Clinical characteristics and epidemiological analysis of 23 cases of tick-borne rickettsiosis in Xinjiang Uygur Autonomous Region.

BackgroundPreviously, at least ten spotted fever group Rickettsia (SFGR) species were detected in wildlife and hard ticks in Xinjiang Uygur Autonomous Region (XUAR, northwestern China), whereas human infection remains scarcely studied.MethodsDuring April 2017 - May 2025, the blood samples of 70 tick-bitten patients in XUAR were collected. Their blood DNAs were individually extracted, and rickettsia-specific gene fragments were further detected by nested polymerase chain reaction (nPCR). Meanwhile, combined with sequencing of 16S rRNA V3/V4 region in blood pools and serological examination, clinical symptoms, laboratory test results and antibiotic treatment were further analyzed.ResultsOut of 70 tick-bitten cases, 23 patients were confirmed to be infected with SFGR, including Rickettsia raoultii (n=15) and R. sibirica (n=8). The main clinical findings were as follows. Firstly, fever, rash, and headache were common clinical manifestations in spotted fever cases. Secondly, 7 indicators were statistically significant between pre- and post-treatment in hospitalized spotted fever cases when detecting laboratory tests. Thirdly, misdiagnosis or delayed administration of doxycycline was associated with progression to severe disease.ConclusionIn this study of 70 tick-bitten patients who visited the First Affiliated Hospital of Shihezi University from April 2017 to May 2025, the SFGR infection rate was 32.9% (23/70). Early diagnosis and timely treatment are crucial in spotted fever cases. Early administration of doxycycline is effective against SFGR infection, and delayed treatment increases the risk of severe outcomes. The methods of nucleic acid diagnosis, such as nPCR and next-generation sequencing (NGS), should be implemented especially in acute tick-bitten patients.