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

Qing-Qing Wei,Li-Ping Guo,Ke Zhang,An-Dong Wang,Chuang-Fu Chen,Wan-Jiang Zhang,Lu-Meng Mu,Yuan-Zhi Wang

doi:10.1186/s13071-015-1242-2

Qing-Qing Wei, Li-Ping Guo + Show 6 more

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https://doi.org/10.1186/s13071-015-1242-2

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Abstract

BackgroundRickettsia 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.FindingsA 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.ConclusionsThis 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1242-2) contains supplementary material, which is available to authorized users.

Highlights

Rickettsia spp. belonging to the spotted fever group (SFG) cause infections in humans, domestic animals and wildlife
This is the first description of R. aeschlimannii and R. massiliae in China
Out of the 21 positive samples, four were confirmed as R. aeschlimannii, four were identified as R. massiliae, and the remaining thirteen were R. sibirica variant based on phylogenetic tree of the representative makers and the 17 kilodalton antigen (17-kDa)-ompA-gltA-rrssca1-ompB concatenated sequence

Summary

Conclusions

This is the first report of the molecular analysis of R. aeschlimannii and R. massiliae in China. The findings of the study suggest that R. massiliae, R. aeschlimannii and R. sibirica variant co-circulate in Rh. turanicus in the region of the China–Kazakhstan border, in northwest China. Additional file 1: The photo of Rhipicephalus turanicus and Phylogenetic tree of Rhipicephalus turanicus 16S rDNA and CO1 gene. (DOC 198 kb) Additional file 2: The single gene Phylogenetic tree of Rickettsia spp. (DOC 863 kb) Additional file 3: Closest relative sequences to the partial 17-kDa, 16S, gltA, ompA, ompB and sca genes, sequences of the Rickettsia aeschlimannii (Table S1A), Rickettsia massiliae (Table S1B) and Rickettsia sibirica (Table S1C) detected in the Rhipicephalus turanicus ticks, Northwest of China. QQW, LPG, ADW and YZW performed the experiments, analyzed the data and drafted the manuscript.

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