Fleas of wild mammals carrying pathogenic bacteria in Argentinian Patagonia: A study based on wildlife roadkill

Fleas (Insecta: Siphonaptera) are recognised vectors of bacteria that affect human and other animal health, whose reservoirs are in the majority mammals. Among these, some species of the genera Rickettsia (Rickettsiales: Rickettsiaceae) and Bartonella (Rhizobiales: Bartonellaceae) are emerging and re-emerging throughout the world; however, their circulation across vast regions of Argentina and numerous animal species, particularly wild species remains largely unknown. The study of wild animal roadkill provides valuable insights into parasitic associations and the presence of pathogenic microorganisms, allowing the generation of a health alert in certain ecosystems. The aim of this study was to describe the diversity of fleas associated with roadkilled wild native meso-mammals in the extreme northeast of Argentinian Patagonia, and to detect the presence of Rickettsia and Bartonella bacteria. Five host species were examined, including Chaetophractus villosus Desmarest (Cingulata: Chlamyphoridae); Didelphis albiventris Lund (Didelphimorphia: Didelphidae); Lagostomus maximus Desmarest (Rodentia: Chinchillidae); Leopardus geoffroyi d'Orbigny and Gervais (Carnivora: Felidae) and Lycalopex gymnocercus Fischer (Carnivora: Canidae). A total of 248 fleas were recovered, identified as Hectopsyllidae: Hectopsylla broscus Jordan and Rothschild and Hectopsylla cypha Jordan; Malacopsyllidae: Phthiropsylla agenoris Rothschild and Malacopsylla grossiventris Weyenbergh; Pulicidae: Ctenocephalides felis Bouché and Pulex irritans Linnaeus. Molecular analysis detected two flea-borne pathogenic bacteria: Rickettsia felis (Bouyer et al.), found in C. felis from D. albiventris, and Bartonella rochalimae (Eremeeva et al.), reported here for the first time in Argentina, detected in P. agenoris from C. villosus, and in P. irritans from L. maximus and L. gymnocercus. The results contribute to knowledge of flea diversity in Argentinian Patagonia and provide new information about flea-borne pathogens circulating in the wildlife of this region. Furthermore, this study is the first in Argentina to investigate ectoparasites and their associated bacteria in roadkilled animals, making a pioneering contribution to the field. The interesting findings highlight the importance of implementing and expanding road ecology studies, which could easily be replicated in other regions where information gaps on flea and flea-borne bacteria diversity still exist.