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

Fleas (Insecta: Siphonaptera) are recognized 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 & Gervais (Carnivora: Felidae)
and Lycalopex gymnocercus Fischer (Carnivora:  Canidae). A total
of 248 fleas were recovered, identified as Hectopsyllidae: Hectopsylla
broscus Jordan & 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.