Flea infestation and molecular detection of Rickettsia and Bartonella spp. in domestic dog-associated fleas from the inter-Andean basin of Cundinamarca, Colombia

Dogs are common companion animals, often infested by fleas that can transmit zoonotic pathogens in rural tropical areas. In Colombia, studies on flea-borne agents in dogs are limited. Understanding the presence of these ectoparasites and associated microorganisms is crucial. To assess flea infestation and detect and identify Rickettsia and Bartonella spp. in fleas collected from dogs in Cundinamarca, Colombia. Between 2019 and 2020, fleas were collected from rural domestic dogs in 24 municipalities of western Cundinamarca. Fleas were morphologically identified and pooled for DNA extraction. Molecular screening of Rickettsia and Bartonella spp. was performed by qPCR. Positive samples underwent further characterization by conventional PCR. Rickettsia was additionally analyzed using RFLP, while Bartonella was evaluated through phylogenetic analysis. Of the 116 dogs examined across 24 municipalities, 39.7% were infested with fleas. A total of 138 fleas were collected and grouped into 46 pools, with Ctenocephalides felis felis identified in 94% of them. Rickettsia was detected in 83% of pools, with Rickettsia asembonensis and Rickettsia felis identified in most positive samples. Bartonella was found in 28% of pools; however, sequencing success was limited, and no species-level identification could be achieved. This study documents flea infestation in domestic dogs in Cundinamarca, predominantly by C. felis felis. High detection of R. asembonensis and presence of R. felis confirm widespread rickettsial circulation in fleas. Bartonella was detected less frequently, but species-level identification was not achieved.