Small subunit ribosomal metabarcoding reveals extraordinary trypanosomatid diversity in Brazilian bats

Abstract

BackgroundBats are a highly successful, globally dispersed order of mammals that occupy a wide array of ecological niches. They are also intensely parasitized and implicated in multiple viral, bacterial and parasitic zoonoses. Trypanosomes are thought to be especially abundant and diverse in bats. In this study, we used 18S ribosomal RNA metabarcoding to probe bat trypanosome diversity in unprecedented detail.Methodology/Principal FindingsTotal DNA was extracted from the blood of 90 bat individuals (17 species) captured along Atlantic Forest fragments of Espírito Santo state, southeast Brazil. 18S ribosomal RNA was amplified by standard and/or nested PCR, then deep sequenced to recover and identify Operational Taxonomic Units (OTUs) for phylogenetic analysis. Blood samples from 34 bat individuals (13 species) tested positive for infection by 18S rRNA amplification. Amplicon sequences clustered to 14 OTUs, of which five were identified as Trypanosoma cruzi I, T. cruzi III/V, Trypanosoma cruzi marinkellei, Trypanosoma rangeli, and Trypanosoma dionisii, and seven were identified as novel genotypes monophyletic to basal T. cruzi clade types of the New World. Another OTU was identified as a trypanosome like those found in reptiles. Surprisingly, the remaining OTU was identified as Bodo saltans–closest non-parasitic relative of the trypanosomatid order. While three blood samples featured just one OTU (T. dionisii), all others resolved as mixed infections of up to eight OTUs.Conclusions/SignificanceThis study demonstrates the utility of next-generation barcoding methods to screen parasite diversity in mammalian reservoir hosts. We exposed high rates of local bat parasitism by multiple trypanosome species, some known to cause fatal human disease, others non-pathogenic, novel or yet little understood. Our results highlight bats as a long-standing nexus among host-parasite interactions of multiple niches, sustained in part by opportunistic and incidental infections of consequence to evolutionary theory as much as to public health.

DNA of free-living bodonids (Euglenozoa: Kinetoplastea) in bat ectoparasites: potential relevance to the evolution of parasitic trypanosomatids

“…Results of the present study are in line with the finding of B. saltans-like DNA in the blood of bats in South America (Dario et al, 2017). Although in the relevant study (Dario et al, 2017) the authors could not entirely rule out that detection of B. saltans-like DNA in bat blood samples resulted from environmental contamination during sampling, their precautions argued against this.…”

“…Although in the relevant study (Dario et al, 2017) the authors could not entirely rule out that detection of B. saltans-like DNA in bat blood samples resulted from environmental contamination during sampling, their precautions argued against this. In the present study environmental contamination related to the sampling procedure can be excluded, because bat ectoparasites were put into ethanol on the premises, and it is very unlikely that B. saltans (or its DNA) would withstand ethanol-based disinfection (Dario et al, 2017).…”

“…In the present study environmental contamination related to the sampling procedure can be excluded, because bat ectoparasites were put into ethanol on the premises, and it is very unlikely that B. saltans (or its DNA) would withstand ethanol-based disinfection (Dario et al, 2017). In addition, bat ectoparasites of the present study were further surface-disinfected under laboratory conditions, and not only the DNA of B. saltans was detected in them (for which the possibility of contamination during sampling was considered on account of its ubiquity: Dario et al, 2017), but also the DNA of a neobodonid.…”

Trypanosoma rangeli is phylogenetically closer to Old World trypanosomes than to Trypanosoma cruzi

“…Mixed infections with T. cruzi and T. rangeli are common in triatomines and mammal hosts, including humans (Hoare, 1972;Maia da Silva et al, 2004,b, 2007Ramirez et al, 2014b;Pinto et al, 2015;Dario et al, 2017). However, despite shared mammal hosts and vectors across Central and South America, life cycles of T. cruzi and T. rangeli differ significantly in both vertebrate and invertebrate hosts.…”

Trypanosomatids in Small Mammals of an Agroecosystem in Central Brazil: Another Piece in the Puzzle of Parasite Transmission in an Anthropogenic Landscape

“…Electrophoresis of PCR products were carried out in a 2% agarose gel, stained with GelRed-Biotium, and then visualized under UV light. Each reaction included sterile distilled water instead of DNA as a negative control and positive control samples from T. cruzi strains that represent the DTUs [22,69].…”