Trypanosoma livingstonei: a new species from African bats supports the bat seeding hypothesis for the Trypanosoma cruzi clade

Abstract Background Bat trypanosomes have been implicated in the evolutionary history of the T. cruzi clade, which comprises species from a wide geographic and host range in South America, Africa and Europe, including bat-restricted species and the generalist agents of human American trypanosomosis T. cruzi and T. rangeli. Methods Trypanosomes from bats (Rhinolophus landeri and Hipposideros caffer) captured in Mozambique, southeast Africa, were isolated by hemoculture. Barcoding was carried out through the V7V8 region of Small Subunit (SSU) rRNA and Fluorescent Fragment Length barcoding (FFLB). Phylogenetic inferences were based on SSU rRNA, glyceraldehyde phosphate dehydrogenase (gGAPDH) and Spliced Leader (SL) genes. Morphological characterization included light, scanning and transmission electron microscopy. Results New trypanosomes from bats clustered together forming a clade basal to a larger assemblage called the T. cruzi clade. Barcoding, phylogenetic analyses and genetic distances based on SSU rRNA and gGAPDH supported these trypanosomes as a new species, which we named Trypanosoma livingstonei n. sp. The large and highly polymorphic SL gene repeats of this species showed a copy of the 5S ribosomal RNA into the intergenic region. Unique morphological (large and broad blood trypomastigotes compatible to species of the subgenus Megatrypanum and cultures showing highly pleomorphic epimastigotes and long and slender trypomastigotes) and ultrastructural (cytostome and reservosomes) features and growth behaviour (when co-cultivated with HeLa cells at 37°C differentiated into trypomastigotes resembling the blood forms and do not invaded the cells) complemented the description of this species. Conclusion Phylogenetic inferences supported the hypothesis that Trypanosoma livingstonei n. sp. diverged from a common ancestral bat trypanosome that evolved exclusively in Chiroptera or switched at independent opportunities to mammals of several orders forming the clade T. cruzi, hence, providing further support for the bat seeding hypothesis to explain the origin of T. cruzi and T. rangeli.

We would like to thank many people who kindly helped us with the fieldwork in Mozambique. We are particularly grateful to our friends Carmen e José Martins for their delightful company and hospitality in their house in Chupanga. We are deeply indebted to Carlos Pereira and the staff of the Gorongosa National Park. We are also grateful to Laerte B. Viola, Arlei Marcili, Bruno R. Fermino and many other students for their efforts in bat capture and sample collection. This work was supported by grants from the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq) within the PROAFRICA, PROTAX, and UNIVERSAL Programs to MMGT and EPC. LL is a postdoctoral fellow sponsored by São Paulo State Research Support Foundation (FAPESP) process nº 2012/149856, EspinosaÁlvarez O is a PhD student sponsored by CNPq (PROTAX).

We would like to thank many people who kindly helped us with the fieldwork in Mozambique. We are particularly grateful to our friends Carmen e José Martins for their delightful company and hospitality in their house in Chupanga. We are deeply indebted to Carlos Pereira and the staff of the Gorongosa National Park. We are also grateful to Laerte B. Viola, Arlei Marcili, Bruno R. Fermino and many other students for their efforts in bat capture and sample collection. This work was supported by grants from the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq) within the PROAFRICA, PROTAX, and UNIVERSAL Programs to MMGT and EPC. LL is a postdoctoral fellow sponsored by São Paulo State Research Support Foundation (FAPESP) process nº 2012/14985-6, Espinosa-Álvarez O is a PhD student sponsored by CNPq (PROTAX).