ABSTRACT
Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted to mammals - including humans - by insect vectors of the subfamily Triatominae. We present the results of a compilation of triatomine occurrence and complementary ecological data that represents the most complete, integrated and updated database (DataTri) available on triatomine species at a continental scale. This database was assembled by collecting the records of triatomine species published from 1904 to 2017, spanning all American countries with triatomine presence. A total of 21815 georeferenced records were obtained from published literature, personal fieldwork and data provided by colleagues. The data compiled includes 24 American countries, 14 genera and 135 species. From a taxonomic perspective, 67.33% of the records correspond to the genus Triatoma, 20.81% to Panstrongylus, 9.01% to Rhodnius and the remaining 2.85% are distributed among the other 11 triatomine genera. We encourage using DataTri information in various areas, especially to improve knowledge of the geographical distribution of triatomine species and its variations in time.
Subject(s)
Insect Vectors , Triatominae , Animals , Chagas Disease/transmission , Databases, Factual , Humans , Trypanosoma cruzi , United StatesABSTRACT
The phylogeographical structure of the closely related species Rhodnius prolixus and R. robustus is presented based on a 663-base pair (bp) fragment of the mitochondrial cytochrome b gene. Twenty haplotypes were recovered from 84 samples examined, representing 26 populations from seven Latin American countries. The resulting phylogenetic tree is composed of five major reciprocally monophyletic clades, one representing R. prolixus and four representing R. robustus. While R. prolixus is a very homogeneous assemblage, R. robustus has deeper clades and is paraphyletic, with the clade comprising R. robustus from Venezuela (Orinoco region) more closely related to the R. prolixus clade than to the other R. robustus populations from the Amazon region. The R. robustus paraphyly was supported further by the analysis of a nuclear gene (D2 region of the 28S RNA) for a subset of specimens. The data support the view that R. robustus represents a species complex. Levels of sequence divergence between clades within each region are compatible with a Pleistocene origin. Nucleotide diversity (pi) for all R. prolixus populations was extremely low (0.0008), suggesting that this species went through a recent bottleneck, and was subsequently dispersed by man.
Subject(s)
Phylogeny , Rhodnius/genetics , Rhodnius/physiology , Animals , Base Sequence , Cytochrome b Group/genetics , DNA Primers , Geography , Molecular Sequence Data , RNA, Ribosomal, 28S/genetics , Rhodnius/classification , South AmericaABSTRACT
We analyzed 64 quantitative and qualitative morphological characters in different populations of Lutzomyia (Nyssomyia) umbratilis Ward & Fraiha from Venezuela (Gran Sabana, Bolívar/BO) and Brazil (Serra do Navio, Amapá/AP Manaus, Amazonas/AM, Monte Dourado, Pará/ PA, and Peixoto de Azevedo, Mato Grosso/MT). Based on an analysis of qualitative characters, no differences were observed that could distinguish between the populations. Parametric tests were used to verify differences between sample means and variance homogeneity. The analysis-of-variance (ANOVA) test showed the existence of differences between character means in the five populations. In the graphic representation of the Student-Newman-Keuls test (Student-Newman-Keuls), we observed that 77% of the analyzed characters displayed disjunctions between the Venezuelan and Brazilian populations. Considering only the Brazilian population averages, we concluded that they are statistically different. When the Student-Newman-Keuls test was applied, no pattern was found that could separate them. However, in part, the phenetic analysis showed some evidences of heterogeneity in MT population.
Subject(s)
Psychodidae/anatomy & histology , Animals , Brazil , Female , Male , Psychodidae/classification , VenezuelaABSTRACT
Revisa o conhecimento atual sobre a epidemiologia da leishmaniose na Venezuela, Colômbia, Equador, Peru e Bolívia, países nos quais a doença é endêmica, tanto nos Andes quanto na Amazônia. Os vetores flebótomos pertencem a vários subgêneros e ao grupo Verrucarum. A maioria dos casos de infecçäo humana é causada pelos parasitas Leishmania do subgênero Viannia. As infecçöes humanas por Leishmania provocam lesöes cutâneas, com uma minoria de infecçöes por L. (Viannia) levando à leishmaniose mucocutânea. Tanto a leishmaniose visceral quanto a leishmaniose cutânea difusa säo raras. Em cada país, parte significativa da transmissäo de Leishmania ocorre no intra ou peridomicílio, muitas vezes próximo à lavoura de café ou cacau. Näo se sabe ao certo quais säo os hospedeiros reservatórios para os ciclos de transmissäo doméstica. Discute-se a carga da doença provocada pela leishmaniose na regiäo, chamando atençäo para os coeficientes de incidência e para a variabilidade dos sintomas. Tal informaçäo fornecerá uma base racional, visando priorizar os recursos voltados para o controle da doença e selecionar esquemas terapêuticos. Descreve também a variaçäo na ecologia da transmissäo, delineando as variáveis que poderiam afetar a definiçäo de estratégias preventivas.
