Surveillance, health promotion and control of Chagas disease in the Amazon Region--Medical attention in the Brazilian Amazon Region: a proposal.

We refer to Oswaldo Cruz's reports dating from 1913 about the necessities of a healthcare system for the Brazilian Amazon Region and about the journey of Carlos Chagas to 27 locations in this region and the measures that would need to be adopted. We discuss the risks of endemicity of Chagas disease in the Amazon Region. We recommend that epidemiological surveillance of Chagas disease in the Brazilian Amazon Region and Pan-Amazon region should be implemented through continuous monitoring of the human population that lives in the area, their housing, the environment and the presence of triatomines. The monitoring should be performed with periodic seroepidemiological surveys, semi-annual visits to homes by health agents and the training of malaria microscopists and healthcare technicians to identify Trypanosoma cruzi from patients' samples and T. cruzi infection rates among the triatomines caught. We recommend health promotion and control of Chagas disease through public health policies, especially through sanitary education regarding the risk factors for Chagas disease. Finally, we propose a healthcare system through base hospitals, intermediate-level units in the areas of the Brazilian Amazon Region and air transportation, considering the distances to be covered for medical care.

Testicular and color variation in the kissing bug, Rhodnius brethesi, in Amazonas, Brazil.

Because of the morphological and morphometric variation of testicular follicles in different genera of the subfamily Triatominae, it was of interest to associate those parameters with the different medial pronotal band patterns (wide and narrow) found in Rhodnius brethesi (Matta) (Hemiptera: Reduviidae). This is a wild species often associated with Leopoldina piassaba Wallace (Arecales: Arecaceae) palm, with a geographical distribution restricted to the Amazon region. The specimens used were from the state of Amazonas, and were kept under conditions of 29 ± 1 °C, 80 ± 5% RH, 12:12 L:D photoperiod, and were fed weekly on blood from Swiss mice. Three-day-old fasting males were separated in accordance with the patterns of the medial pronotal band, dissected, and the testicles removed. After removal of the testicular membrane, the follicles were spread, drawn by camera lucida, and measured. The results showed that the testis of R. brethesi consists of seven follicles, divided into two groups by length; two long and five short. In specimens with a wide medial pronotal band, the long follicles were 5.4 mm in length, but in specimens with a narrow medial band, the long follicles were 5.64 mm in length. The difference was significant. The short follicles were not different in length, suggesting the presence of a possible complex "brethesi" in the Amazon region.

Ancestral genomes, sex, and the population structure of Trypanosoma cruzi.

Acquisition of detailed knowledge of the structure and evolution of Trypanosoma cruzi populations is essential for control of Chagas disease. We profiled 75 strains of the parasite with five nuclear microsatellite loci, 24Salpha RNA genes, and sequence polymorphisms in the mitochondrial cytochrome oxidase subunit II gene. We also used sequences available in GenBank for the mitochondrial genes cytochrome B and NADH dehydrogenase subunit 1. A multidimensional scaling plot (MDS) based in microsatellite data divided the parasites into four clusters corresponding to T. cruzi I (MDS-cluster A), T. cruzi II (MDS-cluster C), a third group of T. cruzi strains (MDS-cluster B), and hybrid strains (MDS-cluster BH). The first two clusters matched respectively mitochondrial clades A and C, while the other two belonged to mitochondrial clade B. The 24Salpha rDNA and microsatellite profiling data were combined into multilocus genotypes that were analyzed by the haplotype reconstruction program PHASE. We identified 141 haplotypes that were clearly distributed into three haplogroups (X, Y, and Z). All strains belonging to T. cruzi I (MDS-cluster A) were Z/Z, the T. cruzi II strains (MDS-cluster C) were Y/Y, and those belonging to MDS-cluster B (unclassified T. cruzi) had X/X haplogroup genotypes. The strains grouped in the MDS-cluster BH were X/Y, confirming their hybrid character. Based on these results we propose the following minimal scenario for T. cruzi evolution. In a distant past there were at a minimum three ancestral lineages that we may call, respectively, T. cruzi I, T. cruzi II, and T. cruzi III. At least two hybridization events involving T. cruzi II and T. cruzi III produced evolutionarily viable progeny. In both events, the mitochondrial recipient (as identified by the mitochondrial clade of the hybrid strains) was T. cruzi II and the mitochondrial donor was T. cruzi III.

[Chronic chagasic cardiopathy in the Rio Negro, Amazon State. Report of three new autochthonous cases confirmed by serology, clinical examination, chest X-rays, electro and echocardiography]. / Cardiopatia chagásica crônica no Rio Negro, Estado do Amazonas. Relato de três novos casos autóctones, comprovados por exames sorológicos, clínicos, radiográficos do tórax, eletro e ecocardiográficos.

We report three new autochthonous cases of chronic chagasic cardiomyopathy from Rio Negro, Amazon State, confirmed by serology (indirect immunofluorescence, ELISA and Western-blot for Trypanosoma cruzi infection), clinical examination, chest X-rays, electro- and echocardiography. The three patients were born and lived all their lives in the Rio Negro region working as piaçaba gatherers, where they were bitten several times by sylvatic triatomine bugs. The clinical feature was congestive heart failure and intraventricular conduction impairment in the three cases (right bundle branch block with left anterior hemiblock in two cases, left bundle branch block of 3rd degree in one), polymorphic ventricular extrasystoles in two cases and primary T wave inversion in another one. The echocardiographic evaluation showed a significant increasing of the left ventricular diameters with ejection fraction lesser than 36%, and myocardial segmental impairment pattern, including apical aneurysm and postero-inferior akinesia in the three patients. These are the first autochthonous cases of chronic Chagasic cardiomyopathy from the Brazilian Amazon state with echocardiographic pattern suggestive of Chagas' disease.

Minicircle organization and diversity in Trypanosoma cruzi populations.

Trypanosoma cruzi strains and isolates can be divided into at least two groups using biochemical and molecular markers such as isoenzymes, ribosomal DNA, mini-exon gene spacers and some maxicircle genes. Despite the accumulating evidence that these major groups are phylogenetically distinct, their kinetoplast minicircle overall organization (i.e. number of conserved regions per length of minicircle molecule) remains conserved in all T. cruzi isolates studied so far, including the two T. cruzi major lineages -T. cruzi I and T. cruzi II - and a third group of uncertain taxonomic status, T. cruzi ZIII. Thus far, despite the extensive intra- and inter-minicircle sequence polymorphism, no group clustering has been observed.

Emerging Chagas disease in Amazonian Brazil.

In the Amazon Basin, Trypanosoma cruzi infection is enzootic, involving a variety of wild mammals and at least 10 of the 16 reported silvatic triatomine bug species. Human cases of Chagas disease are increasing, indicating that the disease may be emerging as a wider public health problem in the region: 38 cases from 1969 to 1992, and 167 in the past eight years. This article reviews the status of Chagas disease in Amazonian Brazil, including known reservoirs and vectors, and the genetic diversity of T. cruzi. At least three subspecific groups of T. cruzi-T. cruzilZ1, T. cruziZ3 and T. cruziZ3/Z1 ASAT--are present. It appears that T. cruzil has an extant capacity for genetic exchange. Attention is also drawn to the risk of domestic endemicity, in addition to the tasks facing the disease control authorities.

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.

Trypanosoma cruzi in Brazilian Amazonia: Lineages TCI and TCIIa in wild primates, Rhodnius spp. and in humans with Chagas disease associated with oral transmission.

In this study, we provide phylogenetic and biogeographic evidence that the Trypanosoma cruzi lineages T. cruzi I (TCI) and T. cruzi IIa (TCIIa) circulate amongst non-human primates in Brazilian Amazonia, and are transmitted by Rhodnius species in overlapping arboreal transmission cycles, sporadically infecting humans. TCI presented higher prevalence rates, and no lineages other than TCI and TCIIa were found in this study in wild monkeys and Rhodnius from the Amazonian region. We characterised TCI and TCIIa from wild primates (16 TCI and five TCIIa), Rhodnius spp. (13 TCI and nine TCIIa), and humans with Chagas disease associated with oral transmission (14 TCI and five TCIIa) in Brazilian Amazonia. To our knowledge, TCIIa had not been associated with wild monkeys until now. Polymorphisms of ssrDNA, cytochrome b gene sequences and randomly amplified polymorphic DNA (RAPD) patterns clearly separated TCIIa from TCIIb-e and TCI lineages, and disclosed small intra-lineage polymorphisms amongst isolates from Amazonia. These data are important in understanding the complexity of the transmission cycles, genetic structure, and evolutionary history of T. cruzi populations circulating in Amazonia, and they contribute to both the unravelling of human infection routes and the pathological peculiarities of Chagas disease in this region.

Comparative phylogeography of Trypanosoma cruzi TCIIc: new hosts, association with terrestrial ecotopes, and spatial clustering.

We characterized 28 new isolates of Trypanosoma cruzi IIc (TCIIc) of mammals and triatomines from Northern to Southern Brazil, confirming the widespread distribution of this lineage. Phylogenetic analyses using cytochrome b and SSU rDNA sequences clearly separated TCIIc from TCIIa according to terrestrial and arboreal ecotopes of their preferential mammalian hosts and vectors. TCIIc was more closely related to TCIId/e, followed by TCIIa, and separated by large distances from TCIIb and TCI. Despite being indistinguishable by traditional genotyping and generally being assigned to Z3, we provide evidence that TCIIa from South America and TCIIa from North America correspond to independent lineages that circulate in distinct hosts and ecological niches. Armadillos, terrestrial didelphids and rodents, and domestic dogs were found infected by TCIIc in Brazil. We believe that, in Brazil, this is the first description of TCIIc from rodents and domestic dogs. Terrestrial triatomines of genera Panstrongylus and Triatoma were confirmed as vectors of TCIIc. Together, habitat, mammalian host and vector association corroborated the link between TCIIc and terrestrial transmission cycles/ecological niches. Analysis of ITS1 rDNA sequences disclosed clusters of TCIIc isolates in accordance with their geographic origin, independent of their host species.

Molecular characterization of Trypanosoma cruzi sylvatic isolates from Rio de Janeiro, Brazil.

Trypanosoma cruzi, the etiologic agent of Chagas disease, presents considerable heterogeneity between isolated populations within the wild and domestic cycles. By using multiplex polymerase chain reaction based on the mini-exon gene, characterization was performed on seven samples isolated from specimens of Triatoma vitticeps that had been collected from the locality of Triunfo in the municipality of Santa Maria Madalena, state of Rio de Janeiro, Brazil. The samples SMM10, SMM53, SMM88, and SMM98 (area A) and SMM36 and SMM82 (area B) revealed the presence of 150 base pairs, corresponding to the zymodeme III (Z3). Our study suggested that one isolate (SMM1) presents a mixed genotype associated with Z3 and TcII. The typing of isolates of T. cruzi has the main aim of identifying strains with different epidemiological and/or clinical characteristics of Chagas disease. Our results corroborate other descriptions in the literature and contribute towards the knowledge and records of the profile of some additional wild isolates of T. cruzi in regions not yet affected by the disease.

Cardiopatia chagásica crônica no Rio Negro, Estado do Amazonas. Relato de três novos casos autóctones, comprovados por exames sorológicos, clínicos, radiográficos do tórax, eletro e ecocardiográficos / Chronic chagasic cardiopathy in the Rio Negro, Amazon State. Report of three new autochthonous cases confirmed by serology, clinical examination, chest X-rays, electro and echocardiography

São relatados três novos casos de miocardiopatia chagásica crônica em pacientes autóctones do Rio Negro, Estado do Amazonas, confirmados por sorologia (imunofluorescência, ELISA e Western-blot para infeccão pelo Trypanosoma cruzi) e por exames clínicos, radiográficos, eletro e ecocardiográficos. Os pacientes nasceram e sempre viveram na região do Rio Negro, tendo sido picados numerosas vezes por triatomíneos silvestres em piacabais da área. O quadro clínico foi de insuficiência cardíaca congestiva e distúrbio da conducão intraventricular nos três casos (BRD com HBAE em dois casos e BRE de terceiro grau em um caso), extra-sístoles ventriculares polimórficas em dois casos e alteracão primária da repolarizacão ventricular em um deles. A avaliacão ecocardiográfica revelou importante aumento dos diâmetros cavitários do VE, com fracão da ejecão < 36 por cento e padrão segmentar de acometimento miocárdico, incluindo aneurisma apical e acinesia ínfero-posterior nos três pacientes. Estes são os primeiros casos descritos de cardiopatia chagásica crônica autóctone do Amazonas com padrão ecocardiográfico sugestivo da doenca.