Molecular characterization of livestock-associated ticks and tick-borne bacteria in Xinjiang, northwestern China

TL;DR

This study identifies tick species and tick-borne bacteria in Xinjiang, China, highlighting zoonotic risks and the need for improved surveillance.

Contribution

First comprehensive molecular survey of livestock-associated ticks and their pathogens in Xinjiang, China.

Findings

Seven tick species were identified, with Rickettsia DNA detected in 50.9% of pools.

Rickettsia massiliae was found in R. turanicus eggs and larvae, indicating transovarial transmission.

Emerging pathogens like Anaplasma capra and Borrelia miyamotoi were detected in ticks from livestock.

Abstract

Xinjiang Uygur Autonomous Region represents a critical pastoral zone at the livestock–tick–human interface in northwestern China, yet molecular data on tick-borne pathogens in this region remain scarce.

Between 2017 and 2018, 6172 ticks were collected from cattle, sheep, goats, horses, and dogs across 18 counties in Xinjiang. Tick species identification was performed through morphological examination and cytochrome oxidase I (COI) gene barcoding. Pooled samples (n = 55) were screened using polymerase chain reaction (PCR) and sequencing targeting Rickettsia (glutamate transporter A [gltA], outer membrane protein A [ompA] genes), Anaplasma (16S ribosomal RNA [16S rRNA]), Borrelia (heat shock protein GroEL [groEL]), and broad-range bacterial diversity (16S rRNA).

Seven tick species were identified: Alveonasus lahorensis (33.7%), Dermacentor marginatus (32.3%), Rhipicephalus turanicus (21.9%), Dermacentor silvarum (5.7%), Hyalomma asiaticum (4.0%), and Haemaphysalis sulcata (2.5%). Rickettsia DNA was detected in 28 of 55 pools (50.9%), with sequences showing relatedness to Rickettsia raoultii, Rickettsia massiliae, and Rickettsia barbariae. Anaplasma capra was identified in D. marginatus collected from goats (1.8% of pools), while Borrelia miyamotoi was detected in R. turanicus from sheep (1.8% of pools). Additional bacterial genera detected included Arsenophonus in D. marginatus, Coxiella in R. turanicus, and Francisella in H. asiaticum. Notably, R. massiliae was detected in both eggs and unfed larvae of R. turanicus, consistent with transovarial transmission.

This study represents the first comprehensive molecular survey of livestock-associated ticks in Xinjiang, revealing high prevalence of spotted fever group rickettsiae and the presence of emerging tick-borne pathogens. Our findings underscore potential zoonotic risks within pastoral systems and emphasize the critical need for enhanced One Health surveillance strategies at the livestock–human interface in this region.

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