saliva, some of which exploit the immunomodulatory activities of their vector's saliva. We report that salivary gland extracts (SGE) derived from Dermacentor reticulatus adult ticks induce a decrease in the natural killer (NK) activity of effector cells obtained from healthy human blood donors. The decrease was observed with SGE from both female and male D. reticulatus fed for either 3 or 5 days on mice, but no significant effect was observed with SGE from unfed ticks or ticks that had fed for 1 day. These results indicate that the tick anti-NK factor(s) is only active after blood-feeding has commenced. Microscopic examination revealed that the first step of NK activity, namely effector/target cell conjugate formation, was affected by SGE. The observed reduction in conjugate formation occurred when effector (but not target) cells were treated with SGE for 30 min, and the effect persisted after 12 h of treatment. Similar but less potent anti-NK activity was detected for SGE from Amblyomma variegatum and Haemaphysalis inermis. By contrast, SGE derived from Ixodes ricinus and Rhipicephalus appendiculatus female ticks did not decrease NK activity. The apparent absence of such activity in these two important vectors of tick-borne viruses suggests that control of NK cells does not play an important role in promoting virus transmission, at least for these particular species.     

用随机扩增多态DNA(RAPD)区分青海血蜱与日本血蜱

目的用随机扩增多态DNA(RAPD)技术确定青海血蜱与日本血蜱的分类地位。方法分别提取青海血蜱与日本血蜱的DNA，确定聚合酶链反应(PCR)总体积、反应条件。选取8条不同的随机排列碱基顺序的多聚核苷酸单链为引物，进行RAPD—PCR扩增反应。将扩增产物制备成DNA图谱，比较青海血蜱与日本血蜱基因组DNA多态性，从DNA水平鉴定这2种蜱。结果2种蜱仅有少部分DNA条带相同，大部分条带不同。结论RAPD技术可准确地鉴别青海血蜱与日本血蜱这2种形态特征十分相似的蜱种。     

从粤东丰溪自然保护区台湾角血蜱体内分离出莱姆病螺旋体

目的：检测台湾角血蜱携带莱姆病螺旋体情况。方法：直接荧光抗体法（ＤＦＡ）和病原分离培养。结果：该蜱是粤东丰溪自然保护区优势蜱种，用采集的该蜱５０只取中肠涂片，ＤＦＡ检测８只为阳性，阳性率１６％；从１１５只（２３组）该蜱中分离出１株莱姆病螺旋体，命名为ＭＤ６。经单克隆抗体鉴定，结果与国内Ｍ７菌种反应相同。结论：从媒介蜱类分离出莱姆病螺旋体，在广东尚属首次，证实该地为莱姆病流行区     

长角血蜱两性生殖株和孤雌生殖株幼蜱发育零点及有效积温的研究

目的研究长角血蜱两性生殖株和孤雌生殖株幼蜱在不同温度下的发育零点和有效积温。方法将长角血蜱两性生殖株和孤雌生殖株饱血幼蜱置于不同温度的环境中,观察发育历期和积温,采用拟合模型方程求出两性株和孤雌株幼蜱发育的零点温度,计算幼蜱发育的有效积温。结果长角血蜱两性株和孤雌株的发育零点分别为14.89℃和14.95℃,平均积温分别为(265.08±99.37)日度和(306.90±176.24)日度,有效积温分别为(101.44±147.66)日度和(116.51±116.79)日度。结论长角血蜱饱血幼蜱的发育历期随温度升高而缩短,两性株比孤雌株发育快,研究结果可以作为长角血蜱生物学的基础理论参数之一。     

Clinical and laboratory evidence of the importance of the tick D. marginatus as a vector of B. burgdorferi in some areas of sporadic Lyme disease in Bulgaria

56 adult ticks D. marginatus and 38 adult ticks H. punctata were sampled by the flagging method, transferred to the laboratory, dissected and tested for infection with Lyme disease spirochetes. 3 (7.9%) of the adult H. punctata and 2 (3.57%) of the adult D. marginatus were infected with B. burgdorferi (Bb). This report also presents the case of a patient, who developed Lyme disease symptoms after he had been bitten by a D. marginatus tick. The clinical diagnosis was confirmed by serological testing and by a biopsy, taken from the patient's skin lesion. The skin biopsy was examined under an electron microscope and Bb was found in the sections of the deeper strata of the dermis in two structural forms: (a) cylindrical bodies (protoplasm cylinder) with circular ends covered with a three-layered membrane; (b) granules, situated among the collagenous fibres either closely adhered to them or covered with a membrane. The result of the study demonstrates that in single cases in some ecosystems, ticks D. marginatus might be implicated in Bb transmission to humans as secondary vectors.     

中国血蜱属（蜱螨目：硬蜱科）研究：嗜鸟血蜱亚属Subgenus Ornithophysalis附一新记载种

中国的血蜱属嗜鸟血蜱亚属已知有3种,即嗜鸟血蜱 Haemaphysalis （Ornithophilis） ornithophila Hoogstraal et Kohls,板齿鼠血蜱 Hae.（Or.） bandicota Hoogstraal et Kohls,钝刺血蜱 Hae.（Or.） doenitzi Warburton et Nuttall,加上本文报道的中国新记载种,啄木鸟血蜱Hae.（Or.） megalaimae Rajagopalan,共4个种,并编制了分种检索表.     

长角血蜱饥饿雌蜱cDNA表达文库的构建及免疫学筛选

目的 构建长角血蜱饥饿雌蜱cDNA表达文库,筛选长角血蜱功能性抗原基因。 方法 在无RNA酶污染的条件下提取长角血蜱总RNA,进而纯化mRNA,以寡脱氧胸腺核苷酸［oligo（dT）］为引物合成双链cDNA,并在其两端加EcoRⅠ/HindⅢ定向接头。将cDNA分子定向克隆至具有EcoRⅠ/HindⅢ黏性末端的λSCREEN载体。用噬菌体包装蛋白对以上连接产物进行体外包装以形成完整的噬菌体,转化大肠埃希菌（Escherichia coli）ER1647,从而构建长角血蜱饥饿雌蜱cDNA表达文库。使用兔抗长角血蜱全蜱血清对该文库进行免疫学筛选,经过2次筛选得到的阳性噬菌体转化E. coli BM25.8亚克隆为重组质粒,转化E. coli JM109,提取重组质粒进行PCR和测序分析。 结果 长角血蜱饥饿雌蜱cDNA表达文库的基础库容量为1.8×106 pfu,重组率为100%,扩增后的滴度为2.4×109 pfu/ml。筛选获得42个阳性克隆,序列分析表明有12个新cDNA序列,其编码蛋白与长角血蜱原肌凝蛋白、环状扇头蜱幼蜱未知蛋白、黑腹果蝇染色体2R、褐黄血蜱线粒体DNA、青海血蜱HqL09、Hq05和肌球蛋白轻链mRNA等具有同源性。 结论 构建了长角血蜱饥饿雌蜱cDNA表达文库,获得的阳性克隆为长角血蜱功能性抗原的研究奠定基础。