【作者】 陈凯；

【导师】 官亚宜； 伍卫平； 王莹；

【作者基本信息】 中国疾病预防控制中心 ， 公共卫生， 2015， 硕士

【摘要】 背景荒漠型黑热病是由婴儿利什曼原虫引起、经白蛉传播的疾病,其患病人群主要是2岁以下婴幼儿,目前在我国主要分布在新疆塔里木盆地北缘、塔里木河流域荒漠和半荒漠绿洲农业区以及内蒙的额济纳旗等地。由于脊椎动物传染源宿主尚未明确,除治疗病人外,尚无有效的防治措施,严重危害当地的婴幼儿的生命安全。目的本研究旨在了解当前新疆荒漠型黑热病流行区黑热病的流行特征及其潜在的黑热病脊椎动物传染源,为该地区制定有针对性的黑热病防治策略提供科学依据。方法于2014年4月在新疆伽师县荒漠型黑热病流行区托里格拉克乡采集人与家养动物的静脉血。以核糖体转录间隔区(ITS-1)为目的基因,采用巢式PCR(nPCR)检测血液中利什曼原虫特异性DNA片段,并对检测结果进行统计分析。对nPCR扩增产物采用限制性酶切片段多样性分析(RFLP)和测序后同源性比对。对家养动物的肝脾组织做肝脾印片进行镜检,对人血和家养动物的肝、脾组织采用NNN氏培养基进行培养。结果人群巢式PCR(nPCR)阳性率为88.18%(97/110),nPCR阳性率在不同性别间、既往患者与其家属间的差异无统计学意义。家畜的rk39免疫试条检测阳性率为19.49%(23/118)。rk39阳性率在本地羊与外地羊、不同性别间差异无统计学意义,不同齿龄间不存在线性趋势。家畜的nPCR阳性率为54.24%(64/118), nPCR阳性率在本地羊与外地羊、不同性别间的差异无统计学意义,不同齿龄间不存在线性趋势。比较rk39与PCR检测方法,两种方法的阳性率差异具有统计学意义(X2=41.0, P<0.05)。家畜和人群感染的原虫基本确定为婴儿利什曼原虫,但镜检及培养结果均为阴性。结论新疆伽师县荒漠型黑热病流行区无症状居民和家畜利什曼原虫感染率较高,二者可能是黑热病的传染源宿主,须进一步研究无症状感染者和家畜在利什曼病传播中的作用。更多还原

【Abstract】 BackgroundDesert-type kala-azar was caused by Leishmania infantum which was transmitted by sandfly. The patients are mainly infants under 2 years old. The endemic areas are distributed in desert areas of the northern margin of Tarim Basin in Xinjiang and in Mesozoic-Cenozoic of Inner Mongolia. Since the vertebrate reservoir host is still unknown, the best strategy for leishmaniasis control is the treatment for the patients, leishmaniasis remains a serious health problem for the infants in these areas.ObjectiveThis study is to clarify the characteristics of the desert-type kala-azar, especially the infection in human and domesticated animals and explore the potential vertebrate hosts in this area in order to understand their roles in the transmission of the disease.MethodsIn April 2014, the blood of the leishmaniasis patients, their family members and domesticated animals were collected in the study township, Jiashi County, Xinjiang, a desert type endemic area for leishmaniasis. The ribosomal internal transcribed spacer (ITS-1) was selected as the target gene and a nested PCR was carried out to detect the specific DNA fragments of Leishmania in the blood of the subjects. The results of the tests were analyzed statistically. The nPCR amplified products were sequenced at first, and then the restriction fragment length polymorphism (RFLP) and homology comparison were performed. For the liver and spleen of the domesticated animals, these tissues were imprinted and examined microscopically. The human blood and some tissues of the liver and spleen of the domesticated animals were cultured in NNN’s medium.ResultsThe positive rate of nPCR in human was 88.18%(97/110). The positive rates had no significant difference between sex, the patients and their family members. A total of 118 animals were detected by rk39 and nPCR test in the study. The positive rates of rk39 and nPCR was 19.49%(23/118) and 54.24%(64/118), respectively. The positive rates of rk39 and nPCR had no significant difference between sex, the local sheep and the exotic sheep. The positive rates at different ages did not showed a linear trend. The positive rates of nPCR was higher than that in rk39 test(X2=41.0, P<0.05). It was thought the parasite detected in the sheep and the patients was Leishmia infantum. However, the results of the microscopy examination and the cultivation were negative.ConclusionThe asytomatic and the domesticated animals may be the host of Leishmania infantum in desert-type kala-azar endemic area. Further study in a wide scope is recommended in order to make clear the role of asymptomatic and domesticated animals in the transmission of leishmaniasis in the study area.更多还原