Phylogenetic Inferences Based on Distinct Molecular Markers Confirm a Novel Babesia Species ( Babesia goianiaensis nov. sp.) in Capybaras ( Hydrochoerus hydrochaeris ) and Associated Ticks.

Piroplasmids (order Piroplasmida) are a diverse group of tick-borne protozoa that may cause disease in animals and occasionally in humans. Novel Piroplasmida clades and species have been found in wild animals from Brazil based on the phylogenetic assessment of near-complete 18S rRNA, mitochondrial and heat-shock protein genes. For instance, a putative novel species has been detected in capybaras and ticks in three Brazilian states. The present work aimed to describe, using phylogenetic assessments based on distinct molecular markers, this novel species in capybaras and associated ticks ( and ) sampled in Goiânia city, Goiás state, midwestern Brazil. While the phylogenetic analysis based on both near-complete 18S rRNA and genes positioned the sequences obtained from capybara blood samples into a new clade sister to the clade, the phylogenetic inference based on the COX-3 amino acid positioned the obtained sequences from capybara blood samples and ticks also into a clade sister to the clade, highlighting the inappropriateness of this marker inferring evolutionary relationships among piroplasmids. Pairwise distance analysis demonstrated that the divergence rates between the 18S rRNA sequences detected in capybaras and other Piroplasmida already described were very high and ranged from 9.4 to 12.9%. Genotype analysis based on the near-full 18S rRNA sequences of the Piroplasmida detected in capybaras and associated ticks demonstrated the occurrence of high genotype diversity at an intra-species level. In conclusion, phylogenetic analyses based on distinct molecular markers supported the description of nov. sp. in capybaras and associated ticks. Additionally, a novel phylogenetic clade, apart from the previously described ones, was described in the present study and contributed to untangling the complex evolutionary history of the Piroplasmida.