Molecular detection of Coxiella burnetii in livestock farmers and cattle from Magdalena Medio in Antioquia, Colombia.
Authors: Cabrera Orrego Ruth, Ríos-Osorio Leonardo Alberto, Keynan Yoav, Rueda Zulma Vanessa, Gutiérrez Lina Andrea
Journal: PloS one
Summary
# Editorial Summary: Q Fever Risk in Colombian Livestock Farmers and Cattle Coxiella burnetii, the causative agent of Q fever in humans and coxiellosis in animals, poses a significant zoonotic threat to those working with livestock, yet its prevalence in many regions remains poorly characterised. Researchers in Antioquia, Colombia used real-time PCR targeting the IS1111 insertion sequence to screen peripheral blood samples from 143 livestock farmers and 192 cattle across 24 farms, with confirmatory 16S rRNA sequencing of positive samples. The findings revealed that just over one-quarter (25.9%) of farmers tested positive for C. burnetii, whilst 19.5% of cattle carried Coxiella-type bacteria; in humans, infection was significantly associated with exposure to horses (adjusted prevalence ratio 1.61), presence of ticks on the property (2.36), raw milk consumption (1.47), and geographic location, whereas in cattle, longer farm residency (≥49 months) doubled the likelihood of detection. For equine practitioners and farm health advisors, these results underscore the importance of acknowledging Q fever as an occupational hazard in cattle-farming regions—particularly where mixed livestock systems include horses—and suggest that biosecurity measures addressing tick control and milk handling practices warrant consideration as part of comprehensive herd health protocols.
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Practical Takeaways
- •Horses and other livestock on farms may serve as transmission vectors for C. burnetii to farmers; implement biosecurity measures including tick control on mixed farms
- •Raw milk consumption represents a significant infection risk for farmers working with cattle; promote pasteurization and safe handling practices
- •Cattle may harbor related Coxiella species with unclear pathogenic roles; further investigation needed to determine if these are disease agents or commensals in equine/bovine populations
Key Findings
- •Molecular detection identified C. burnetii in 25.9% of livestock farmers and 19.5% of cattle samples using real-time PCR
- •In farmers, risk factors included location in Puerto Berr√≠o (aPR: 2.13), presence of horses (aPR: 1.61), ticks (aPR: 2.36), hens (aPR: 1.47), and raw milk consumption (aPR: 1.47)
- •In cattle, longer farm residence (≥49 months) was associated with Coxiella-type bacteria (aPR: 2.28), while Puerto Nare location was protective (aPR: 0.39)
- •16S rRNA sequencing confirmed C. burnetii in farmers but only identified Coxiella-type bacteria in cattle, suggesting mixed bacterial populations