Caracterização e distribuição da resistência a deltametrina de populações silvestres e domésticas de Triatoma infestans da Bolívia

Submitted by Nuzia Santos ([email protected]) on 2017-03-13T18:52:07Z No. of bitstreams: 1 Tese_DIP_MarinelyBlancaBustamanteGomez.pdf: 3607704 bytes, checksum: 38ddca2adac24ede36cc8ba6a56f51bc (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2017-03-13T19:01:47Z (GMT) No. of bitstreams: 1 Tese_DIP_MarinelyBlancaBustamanteGomez.pdf: 3607704 bytes, checksum: 38ddca2adac24ede36cc8ba6a56f51bc (MD5)Made available in DSpace on 2017-03-13T19:01:47Z (GMT). No. of bitstreams: 1 Tese_DIP_MarinelyBlancaBustamanteGomez.pdf: 3607704 bytes, checksum: 38ddca2adac24ede36cc8ba6a56f51bc (MD5) Previous issue date: 2016Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.A persistência do Triatoma infestans e a transmissão contínua de Trypanosoma cruzi nos Vales Inter-Andinos e no Grande Chaco da Bolívia são de grande importância. Na última década, focos silvestres desta espécie foram descritos em amplas áreas, na qual o alcance das estratégias de controle do vetor é limitado, sendo frequentes os relatos de resistência do T. infestans a inseticidas, que incluem populações silvestres e domésticas. O presente estudo teve como objetivo caracterizar o perfil de suscetibilidade (1) e hereditariedade (2) de populações silvestres e domésticas de T. infestans da Bolívia à deltametrina, bem como descrever a área de distribuição das populações resistentes a diferentes piretróides na América do Sul (3). 1) Foram avaliadas nove populações de T. infestans silvestres e domésticas do Grande Chaco e dos Vales Inter-Andinos da Bolívia. Três amostras silvestres de T. infestans (dark morph) do Chaco (Santa Cruz) foram suscetíveis a deltametrina (RR50 de <2), com 100% de mortalidade em resposta a dose diagnóstica (DD). A população doméstica de Villa Montes do Grande Chaco (Tarija) apresentou altos níveis de resistência (RR50 = 129,12 e 0% DD). Do mesmo modo, as populações domésticas dos Vales Inter-Andinos (Cochabamba) apresentaram RR50 > 9, sendo as populações silvestres menos suscetíveis, com RR50 >5 do que SRL. 2) Cruzamentos experimentais foram realizados entre uma colônia suscetível RR50=0,62 (S), uma resistente RR50=129,12 (R) e com susceptibilidade reduzida RR50=5,04 (SR), em ambas as direções (♀x♂ e ♂x♀). O modo de herança do caráter resistente foi determinado pelo grau de dominância (DO) e dominância efetiva (DML). A hereditariedade (h2) foi estimada a partir da colônia R selecionada durante duas gerações, utilizando a dose diagnóstica (10 ng.i.a./ninfa). O resultado para DO e DML (<1) indica que a resistência é um caráter de dominância incompleta e de herança autossômica. A Dose Letal 50% (DL50) para F1 de ♀Sx♂R e ♂Sx♀R foi de 0,74 e 3,97 respectivamente, revelando efeito de diluição da resistência inicialmente observada. Por outro lado, foi observado um incremento da RR50 de 2,25 vezes (F1) e 26,83 vezes (F2) na população selecionada em comparação com a colônia parental. 3) Foi compilado um total de 24 artigos que avaliaram a suscetibilidade a diferentes piretróides em 222 populações de T. infestans coletadas no campo dos países de Argentina, Bolívia, Brasil e Paraguai. A relação entre resistência aos inseticidas (avaliada por critérios diferentes) e diferentes variáveis ambientais foi estudada utilizando modelo linear generalizado. A DL50 mostrou uma forte relação linear com a RR50. Análise estatística descritiva demonstrou que a distribuição de frequência da Log (DL50) é bimodal, sugerindo a existência de dois grupos estatísticos (um grupo de menor e outro com maior Log (DL50). Finalmente, o modelo significativo incluindo 5 variáveis ambientais referentes a temperatura e precipitação, revelou concentração das populações com altas DL50 sobre a região identificada como o centro de dispersão de T. infestans. Os dados obtidos neste estudo contribuem com informações sobre a variabilidade do perfil de resistência, ocorrência e distribuição de populações resistentes na Bolívia.Both the persistence of Triatoma infestans and the uninterrupted transmission of Trypanosoma cruzi in the inter-Andean valleys and Grande Chaco regions in Bolivia are of high relevance. Wild foci of this species have been described within a wide area this past decade. In places where the reach of the vector control strategies is limited, accounts of wild and domestic populations of insecticide resistant T infestans are frequent. The following study aimed to characterize the deltamethrin susceptibility profile (1) and heritability (2) in wild and domestic T. infestans Bolivian populations. Additionally, we describe the geographic distribution of pyrethroid resistant South American populations of this species.1) We evaluated 9 populations of wild and domestic T. infestans from Grande Chaco and two from the Bolivian inter-Andean valleys. Three wild T. infestans (dark morph) from Chaco (Santa Cruz) were susceptible towards deltamethrin (RR50 de 9, whereas the wild populations were less susceptible (RR50 > 5 than SRL).2) We performed experimental crosses between susceptible (S) [RR50=0.62], resistant (R) [RR50=129.12], and a reduced susceptibility (SRL) [RR50=5.04] colonies, in both directions (♀x♂ e ♂x♀). The heritability mode of the resistance trait was determined by the degree of dominance (DD) and effective dominance (DML). Heritability (h2) was estimated considering R colony individuals selected after two generations using the diagnostic dose (10 ng.a.i./nymph). The results regarding the DD and DML (<1) indicate that resistance is an incomplete dominance trait of autosomal inheritance. The lethal doses 50% (DL50) for the F1 ♀Sx♂R and ♂Sx♀R crosses were 0.74 and 3.97 respectively. This revealed a dilution effect upon the resistance observed initially. Oppositely, we observed a 2.25 fold increase in the RR50 for the F1 and 26.83 fold for F2 when comparing between the selected population and the parental colony.3) We reviewed 24 scientific publications that assess pyrethroid susceptibility in 222 T. infestans field collected populations from Argentina, Bolivia, Brasil, and Paraguay. The relation between insecticide resistance (assessed with various criteria) and multiple environmental variables was studied using a General Linear Model. The DL50 presented a strong linear relation with RR50. Descriptive statistical analyses revealed that the frequency distribution of log (DL50) values is bimodal, which suggests the existence of two statistical groups of lower and higher log (DL50) values. Finally, a significant model considering 5 environmental variables, regarding temperature and precipitation revealed the concentration of the populations with high DL50 on the region identified as the T. infestans origin of dispersion.The data collected and results obtained in this study bring forth valuable information regarding variability in resistance profiles, as well as the occurrence and distribution of resistant populations in Bolivia

Distribution of Pyrethroid Resistant Populations of Triatoma infestans in the Southern Cone of South America

A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria) with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD 50 ) showed a strong linear relationship with the corresponding resistance ratio (RR 50 ). The statistical descriptive analysis of showed that the frequency distribution of the Log(LD 50 ) is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD 50 groups with a particular concentration of the highest LD 50 populations over the region identified as the putative center of dispersion of T. infestans.The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans, never before exposed to pyrethroid insecticides, representing natural and wild toxicological phenotypes. The strong linear relationship found between LD 50 and RR 50 suggest RR 50 might not be the best indicator of insecticide resistance in triatomines.Fil: Bustamante Gomez, Marinely. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomínueos e Epidemiologia da Doença de Chagas; BrasilFil: Gonçalves Diotaiuti, Liléia. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomínueos e Epidemiologia da Doença de Chagas; BrasilFil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Geographic distribution of the 222 <i>T</i>. <i>infestans</i> populations evaluated for susceptibility to pyrethroids.

<p>Red circles: populations identified as resistant by PAHO and WHO criteria (RR₅₀> 5 or mortality DD <80%); blue circles: populations identified as susceptible by PAHO and WHO criteria (RR₅₀ < 5 or mortality DD > 80%).</p

Frequency distribution of Log (LD₅₀) in the <i>T</i>. <i>infestans</i> studied populations (n = 141).

<p>The value Log (LD₅₀) = 2.6 (equivalent to 13.6 ng a.i./insect) is the threshold value that best separates the two subpopulations.</p

Best GLM models for each response variable as a function of bioclimatic variables (Bioxx).

<p>Response variables are of binary type (0,1).</p

Number of <i>T</i>. <i>infestans</i> populations studied for pyrethroid resistance according to each criterion (response variable) for resistance evaluation in triatomines.

<p>Number of <i>T</i>. <i>infestans</i> populations studied for pyrethroid resistance according to each criterion (response variable) for resistance evaluation in triatomines.</p

Inheritance and heritability of deltamethrin resistance under laboratory conditions of Triatoma infestans from Bolivia

Submitted by Nuzia Santos ([email protected]) on 2016-04-05T18:53:58Z No. of bitstreams: 1 Inheritance and heritability of deltamethrin resistance under laboratory conditions of Triatoma infestans from Bolivia.pdf: 5217942 bytes, checksum: 285b1b55bc8ff585ef9878da7e69dd2b (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2016-04-05T18:57:36Z (GMT) No. of bitstreams: 1 Inheritance and heritability of deltamethrin resistance under laboratory conditions of Triatoma infestans from Bolivia.pdf: 5217942 bytes, checksum: 285b1b55bc8ff585ef9878da7e69dd2b (MD5)Made available in DSpace on 2016-04-05T18:57:36Z (GMT). No. of bitstreams: 1 Inheritance and heritability of deltamethrin resistance under laboratory conditions of Triatoma infestans from Bolivia.pdf: 5217942 bytes, checksum: 285b1b55bc8ff585ef9878da7e69dd2b (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilBackground: Over the last few decades, pyrethroid-resistant in Triatoma infestans populations have been reported, mainly on the border between Argentina and Bolivia. Understanding the genetic basis of inheritance mode and heritability of resistance to insecticides under laboratory conditions is crucial for vector management and monitoring of insecticide resistance. Currently, few studies have been performed to characterize the inheritance mode of resistance to pyrethroids in T. infestans; for this reason, the present study aims to characterize the inheritance and heritability of deltamethrin resistance in T. infestans populations from Bolivia with different toxicological profiles. Methods: Experimental crosses were performed between a susceptible (S) colony and resistant (R) and reduced susceptibility (RS) colonies in both directions (♀ x ♂ and ♂ x ♀), and inheritance mode was determined based on degree of dominance (DO) and effective dominance (DML). In addition, realized heritability (h2) was estimated based on a resistant colony, and select pressure was performed for two generations based on the diagnostic dose (10 ng. i. a. /nymph). The F1 progeny of the experimental crosses and the selection were tested by a standard insecticide resistance bioassay. Results: The result for DO and DML (< 1) indicates that resistance is an incompletely dominant character, and inheritance is autosomal, not sex-linked. The LD50 for F1 of ♀S x ♂R and ♂S x ♀R was 0.74 and 3.97, respectively, which is indicative of dilution effect. In the resistant colony, after selection pressure, the value of h2 was 0.37; thus, the LD50 value increased 2.25-fold (F2) and 26.83-fold (F3) compared with the parental colony. Conclusion: The inheritance mode of resistance of T. infestans to deltamethrin, is autosomal and an incompletely dominant character; this is a previously known process, confirmed in the present study on T. infestans populations from Bolivia. The lethal doses (LD50) increase from one generation to another rapidly after selection pressure with deltamethrin. This suggests that resistance is an additive and cumulative factor, mainly in highly structured populations with limited dispersal capacity, such as T. infestans. This phenomenon was demonstrated for the first time for T. infestans in the present study. These results are very important for vector control strategies in problematic areas where high resistance ratios of T. infestans have been reported

Susceptibility to deltamethrin of wild and domestic populations of Triatoma infestans of the Gran Chaco and the Inter-Andean Valleys of Bolivia

Submitted by Nuzia Santos ([email protected]) on 2015-03-11T17:51:49Z No. of bitstreams: 1 2014_143.pdf: 250437 bytes, checksum: 81a5a4aefb7c94b17c57b61f712f3dee (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2015-03-11T17:51:57Z (GMT) No. of bitstreams: 1 2014_143.pdf: 250437 bytes, checksum: 81a5a4aefb7c94b17c57b61f712f3dee (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2015-03-11T17:57:01Z (GMT) No. of bitstreams: 1 2014_143.pdf: 250437 bytes, checksum: 81a5a4aefb7c94b17c57b61f712f3dee (MD5)Made available in DSpace on 2015-03-11T17:57:01Z (GMT). No. of bitstreams: 1 2014_143.pdf: 250437 bytes, checksum: 81a5a4aefb7c94b17c57b61f712f3dee (MD5) Previous issue date: 2014FAPEMIG/FIOCRUZ/CPQRR/DEMANDA UNIVERSAL; PEC-PG Capes Escuela Técnica de Salud / Bolivia and to the National Chagas DeseaseFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrazilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrazilUniversidad Mayor de San Simón. Facultad de Medicina. Instituto de Investigaciones Biomédicas. Cochabamba, Bolivia.CEADES Salud y Medio Ambiente. Cochabamba, Bolivia.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrazilInstitute de Recherche pour le Developemente. La Paz, Bolivia.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrazilBackground: The persistence of Triatoma infestans and the continuous transmission of Trypanosoma cruzi in the Inter-Andean Valleys and in the Gran Chaco of Bolivia are of great significance. Coincidentally, it is in these regions the reach of the vector control strategies is limited, and reports of T. infestans resistance to insecticides, including in wild populations, have been issued. This study aims to characterize the susceptibility to deltamethrin of wild and domestic populations of T. infestans from Bolivia, in order to better understand the extent of this relevant problem. Methods: Susceptibility to deltamethrin was assessed in nine, wild and domestic, populations of T. infestans from the Gran Chaco and the Inter-Andean Valleys of Bolivia. Serial dilutions of deltamethrin in acetone (0.2 ¿L) were topically applied in first instar nymphs (F1, five days old, fasting, weight 1.2¿±¿0.2 mg). Dose response results were analyzed with PROBIT version 2, determining the lethal doses, slope and resistance ratios (RR). Qualitative tests were also performed. Results: Three wild T. infestans dark morph samples of Chaco from the Santa Cruz Department were susceptible to deltamethrinwithRR50of <2, and 100% mortality to the diagnostic dose (DD); however, two domestic populations from the same region were less susceptible than the susceptibility reference lineage (RR50 of 4.21 and 5.04 respectively and 93% DD). The domestic population of Villa Montes from the Chaco of the Tarija Department presented high levels of resistance (RR50 of 129.12 and 0% DD). Moreover, the domestic populations from the Valleys of the Cochabamba Department presented resistance (RR50 of 8.49 and 62% DD), the wild populations were less susceptible than SRL and T. infestans dark morph populations (RR50¿<¿5).ConclusionThe elimination of T. infestans with pyrethroid insecticides in Brazil, Uruguay, Chile, and its drastic reduction in large parts of Paraguay and Argentina, clearly indicates that pyrethroid resistance was very uncommon in non-Andean regions. The pyrethroid susceptibility of non-Andean T. infestans dark morph population, and the resistance towards it, of Andean T. infestans wild and domestic populations, indicates that the Andean populations from Bolivia are less susceptibl

Insights from tissue-specific transcriptome sequencing analysis of Triatoma infestans.

Submitted by Nuzia Santos ([email protected]) on 2018-05-03T13:54:51Z No. of bitstreams: 1 Insights from tissue-specific transcriptome sequencing analysis of Triatoma infestans.pdf: 200582 bytes, checksum: 77e317bb438545325d5e59d2579c42ac (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2018-05-03T14:02:07Z (GMT) No. of bitstreams: 1 Insights from tissue-specific transcriptome sequencing analysis of Triatoma infestans.pdf: 200582 bytes, checksum: 77e317bb438545325d5e59d2579c42ac (MD5)Made available in DSpace on 2018-05-03T14:02:07Z (GMT). No. of bitstreams: 1 Insights from tissue-specific transcriptome sequencing analysis of Triatoma infestans.pdf: 200582 bytes, checksum: 77e317bb438545325d5e59d2579c42ac (MD5) Previous issue date: 2017Fundação Oswaldo Cruz. Instituto René Rachou. Grupo Informática de Biossistemas e Genômica. Belo Horizonte, MG, Brasil/ Fundação Oswaldo Cruz. Instituto René Rachou. Programa de Pós-Graduação em Ciências da Saúde. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Grupo Informática de Biossistemas e Genômica. Belo Horizonte, MG, Brasil/Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Programa de Pós-Graduação em Bioinformática. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Grupo Informática de Biossistemas e Genômica. Belo Horizonte, MG, Brasil/Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Programa de Pós-Graduação em Biologia Computacional e Sistemas. Rio de Janeiro, RJ, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Instituto René Rachou. Grupo Informática de Biossistemas e Genômica. Belo Horizonte, MG, BrasilTriatoma infestans is an insect of subfamily Triatominae (Hemiptera: Reduviidae) and an important vector of Trypanosoma cruzi, the etiologic agent of human Chagas disease. In this work we reported a transcriptome assembly and annotation of T. infestans heads obtained by Next Generation Sequencing (NGS) technologies