Trypanosoma spp. Neobats: Insights about those poorly known trypanosomatids

Trypanosomatid diversity in a bat community of an urban area in Campo Grande, Mato Grosso do Sul, Brazil

Bats have a long evolutionary history with trypanosomatids, but the role of these flying mammals on parasite transmission cycles in urban areas, especially for Trypanosoma and Leishmania species, remains poorly known. The objective of this study was to evaluate the species richness of trypanosomatids parasitizing a bat community in Campo Grande (CG), a state capital within the Cerrado of the Brazilian Midwest. We evaluated 237 bats of 13 species by means of hemoculture and molecular detection in spleen samples. The bat community of CG appears to participate in the transmission cycles of various species of trypanosomatids. We report an overall trypanosomatid detection rate of 34.2% (n = 81), involving 11 out of 13 sampled bat species. We identified six species of trypanosomatids from 61 bats by analyzing SSU rRNA and/or kDNA: Trypanosoma cruzi DTU TcI, T. c. marinkellei, T. dionisii, Leishmania infantum, L. amazonensis, and T. janseni, with this latter being detected by hemoculture for the first time in a bat species. We also detected a Molecular Operational Taxonomic Unit, Trypanosoma sp. DID, in the phyllostomids Glossophaga soricina and Platyrrhinus lineatus. The highest trypanosomatid richness was observed for Sturnira lilium, which hosted three species: L. infantum, T. dionisii and T. janseni. Given that visceral leishmaniasis is endemic in CG, special focus should be placed on L. infantum. Moreover, L. amazonensis and T. cruzi warrant attention, since these are zoonotic parasites responsible for human cases of tegumentary leishmaniasis and Chagas disease, respectively. In this respect, we discuss how bat communities may influence the Leishmania spp. transmission in endemic areas.

Unraveling the diversity of Trypanosoma species from Central Mexico: Molecular confirmation on the presence of Trypanosoma dionisii and novel Neobat linages

Bats are one of the groups of mammals with the highest number of associated Trypanosoma taxa. There are 50 Trypanosoma species and genotypes infecting more than 75 species of bats across five continents. However, in Mexico, the inventory of species of the genus Trypanosoma associated with bats is limited to only two species (Trypanosoma vespertilionis and Trypanosoma cruzi) even though 140 species of bats inhabit this country. Specifically, 91 bat species have been recorded in the state of Veracruz, but records of trypanosomatids associated with this mammalian group are absent. Due to the complex Trypanosoma-bat relationship, the high diversity of bat species in Veracruz, as well as the lack of records of trypanosomatids associated with bats for this state, the aim of this work was to analyze the diversity of species of the genus Trypanosoma and their presence from a bat community in the central area of the state of Veracruz, Mexico. During the period of January to August 2022 in the Tequecholapa Environmental Management Unit where bats were collected using mist nets and blood samples were obtained from their thumbs. We extracted genetic material and amplified a fragment of 800 bp of the 18S ribosomal gene of the genus Trypanosoma by conventional PCR. The positive amplicons were sequenced, and phylogenetic reconstruction was performed to identify the parasite species. A total of 285 bats (149♀, 136♂) belonging to 13 species from 10 genera and a single family (Phyllostomidae) were collected. Twenty-three specimens from six species tested positive for the presence of Trypanosoma dionisii, Trypanosoma sp. Neobat 4, and a potential novelty species provisionally named as Trypanosoma sp. Neobat 6. The results of the present work increase the number of species of the genus Trypanosoma infecting bats in Mexico and in the Neotropical region.

The Mite Steatonyssus periblepharus Is a Novel Potential Vector of the Bat Parasite Trypanosoma dionisii

Trypanosoma dionisii, for which only bat bugs (Cimicidae) had previously been demonstrated as vectors, was, for the first time, detected in the gamasine mite Steatonyssus periblepharus in Russia. The molecular phylogenetic analysis indicated that trypanosomes found in these mites belong to the "clade A" of T. dionisii, which, based on genetic distances, can be considered as a species separate from the sister clade B, and according to available data also has a distinct geographic distribution. The presence of developmental forms of T. dionisii resembling those previously described during the development of this trypanosome in cimicids suggests that S. periblepharus is a novel vector of the studied trypanosome.

Old Methods, New Insights: Reviewing Concepts on the Ecology of Trypanosomatids and Bodo sp. by Improving Conventional Diagnostic Tools

Mixed infections by different Trypanosoma species or genotypes are a common and puzzling phenomenon. Therefore, it is critical to refine the diagnostic techniques and to understand to what extent these methods detect trypanosomes. We aimed to develop an accessible strategy to enhance the sensitivity of the hemoculture, as well as to understand the limitations of the hemoculture and the blood clot as a source of parasitic DNA. We investigated trypanosomatid infections in 472 bats by molecular characterization (18S rDNA gene) of the DNA obtained from the blood clot and, innovatively, from three hemoculture sample types: the amplified flagellates ("isolate"), the pellet of the culture harvested in its very initial growth stage ("first aliquot"), and the pellet of non-grown cultures with failure of amplification ("sediment"). We compared (a) the characterization of the flagellates obtained by first aliquots and isolates; and (b) the performance of the hemoculture and blood clot for trypanosomatid detection. We observed: (i) a putative new species of Bodo in Artibeus lituratus; (ii) the potential of Trypanosoma cruzi selection in the hemoculture; (iii) that the first aliquots and sediments overcome the selective pressure of the hemoculture; and (iv) that the blood clot technique performs better than the hemoculture. However, combining these methods enhances the detection of single and mixed infections.

Trypanosomatid Richness Among Rats, Opossums, and Dogs in the Caatinga Biome, Northeast Brazil, a Former Endemic Area of Chagas Disease

Parasites are important components of the immense n-dimensional trophic network that connects all living beings because they, among others, forge biodiversity and deeply influence ecological evolution and host behavior. In this sense, the influence of Trypanosomatidae remains unknown. The aim of this study was to determine trypanosomatid infection and richness in rats, opossums, and dogs in the semiarid Caatinga biome. We submitted DNA samples from trypanosomatids obtained through axenic cultures of the blood of these mammals to mini exon multiplex-PCR, Sanger, and next-generation sequencing targeting the 18S rDNA gene. Phylogenetic analyses were performed to identify genetic diversity in the Trypanosomatidae family. Shannon, Simpson, equability, and beta-diversity indices were calculated per location and per mammalian host. Dogs were surveyed for trypanosomatid infection through hemocultures and serological assays. The examined mammal species of this area of the Caatinga biome exhibited an enormous trypanosomatid species/genotypes richness. Ten denoised Operational Taxonomic Units (ZOTUs), including three species (Trypanosoma cruzi, Trypanosoma rangeli and Crithidia mellificae) and one Trypanosoma sp. five genotypes/lineages (T. cruzi DTU TcI, TcII, and TcIV; T. rangeli A and B) and four DTU TcI haplotypes (ZOTU1, ZOTU2, ZOTU5, and ZOTU10 merged), as well as 13 Amplicon Sequence Variants (ASVs), including five species (T. cruzi, T. rangeli, C. mellificae, Trypanosoma dionisii, and Trypanosoma lainsoni), five genotypes/lineages (same as the ZOTUs) and six DTU TcI haplotypes (ASV, ASV1, ASV2, ASV3, ASV5 and ASV13), were identified in single and mixed infections. We observed that trypanosomatids present a broad host spectrum given that species related to a single host are found in other mammals from different taxa. Concomitant infections between trypanosomatids and new host-parasite relationships have been reported, and this immense diversity in mammals raised questions, such as how this can influence the course of the infection in these animals and its transmissibility. Dogs demonstrated a high infection rate by T. cruzi as observed by positive serological results (92% in 2005 and 76% in 2007). The absence of positive parasitological tests confirmed their poor infectivity potential but their importance as sentinel hosts of T. cruzi transmission.

Trypanosoma Species in Small Nonflying Mammals in an Area With a Single Previous Chagas Disease Case

Trypanosomatids are hemoflagellate parasites that even though they have been increasingly studied, many aspects of their biology and taxonomy remain unknown. The aim of this study was to investigate the Trypanosoma sp. transmission cycle in nonflying small mammals in an area where a case of acute Chagas disease occurred in Mangaratiba municipality, Rio de Janeiro state. Three expeditions were conducted in the area: the first in 2012, soon after the human case, and two others in 2015. Sylvatic mammals were captured and submitted to blood collection for trypanosomatid parasitological and serological exams. Dogs from the surrounding areas where the sylvatic mammals were captured were also tested for T. cruzi infection. DNA samples were extracted from blood clots and positive hemocultures, submitted to polymerase chain reaction targeting SSU rDNA and gGAPDH genes, sequenced and phylogenetic analysed. Twenty-one wild mammals were captured in 2012, mainly rodents, and 17 mammals, mainly marsupials, were captured in the two expeditions conducted in 2015. Only four rodents demonstrated borderline serological T. cruzi test (IFAT), two in 2012 and two in 2015. Trypanosoma janseni was the main Trypanosoma species identified, and isolates were obtained solely from Didelphis aurita. In addition to biological differences, molecular differences are suggestive of genetic diversity in this flagellate species. Trypanosoma sp. DID was identified in blood clots from D. aurita in single and mixed infections with T. janseni. Concerning dogs, 12 presented mostly borderline serological titers for T. cruzi and no positive hemoculture. In blood clots from 11 dogs, T. cruzi DNA was detected and characterized as TcI (n = 9) or TcII (n = 2). Infections by Trypanosoma rangeli lineage E (n = 2) and, for the first time, Trypanosoma caninum, Trypanosoma dionisii, and Crithidia mellificae (n = 1 each) were also detected in dogs. We concluded that despite the low mammalian species richness and degraded environment, a high Trypanosoma species richness species was being transmitted with the predominance of T. janseni and not T. cruzi, as would be expected in a locality of an acute case of Chagas disease.