Parasites of the genusTrypanosomaare unicellular flagellated microorganisms of theTrypanosomatidae. This study describes an isolate of the genusTrypanosomanaturally infectingRhipicephalus microplusticks, characterized through molecular, morphological and biological analysis. Trypanosome cultures, designated strain P1RJ, were obtained by isolation fromR. microplushaemolymph in cultures of the tick cell line IDE8. After isolation, strain P1RJ grew well axenically in L15B medium at temperatures of 30, 32 and 34 °C. The new trypanosome remained stable in axenic culture over 14 passages in L15B at 30 °C and was successfully cryopreserved and resuscitated. Morphometric analysis was performed on randomly selected developmental forms. 18S rRNA and 24Sα rDNA sequence analyses confirmed that strain P1RJ is a new species of the genusTrypanosoma. The nucleotide sequences described were submitted to Genbank. Pathogenicity, involvement in vertebrate hosts, epidemiology, developmental cycle and transmission mechanisms of strain P1RJ are still unknown. Therefore, more studies will be necessary to determine life cycle aspects of this trypanosome, for which we propose the nameTrypanosoma rhipicephalissp. nov.

Parasites of the genusTrypanosomaare microorganisms that display wide morphological, biological and genetic variability. Here we present the first description of an isolate of the genusTrypanosomanaturally infecting the tickAmblyomma brasiliense. The ticks were collected from a specimen ofTayassu pecari(Queixada, white-lipped peccary) from the Itatiaia National Park, Itatiaia, Rio de Janeiro, Brazil. The isolate was characterized by molecular, morphometric and biological analyses. ATrypanosomaculture was isolated from crushed nymphal and adult ticks, propagated in the tick cell line IDE8 and maintained in L15B culture medium, incubated at 32 °C. The isolate grew well in L15B medium at 30, 32 and 34 °C but not at lower or higher temperatures. The culture remained stable in axenic L15B medium at 30 °C. Cryopreserved cultures retained viability after cryopreservation in liquid nitrogen. Growth in axenic medium and developmental forms of the trypanosomes were analysed. Analysis of the 18S rDNA region confirmed the authenticity of this new species and the nucleotide sequence was deposited in Genbank. The species was namedTrypanosoma amblyommisp. nov. strain C1RJ. Characteristics related to pathogenicity, involvement with vertebrate hosts, epidemiology, developmental cycle and transmission mechanisms are still unknown. Therefore, further studies are necessary to understand the aspects of the biological cycle ofT. amblyommisp. nov.

The aim of this study is to detect the presence of tick-borne agents of genera Rickettsia, Borrelia, Babesia, Ehrlichia and Anaplasma in ticks collected from native wild birds in the state of Rio de Janeiro. Birds were captured and observed carefully to find the ectoparasites. DNA detection of hemoparasites was performed by means of the polymerase chain reaction (PCR). The sequences obtained were analyzed and their homologies were compared to the available isolates in the GenBank platform database. A total of 33 birds were captured from 20 different species, of which 14 were parasitized by Amblyomma longirostre (n = 22). There was absence of DNA from agents of the genera Babesia, Anaplasma and Ehrlichia in the evaluated samples. The phylogenetic analysis indicated that one sample had 100% identity with Rickettsia bellii (KJ534309), the other two samples showed 100% identity with Rickettsia sp. Aranha strain and strain AL (EU274654 and AY360216). The positive sample for R. bellii was also demonstrated to be positive for Borrelia sp., which presented a similarity of 91% with Borrelia turcica (KF422815). This is the first description of Borrelia sp. in ticks of the genus Amblyomma in South America.

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Borrelia burgdorferi sensu stricto is the main etiological agent of Lyme disease (LD) in the USA. In Brazil, it is believed that a similar spirochete is the causal agent of the Baggio-Yoshinari syndrome (BYS), a zoonosis also transmitted by ticks, whose clinical manifestations are similar to those of LD. Despite the epidemiological importance, there are no studies reporting the presence and the prevalence of B. burgdorferi among horses in Mato Grosso State. The aim of this study was to detect and measure the frequency of IgG antibodies anti-B. burgdorferi American strain G39/40 in horses in the municipality of Sinop, MT-Brazil, using the indirect enzyme-linked immunosorbent assay (ELISA) for serological diagnosis. Blood samples from 367 horses were collected in 81 farms. An epidemiological questionnaire was applied during the visits to obtain information related to the animals and the farms. From the 367 horses, 214 were positive for B. burgdorferi sensu stricto according to the results of the ELISA test, representing an apparent prevalence of 54.04% [CI = 0.4548051-0.6237234]. Concomitantly, 89 blood samples were taken for molecular analysis by nested polymerase chain reaction (PCR). According to the PCR test results, none of the samples were reactive, although 53 of these samples were reactive according to ELISA. Seventy five farms (92.59%) had at least one reactive horse for B. burgdorferi. Our results support the hypothesis of the presence of anti-Borrelia spp. antibodies in horses in Mato Grosso, reaching a high animal prevalence. Besides that, leisure/sport purposes proved to be a risk factor, with an odds ratio of 3.16. These findings clearly indicate the need of borreliosis control in Sinop and make a significant contribution to the knowledge of the disease in Mato Grosso.