Bats, Trypanosomes, and Triatomines in Ecuador: New Insights into the Diversity, Transmission, and Origins of Trypanosoma cruzi and Chagas Disease

Abstract

The generalist parasite Trypanosoma cruzi has two phylogenetic lineages associated almost exclusively with bats—Trypanosoma cruzi Tcbat and the subspecies T. c. marinkellei. We present new information on the genetic variation, geographic distribution, host associations, and potential vectors of these lineages. We conducted field surveys of bats and triatomines in southern Ecuador, a country endemic for Chagas disease, and screened for trypanosomes by microscopy and PCR. We identified parasites at species and genotype levels through phylogenetic approaches based on 18S ribosomal RNA (18S rRNA) and cytochrome b (cytb) genes and conducted a comparison of nucleotide diversity of the cytb gene. We document for the first time T. cruzi Tcbat and T. c. marinkellei in Ecuador, expanding their distribution in South America to the western side of the Andes. In addition, we found the triatomines Cavernicola pilosa and Triatoma dispar sharing shelters with bats. The comparisons of nucleotide diversity revealed a higher diversity for T. c. marinkellei than any of the T. c. cruzi genotypes associated with Chagas disease. Findings from this study increased both the number of host species and known geographical ranges of both parasites and suggest potential vectors for these two trypanosomes associated with bats in rural areas of southern Ecuador. The higher nucleotide diversity of T. c. marinkellei supports a long evolutionary relationship between T. cruzi and bats, implying that bats are the original hosts of this important parasite.

Is Predominant Clonal Evolution a Common Evolutionary Adaptation to Parasitism in Pathogenic Parasitic Protozoa, Fungi, Bacteria, and Viruses?

“…This observation illustrates the strength of PCE in T. cruzi, which is reflected in all genes of this parasite, including strongly selected ones. An additional near-clade, referred to as Tc-Bat (because it has been isolated from bats only), has been recorded in Brazil, Colombia, Ecuador and Panama years apart, in different species of bats (Lima et al, 2015;Marcili et al, 2009;Pinto et al, 2012Pinto et al, , 2016. This is a striking illustration of the permanency of the near-clades.…”

“…Considering that such a pattern was 'self-evident' (Ramírez and Llevellyn, 2015) is easy when arriving long after the battle and amounts to saying that the results of any phylogenetic analysis are self-evident. With such a view, the discovery of the newly described Trypanosoma cruzi near-clades Tc-Bat (Lima et al, 2015;Marcili et al, 2009;Pinto et al, 2012Pinto et al, , 2016 was self-evident, as was the description of the lesser near-clades within the T. cruzi near-clade TCI . Evidencing near-clades is all the less self-evident, since even the widely accepted number of near-clades within the thoroughly studied species T. cruzi (Brisse et al, 2000;Zingales et al, 2012) still is under debate (Barnabé et al, 2016).…”

Bat trypanosomatids (first report of T. wauwau) in Triângulo Mineiro, Brazil

“…The only species of Leishmania identified was L. braziliensis, in the bats Anoura caudifer and Phyllostomus discolor ( Table 2). 8…”

“…Until now, more than up to 30 species of trypanosomatids have been isolated from bats [1][2][3][4]. The most frequently reported species of Trypanosoma in bats are T. cruzi, T. cruzi marinkellei, T. dionisii, T. hedricki, T. myoti, T. leonidasdeanei, T. desterrensis, T. pifanoi, T. pessoai, T. megaderma-like, T. theileri, and T. rangeli [5][6][7][8][9][10]. An additional species, T. wauwau, was also recently described in Brazil [9][10].…”

Le troisième et nouveau visage de la maladie de Chagas

“…Nous utilisons l'expression binominale Trypanosoma cruzi comme cela se fait couramment bien que Trypanosoma cruzi soit considéré de plus en plus comme une sous-espèce (T. cruzi cruzi), l'autre sousespèce de T. cruzi étant un trypanosome inféodé aux chauves-souris (T. cruzi marinkellei) que certains considèrent comme étant l'ancêtre de T. cruzi cruzi[18].Bull. Soc.…”