Rehabilitación estética y funcional en paciente con compromiso gastroesofágico y desorden temporomandibular: reporte de un caso / Rehabilitación estética y funcional en paciente con compromiso gastroesofágico y desorden temporomandibular: reporte de un caso

Paciente masculino, de 32 años, acudió a la Clínica de Prótesis Parcial Fija (PPF), de la Facultad de Odontología de Araçatuba-Universidad Estadual Paulista, manifestando como queja principal que sus dientes anteriores estaban "feos y rotos". Después del exa- men clínico, el paciente fue diagnosticado con desorden temporomandibular, bruxismo y presencia de erosiones dentarias (intrínsecas y extrínsecas). Se propuso el acompaña- miento de un médico gastroenterólogo y la rehabilitación con prótesis libres de metal (11, 12, 21 y 22) confeccionadas en silicato de litio reforzado con zirconio por el sistema CAD/CAM. Después de la endodoncia de los incisivos antero-superiores, fueron insta- lados los pernos de fibra de vidrio anatomizados con resina compuesta; la impresión fue realizada con hilo retractor y silicona de adición. Después de la prueba estética y ajustes oclusales, las PPFs de e-max Ceram, fueron preparadas para cementación resinosa con el sistema Variolink II color Light. Después de 1 semana, se tomó la impresión de la arcada superior y posteriormente se le instaló una placa miorrelajante. El paciente y los profesionales involucrados aprobaron el resultado final, comprobando la eficacia estética asociada al uso de prótesis libre de metal, a pesar de que el paciente presenta compromiso gastroesofágico y desorden temporomandibular.

A 32-year-old male patient attended in the Fixed Partial Prosthesis Clinic (PPF), of the Araçatuba Dental School-Paulista State University, stating as the main complaint that his anterior teeth were "ugly and broken". After clinical examination, the patient was diagnosed with temporomandibular disorder, bruxism and the presence of dental ero- sions (intrinsic and extrinsic). It was proposed to be followed up by a gastroenterologist and rehabilitation with metal-free prostheses (11, 12, 21 and 22) made of lithium silicate reinforced with zirconium by the CAD / CAM system were proposed. After endodontics of the anterior-superior incisors, the anatomized fiberglass posts with composite resin were installed; the impression was made with retractor wire and addition silicone. After aesthetic testing and occlusal adjustments, the e-max Ceram PPF ̈s were prepared for resin cementation with the Variolink II color Light system. After 1 week, the impression of the upper arch was taken and subsequently a muscle relaxant plate was installed. The patient and the professionals involved approved the final result, verifying the aesthetic efficacy associated with the use of a metal-free prosthesis, despite the fact that the patient has gastroesophageal involvement and temporomandibular disorder.

Phylogenetic, morphological and behavioural analyses support host switching of Trypanosoma (Herpetosoma) lewisi from domestic rats to primates.

We characterized four Brazilian trypanosomes isolated from domestic rats and three from captive non-human primates that were morphologically similar to T. lewisi, a considered non-pathogenic species restricted to rodents and transmitted by fleas, despite its potential pathogenicity for infants. These isolates were identified as T. lewisi by barcoding using V7V8 SSU rDNA sequences. In inferred phylogenetic trees, all isolates clustered tightly with reference T. lewisi and T. lewisi-like trypanosomes from Europe, Asia and Africa and despite their high sequence conservation formed a homogeneous clade separate from other species of the subgenus T. (Herpetosoma). With the aim of clearly resolving the relationships between the Brazilian isolates from domestic rats and primates, we compared sequences from more polymorphic ITS rDNA. Results corroborated that isolates from Brazilian rats and monkeys were indeed of the same species and quite close to T. lewisi isolates of humans and rats from different geographical regions. Morphology of the monkey isolates and their behaviour in culture and in experimentally infected rats were also compatible with T. lewisi. However, infection with T. lewisi is rare among monkeys. We have examined more than 200 free-ranging and 160 captive monkeys and found only three infected individuals among the monkeys held in captivity. The findings of this work suggest that proximity of monkeys and infected rats and their exposure to infected fleas may be responsible for the host switching of T. lewisi from their natural rodent species to primates. This and previous studies reporting T. lewisi in humans suggest that this trypanosome can cause sporadic and opportunistic flea-borne infection in primates.

Characterization of spliced leader genes of Trypanosoma ( Megatrypanum) theileri: phylogeographical analysis of Brazilian isolates from cattle supports spatial clustering of genotypes and parity with ribosomal markers.

Trypanosoma (Megatrypanum) theileri from cattle and trypanosomes of other artiodactyls form a clade of closely related species in analyses using ribosomal sequences. Analysis of polymorphic sequences of a larger number of trypanosomes from broader geographical origins is required to evaluate the clustering of isolates as suggested by previous studies. Here, we determined the sequences of the spliced leader (SL) genes of 21 isolates from cattle and 2 from water buffalo from distant regions of Brazil. Analysis of SL gene repeats revealed that the 5S rRNA gene is inserted within the intergenic region. Phylogeographical patterns inferred using SL sequences showed at least 5 major genotypes of T. theileri distributed in 2 strongly divergent lineages. Lineage TthI comprises genotypes IA and IB from buffalo and cattle, respectively, from the Southeast and Central regions, whereas genotype IC is restricted to cattle from the Southern region. Lineage TthII includes cattle genotypes IIA, which is restricted to the North and Northeast, and IIB, found in the Centre, West, North and Northeast. PCR-RFLP of SL genes revealed valuable markers for genotyping T. theileri. The results of this study emphasize the genetic complexity and corroborate the geographical structuring of T. theileri genotypes found in cattle.

Genes of cathepsin L-like proteases in Trypanosoma rangeli isolates: markers for diagnosis, genotyping and phylogenetic relationships.

We have sequenced genes encoding cathepsin L-like (CatL-like) cysteine proteases from isolates of Trypanosoma rangeli from humans, wild mammals and Rhodnius species of Central and South America. Phylogenetic trees of sequences encoding mature CatL-like enzymes of T. rangeli and homologous genes from other trypanosomes, Leishmania spp. and bodonids positioned sequences of T. rangeli (rangelipain) closest to T. cruzi (cruzipain). Phylogenetic tree of kinetoplastids based on sequences of CatL-like was totally congruent with those derived from SSU rRNA and gGAPDH genes. Analysis of sequences from the CatL-like catalytic domains of 17 isolates representative of the overall phylogenetic diversity and geographical range of T. rangeli supported all the lineages (A-D) previously defined using ribosomal and spliced leader genes. Comparison of the proteolytic activities of T. rangeli isolates revealed heterogeneous banding profiles of cysteine proteases in gelatin gels, with differences even among isolates of the same lineage. CatL-like sequences proved to be excellent targets for diagnosis and genotyping of T. rangeli by PCR. Data from CatL-like encoding genes agreed with results from previous studies of kDNA markers, and ribosomal and spliced leader genes, thereby corroborating clonal evolution, independent transmission cycles and the divergence of T. rangeli lineages associated with sympatric species of Rhodnius.

A new genotype of Trypanosoma cruzi associated with bats evidenced by phylogenetic analyses using SSU rDNA, cytochrome b and Histone H2B genes and genotyping based on ITS1 rDNA.

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.

Evolutionary history of trypanosomes from South American caiman (Caiman yacare) and African crocodiles inferred by phylogenetic analyses using SSU rDNA and gGAPDH genes.

In this study, using a combined data set of SSU rDNA and gGAPDH gene sequences, we provide phylogenetic evidence that supports clustering of crocodilian trypanosomes from the Brazilian Caiman yacare (Alligatoridae) and Trypanosoma grayi, a species that circulates between African crocodiles (Crocodilydae) and tsetse flies. In a survey of trypanosomes in Caiman yacare from the Brazilian Pantanal, the prevalence of trypanosome infection was 35% as determined by microhaematocrit and haemoculture, and 9 cultures were obtained. The morphology of trypomastigotes from caiman blood and tissue imprints was compared with those described for other crocodilian trypanosomes. Differences in morphology and growth behaviour of caiman trypanosomes were corroborated by molecular polymorphism that revealed 2 genotypes. Eight isolates were ascribed to genotype Cay01 and 1 to genotype Cay02. Phylogenetic inferences based on concatenated SSU rDNA and gGAPDH sequences showed that caiman isolates are closely related to T. grayi, constituting a well-supported monophyletic assemblage (clade T. grayi). Divergence time estimates based on clade composition, and biogeographical and geological events were used to discuss the relationships between the evolutionary histories of crocodilian trypanosomes and their hosts.

Trypanosoma rangeli isolates of bats from Central Brazil: genotyping and phylogenetic analysis enable description of a new lineage using spliced-leader gene sequences.

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.

Infection rates and genotypes of Trypanosoma rangeli and T. cruzi infecting free-ranging Saguinus bicolor (Callitrichidae), a critically endangered primate of the Amazon Rainforest.

Parasites of wild primates are important for conservation biology and human health due to their high potential to infect humans. In the Amazon region, non-human primates are commonly infected by Trypanosoma cruzi and T. rangeli, which are also infective to man and several mammals. This is the first survey of trypanosomiasis in a critically endangered species of tamarin, Saguinus bicolor (Callitrichidae), from the Brazilian Amazon Rainforest. Of the 96 free-ranging specimens of S. bicolor examined 45 (46.8%) yielded blood smears positive for trypanosomes. T. rangeli was detected in blood smears of 38 monkeys (39.6%) whereas T. cruzi was never detected. Seven animals (7.3%) presented trypanosomes of the subgenus Megatrypanum. Hemocultures detected 84 positive tamarins (87.5%). Seventy-two of 84 (85.7%) were morphologically diagnosed as T. rangeli and 3 (3.1%) as T. cruzi. Nine tamarins (9.4%) yielded mixed cultures of these two species, which after successive passages generated six cultures exclusively of T. cruzi and two of T. rangeli, with only one culture remaining mixed. Of the 72 cultures positive for T. rangeli, 62 remained as established cultures and were genotyped: 8 were assigned to phylogenetic lineage A (12.9%) and 54 to lineage B (87.1%). Ten established cultures of T. cruzi were genotyped as TCI lineage (100%). Transmission of both trypanosome species, their potential risk to this endangered species and the role of wild primates as reservoirs for trypanosomes infective to humans are discussed.

Phylogeny of snake trypanosomes inferred by SSU rDNA sequences, their possible transmission by phlebotomines, and taxonomic appraisal by molecular, cross-infection and morphological analysis.

Blood examination by microhaematocrit and haemoculture of 459 snakes belonging to 37 species revealed 2.4% trypanosome prevalence in species of Viperidae (Crotalus durissus and Bothrops jararaca) and Colubridae (Pseudoboa nigra). Trypanosome cultures from C. durissus and P. nigra were behaviourally and morphologically indistinguishable. In addition, the growth and morphological features of a trypanosome from the sand fly Viannamyia tuberculata were similar to those of snake isolates. Cross-infection experiments revealed a lack of host restriction, as snakes of 3 species were infected with the trypanosome from C. durissus. Phylogeny based on ribosomal sequences revealed that snake trypanosomes clustered together with the sand fly trypanosome, forming a new phylogenetic lineage within Trypanosoma closest to a clade of lizard trypanosomes transmitted by sand flies. The clade of trypanosomes from snakes and lizards suggests an association between the evolutionary histories of these trypanosomes and their squamate hosts. Moreover, data strongly indicated that these trypanosomes are transmitted by sand flies. The flaws of the current taxonomy of snake trypanosomes are discussed, and the need for molecular parameters to be adopted is emphasized. To our knowledge, this is the first molecular phylogenetic study of snake trypanosomes.

Comparative phylogeography of Trypanosoma rangeli and Rhodnius (Hemiptera: Reduviidae) supports a long coexistence of parasite lineages and their sympatric vectors.

To make reliable interpretations about evolutionary relationships between Trypanosoma rangeli lineages and their insect vectors (triatomine bugs of the genus Rhodnius) and, thus, about the determinant factors of lineage segregation within T. rangeli, we compared phylogenies of parasite isolates and vector species. Sixty-one T. rangeli isolates from invertebrate and vertebrate hosts were initially evaluated in terms of polymorphism of the spliced-leader gene (SL). Further analysis based on SL and SSUrRNA sequences from 33 selected isolates, representative of the overall phylogenetic diversity and geographical range of T. rangeli, supported four phylogenetic lineages within this species. By comparing the phylogeny of Rhodnius species with that inferred for T. rangeli isolates and through analysis of the geographical range of the isolates, we showed that there is a very significant overlap in the distribution of Rhodnius species and T. rangeli lineages. Congruence between phylogeographical analysis of both T. rangeli lineages and complexes of Rhodnius species are consistent with the hypothesis of a long coexistence of parasites and their vectors, with lineage divergence associated with sympatric species of Rhodnius apparently without association with particular vertebrate hosts. Separation of T. rangeli isolates from vectors of distinct complexes living in sympatry favours the absence of gene flow between the lineages and suggests evolution of T. rangeli lineages in independent transmission cycles, probably associated to specific Rhodnius spp. ecotopes. A polymerase chain reaction assay based on SL intergenic sequences was developed for simultaneous identification and lineage genotyping of T. rangeli in epidemiological surveys.

Morphological and molecular diversity and phylogenetic relationships among anuran trypanosomes from the Amazonia, Atlantic Forest and Pantanal biomes in Brazil.

We examined for the presence of trypanosomes in blood samples from 259 anurans (47 species from 8 families), the majority of which were from the Brazilian Amazonia, Atlantic Forest and Pantanal biomes. Trypanosomes were detected by a combination of microhaematocrit and haemoculture methods in 45% of the anurans, and 87 cultures were obtained: 44 from Hylidae, 22 from Leptodactylidae, 15 from Bufonidae, 5 from Leiuperidae and 1 from an unidentified anuran. High morphological diversity (11 morphotypes) was observed among blood trypanosomes from anurans of different species and of the same species as well as among trypanosomes from the same individual. Conversely, morphologically similar trypanosomes were found in anurans from distinct species and biomes. ITS and SSU rDNA polymorphisms revealed high diversity among the 82 isolates examined. Twenty-nine genotypes could be distinguished, the majority distributed in 11 groups. Phylogenetic relationships based on rDNA sequences indicated that isolates from more phylogenetically related anurans are more closely related. Comparison of anuran trypanosomes from Brazil and other countries revealed several new species among the isolates examined in this study. Phylogenetic relationships suggest that host restriction, host switching and overall ecogeographical structure may have played a role in the evolution of the anuran trypanosomes.

Phylogeny of Trypanosoma ( Megatrypanum ) theileri and related trypanosomes reveals lineages of isolates associated with artiodactyl hosts diverging on SSU and ITS ribosomal sequences.

SSU ribosomal sequences of trypanosomes from Brazilian cattle and water buffalo were used to infer phylogenetic relationships between non-pathogenic T. theileri and allied species parasitic in artiodactyls. T. theileri trypanosomes from distinct geographical regions in Brazil and from other countries were tightly clustered into the 'clade T. theileri' distant from the 'T. brucei clade' of pathogenic parasites of artiodactyls, and also distinct from trypanosomes of other mammals. The existence of this monophyletic assemblage (T. theileri clade) composed only by isolates from artiodactyl species justifies the continued recognition of the subgenus T. (Megatrypanum) with T. theileri as its type species. Phylogenies based on SSU and ITS1 ribosomal sequences produced the same branching pattern with isolates from different mammalian hosts clustered in 5 lineages: A, related to water buffalo; B, C and D, to cattle; E, to fallow deer. The pattern of host specificity allied to some congruence between host and parasite phylogenies suggested association of these trypanosomes with their respective hosts. Segregation of cattle isolates into three lineages revealed an overall geographical structure. Moreover, positioning of trypanosomes infecting tabanids in the T. theileri clade is consistent with the role of these flies as important vectors of these trypanosomes.

Phylogeny, taxonomy and grouping of Trypanosoma rangeli isolates from man, triatomines and sylvatic mammals from widespread geographical origin based on SSU and ITS ribosomal sequences.

Phylogenetic relationships among Trypanosoma rangeli isolates from man, wild mammals and triatomine bugs from widespread geographical origin were inferred by comparison of the small subunit of ribosomal gene sequences. The phylogenetic trees indicated that the subgenus Herpetosoma is polyphyletic and strongly supported division of this group into two monophyletic lineages, one made up of T. rangeli, T. rangeli-like and allied species and other consisting of T. lewisi and related taxa. Based on phylogenetic analysis, morphology, behaviour in vertebrate and invertebrate hosts and epidemiology we propose: a) the validation of Herpetosoma as a taxon comprised only for species of group lewisi and the maintenance of T. lewisi as the type-species of this subgenus; b) the classification of T. rangeli, T. rangeli-like and allied species into a 'T. rangeli-clade' more closely related to Schizotrypanum than to T. lewisi or T. brucei. The phylogenetic tree disclosed at least 4 groups within the clade T. rangeli, all confirmed by polymorphism of the internal transcribed spacer, thus conferring for the first time phylogenetic support to groups of T. rangeli and corroborating the high complexity of this taxon. Grouping was independent of their mammalian host-species and geographical origin, indicating that other factors are determining this segregation.

Randomly amplified polymorphic DNA analysis of Trypanosoma rangeli and allied species from human, monkeys and other sylvatic mammals of the Brazilian Amazon disclosed a new group and a species-specific marker.

We characterized 14 trypanosome isolates from sylvatic mammals (9 from primates, 1 from sloth, 2 from anteaters and 2 from opossum) plus 2 human isolates of Brazilian Amazon. These isolates were proven to be Trypanosoma rangeli by detection of metacyclic trypomastigotes in the salivary glands of triatomines and by a specific PCR assay. Polymorphism determined by randomly amplified polymorphic DNA (RAPD) revealed that most (12) of the Brazilian T. rangeli isolates from the Amazon differed from those of other geographical regions, thus constituting a new group of T. rangeli. Four Brazilian isolates clustered together with a previously described group (A) that was described as being composed of isolates from Colombia and Venezuela. Isolates from Panama and El Salvador form another group. The isolate from Southern Brazil did not cluster to any of the above-mentioned groups. This is the first study that assesses the genetic relationship of a large number of isolates from wild mammals, especially from non-human primates. A randomly-amplified DNA fragment (Tra625) exclusive to T. rangeli was used to develop a PCR assay able to detect all T. rangeli groups.

Brazilian isolates of Trypanosoma (Megatrypanum) theileri: diagnosis and differentiation of isolates from cattle and water buffalo based on biological characteristics and randomly amplified DNA sequences.

We detected and cultivated isolates of Trypanosoma (Megatrypanum) theileri from cattle and water buffaloes in São Paulo state, southeastern Brazil, which were characterized by comparing morphological, growth and molecular features. Although isolates from cattle and water buffalo were morphologically indistinguishable, they differed in their growth characteristics. A dendrogram based on randomly amplified polymorphic DNA (RAPD) patterns indicated close-genetic relationships among all isolates from both species, which were all tightly clustered together and distant from Megatrypanum species from wild mammals. In addition, isolates within the T. theileri-cluster were clearly segregated into two host-associated groups. The sequence of a synapomorphic RAPD-derived DNA fragment (Tth625), which was shared by all T. theileri trypanosomes from cattle and buffalo but not detected in any of 13 other trypanosome species, was used as target for a conventional T. theileri-specific PCR assay. We also defined RAPD fragments (Tthc606 and Tthb606) that distinguished cattle from buffalo isolates. Thus, distinct growth features and genetic variability distinguished between isolates from cattle and water buffaloes of the same geographic origin, suggesting an association of these isolates with their host species. The trypanosomes from water buffalo reported here are the first T. theileri-like isolates from the Asiatic buffalo (Bubalus bubalis) to be continuously cultured and compared with cattle isolates using biological and molecular methods.

Classification of trypanosomatids from fruits and seeds using morphological, biochemical and molecular markers revealed several genera among fruit isolates.

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.

PCR amplification of the spliced leader gene for the diagnosis of trypanosomatid parasites of plants and insects in methanol-fixed smears.

A PCR-based method was adapted for the amplification of DNA from methanol-fixed smears of insects and plants parasitized by trypanosomatids. The PCR target was the multicopy spliced leader (SL) gene. Amplicons were hybridized with an oligonucleotide probe (SL3') specific for Phytomonas. The method has the advantage of dispensing with the cultivation of parasites, many of which are very fastidious or non-cultivable. The technique was applied to archival glass slides and to newly collected material. It proved to specific for Phytomonas spp., enabling their detection in plants and insects. Sequence comparison of the amplicons obtained revealed the existence of different strains/species of Phytomonas circulating among diseased palsms and fruit.

Trypanosomatidae: Phytomonas detection in plants and phytophagous insects by PCR amplification of a genus-specific sequence of the spliced leader gene.

In this paper we describe a method for the detection of Phytomonas spp. from plants and phytophagous insects using the PCR technique by targeting a genus-specific sequence of the spliced leader (SL) gene. PCR amplification of DNA from 48 plant and insect isolates previously classified as Phytomonas by morphological, biochemical, and molecular criteria resulted in all cases in a 100-bp fragment that hybridized with the Phytomonas-specific spliced leader-derived probe SL3'. Moreover, this Phytomonas-specific PCR could also detect Phytomonas spp. in crude preparations of naturally infected plants and insects. This method shows no reaction with any other trypanosomatid genera or with plant and insect host DNA, revealing it to be able to detect Phytomonas spp. from fruit, latex, or phloem of various host plants as well as from salivary glands and digestive tubes of several species of insect hosts. Results demonstrated that SLPCR is a simple, fast, specific, and sensitive method that can be applied to the diagnosis of Phytomonas among cultured trypanosomatids and directly in plants and putative vector insects. Therefore, the method was shown to be a very specific and sensitive tool for diagnosis of Phytomonas without the need for isolation, culture, and DNA extraction of flagellates, a feature that is very convenient for practical and epidemiological purposes.

Ribosomal and kDNA markers distinguish two subgroups of Herpetomonas among old species and new trypanosomatids isolated from flies.

We examined files of various families for the presence of trypanosomatids. Of 592 insects, 113 (19%) were positive. From these insects, we obtained 42 cultures and selected 14 for further analysis. Seven of the cultures had the characteristics of Herpetomonas species, they displayed typical opisthomastigotes, lacked arginase, possessed a Pvu II restriction site at 360 bp from the 5' end of the small subunit ribosomal gene, and did not possess a Hin dIII site at 1,500 bp from the ribosomal alpha-large subunit 5' end. Hybridization with synthetic oligonucleotides complementary to the sequences flanking the Pvu II site in Herpetomonas samuelpessoai and Herpetomonas muscarum, permitted the distribution of the old species and the 7 isolates into 2 subgroups of Herpetomonas spp. Of the remaining 7 cultures, 4 were probably Leptomonas spp., whereas the other 3, together with Herpetomonas roitmani, seem to constitute a novel group with morphological and molecular characteristics quite distinct from those of Herpetomonas spp. or any other genera of Trypanosomatidae. We also studied some trypanosomatid species of questionable taxonomic status, Leptomonas samueli and Phytomonas davidi yielded results identical to those of Herpetomonas spp., thus confirming their already suspected affiliation to this genus. On the other hand, Herpetomonas anglusteri, Herpetomonas dedonderi, and Herpetomonas mcgheei displayed morphological and molecular characteristics incompatible with their placement in the genus Herpetomonas.