RESUMO
We characterized 15 Trypanosoma cruzi isolates from bats captured in the Amazon, Central and Southeast Brazilian regions. Phylogenetic relationships among T. cruzi lineages using SSU rDNA, cytochrome b, and Histone H2B genes positioned all Amazonian isolates into T. cruzi I (TCI). However, bat isolates from the other regions, which had been genotyped as T. cruzi II (TC II) by the traditional genotyping method based on mini-exon gene employed in this study, were not nested within any of the previously defined TCII sublineages, constituting a new genotype designated as TCbat. Phylogenetic analyses demonstrated that TCbat indeed belongs to T. cruzi and not to other closely related bat trypanosomes of the subgenus Schizotrypanum, and that although separated by large genetic distances TCbat is closest to lineage TCI. A genotyping method targeting ITS1 rDNA distinguished TCbat from established T. cruzi lineages, and from other Schizotrypanum species. In experimentally infected mice, TCbat lacked virulence and yielded low parasitaemias. Isolates of TCbat presented distinctive morphological features and behaviour in triatomines. To date, TCbat genotype was found only in bats from anthropic environments of Central and Southeast Brazil. Our findings indicate that the complexity of T. cruzi is larger than currently known, and confirmed bats as important reservoirs and potential source of T. cruzi infections to humans.
Assuntos
Quirópteros/parasitologia , DNA de Protozoário/genética , Genes de Protozoários/genética , Filogenia , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética , Tripanossomíase/veterinária , Animais , Brasil , Grupo dos Citocromos b/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Genótipo , Histonas/genética , Cariotipagem , Camundongos , Dados de Sequência Molecular , Técnica de Amplificação ao Acaso de DNA Polimórfico , Triatominae/parasitologia , Trypanosoma cruzi/citologia , Tripanossomíase/parasitologiaRESUMO
Trypanosoma rangeli infects several mammalian orders but has never confidently been described in Chiroptera, which are commonly parasitized by many trypanosome species. Here, we described trypanosomes from bats captured in Central Brazil identified as T. rangeli, T. dionisii, T. cruzimarinkellei and T. cruzi. Two isolates, Tra643 from Platyrrhinus lineatus and Tra1719 from Artibeus planirostris were identified as T. rangeli by morphological, biological and molecular methods, and confirmed by phylogenetic analyses. Analysis using SSU rDNA sequences clustered these bat trypanosomes together with T. rangeli from other hosts, and separated them from other trypanosomes from bats. Genotyping based on length and sequence polymorphism of PCR-amplified intergenic spliced-leader gene sequences assigned Tra1719 to the lineage A whereas Tra643 was shown to be a new genotype and was assigned to the new lineage E. To our knowledge, these two isolates are the earliest T. rangeli from bats and the first isolates from Central Brazil molecularly characterized. Rhodnius stali captured for this study was found infected by T. rangeli and T. cruzi.
Assuntos
Quirópteros/parasitologia , RNA Líder para Processamento/genética , Trypanosoma/classificação , Trypanosoma/isolamento & purificação , Tripanossomíase/veterinária , Animais , Brasil , Análise por Conglomerados , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genótipo , Dados de Sequência Molecular , Filogenia , Polimorfismo Genético , Análise de Sequência de DNA , Homologia de Sequência , Trypanosoma/citologia , Trypanosoma/genéticaRESUMO
Trypanosomatids are widespread in several plant families and although most isolates have been classified as Phytomonas, other trypanosomatid genera can also infect plants. In order to assess the natural occurrence of non-Phytomonas trypanosomatids in plants we characterized 21 new trypanosomatid cultures, 18 from fruits and three from seeds of 17 plant species. The trypanosomatids from fruit and seeds were compared in terms of morphological, growth, biochemical and molecular features. The high diversity among the isolates permitted the classification of the new flagellates into the genera Crithidia and Leptomonas as well as Phytomonas. The data showed that natural fruit infection with non-Phytomonas trypanosomatids is more common than usually thought, being detected in 43% of the fruit isolates.
Assuntos
Frutas/parasitologia , Sementes/parasitologia , Trypanosomatina/classificação , Animais , Crithidia/classificação , Crithidia/citologia , Crithidia/isolamento & purificação , Crithidia/fisiologia , Impressões Digitais de DNA , Técnica Indireta de Fluorescência para Anticorpo , Hibridização de Ácido Nucleico , Reação em Cadeia da Polimerase , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ribotipagem , Trypanosomatina/citologia , Trypanosomatina/isolamento & purificação , Trypanosomatina/fisiologiaRESUMO
The defense response of Veneza zonata (Hemiptera: Coreidae) against three different trypanosomatid infections was assessed: (1) strain 714TD, a Leptomonas which has V. zonata as vector of a plant trypanosomatid, (2) strain 563TD, a Leptomonas isolated from the digestive tract of Euchistus heros (Hemiptera: Pentatomidae), and (3) Leishmania (L.) amazonensis, a human parasite that cannot infect V. zonata. Experiments with V. zonata hemolymph showed agglutination only of L. (L.) amazonensis culture forms and hemocytic recognition was more intense with this strain. L. (L.) amazonensis also activated the prophenoloxidase system, whereas strains 714TD and 563TD did not activate this system but rather seemed to inhibit phenoloxidase activity. No flagellates were seen in the digestive tract, hemolymph, or salivary glands in insects infected with L. (L.) amazonensis. The digestive tract, the hemolymph, and the salivary glands of insects fed on tomatoes inoculated with 714TD are sequentially invaded by the flagellate, which is inoculated in plants together with saliva. Insects fed on tomatoes inoculated with 563TD exhibited culture forms in the digestive tract (6 days after) and hemocoel (three additional days); however, they died 12 to 14 days after exposure. The salivary glands in insects inoculated in the hemocoel with 714TD strain are rapidly invaded, whereas those with 563TD culture forms died approximately 24 h after infection. Bacterial proliferation in the hemocoel and hemocyte surface blebbing were seen in insects infected only with 563TD strain as the probable pathogenic mechanism of insect death.
Assuntos
Hemípteros/parasitologia , Hemolinfa/fisiologia , Infecções por Protozoários/fisiopatologia , Trypanosomatina/fisiologia , Animais , Interações Hospedeiro-Parasita , Técnicas In VitroRESUMO
In the present study, we investigated the genetic variability among 49 new isolates of trypanosomatids from phytophagous Hemiptera by means of morphological characters, growth features, and biochemical (enzymes of ornithine-arginine cycle) and molecular markers (based on spliced-leader, and ribosomal genes). From 402 phytophagous insects dissected and examined for the presence of trypanosomatids, 228 species belonging to Pyrrhocoridae, Coreidae, Lygaeidae, and Pentatomidae families harbored trypanosomatids in their salivary glands, or digestive tubes. Among these insects, 211 carried promastigotes and only 17 had choanomastigote forms. The results show a strong association among morphology, growth features, and biochemical and molecular markers and reveal the genetic diversity of the isolates, which were assigned to Crithidia, Phytomonas, and Leptomonas; we found genetic polymorphism within all these genera, thus indicating high genetic variability among trypanosomatids from phytophagous insects.
Assuntos
Variação Genética , Hemípteros/parasitologia , Plantas/parasitologia , Trypanosomatina/genética , Animais , Arginina/metabolismo , Crithidia/isolamento & purificação , Ornitina/metabolismo , Trypanosomatina/classificação , Trypanosomatina/enzimologia , Trypanosomatina/isolamento & purificaçãoRESUMO
The Western blot method, using antigens from epimastigote forms of the Trypanosoma cruzi Y strain, was evaluated for the confirmatory diagnosis of Chagas' disease. Serum samples were obtained from 136 chagasic patients (Group I), 23 patients with inconclusive serologic results for Chagas' disease (Group II), 53 patients with other diseases (Group III), and 50 healthy individuals (Group IV). The Western blot results for Group I gave a confirmatory diagnosis of Chagas' diseases in 118 (86.80%), an indeterminate pattern of reactivity in 16 (11.76%), and a negative pattern in only two (1.47%). Of the samples from Groups II, III and IV, none had a positive result in the Western blot; 60.86%, 52.83%, and 16.0%, respectively, showed indeterminate results; and 39.13%, 47,16% and 84,0%, respectively, showed negative results. The Western blot method showed a sensitivity of 86.60%, a specificity of 100.0%, a positive predictive value of 100.0%, and a negative predictive value of 73.50%, and the concordance coefficient kappa was high (0.7789). The results suggest that the previous serologic results for Chagas' disease could be confirmed by Western blot for the detection of specific antibodies to T. cruzi antigenic fractions, which may reduce the medical, legal, and social consequences of an inconclusive serologic result for Chagas' disease and also underscore the need for additional studies for continued efforts in the development of an ideal standard confirmatory test for Chagas' disease.