Phylogeographical, ecological and biological patterns shown by nuclear (ssrRNA and gGAPDH) and mitochondrial (Cyt b) genes of trypanosomes of the subgenus Schizotrypanum parasitic in Brazilian bats

The genetic diversity and phylogeographical patterns of Trypanosoma species that infect Brazilian bats were evaluated by examining 1043 bats from 63 species of seven families captured in Amazonia, the Pantanal, Cerrado and the Atlantic Forest biomes of Brazil. The prevalence of trypanosome-infected bats, as estimated by haemoculture, was 12.9%, resulting in 77 cultures of isolates, most morphologically identified as Trypanosoma cf. cruzi, classified by barcoding using partial sequences from ssrRNA gene into the subgenus Schizotrypanum and identified as T. cruzi (15), T. cruzi marinkellei (37) or T. cf. dionisii (25). Phylogenetic analyses using nuclear ssrRNA, glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) and mitochondrial cytochrome b (Cyt b) gene sequences generated three clades, which clustered together forming the subgenus Schizotrypanum. In addition to vector association, bat trypanosomes were related by the evolutionary history, ecology and phylogeography of the bats. Trypanosoma cf. dionisii trypanosomes (32.4%) infected 12 species from four bat families captured in all biomes, from North to South Brazil, and clustered with T. dionisii from Europe despite being separated by some genetic distance. Trypanosoma cruzi marinkellei (49.3%) was restricted to phyllostomid bats from Amazonia to the Pantanal (North to Central). Trypanosoma cruzi (18.2%) was found mainly in vespertilionid and phyllostomid bats from the Pantanal/Cerrado and the Atlantic Forest (Central to Southeast), with a few isolates from Amazonia.     

Rickettsia monteiroi sp. nov., infecting the tick Amblyomma incisum in Brazil

Free-living adult Amblyomma incisum ticks were collected in an Atlantic rainforest area at Intervales State Park, State of São Paulo, Brazil. From an A. incisum specimen, rickettsiae were successfully isolated in Vero cell culture by the shell vial technique. Rickettsial isolation was confirmed by optical microscopy, transmission electron microscopy, and PCRs targeting portions of the rickettsial genes gltA, htrA, rrs, and sca1 on infected cells. Fragments of 1,089, 457, 1,362, and 443 nucleotides of the gltA, htrA, rrs, and sca1 genes, respectively, were sequenced. By BLAST analysis, the partial sequence of rrs of the A. incisum rickettsial isolate was closest to the corresponding sequence of Rickettsia bellii (99.1% similarity). The gltA partial sequence was closest to the corresponding sequences of “Candidatus Rickettsia tarasevichiae” (96.1% similarity) and Rickettsia canadensis (95.8% similarity). The htrA partial sequence was closest to the corresponding sequence of R. canadensis (89.8% similarity). The sca1 partial sequence was closest to the corresponding sequence of R. canadensis (95.2% similarity). Since our rickettsial isolate was genetically distinct from other Rickettsia species, we propose a new species designated Rickettsia monteiroi sp. nov. Phylogenetic analyses indicated that R. monteiroi belongs to the canadensis group within the genus Rickettsia, together with the species R. canadensis and “Candidatus R. tarasevichiae”. Little or no antibody cross-reaction was observed between sera of R. monteiroi-inoculated guinea pigs and R. bellii-, Rickettsia rickettsii-, or R. canadensis-inoculated guinea pigs.     

Morphological and molecular analysis of <Emphasis Type="Italic">Ornithonyssus</Emphasis> spp. (Acari: Macronyssidae) from small terrestrial mammals in Brazil

Based on chaetotaxy of the dorsal shield, the taxonomic status of many species of Ornithonyssus has been considered invalid, resulting in the synonymy of all Brazilian Ornithonyssus from small terrestrial wild mammals into one of the following four species: Ornithonyssus bacoti (Hirst, 1913), Ornithonyssus matogrosso (Fonseca, 1954), Ornithonyssus pereirai (Fonseca, 1935) or Ornithonyssus wernecki (Fonseca, 1935). Despite the revision of this genus in 1980, including all known species worldwide, the knowledge of Ornithonyssus in Brazil has not progressed for more than 40 years. Considering the potential importance of these haematophagous mites in transmitting rickettsial disease agents to animals and humans, we have revised Ornithonyssus species collected from small mammals in Brazil by means of morphological and molecular studies. Types and other material deposited in the Acari Collection of the Instituto Butantan (IBSP) were examined in addition to recently collected specimens. Morphological and genetic analysis of the 16S rDNA mitochondrial gene revealed that small terrestrial mammals in Brazil are parasitized by six species of Ornithonyssus mites: Ornithonyssus brasiliensis (Fonseca, 1939), O. matogrosso, O. monteiroi (Fonseca, 1941), O. pereirai, O. vitzthumi (Fonseca, 1941), and O. wernecki. An illustrated key to females of the valid Brazilian species of Ornithonyssus is included, based on optical and scanning electron microscopy.     

A morphological and phylogenetic analysis of <Emphasis Type="Italic">Ornithodoros marinkellei</Emphasis> (Acari: Argasidae), with additional notes on habitat and host usage

Ornithodoros marinkellei was described from larvae collected on Pteronotus spp. bats in Colombia and Panama. More recently, this tick was reported in the Brazilian Amazon. Because some morphometric differences were observed between O. marinkellei larvae from Colombia and Brazil, it was proposed that further investigations were needed to assess whether the differences could be attributed to intra- or inter-specific polymorphism. Herein, we collected O. marinkellei specimens in the type locality of Colombia, in Brazil, and in a new locality in Nicaragua, expanding the distribution of the species to Nicaragua. Morphometric analysis of larvae and adults, corroborated by a principal component analysis (PCA), indicated that the Brazilian specimens were larger than specimens from Colombia and Nicaragua. Phylogenetic analysis inferred from the mitochondrial 16S rRNA gene showed ticks from Colombia and Nicaragua more genetically related than any of them with ticks from Brazil, although ticks from the three countries grouped in a clade sister to a major clade containing sequences of various Neotropical Ornithodoros species. We concluded that ticks identified as O. marinkellei from Colombia, Nicaragua, and Brazil represent the same taxon, and that the genetic and morphological differences between them are likely to have a geographical bias. We redescribed the nymph of O. marinkellei, which has a vestigial hypostome, probably incompatible with blood feeding. We also report human infestation by O. marinkellei adults. As all reports of O. marinkellei adults have been from hot caves (temperature?>?35 °C), this abiotic condition could be a limiting factor for the occurrence of this tick species.     

Description of a new species of bat-associated argasid tick (Acari: Argasidae) from Brazil

A new species of argasid tick (Acari: Argasidae) is described from immature and adult specimens collected from several localities in Brazil. A complete morphological account is provided for all postembryonic life stages, i.e., larva, nymph, female, and male. Ornithodoros cavernicolous n. sp. is the 113(th) in the genus. Morphologically, the new species shares common features, e.g., presence of well-developed cheeks and legs with micromammillate cuticle, with other bat-associated argasid ticks included in the subgenus Alectorobius. In particular, the new species is morphologically related to Ornithodoros azteci Matheson, with which it forms a species group. Phylogenetic analysis based on the 16S rRNA gene sequences supports the placement of the new species within a large clade that includes other New World bat-associated argasids. However, the new species seems to represent an independent lineage within the genus Ornithodoros.     

Detection of <Emphasis Type="Italic">Rickettsia</Emphasis> spp. in ticks associated to wild mammals in Northeastern Brazil,with notes on an undetermined <Emphasis Type="Italic">Ornithodoros</Emphasis> sp. collected from marsupials

We report tick infestations and rickettsial detection in ticks infesting free-living wild mammals (Monodelphis domestica, Tolypeutes tricinctus, Thrichomys inermis and Kerodon rupestris) captured in the Caatinga ecoregion of Bahia state, northeastern Brazil, during September to December 2016. Overall, 117 ticks (61 larvae, 25 nymphs, 25 males, 6 females) belonging to two genera, and at least three species were collected: Amblyomma auricularium, Amblyomma parvum, Amblyomma sp., Ornithodoros rietcorreai and an unidentified Ornithodoros sp. We provide new host records to the rodent T. inermis parasitized by larva and nymphs of A. auricularium and to the marsupial M. domestica infested by larvae of A. auricularium. Furthermore, we describe new tick-host association for larvae of O. rietcorreai on the rodents K. rupestris and T. inermis. Concerning tick-Rickettsia associations, we detected Rickettsia amblyommatis and an uncharacterized species of Rickettsia belonging to the spotted fever group (SFG) in both A. auricularium and A. parvum. Additionally, ‘Candidatus Rickettsia andeanae’ was detected in A. parvum as well.