College of Veterinary Medicine, Longzihu Campus of Henan Agricultural University, No. 15 Longzihu University Area, Zhengdong New District, Zhengzhou, 450046, People's Republic of China.
School of Biotechnology and Food, Shangqiu Normal University, Shangqiu, 476000, People's Republic of China.
Sci Rep. 2021 Jul 8;11(1):14155. doi: 10.1038/s41598-021-93629-3.
Anaplasma species, which are distributed worldwide, are gram-negative obligate intracellular tick-borne bacteria that pose a threat to human and animal health. Haemaphysalis longicornis ticks play a vital role as vectors in the transmission of Anaplasma pathogens. However, the Anaplasma species carried by H. longicornis in China are yet to be characterized. In this study, 1074 H. longicornis specimens were collected from goats in four provinces of China from 2018 to 2019 and divided into 371 sample pools. All tick sample pools were examined for the presence of Anaplasma species via nested PCR amplification of 16S ribosomal RNA, major surface protein 4 (msp4), or citric acid synthase (gltA) genes, which were sequenced to determine the molecular and phylogenetic characteristics of the isolates. The overall Anaplasma spp-positive rate of H. longicornis was determined to be 26.68% (99/371). The percentage prevalence of A. phagocytophilum-like1, A. bovis, A. ovis, A. marginale, and A. capra were 1.08% (4/371), 13.21% (49/371), 13.21% (49/371), 1.35% (5/371), and 10.24% (38/371), respectively, and the co-infection rate of two or more types of Anaplasma was 6.47% (24/371). Phylogenetic analyses led to the classification of A. phagocytophilum into an A. phagocytophilum-like1 (Anaplasma sp. Japan) group. Anaplasma bovis sequences obtained in this study were 99.8-100% identical to those of an earlier strain isolated from a Chinese tick (GenBank accession no. KP314251). Anaplasma ovis sequences showed 99.3-99.6% identity to an A. ovis human strain identified from a Cypriot patient (GenBank accession no. FJ460443). Only one msp4 sequence of A. marginale was detected and was grouped with those of other A. marginale isolates, and these A. capra isolates obtained in this present study may be zoonotic. The detection and characterization of four Anaplasma species in H. longicornis in this study have added to the current knowledge of the parasite and provided data on multiple Anaplasma species with veterinary and medical significance from four provinces of China.
恙螨种分布于世界各地，是革兰氏阴性专性细胞内蜱传播的细菌，对人类和动物健康构成威胁。长角血蜱作为传播立克次体病原体的媒介，起着至关重要的作用。然而，中国长角血蜱携带的恙虫病螺旋体种类尚未确定。在这项研究中，2018 年至 2019 年，从中国四个省份的山羊中采集了 1074 只长角血蜱标本，并分为 371 个样本池。通过嵌套 PCR 扩增 16S 核糖体 RNA、主要表面蛋白 4（msp4）或柠檬酸合酶（gltA）基因，对所有蜱样本池进行检测，以确定分离株的分子和系统发育特征。确定长角血蜱的恙虫病螺旋体总阳性率为 26.68%（99/371）。A. phagocytophilum-like1、A. bovis、A. ovis、A. marginale 和 A. capra 的流行率分别为 1.08%（4/371）、13.21%（49/371）、13.21%（49/371）、1.35%（5/371）和 10.24%（38/371），两种或多种恙虫病螺旋体的混合感染率为 6.47%（24/371）。系统发育分析将 A. phagocytophilum 分为 A. phagocytophilum-like1（日本恙虫病螺旋体）组。本研究获得的牛支原体序列与从中国蜱中分离到的早期菌株完全相同（GenBank 登录号：KP314251）。绵羊恙虫病螺旋体序列与从塞浦路斯患者中分离到的人类 A. ovis 株的相似度为 99.3-99.6%（GenBank 登录号：FJ460443）。仅检测到一个 A. marginale 的 msp4 序列，并与其他 A. marginale 分离株分组，本研究中获得的这些 A. capra 分离株可能是人畜共患病。本研究在长角血蜱中检测到四种恙虫病螺旋体，增加了对寄生虫的现有认识，并提供了来自中国四个省份具有兽医和医学意义的多种恙虫病螺旋体的数据。
