Borrelia genospecies in Ixodes sp. cf. Ixodes affinis (Acari: Ixodidae) from Argentina.

The aim of this work was to evaluate the presence of Borrelia infection in Ixodes sp. cf. Ixodes affinis ticks from Argentina. Specimens of Ixodes sp. cf. I. affinis were collected on vegetation and birds in five locations belonging the most humid part of the Chaco Biogeographic Province. Specimens were tested for Borrelia infection by nested-PCR targeting the flaB gene and the rrfA-rrlB intergenic spacer region (IGS), sequenced and phylogenetically analyzed. A total of 48 Ixodes sp. cf. I. affinis (12 questing adults from vegetation and 20 nymphs and 16 larvae on nine bird species: Arremon flavirostris, Basileuterus culicivorus, Campylorhamphus trochilirostris, Myiothlypis leucoblephara, Tachyphonus rufus, Thlypopsis sordida, Turdus amaurochalinus, Turdus rufiventris and Troglodytes aedon) were collected. Twelve adults, 14 nymphs and 11 larvae (3 individually and 8 in 3 pools) were analyzed. Partial sequences were detected in 6 adults, 11 nymphs and 4 larvae (2 individual and 2 pools). Phylogenetically, the Borrelia found in Ixodes sp. cf. I. affinis belongs to the B. burgdorferi sensu lato (s. l.) complex. The partial sequences obtained from the borrelian gene flaB and IGS were associated to two groups formed by sequences previously detected in Ixodes fuscipes, Ixodes longiscutatus and Ixodes pararicinus from the Southern Cone of America in northern Argentina, southern Brazil and Uruguay. The results of this work suggest that the haplotypes of B. burgdorferi s. l. complex detected in the three species of the I. ricinus complex distributed in the Southern Cone of America are related and widely distributed.