Abstract: Objective　To investigate the species of sandflies and the prevalence of Leishmania infections in sandflies from selected areas of northern and northwestern China, so as to provide insights into identification of leishmaniasis vectors and assessment of epidemiological trends of leishmaniasis in China. Methods　Sandfly samples were collected from Mentougou District of Beijing Municipality, Xiangning County in Linfen City of Shanxi Province, Ejin Banner in Alxa League of Inner Mongolia Autonomous Region, and Payzawat County of Karamay District of Karamay City, Gaochang District of Turpan City in Xinjiang Uygur Autonomous Region from July 2023 to July 2024. Approximately 100 intact female sandfly samples were randomly selected from each site and the species of sandflies was identified according to morphological characteristics and molecular assays. Female sandflies originating from the same habitat were grouped into pools of 10 individuals. Leishmania infection was detected using polymerase chain reaction (PCR) assay targeting the internal transcribed spacer 1 (ITS⁃1) gene, and the prevalence of Leishmania infection was calculated in sandflies from different sampling sites using the minimum infection rate (MIR) method. In addition, positive amplicons were sequenced and subjected to phylogenetic analysis. Results　A total of 6 155 sandflies were collected from different environments at sampling sites across the six aforementioned regions from July 2023 to July 2024. Phlebotomus chinensis (96.00%) was the dominant sandfly species in Mentougou District, Beijing Municipality, with a small proportion of Ph. sergenti (4.00%), and only Ph. chinensis was found in Xiangning County, Linfen City, Shanxi Province. Ph. wui was the only sandfly species detected in Ejin Banner, Alxa League, Inner Mongolia Autonomous Region, and Payzawat County, Kashgar City, Xinjiang Uygur Autonomous Region, and Ph. caucasicus (97.70%) was the dominant sandfly species in Karamay District, Karamay City, Xinjiang Uygur Autonomous Region, with a small proportion of Ph. wui (2.30%), while Ph. alexandri was the only species in Gaochang District, Turpan City, Xinjiang Uygur Autonomous Region. A total of 40, 60, 34, 18, 18, and 22 pools of sandfly samples were tested from Mentougou District in Beijing Municipality, Xiangning County in Linfen City of Shanxi Province, Ejin Banner in Alxa League of Inner Mongolia Autonomous Region, Payzawat County in Kashgar City, Karamay District in Karamay City, and Gaochang District in Turpan City of Xinjiang Uygur Autonomous Region, respectively. L. infantum was detected in Ph. chinensis samples from Mentougou District in Beijing Municipality, and Xiangning County of Linfen City in Shanxi Province, with MIR of 0.25% to 1.00%, and L. donovani was detected in Ph. wui from Ejin Banner in Alxa League of Inner Mongolia Autonomous Region, and Payzawat County in Kashgar City of Xinjiang Uygur Autonomous Region, with MIR of 0.56% to 0.88%; however, no Leishmania infection was detected in Ph. caucasicus from Karamay District in Karamay City or Ph. alexandri from Gaochang District in Turpan City of Xinjiang Uygur Autonomous Region. Phylogenetic analysis showed that the Leishmania ITS⁃1 gene sequences obtained from Mentougou District in Beijing Municipality and Xiangning County in Linfen City of Shanxi Province were clustered into the same clade with the reference sequences of L. infantum ITS⁃1 gene, while the Leishmania ITS⁃1 gene sequences obtained from Ejin Banner in Alxa League of Inner Mongolia Autonomous Region and Payzawat County in Kashgar City of Xinjiang Uygur Autonomous Region were clustered into the same clade with the reference sequences of L. donovani ITS⁃1 gene. Conclusions　There are variations in sandfly species in selected areas of northern and northwestern China, and variations in the species of Leishmania infecting sandflies. Improved surveillance of sandfly vectors and targeted control strategies with adaptations to geographical features and leishmaniasis vectors are recommended.

Key words: Sandfly, Leishmania, Species identification, Phylogenetic analysis, Northwestern China, Northern China

摘要： 目的　调查我国华北及西北部分地区的媒介白蛉种类并检测其利什曼原虫感染情况，为我国利什曼病传播媒介识别与流行趋势判断提供科学依据。方法　2023年7月—2024年7月在北京市门头沟区、山西省临汾市乡宁县、内蒙古自治区阿拉善盟额济纳旗、新疆维吾尔自治区喀什市伽师县、克拉玛依市克拉玛依区和吐鲁番市高昌区采集白蛉样本，并分别随机挑选完整的单只雌性白蛉样本约100只，通过形态学与分子生物学方法鉴定确定白蛉蛉种。在各采样点采集的白蛉样本中，选取来源于同一种生境的雌性白蛉，每10只分为1组；以利什曼原虫内转录间隔区1（internal transcribed spacer 1，ITS⁃1）为目的基因，采用PCR法检测上述地区各组白蛉利什曼原虫感染情况。利用最小感染率（minimum infection rate，MIR）法计算不同采样点白蛉的利什曼原虫感染率。此外，扩增的阳性片段经测序后进行系统发育分析。结果　2023年7月—2024年7月，共在上述6个地区采样点的不同环境采集白蛉样本6 155只。经鉴定，北京市门头沟区采集的100只白蛉样本主要为中华白蛉（96.00%），其间混杂少许鳞喙司蛉（4.00%）；山西省临汾市乡宁县采集的100只白蛉样本均为中华白蛉；内蒙古自治区阿拉善盟额济纳旗、新疆维吾尔自治区喀什市伽师县采集的100只白蛉样本均为吴氏白蛉；新疆维吾尔自治区克拉玛依市克拉玛依区采集的100只白蛉样本主要为高加索白蛉（97.70%），其间混杂少许吴氏白蛉（2.30%）；新疆维吾尔自治区吐鲁番市高昌区采集的100只白蛉样本均为亚历山大白蛉。北京市门头沟区、山西省临汾市乡宁县、内蒙古自治区阿拉善盟额济纳旗、新疆维吾尔自治区喀什市伽师县、克拉玛依市克拉玛依区和吐鲁番市高昌区分别检测40、60、34、18、18、22组白蛉样本，其中北京市门头沟区、山西省临汾市乡宁县中华白蛉样本中检出婴儿利什曼原虫，MIR在0.25%～1.00%；内蒙古自治区阿拉善盟额济纳旗、新疆维吾尔自治区喀什市伽师县吴氏白蛉样本中检出杜氏利什曼原虫，MIR在0.56%～0.88%；新疆维吾尔自治区克拉玛依市克拉玛依区高加索白蛉、吐鲁番市高昌区亚历山大白蛉均未检出利什曼原虫。系统进化分析显示，北京市门头沟区、山西省临汾市乡宁县采样点所获序列与婴儿利什曼原虫参考序列聚为一支，内蒙古自治区阿拉善盟额济纳旗、新疆维吾尔自治区喀什市伽师县采样点所获序列与杜氏利什曼原虫参考序列聚为一支。结论　我国华北及西北部分地区白蛉种类存在差异，且感染利什曼原虫虫种不同。建议加强上述地区媒介白蛉监测，并结合当地地理环境和传播媒介制定针对性的防控策略。

关键词: 白蛉, 利什曼原虫, 物种鉴定, 系统发育分析, 西北地区, 华北地区