生物素DNA探针/PCR系统用于班氏丝虫蚊媒监测的研究

Detection of Filarial Larvae in Mosquitoes with Wuchereria Bancrofti Specific DNA Probe Labeled with Biotin/PCR System

目的 :评价班氏丝虫特异生物素DNA探针 /PCR系统用于丝虫病防治后期蚊媒监测的效果。方法 :应用长臂光敏生物素标记的班氏丝虫种特异的DNA片段 (4 90bp)为探针 ,结合聚合酶链反应技术 ,对实验室感染蚊虫和现场捕获蚊虫进行检测。结果 :该探针只与班氏丝虫感染蚊提取的DNA杂交 ,不与马来丝虫感染蚊提取的DNA、其他动物丝虫DNA以及正常蚊DNA杂交。同批人工感染班氏微丝蚴蚊虫 ,人工解剖镜检阳性率为 2 1.2 8% ,探针检测阳性率为 30 .6 7% ,差异无显著性 (P >0 .0 5)。在平均感染度为 1.6条幼虫 /蚊情况下 ,50只蚊虫中有 1只感染蚊即可被探针检出。在河南省班氏丝虫病流行区自病家和病村其他户分别捕获蚊虫 ,应用探针每 2 0只为一组进行检测 ,蚊虫最低阳性率分别为 0 .75%和 0 .19% ,检测非病村正常蚊均为阴性。结论 :该DNA探针 /PCR系统的敏感性和特异性均达到实用水平 。

AIM: To evaluate the usefulness of biotin-DNA probe/PCR system for post control surveillance of Bancroftian filariasis in mosquito. Methods: This assay was used to detect the mosquitoes infected in a laboratory and in an endemic area by the way of W.bancrofti specific DNA probe labelled with photobiotin, after samples amplified by PCR. Results: This probe hybridized with DNA of W.bancrofti only, not with DNAs of B. malayi , some animal filariae and normal mosquitoes. Among the same batch mosquitoes artificially infected with W. bancrofti , the positive rates were 30.67 % by probe, and 21.28 % by dissectting microscopy. Under infectiosity of 1.6 filarial larvae/mosquito, it was detectable when 1 out of 50 mosquitoes was infected. When each group with 20 mosquitoes was detected by the system of DNA probe/PCR system, the lowest positive rates of mosquitoes caught from patients and non patientshouse in the same village of Henan province( W.bancrofti endemic area) were 0.75 % and 0.19 % respectively, but the mosquitoes caught from non patient village were all negative. Conclusion: Results show that the method had reached the practical level because its high sensitivity and specifty and also proved a new useful tool for the surveillance of filariasis in the late stage control.