Morphological and molecular characterization and phylogenetic relationships of a new species of trypanosome in Tapirus terrestris (lowland tapir), Trypanosoma terrestris sp. nov., from Atlantic Rainforest of southeastern Brazil

Acosta, Igor da Cunha Lima; Costa, Andréa Pereira da; Nunes, Pablo Henrique; Gondim, Maria Fernanda Naegeli; Gatti, Andressa; Rossi, João Luiz; Gennari, Solange Maria; Marcili, Arlei

doi:10.1186/1756-3305-6-349

Cited by 16 publications

(13 citation statements)

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“…6). Additionally, as envisaged by Acosta et al [29], T. terrestris and T. grayi are sister clades (Fig. 6), further indicating that host-switching is a common feature promoting trypanosome evolution [28].…”

Section: Discussionmentioning

confidence: 93%

“…Examining the causes of genetic variation in parasite populations is often challenging and difficult to track. In this regard, some trypanosomes are known to exhibit complex life-cycles involving multiple hosts and/or vector species, and there are many cases where the vector species is not yet identified [19] as is the case of T. terrestris [29]. To overcome this, we observed patterns of genetic variation and parasite population dynamics based on a host capture–recapture strategy (tapir radio tagging over years 2012–2015) at microgeographical scale within the Nhecolândia landscape in Pantanal (14 km 2 ), from which the samples were collected.…”

Section: Methodsmentioning

confidence: 99%

“…To simplify the molecular clock assumption and thus circumvent possible bias in estimating divergence times, we did not add more trypanosome species due to great differences in molecular evolutionary rates of trypanosomes and because T. cruzi and T. grayi clades were previously placed as close relatives in phylogenomic studies [56]. Moreover, observations made by Acosta et al [29] included high genetic similarity between T. grayi and T. terrestris.…”

Section: Methodsmentioning

confidence: 99%

“…To help fill these knowledge gaps and test alternative scenarios on ecological fitting and coevolution, we used new target isolates of Trypanosoma terrestris , a sylvatic trypanosome species first described in 2013 and retrieved from blood culture isolates of lowland tapirs ( Tapirus terrestris ; Perissodactyla: Tapiridae) in the Brazilian Atlantic Forest [29]. Trypanosoma terrestris is an ancient and divergent parasite that was proposed as a new clade and is thought to be specific to its vertebrate host as it apparently only grows in tapirs [29]. However, isolation of additional species of the T. terrestris clade from other perissodactyl hosts, pathogenicity, biological behavior in natural hosts, potential vectors, as well its evolutionary history remain unaddressed [29].…”

Section: Introductionmentioning

confidence: 99%

“…Trypanosoma terrestris is an ancient and divergent parasite that was proposed as a new clade and is thought to be specific to its vertebrate host as it apparently only grows in tapirs [29]. However, isolation of additional species of the T. terrestris clade from other perissodactyl hosts, pathogenicity, biological behavior in natural hosts, potential vectors, as well its evolutionary history remain unaddressed [29].…”

Section: Introductionmentioning

confidence: 99%

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Phylogenetics, patterns of genetic variation and population dynamics of Trypanosoma terrestris support both coevolution and ecological host-fitting as processes driving trypanosome evolution

et al. 2019

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Background A considerable amount of evidence has favored ecological host-fitting, rather than coevolution, as the main mechanism responsible for trypanosome divergence. Nevertheless, beyond the study of human pathogenic trypanosomes, the genetic basis of host specificity among trypanosomes isolated from forest-inhabiting hosts remains largely unknown. Methods To test possible scenarios on ecological host-fitting and coevolution, we combined a host capture recapture strategy with parasite genetic data and studied the genetic variation, population dynamics and phylogenetic relationships of Trypanosoma terrestris, a recently described trypanosome species isolated from lowland tapirs in the Brazilian Pantanal and Atlantic Forest biomes. Results We made inferences of T. terrestris population structure at three possible sources of genetic variation: geography, tapir hosts and ‘putative’ vectors. We found evidence of a bottleneck affecting the contemporary patterns of parasite genetic structure, resulting in little genetic diversity and no evidence of genetic structure among hosts or biomes. Despite this, a strongly divergent haplotype was recorded at a microgeographical scale in the landscape of Nhecolândia in the Pantanal. However, although tapirs are promoting the dispersion of the parasites through the landscape, neither geographical barriers nor tapir hosts were involved in the isolation of this haplotype. Taken together, these findings suggest that either host-switching promoted by putative vectors or declining tapir population densities are influencing the current parasite population dynamics and genetic structure. Similarly, phylogenetic analyses revealed that T. terrestris is strongly linked to the evolutionary history of its perissodactyl hosts, suggesting a coevolving scenario between Perissodactyla and their trypanosomes. Additionally, T. terrestris and T. grayi are closely related, further indicating that host-switching is a common feature promoting trypanosome evolution. Conclusions This study provides two lines of evidence, both micro- and macroevolutionary, suggesting that both host-switching by ecological fitting and coevolution are two important and non-mutually-exclusive processes driving the evolution of trypanosomes. In line with other parasite systems, our results support that even in the face of host specialization and coevolution, host-switching may be common and is an important determinant of parasite diversification.

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Section: Discussionmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%