First Molecular Typing of Tick-Derived Coxiella burnetii From Wildlife in South Korea: Surveillance and Genetic Characterization

초록

Q fever, caused by Coxiella burnetii, is a widespread zoonosis characterized by environmental persistence and a broad host range. Wildlife and their associated ticks are increasingly recognized as crucial elements in the ecology of this pathogen; however, molecular data from these reservoirs in South Korea remain scarce. From April to December 2024, 2747 ticks were collected from 297 wild animals across 16 regions of South Korea. Tick species were identified, and the spatial and temporal distributions of C. burnetii and Coxiella-like bacteria (CLB) were analyzed using molecular detection and minimum infection rate (MIR) estimation. Multilocus variable-number tandem-repeat analysis (MLVA) and multispacer sequence typing (MST) were used to genetically characterize C. burnetii detected in ticks. Four tick species were identified, with Haemaphysalis longicornis as the predominant species (84.6%). C. burnetii was detected at an overall MIR of 2.2%, varying by host species, tick species, region, and season. CLB was detected at a low MIR (0.5%), exclusively in ticks from Korean water deer. All C. burnetii-positive samples exhibited an MST77-like profile, and MLVA revealed a genotype closely related to those previously identified in placental samples from goats in France. This is the first report of this genotype in tick-derived samples from South Korea. These findings highlight the ecological importance of wildlife-particularly Korean water deer, raccoon dogs, roe deer, mountain rabbit, and badgers-in the maintenance and transmission of C. burnetii. The identification of genetically distinct C. burnetii genotypes and CLB underscores the need for ongoing molecular surveillance. This study supports a One Health approach to Q fever prevention and advances our understanding of the genetic diversity and transmission dynamics of the pathogen in wild ecosystems.

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