Detection and Genotyping of Coxiella burnetii and Coxiella-Like Bacteria in Horses in South Korea.
Authors: Seo Min-Goo, Lee Seung-Hun, VanBik Dorene, Ouh In-Ohk, Yun Sun-Hee, Choi Eunsang, Park Yong-Soo, Lee Sang-Eun, Kim Jong Wan, Cho Gil-Jae, Kwon Oh-Deog, Kwak Dongmi
Journal: PloS one
Summary
# Editorial Summary: Coxiella Detection in South Korean Horses Q fever (Coxiella burnetii) and related Coxiella-like bacteria (CLB) represent an underexamined zoonotic risk in equine populations, particularly given that infected horses can shed organisms via respiratory secretions and tick exposure during routine handling and riding activities. Researchers tested 816 equine blood samples collected across South Korea between 2007 and 2013, employing ELISA screening for C. burnetii and 16S rRNA gene sequencing to identify and genotype Coxiella species. The prevalence of C. burnetii was low at 1.3% (11 samples), whilst CLB detection at 0.7% (6 samples) proved significant because CLB had previously been identified only in ticks—this represents the first documented detection in mammals. Genetic analysis revealed geographical clustering, with Jeju Island isolates matching known clade B sequences (97.9–100% homology), whilst northern samples formed a distinct, previously uncharacterised clade, indicating substantially greater diversity within the genus than previously recognised. These findings underscore the need for establishment of systematic surveillance programmes and tick control strategies on stud farms and riding facilities, particularly in regions with high tick burden, to mitigate occupational exposure risk for equine personnel and identify whether asymptomatic carrier horses contribute to environmental contamination.
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Practical Takeaways
- •Horses can carry Coxiella bacteria that pose zoonotic risk to handlers and riders; standard biosecurity and tick control measures are warranted
- •Geographic variation in Coxiella prevalence and genotypes suggests regional risk assessment and monitoring programs should be implemented
- •Consider Coxiella as a potential infectious agent in horses with unexplained systemic illness, particularly in endemic regions
Key Findings
- •C. burnetii detected in 1.3% (11/816) of horse blood samples from South Korea
- •Coxiella-like bacteria (CLB) detected in 0.7% (6/816) of samples, representing first documented detection in mammals
- •Five CLB sequences from northern region formed a new genetic clade, indicating previously unrecognized sequence diversity
- •Zoonotic pathogen with potential transmission risk via inhalation or tick contact during equestrian activities