Department of Parasitic Disease Research, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, (AREEO), Karaj, Iran.
Prev Vet Med. 2020 Oct;183:105118. doi: 10.1016/j.prevetmed.2020.105118. Epub 2020 Aug 13.
Anaplasma phagocytophilum is a tick-borne pathogen affecting humans and domestic animals worldwide. This study aimed to determine the molecular epidemiology and its associated risk factors of A. phagocytophilum infection in cattle in four ecological zones of Iran. A multi-stage stratified random sampling method was utilized during 2017-2018. A total of 1851 blood samples from 320 cattle farms were collected and examined using specific nested polymerase chain reaction (nPCR) based on the 16S rRNA gene. The overall prevalence of A. phagocytophilum was 15.5% (286/1851) by using nPCR. All four zones were A. phagocytophilum positive, the presence of A. phagocytophilum DNA was detected in eight out of nine tested provinces. Univariable analysis of risk factors indicated that climate, altitude, longitude, latitude, season, farm-type, feeding method, hygiene of the farm, tick infestation, use of acaricides by the farmer, distance from other farms, contact with wild animals, race, sex, and milk yield were significant determinants (P < 0.05) for A. phagocytophilum infection. The multivariable analysis determined that longitude, latitude, season, feeding method, and hygiene of the farm remained as significant risk factors for A. phagocytophilum infection (P < 0.05). Specific (SaTScan) cluster analysis identified two high risks and four low risks statistically significant clusters for A. phagocytophilum infection amongst the study areas (P < 0.001). Phylogenetic analysis indicated that A. phagocytophilum 16S rRNA isolates were 96-99% identical to sequences deposited in the GenBank. To the best of our knowledge, this is the first comprehensive molecular study on the epidemiology and risk factors analysis of A. phagocytophilum infection in cattle in different climatic zones of Iran. Further investigations are necessary to be performed regarding the tick vectors, reservoir animals, and the zoonotic potential of the A. phagocytophilum in the endemic region of Iran.
嗜吞噬细胞无形体是一种蜱传病原体，影响全球的人类和家畜。本研究旨在确定 2017-2018 年在伊朗四个生态区牛中嗜吞噬细胞无形体感染的分子流行病学及其相关危险因素。采用多阶段分层随机抽样方法。从 320 个牛场采集了 1851 份血液样本，使用基于 16S rRNA 基因的特异性嵌套聚合酶链反应（nPCR）进行检测。使用 nPCR 检测，嗜吞噬细胞无形体的总流行率为 15.5%（286/1851）。所有四个区均为嗜吞噬细胞无形体阳性，在所检测的 9 个省份中有 8 个检测到嗜吞噬细胞无形体 DNA。危险因素的单变量分析表明，气候、海拔、经度、纬度、季节、农场类型、喂养方式、农场卫生、蜱虫感染、农民使用杀蜱剂、与其他农场的距离、与野生动物接触、种族、性别和产奶量是嗜吞噬细胞无形体感染的重要决定因素（P<0.05）。多变量分析确定，经度、纬度、季节、喂养方式和农场卫生仍然是嗜吞噬细胞无形体感染的重要危险因素（P<0.05）。特定的（SaTScan）聚类分析确定了研究区域中嗜吞噬细胞无形体感染的两个高风险和四个低风险统计学显著聚类（P<0.001）。系统发育分析表明，嗜吞噬细胞无形体 16S rRNA 分离株与 GenBank 中保存的序列完全相同，相似度为 96-99%。据我们所知，这是伊朗不同气候区牛中嗜吞噬细胞无形体感染的首次全面分子流行病学和危险因素分析研究。有必要在伊朗流行地区对蜱传媒介、储存动物和嗜吞噬细胞无形体的人畜共患病潜力进行进一步调查。
