The first detection of Rickettsia aeschlimannii and Rickettsia massiliae in Rhipicephalus turanicus ticks, in northwest China.

BACKGROUND: Rickettsia spp. belonging to the spotted fever group (SFG) cause infections in humans, domestic animals and wildlife. At least five SFG rickettsial species have been reported in China, but the occurrence of Rickettsia aeschlimannii and R. massiliae in ticks has not been characterized to date. FINDINGS: A total of 114 adult ticks were collected from sheep in Yining County, Xinjiang Uygur Autonomous Region, in northwest China. The ticks were identified from morphological and molecular characteristics. All samples were examined by polymerase chain reaction (PCR), and six genetic markers were used to determine the Rickettsia spp. in the ticks. The ticks collected were identified as Rhipicephalus turanicus. Three different lineages of Rh. turanicus from Yining County were discovered on phylogenetic analysis of 16S rDNA and cox1. Twenty-one of the 114 samples (18.42%) were positive for rickettsial agents. Phylogenetic analysis based on six genetic sequences showed that three rickettsial species were present, namely: R. aeschlimannii (19.05%, 4/21), R. massiliae (19.05%, 4/21) and R. sibirica variant (61.90%, 13/21), which is clustered in the clade of R. sibirica subsp. sibirica. CONCLUSIONS: This is the first description of R. aeschlimannii and R. massiliae in China. R. massiliae, R. aeschlimannii and R. sibirica variant co-circulate in the region of the China-Kazakhstan border, in northwest China. Rickettsial agents in ticks of the genus Rhipicephalus from migrant birds, transported livestock, wildlife and human beings should be investigated further in the region of the China-Central Asian border.

A broad-range survey of ticks from livestock in Northern Xinjiang: changes in tick distribution and the isolation of Borrelia burgdorferi sensu stricto.

BACKGROUND: Borreliosis 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. METHODS: We 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. RESULTS: A 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. CONCLUSIONS: Warmer 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.

Rickettsia raoultii in Haemaphysalis erinacei from marbled polecats, China-Kazakhstan border.

We found Rickettsia raoultii DNA in 2 out of 32 (6.25 %) Haemaphysalis erinacei ticks. Result showed that the sequences of five genes (17-kDa, gltA, ompA, rrs, and ompB) were 100 % identity with that of R. Raoultii in GenBank. This study is the first report on the presence of R. raoultii in H. erinacei from wild marbled polecat, Vormela peregusna. Our findings suggest that H. erinacei parasitizing wild marbled polecat may serve as reservoir and carriers for R. raoultii in areas around the China-Kazakhstan border. The transmission of tick-borne diseases originated from wildlife should not be underestimated in border region.