A broad-range survey of ticks from livestock in Northern Xinjiang: changes in tick distribution and the isolation of Borrelia burgdorferi sensu stricto
BackgroundBorreliosis is highly prevalent in Xinjiang Uygur Autonomous Region, China. However, little is known about the presence of Borrelia pathogens in tick species in this region, in addition Borrelia pathogens have not been isolated from domestic animals.MethodsWe collected adult ticks from domestic animals at 19 sampling sites in 14 counties in northern Xinjiang from 2012 to 2014. Ticks were identified to species by morphology and were molecularly analysed by sequences of mitochondrial 16S rDNA gene; 4–8 ticks of each species at every sampling site were sequenced. 112 live adult ticks were selected for each species in every county, and were used to culture Borrelia pathogens; the genotypes were then determined by sequences of the 5S-23S rRNA intergenic spacer and the outer surface protein A (ospA) gene.ResultsA total of 5257 adult ticks, belonging to four genera and seven species, were collected. Compared with three decades ago, the abundance of the five common tick species during the peak ixodid tick season has changed. Certain tick species, such as Rhipicephalus turanicus (Rh. turanicus), was found at Jimusaer, Yining, Fukang, and Chabuchaer Counties for the first time. Additionally, the sequence analyses showed that the Hyalomma asiaticum (Hy. asiaticum), Haemaphysalis punctata (Ha. punctata), and Dermacentor marginatus (D. marginatus) that were collected from different sampling sites (≥3 sites) shared identical 16S rDNA sequences respectively. For the tick species that were collected from the same county, such as Hy. asiaticum from Shihezi County and Rh. turanicus from Yining County, their 16S rDNA sequences showed genetic diversity. In addition, sixteen Borrelia isolates were found in Hy. asiaticum, Ha. punctata, D. marginatus and Rh. turanicus, which infested cattle, sheep, horse and camel in Yining, Chabuchaer, Shihezi and Shawan Counties. All of the isolates were genetically identified as B. Burgdorferi sensu stricto.ConclusionsWarmer and wetter climate may have contributed to the altered distribution and abundance of the five most common ticks in northern Xinjiang. The genetic analyses showed that certain tick species, such as Hy. asiaticum or Rh. turanicus, exhibit genetic commonness or diversity. Additionally, this study is the first to isolate B. burgdorferi sensu stricto in Hy. asiaticum asiaticum, H. punctata, D. nuttalli and D. marginatus ticks from domestic animals. These ticks may transmit borreliosis among livestock.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1021-0) contains supplementary material, which is available to authorized users.
[…] Data comparisons were performed using those tick species that had more than 10 available specimens. Sequence alignments to determine the nucleotide percentage from each species were performed using Clustal X 2.0 , and the phylogenic relationships among the representative tick specimens were inferred using MEGA5 . A phylogenic tree was then constructed using the neighbor-joining method .A total of 67 reference sequences, including sequences from the Dermanyssus gallinae (L34326.1) and Spinturnix myoti (FJ225960) outgroups, were used for the phylogenetic analysis, and 23 nucleotide sequences from our study have been deposited in the GenBank database (16S rDNA: KF547980, KF547981, KF547982, KF547983, KF547984, KF547985, KF547986, KF547987, KF547988, KF547989, KF547990, KF547991, KF547992, KF547993, KF547994, and KF547995; 5S-23S rDNA intergenic spacer of Borrelia: KF547996, KF547997, KF547998, KJ459337, KJ459338, KJ459339 and KJ459340). […]