Tick-borne pathogens (TBPs) represent an increasing threat to both human and animal health, driven by the expanding distribution and abundance of tick populations, even in regions traditionally considered unsuitable for their development. Among TBPs, Ehrlichia canis is primarily known as the causative agent of canine ehrlichiosis, mainly transmitted by the brown dog tick Rhipicephalus sanguineus. However, recent evidence indicates a broader host range, including potential zoonotic transmission to humans. In this study, adult ticks were collected from carcasses of domestic and wild animals and tested in pools of 5 specimens by real-time PCR to detect E. canis, aiming to assess infection rates and identify animal species potentially involved in transmission dynamics. Minimum Infection Rate (MIR) was used as a conservative estimate of pathogen prevalence in pooled samples showing an overall prevalence of 2.75%. As expected, R. sanguineus showed the highest positivity rate (MIR = 3.41%), with specimens collected from dogs and wolves, while no E. canis DNA was detected in ticks from red foxes. Interestingly, E. canis DNA was also detected in 2.61% of Dermacentor marginatus collected from wild boars and roe deer, whereas Ixodes ricinus specimens tested negative. These findings suggest that D. marginatus may be involved in the local circulation of E. canis or possibly reflect pathogen acquisition during earlier developmental stages or co-feeding on other infected hosts rather than active vector competence. Given that D. marginatus is among the most anthropophilic ixodid species, its potential role in E. canis transmission may represent a possibly underestimated risk for human exposure.
Picazio et al. (Thu,) studied this question.