Tick-borne bacterial agents in Hyalomma asiaticum ticks from Xinjiang Uygur Autonomous Region, Northwest China

Abstract

Background: Hyalomma ticks are widely distributed in semi-arid zones in Northwest China. They have been reported to harbor a large number of zoonotic pathogens.

Methods: In this study, a total of 334 Hyalomma asiaticum ticks infesting domestic animals were collected from four locations in Xinjiang, Northwest China, and the bacterial agents in them were investigated.

Results: A putative novel Borrelia species was identified in ticks from all four locations, with an overall positive rate of 6.59%. Rickettsia sibirica subsp. mongolitimonae, a human pathogen frequently reported in Europe, was detected for the second time in China. Two Ehrlichia species (Ehrlichia minasensis and Ehrlichia sp.) were identified. Furthermore, two Anaplasma species were characterized in this study: Candidatus Anaplasma camelii and Anaplasma sp. closely related to Candidatus Anaplasma boleense. It is the first report of Candidatus Anaplasma camelii in China.

Conclusions: Six bacterial agents were reported in this study, many of which are possible or validated pathogens for humans and animals. The presence of these bacterial agents may suggest a potential risk for One Health in this area.

Keywords: Candidatus Anaplasma camelii; Candidatus Borrelia hyalommii; Hyalomma asiaticum; Rickettsia sibirica subsp. mongolitimonae; Recombination; Xinjiang.

Fig. 1

Map showing the four locations where the Hyalomma asiaticum ticks were collected in Xinjiang

Fig. 2

Phylogenetic trees based on the flaB and 16S sequences of Candidatus Borrelia hyalommii strains

Fig. 3

Phylogenetic trees based on the 16S, gltA, groEL, and ompA nucleotide sequences of Rickettsia sibirica subsp. mongolitimonae strains

Fig. 4

Phylogenetic trees based on the 16S, gltA, and groEL gene sequences of the Ehrlichia strains

Fig. 5

Phylogenetic trees based on the 16S, gltA, and groEL gene sequences of the Anaplasma strains