Rickettsia felis in Rhipicephalus sanguineus from two distant Chilean cities

Area of Science:

• Veterinary Entomology
• Infectious Diseases
• Molecular Biology

Background:

• Rickettsia felis is an emerging infectious agent with potential human health implications.
• While cat fleas are the primary vector, R. felis has been detected in other arthropods, including Rhipicephalus sanguineus ticks.
• Previous identification of R. felis in Chile was limited to cat fleas and a single Rhipicephalus sanguineus specimen.

Purpose of the Study:

• To determine the prevalence of Rickettsia species in Rhipicephalus sanguineus ticks collected from dogs.
• To investigate the geographical distribution of Rickettsia felis within Rhipicephalus sanguineus in Chile.

Main Methods:

• Domiciliary sampling of ectoparasites from dogs in two geographically distinct areas of Chile: the Metropolitan Region and Arica.
• Molecular detection and gene sequencing (gltA, ompA, ompB) to identify Rickettsia species within collected Rhipicephalus sanguineus ticks.

Main Results:

• Rhipicephalus sanguineus ticks were found on 50% of the 460 dogs sampled.
• Rickettsia felis was successfully identified in Rhipicephalus sanguineus ticks from both sampled regions.
• A higher prevalence of R. felis was observed in ticks collected from Arica compared to the Metropolitan Region.

Conclusions:

• The presence of Rickettsia felis in Rhipicephalus sanguineus across two distant regions of Chile suggests the agent is well-established nationally.
• The findings highlight the potential for Rhipicephalus sanguineus to act as a significant vector for R. felis transmission in Chile.
• Clinicians should be aware of the possibility of spotted fever group rickettsial infections, as none have been formally recognized in Chile to date.