Laboratory of Microorganisms of Cerrado (Savannah), Department of Microbiology, Instituto De Ciências Biomédicas, Universidade Federal De Uberlândia (UFU), Uberlândia, Brazil.
Laboratory of Ixodology, Faculdade De Medicina Veterinária, UFU, Brazil; Programa De Pós-Graduação Em Ecologia e Conservação De Recursos Naturais, Instituto De Biologia, UFU, Brazil.
Ticks Tick Borne Dis. 2020 Nov;11(6):101519. doi: 10.1016/j.ttbdis.2020.101519. Epub 2020 Jul 25.
Gram-negative spirochetes of the genus Borrelia are transmitted to vertebrate hosts through the tick bite during blood intake. Pathogenic Borrelia species may cause relapsing fever or Lyme borreliosis in humans. Our study aimed to molecularly detect and characterize bacteria of this genus in ticks collected in the Iguaçu National Park, located in southern Brazil. Ticks were collected from the environment (free living) and from hosts from May 2015 to July 2017. In total, 829 ticks were tested, being 741 from the environment and 88 from hosts; 128 ticks were larvae, 523 were nymphs, and 178 were adults (80 males and 98 females). The species identified were: Amblyomma brasiliense (42.9 %), Amblyomma coelebs (16.8 %), Amblyomma sp. (15.0 %), Amblyomma incisum (10.3 %), Amblyomma ovale (8.7 %), Haemaphysalis juxtakochi (5.5 %), Rhipicephalus microplus (0.5 %), Amblyomma longirostre (0.2 %), and Rhipicephalus sanguineus sensu lato (0.1 %). DNA extraction was performed with pools of larvae or nymphs, or individually with adults, for a total of 394 samples. The PCR technique used to detect Borrelia DNA was performed with two rounds of amplification reactions targeting a segment of the flagellin B gene (flaB). Amplification occurred in only one DNA sample, which was obtained from nymphs of A. brasiliense collected from the vegetation of a trail. The nucleotide sequence analysis revealed 90.8 % identity to a sequence of Borrelia sp. from Côte d'Ivoire, and 89.1 % identity to a sequence from Ethiopia. Phylogenetic analysis revealed that the Borrelia sequence from A. brasiliense was distinct from the Borrelia species of the groups belonging to Lyme borreliosis, relapsing fever and the one associated with reptile and echidna as hosts. The sequence is likely from a putative new species of Borrelia and was detected for the first time in A. brasiliense ticks.
革兰氏阴性螺旋体属的伯氏疏螺旋体通过蜱虫吸血时的叮咬传播给脊椎动物宿主。致病性伯氏疏螺旋体可引起人类回归热或莱姆病。本研究旨在通过分子手段检测和鉴定在巴西南部伊瓜苏国家公园采集的蜱虫中该属细菌。从环境（自由生活）和 2015 年 5 月至 2017 年 7 月期间从宿主身上采集了 829 只蜱虫。总共测试了 128 只幼虫、523 只若虫和 178 只成虫（80 只雄性和 98 只雌性）。鉴定出的物种有：巴西钝缘蜱（42.9%）、库蠓蜱（16.8%）、美洲钝缘蜱（15.0%）、刻点钝缘蜱（10.3%）、卵圆钝缘蜱（8.7%）、镰形扇头蜱（5.5%）、微小牛蜱（0.5%）、长角血蜱（0.2%）和莱姆病伯氏疏螺旋体（0.1%）。从幼虫或若虫的幼虫池中提取 DNA，或单独从成虫中提取 DNA，共提取了 394 个样本。用于检测伯氏疏螺旋体 DNA 的 PCR 技术进行了两轮扩增反应，针对鞭毛蛋白 B 基因（flaB）的一个片段。只有一个 DNA 样本在扩增中发生，该样本来自从步道植被中采集的巴西钝缘蜱的若虫。核苷酸序列分析显示，与来自科特迪瓦的伯氏疏螺旋体序列的同一性为 90.8%，与来自埃塞俄比亚的序列的同一性为 89.1%。系统发育分析表明，巴西钝缘蜱中的伯氏疏螺旋体序列与属于莱姆病、回归热以及与爬行动物和针鼹为宿主的伯氏疏螺旋体物种的组群不同。该序列可能来自一种假定的新的伯氏疏螺旋体物种，这是首次在巴西钝缘蜱中检测到该序列。
