Molecular Detection of a Bartonella sp. in Fleas and Mites Collected from Wild Rodents (Cricetidae: Sigmodontinae) in the Northeast of Argentine Patagonia

Ectoparasite-borne infections have become a global public health problem. This study investigated the diversity of fleas and mites associated with wild rodents in the northeastern region of Argentine Patagonia and analyzed the molecular presence of Rickettsia and Bartonella within these arthropods. Research was conducted in the Monte Desierto biome, focusing on areas where wildlife, livestock, and human activities overlap. Ectoparasites (n = 32) were collected from captured rodents and subjected to PCR amplification and phylogenetic analysis using gltA and rpoB for Bartonella and OmpA, OmpB and gltA for Rickettsia. Bartonella DNA was detected in all studied ectoparasites, with the obtained gltA and rpoB sequences showing 100% and 99% identity, respectively, to reference sequences of Bartonella sp. closely related to Bartonella quintana, whereas no Rickettsia DNA was detected. Specifically, the pathogen was identified in four flea species (Craneopsylla minerva wolffhuegeli, Neotyphloceras crackensis, Polygenis rimatus, and Ectinorus sp.) and the mite Gigantolaelaps wolffsohni, while Rickettsia was not detected in any samples. These findings constitute the first report of Bartonella sp. closely related to B. quintana in this geographical region as well as the first detection of the bacterium in these specific flea and mite species in South America. Our results suggest an active wild cycle of Bartonella sp., emphasizing the importance of the One Health approach in monitoring emerging infectious diseases.