Diversity and evolution of anuran trypanosomes: insights from the study of European species

Abstract

BackgroundAmphibian trypanosomes were the first ever described trypanosomatids. Nevertheless, their taxonomy remains entangled because of pleomorphism and high prevalence of mixed infections. Despite the fact that the first species in this group were described in Europe, virtually none of the trypanosomes from European anurans was analyzed using modern molecular methods.MethodsIn this study, we explored the diversity and phylogeny of trypanosomes in true frogs from Europe using light microscopy and molecular methods.ResultsA comparison of observed morphotypes with previous descriptions allowed us to reliably identify three Trypanosoma spp., whereas the remaining two strains were considered to represent novel taxa. In all cases, more than one morphotype per blood sample was observed, indicating mixed infections. One hundred and thirty obtained 18S rRNA gene sequences were unambiguously subdivided into five groups, correspondent to the previously recognized or novel taxa of anuran trypanosomes.ConclusionsIn this work we studied European frog trypanosomes. Even with a relatively moderate number of isolates, we were able to find not only three well-known species, but also two apparently new ones. We revealed that previous assignments of multiple isolates from distant geographical localities to one species based on superficial resemblance were unjustified. Our work also demonstrated a high prevalence of mixed trypanosome infections in frogs and proposed a plausible scenario of evolution of the genus Trypanosoma.

18S rDNA Sequence-Structure Phylogeny of The Trypanosomatida (Kinetoplastea, Euglenozoa) with Special Reference on Trypanosoma

“…This positioning of T. chattoni was shown in a previous study using complete 18S rDNA sequences and nontrypanosomes as the outgroup [54]. However, recent trees using complete 18S rDNA sequences and concatenated analysis of v7v8 hypervariable region and gGAPDH rooted by other trypanosomes sustained a monophyletic anuran clade [39,40]. Thus, T. chattoni positioning in our tree can be related to the use of non-trypanosomes as the outgroup.…”

“…The trypanosomes of the Aquatic lineage branched together (Fig. 2) [14,15,39,40]. Interestingly, the anuran parasite, Trypanosoma chattoni Mathis & Leger, 1911, appears in our analysis more related to sh and platypus trypanosomes than to the anuran clade.…”

“…1) and selection of 43 different species (Fig. 2 [38]; the Trypanosoma theileri Laveran, 1902 clade, with T. theileri, a worldwide distributted cattle parasite, and the subclade representant Trypanosoma cyclops Weinman, 1972 [13,21]; and the Aquatic clade, harboring trypanosomes from sh, anurans and platypus [14,39,40]. Interestingly, the lizard/snake clade is also represented in our tree with Trypanosoma varani Wenyon, 1908, a snake trypanosome, branching together with the mammal parasite Trypanosoma freitasi Rego et al, 1957.…”

Isolation and partial characterisation of a novel Trypanosoma from the tick Ixodes ricinus

“…Trypanosomes are protozoan parasites recognised as the causative agents of numerous important human and livestock diseases, such as Chagas' disease caused by Trypanosoma cruzi , African sleeping sickness caused by Trypanosoma brucei and surra caused by Trypanosoma evansi ( Haag et al, 1998 ). Trypanosomes have been associated with infection in all vertebrate groups, including amphibians and fish ( Grybchuk-Ieremenko et al, 2014 ; Ferreira et al, 2015 ; Spodareva et al, 2018 ), and typically demonstrate a degree of specificity with regards to host and vector ( Hamilton et al, 2007 ; Cooper et al, 2017 ). Whilst transmission is frequently via insect vectors, other blood-feeding organisms have also been shown to be vectors, including leeches ( Haag et al, 1998 ).…”

The First Non-LRV RNA Virus in Leishmania

“…Transfer of viruses between different species of trypanosomatids is possible because of coinfections, which are quite common in these parasites [81][82][83][84][85]. Coinfections were previously reported for Leptomonas moramango [39].…”