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Eric Dumonteil - One of the best experts on this subject based on the ideXlab platform.
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disentangling trypanosoma cruzi transmission cycle dynamics through the identification of blood meal sources of natural populations of Triatoma dimidiata in yucatan mexico
Parasites & Vectors, 2019Co-Authors: Joel Israel Moomillan, Eric Dumonteil, Audrey Arnal, Silvia Perezcarrillo, Anette Hernandezandrade, M J Ramirezsierra, Miguel Rosadovallado, Etienne WaleckxAbstract:Background In the Yucatan Peninsula, Mexico, Triatoma dimidiata is the main vector of Trypanosoma cruzi, the causative agent of Chagas disease. Little effort has been made to identify blood meal sources of T. dimidiata in natural conditions in this region, although this provides key information to disentangle T. cruzi transmission cycles and dynamics and guide the development of more effective control strategies. We identified the blood meals of a large sample of T. dimidiata bugs collected in different ecotopes simultaneously with the assessment of bug infection with T. cruzi, to disentangle the dynamics of T. cruzi transmission in the region.
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sleeping habits affect access to host by chagas disease vector Triatoma dimidiata
Parasites & Vectors, 2016Co-Authors: Etienne Waleckx, Rafael Pasosalquicira, Maria Jesus Ramirezsierra, Eric DumonteilAbstract:Background Chagas disease, caused by the parasite Trypanosoma cruzi, is mainly transmitted by blood-sucking bugs called triatomines. In the Yucatan Peninsula, Mexico, the main vector of T. cruzi is Triatoma dimidiata. While this species may colonize houses in other regions, it is mostly intrusive in Yucatan: it generally lives in sylvan and peridomestic areas, and frequently enters inside homes, likely attracted by potential vertebrate hosts, without establishing colonies. Bugs collected inside homes have a low nutritional status, suggesting that they cannot efficiently feed inside these houses. We hypothesized that this low nutritional status and limited colonization may be associated, at least in part, with the local practice in Mayan communities to sleep in hammocks instead of beds, as this sleeping habit could be an obstacle for triatomines to easily reach human hosts, particularly for nymphal instars which are unable to fly.
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molecular epidemiology of trypanosoma cruzi and Triatoma dimidiata in costal ecuador
Infection Genetics and Evolution, 2016Co-Authors: Yim Yan Wong, Maria Jesus Ramirezsierra, Eric Dumonteil, Karen Jeniffer Sornosa Macias, Doris Guale Martinez, Luis Solorzano, Claudia HerreraAbstract:Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. In Ecuador, Triatoma dimidiata and Rhodnius ecuadoriensis are the main vector species, responsible for over half of the cases of T. cruzi infection in the country. T. dimidiata is believed to have been introduced in Ecuador during colonial times, and its elimination from the country is thus believed to be feasible. We investigated here the molecular ecology of T. dimidiata and T. cruzi in costal Ecuador to further guide control efforts. Analysis of the Internal Transcribed Spacer 2 (ITS-2) of 23 specimens from Progreso, Guayas, unambiguously supported the likely importation of T. dimidiata from Central America to Ecuador. The observation of a very high parasite infection rate (54%) and frequent feeding on humans (3/5) confirmed a continued risk of transmission to humans. All genotyped parasites corresponded to TcI DTU and Trypanosoma rangeli was not detected in T. dimidiata. TcI subgroups corresponded to TcIa (25%), and mixed infections with TcIa and TcId (75%). Further studies should help clarify T. cruzi genetic structure in the country, and the possible impact of the introduction of T. dimidiata on the circulating parasite strains. The elevated risk posed by this species warrants continuing efforts for its control, but its apparent mobility between peridomestic and domestic habitats may favor reinfestation following insecticide spraying.
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infection rate by trypanosoma cruzi and biased vertebrate host selection in the Triatoma dimidiata hemiptera reduvidae species complex
Journal of Medical Entomology, 2016Co-Authors: M J Ramirezsierra, Eric DumonteilAbstract:Chagas disease is a vector-borne disease, caused by the protozoan parasite Trypanosoma cruzi and transmitted by hematophagous insects. Triatoma dimidiata (Hemiptera: Reduvidae (Latreille 1811)) is one of the main vectors, and recent molecular studies indicate that it is a species complex, with potentially different vectorial competences. We investigated the differences in natural T. cruzi infection rate within T. dimidiata complex in Yucatan, Mexico. ITS-2 hybrid bugs had a twofold higher infection rate than ITS-2 Groups 2 and 3 bugs, and this pattern was consistent over time and in several villages. To test if T. dimidiata ITS-2 hybrid bugs could feed more frequently on T. cruzi -infected hosts, we evaluated their host-seeking behavior in a dual-choice chamber. Group 2 and 3 bugs were equally attracted to T. cruzi -infected or uninfected mice. On the contrary, ITS-2 hybrid bugs reached three times more frequently the T. cruzi -infected mouse, compared to the uninfected one, indicating a significant bias toward an infected host. This behavior may explain in part their higher natural infection rate. Further studies should explore the complex and unique interactions among T. cruzi , triatomines vectors, and mammalian hosts, as this may led to new strategies to interfere with transmission cycles and improve Chagas disease control.
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ecological niche and geographic distribution of the chagas disease vector Triatoma dimidiata reduviidae triatominae evidence for niche differentiation among cryptic species
Infection Genetics and Evolution, 2015Co-Authors: Andres Gomezpalacio, Eric Dumonteil, Sair Arboleda, Townsend A PetersonAbstract:The principal vector of Chagas disease in Central America, Triatoma dimidiata, shows considerable diversity of habitat, phenotype, and genotype across its geographic range (central Mexico to southern Ecuador), suggesting that it constitutes a complex of cryptic species. However, no consistent picture of the magnitude of ecological differentiation among populations of this complex has yet been developed. To assess ecological variation across the complex, we broadened the geographic coverage of phylogeographic data and analyses for the complex into Colombia and Mexico, with additional nuclear (ITS-2) and mitochondrial (ND4) DNA sequences. This information allowed us to describe distributions of previously documented clades in greater detail: Group I, from central Guatemala south to Ecuador; Group II, across Mexico south through the Yucatan Peninsula to Belize and northern Guatemala; and Group III, in northern Guatemala, Belize, and the Yucatan Peninsula. Using ecological niche modeling, we assessed ecological niche differentiation among the groups using four hypotheses of accessible areas (M) across the distribution of the complex. Results indicated clear niche divergence of Group I from Group II: the speciation process thus appears to have involved genetic and ecological changes, suggesting divergence in populations in response to environmental conditions.
Carlota Monroy - One of the best experts on this subject based on the ideXlab platform.
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infestation dynamics of Triatoma dimidiata in highly deforested tropical dry forest regions of guatemala
Memorias Do Instituto Oswaldo Cruz, 2020Co-Authors: Daniel Penados, Emmanuel Agreda, Lori Stevens, Jose Pineda, Michelle Catalan, Miguel Avila, Carlota MonroyAbstract:Background Deforestation, driven by anthropogenic change in land use, influences the behaviour and abundance of vector-borne diseases. For various species of Chagas disease vectors, there is evidence that change in land use affects population density and abundance. Triatoma dimidiata is the most important Chagas vector in Guatemala, and at least one million people live in T. dimidiata endemic areas; however, infestation dynamics vary among regions, from high infestation with all life stages to low seasonal infestation by sylvatic adults. Objectives The aim of this study was to evaluate how land-use, combined with domiciliary risk factors, influences the infestation dynamics of T. dimidiata for four villages in a dry forest region with a strong deforestation history. Methods Land use, measured with drone and satellite images, was classified into four categories (houses, monocultures and pastures, woodland and shrubland, and bare soil). Domiciliary risk factors and infestation were assessed through entomological surveys. Statistical analyses compared infestation indices and the ability of land use and domiciliary risk factors to explain infestation. Findings Two villages had significantly higher infestation (26 and 30% vs. 5 and 6%), yet all villages had high colonisation (71-100% of infested houses had immature insects), with no significant difference among them. Because of the high level of deforestation across the study area, land use was not related to infestation; however, domiciliary risk factors were. A model based on four weighted domiciliary risk factors (adobe or bajareque walls, intradomicile animals, intradomicile clutter, and dirt floors) explains the infestation risk. Main conclusions Because almost all infested houses have reproducing populations in this deforested dry forest region and statistical analysis identified the domiciliary risk factors for infestation, intermediate and long-term control of Chagas disease vectors in this region requires management of these risk factors.
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novel evolutionary algorithm identifies interactions driving infestation of Triatoma dimidiata a chagas disease vector
American Journal of Tropical Medicine and Hygiene, 2020Co-Authors: John P. Hanley, Antonieta Rodas, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Sara Helms Cahan, Leslie A Morrissey, Lucia Orantes, Carlota MonroyAbstract:Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used in tandem to identify sets of risk factor combinations associated with infestation. The optimal model includes 10 risk factors in what is known as a third-order disjunctive normal form (i.e., infested households have chicken coops AND deteriorated bedroom walls OR an accumulation of objects AND dirt floors AND total number of occupants ≥ 5 AND years of electricity ≥ 5 OR poor hygienic condition ratings AND adobe walls AND deteriorated walls AND dogs). Houses with dirt floors and deteriorated walls have been reported previously as risk factors and align well with factors currently targeted by Ecohealth interventions to minimize infestation. However, the tandem evolutionary algorithms also identified two new socioeconomic risk factors (i.e., households having many occupants and years of electricity ≥ 5). Identifying key risk factors may help with the development of new Ecohealth interventions and/or reduce the survey time needed to identify houses most at risk.
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common pattern of distribution for mesoamerican Triatoma dimidiata suggest geological and ecological association
Acta Tropica, 2020Co-Authors: Patricia Landaverdegonzalez, Sergio Melgar, Dulce Maria Bustamante, Marianela Menes, Carlota MonroyAbstract:The phylogeny of the Triatoma dimidiata complex has been widely assessed with different genetic and morphological data, which has allowed to reach the consensus that the complex consists of at least three taxonomic units. However, these taxonomic units seem to have a distribution related to geography throughout Mesoamerica, with different groupings depending on the source of information used. In the present study, we aimed to determine if there is a common biogeographical, genetic and phenetic distribution pattern among the T. dimidiata species in Mesoamerica and if this pattern is related to ecological and geological variability of the region. We found that panbiogeographical analysis showed three generalized tracks that coincide with genetic/phenetic data which showed a general pattern of distribution in two big clusters to the north and south of Mesoamerica. We also found that these clusters were significantly related to geological tectonic plates and ecotypes. We conclude that the geological history may be a plausible explanation for the greater differentiation observed in the T. dimidiata complex, but that the current ecological characteristics of the morphotectonic units or ecotypes may be responsible for the additional variation observed and therefore differential control strategies for each cluster considering geological history and ecotype should be used. Further, more detailed biogeographical and landscape genetic analyses are necessary with the goal to elucidate T. dimidiata differentiation related with ecological and geological variables in the region and the possible epidemiological and evolutionary consequences.
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residual survival and local dispersal drive reinfestation by Triatoma dimidiata following insecticide application in guatemala
Infection Genetics and Evolution, 2019Co-Authors: Sara Helms Cahan, Antonieta Rodas, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, John P. Hanley, Kimberly F. Wallin, Lucia Orantes, Carlota MonroyAbstract:Abstract Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine insect vectors. In Guatemala, insecticide spraying is an integral part of management of the main vector, Triatoma dimidiata. Spraying typically has low efficacy, which may be due to incomplete elimination from infested houses, within-village dispersal, or influx from other villages or sylvan environments. To evaluate how these mechanisms contribute to reinfestation, we conducted a time-course analysis of T. dimidiata infestation, abundance and household genetic structure in two nearby villages in Jutiapa, Guatemala; houses in the first village were surveyed, treated with insecticide if infested and then re-surveyed at eight and 22 months following spraying, while the second village served as an untreated control to quantify changes associated with seasonal dispersal. Insects were genotyped at 2–3000 SNP loci for kinship and population genetic analyses. Insecticide application reduced overall infestation and abundance, while the untreated village was stable over time. Nevertheless, within two years 35.5% of treated houses were reinfested and genetic diversity had largely recovered. Insects collected from reinfested houses post-spraying were most closely related to pre-spray collections from the same house, suggesting that infestations had not been fully eliminated. Immigration by unrelated insects was also detected within a year of spraying; when it occurred, dispersal was primarily local from neighboring houses. Similar dispersal patterns were observed following the annual dispersal season in the untreated village, with high-infestation houses serving as sources for neighboring homes. Our findings suggest that the efficacy of pyrethroid application is rapidly diminished by both within-house breeding by survivors and annual cycles of among-house movement. Given these patterns, we conclude that house structural improvements, an integral part of the Ecohealth approach that makes houses refractory to vector colonization and persistence, are critical for long-term reduction of T. dimidiata infestation.
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vectors of diversity genome wide diversity across the geographic range of the chagas disease vector Triatoma dimidiata sensu lato hemiptera reduviidae
Molecular Phylogenetics and Evolution, 2018Co-Authors: Silvia A Justi, Carlota Monroy, Lori Stevens, Sara Helms Cahan, Raquel Limacordon, Patricia L. DornAbstract:To date, the phylogeny of Triatoma dimidiata sensu lato (s. l.) (Hemiptera: Reduviidae: Triatominae), the epidemiologically most important Chagas disease vector in Central America and a secondary vector in Mexico and northern South America, has only been investigated by one multi-copy nuclear gene (Internal Transcribed Spacer - 2) and a few mitochondrial genes. We examined 450 specimens sampled across most of its native range from Mexico to Ecuador using reduced representation next-generation sequencing encompassing over 16,000 single nucleotide polymorphisms (SNPs). Using a combined phylogenetic and species delimitation approach we uncovered two distinct species, as well as a well-defined third group that may contain multiple species. The findings are discussed with respect to possible drivers of diversification and the epidemiological importance of the distinct species and groups.
Patricia L. Dorn - One of the best experts on this subject based on the ideXlab platform.
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novel evolutionary algorithm identifies interactions driving infestation of Triatoma dimidiata a chagas disease vector
American Journal of Tropical Medicine and Hygiene, 2020Co-Authors: John P. Hanley, Antonieta Rodas, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Sara Helms Cahan, Leslie A Morrissey, Lucia Orantes, Carlota MonroyAbstract:Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used in tandem to identify sets of risk factor combinations associated with infestation. The optimal model includes 10 risk factors in what is known as a third-order disjunctive normal form (i.e., infested households have chicken coops AND deteriorated bedroom walls OR an accumulation of objects AND dirt floors AND total number of occupants ≥ 5 AND years of electricity ≥ 5 OR poor hygienic condition ratings AND adobe walls AND deteriorated walls AND dogs). Houses with dirt floors and deteriorated walls have been reported previously as risk factors and align well with factors currently targeted by Ecohealth interventions to minimize infestation. However, the tandem evolutionary algorithms also identified two new socioeconomic risk factors (i.e., households having many occupants and years of electricity ≥ 5). Identifying key risk factors may help with the development of new Ecohealth interventions and/or reduce the survey time needed to identify houses most at risk.
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residual survival and local dispersal drive reinfestation by Triatoma dimidiata following insecticide application in guatemala
Infection Genetics and Evolution, 2019Co-Authors: Sara Helms Cahan, Antonieta Rodas, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, John P. Hanley, Kimberly F. Wallin, Lucia Orantes, Carlota MonroyAbstract:Abstract Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine insect vectors. In Guatemala, insecticide spraying is an integral part of management of the main vector, Triatoma dimidiata. Spraying typically has low efficacy, which may be due to incomplete elimination from infested houses, within-village dispersal, or influx from other villages or sylvan environments. To evaluate how these mechanisms contribute to reinfestation, we conducted a time-course analysis of T. dimidiata infestation, abundance and household genetic structure in two nearby villages in Jutiapa, Guatemala; houses in the first village were surveyed, treated with insecticide if infested and then re-surveyed at eight and 22 months following spraying, while the second village served as an untreated control to quantify changes associated with seasonal dispersal. Insects were genotyped at 2–3000 SNP loci for kinship and population genetic analyses. Insecticide application reduced overall infestation and abundance, while the untreated village was stable over time. Nevertheless, within two years 35.5% of treated houses were reinfested and genetic diversity had largely recovered. Insects collected from reinfested houses post-spraying were most closely related to pre-spray collections from the same house, suggesting that infestations had not been fully eliminated. Immigration by unrelated insects was also detected within a year of spraying; when it occurred, dispersal was primarily local from neighboring houses. Similar dispersal patterns were observed following the annual dispersal season in the untreated village, with high-infestation houses serving as sources for neighboring homes. Our findings suggest that the efficacy of pyrethroid application is rapidly diminished by both within-house breeding by survivors and annual cycles of among-house movement. Given these patterns, we conclude that house structural improvements, an integral part of the Ecohealth approach that makes houses refractory to vector colonization and persistence, are critical for long-term reduction of T. dimidiata infestation.
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vectors of diversity genome wide diversity across the geographic range of the chagas disease vector Triatoma dimidiata sensu lato hemiptera reduviidae
Molecular Phylogenetics and Evolution, 2018Co-Authors: Silvia A Justi, Carlota Monroy, Lori Stevens, Sara Helms Cahan, Raquel Limacordon, Patricia L. DornAbstract:To date, the phylogeny of Triatoma dimidiata sensu lato (s. l.) (Hemiptera: Reduviidae: Triatominae), the epidemiologically most important Chagas disease vector in Central America and a secondary vector in Mexico and northern South America, has only been investigated by one multi-copy nuclear gene (Internal Transcribed Spacer - 2) and a few mitochondrial genes. We examined 450 specimens sampled across most of its native range from Mexico to Ecuador using reduced representation next-generation sequencing encompassing over 16,000 single nucleotide polymorphisms (SNPs). Using a combined phylogenetic and species delimitation approach we uncovered two distinct species, as well as a well-defined third group that may contain multiple species. The findings are discussed with respect to possible drivers of diversification and the epidemiological importance of the distinct species and groups.
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Collection information for Triatoma dimidiata specimens used for RAD-sequencing.
2018Co-Authors: Lucia C. Orantes, Carlota Monroy, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Leslie Morrissey, John P. Hanley, Antonieta Guadalupe Rodas, Bethany Richards, Kimberly F. WallinAbstract:Collection information for Triatoma dimidiata specimens used for RAD-sequencing.
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F-statistics and summary statistics for Triatoma dimidiata clusters identified by k-means clustering.
2018Co-Authors: Lucia C. Orantes, Carlota Monroy, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Leslie Morrissey, John P. Hanley, Antonieta Guadalupe Rodas, Bethany Richards, Kimberly F. WallinAbstract:F-statistics and summary statistics for Triatoma dimidiata clusters identified by k-means clustering.
Janine M Ramsey - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity indices for Triatoma dimidiata haplogroups using the fragments ND4A and ND4B.
2019Co-Authors: Angélica Pech-may, Carlos Jesús Mazariegos-hidalgo, Amaia Izeta-alberdi, Sury Antonio López-cancino, Ezequiel Tun-ku, Keynes De La Cruz-félix, Carlos N. Ibarra-cerdeña, Raúl González E. Ittig, Janine M RamseyAbstract:Genetic diversity indices for Triatoma dimidiata haplogroups using the fragments ND4A and ND4B.
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Genetic diversity indices for Triatoma dimidiata Hg2 from Berriozábal sub-regions using fragments ND4A and ND4B.
2019Co-Authors: Angélica Pech-may, Carlos Jesús Mazariegos-hidalgo, Amaia Izeta-alberdi, Sury Antonio López-cancino, Ezequiel Tun-ku, Keynes De La Cruz-félix, Carlos N. Ibarra-cerdeña, Raúl González E. Ittig, Janine M RamseyAbstract:Genetic diversity indices for Triatoma dimidiata Hg2 from Berriozábal sub-regions using fragments ND4A and ND4B.
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Geographic distribution of Triatoma dimidiata haplogroups encountered across the Mexican Neotropical region, and across the Berriozábal region in northern Chiapas (borders on the eastern edge of the Chimalapas, and the Grijalva watershed).
2019Co-Authors: Angélica Pech-may, Carlos Jesús Mazariegos-hidalgo, Amaia Izeta-alberdi, Sury Antonio López-cancino, Ezequiel Tun-ku, Keynes De La Cruz-félix, Carlos N. Ibarra-cerdeña, Raúl González E. Ittig, Janine M RamseyAbstract:The origin of Triatoma dimidiata samples included in all analyses are listed in S1 Table. The map was created using ArcGIS 10.3 (www.arcgis.com).
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behavioural and electrophysiological responses of Triatoma dimidiata nymphs to conspecific faecal volatiles
Medical and Veterinary Entomology, 2018Co-Authors: Z Galvezmarroquin, Janine M Ramsey, Leopoldo Cruzlopez, Edi A Malo, Julio C RojasAbstract:The behavioural and electrophysiological (electroantennography) responses of the first two instars of Triatoma dimidiata (Hemiptera: Reduviidae) Latreille to fresh and dry faecal headspace volatile extracts from fifth instar conspecific nymphs and synthetic compounds were analysed in this study. Recently emerged nymphs (3-5 days) aggregated around filter paper impregnated with dry faeces and around filter paper impregnated with extracts from both fresh and dry faeces. Older first instars (10-15 days) and second instars aggregated around filter paper impregnated with fresh and dry faeces, and their respective headspace extracts. Dry faecal volatile extracts elicited the strongest antennal responses, followed by fresh faecal extracts. Gas chromatography-mass spectrometry analysis of dried faecal headspace volatiles demonstrated the presence of 12 compounds: 2-ethyl-1-hexanol, 1,2,4-trimethylbenzene, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-tricosane, n-pentaeicosane, n-hexaeicosane, n-octaeicosane, nonanal, and 4-methyl quinazoline. In fresh faecal headspace extracts, only nonanal was clearly detected, although there were other trace compounds, including several unidentified sesquiterpenes. Four of the 11 compounds tested individually elicited aggregation behaviour at concentrations of 100 ng/µL and 1 µg/µL. A blend containing these four components also mediated the aggregation of nymphs. These volatiles may be valuable for developing monitoring methods and designing sensitive strategies to detect and measure T. dimidiata infestation.
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antennal phenotype of mexican haplogroups of the Triatoma dimidiata complex vectors of chagas disease
Infection Genetics and Evolution, 2016Co-Authors: Irving Mayconcha, Janine M Ramsey, Julio C Rojas, Pablo G Guerenstein, Silvia CatalaAbstract:Triatoma dimidiata (Latreille) is a species complex that spans North, Central, and South America and which is a key vector of all known discrete typing units (DTU) of Trypanosoma cruzi, the etiologic agent of Chagas disease. Morphological and genetic studies indicate that T. dimidiata is a species complex with three principal haplogroups (hg) in Mexico. Different markers and traits are still inconclusive regarding if other morphological differentiation may indicate probable behavioral and vectorial divergences within this complex. In this paper we compared the antennae of three Mexican haplogroups (previously verified by molecular markers ND4 and ITS-2) and discussed possible relationships with their capacity to disperse and colonized new habitats. The abundance of each type of sensillum (bristles, basiconics, thick- and thin-walled trichoids) on the antennae of the three haplogroups, were measured under light microscopy and compared using Kruskal–Wallis non-parametric and multivariate non-parametric analyses. Discriminant analyses indicate significant differences among the antennal phenotype of haplogroups either for adults and some nymphal stages, indicating consistency of the character to analyze intraspecific variability within the complex. The present study shows that the adult antennal pedicel of the T. dimidiata complex have abundant chemosensory sensilla, according with good capacity for dispersal and invasion of different habitats also related to their high capacity to adapt to conserved as well as modified habitats. However, the numerical differences among the haplogroups are suggesting variations in that capacity. The results here presented support the evidence of T. dimidiata as a species complex but show females and males in a different way. Given the close link between the bug's sensory system and its habitat and host-seeking behavior, AP characterization could be useful to complement genetic, neurological and ethological studies of the closely related dimidiata Complex haplogroups for a better knowledge of their vectorial capacity and a more robust species differentiation.
Antonieta Rodas - One of the best experts on this subject based on the ideXlab platform.
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novel evolutionary algorithm identifies interactions driving infestation of Triatoma dimidiata a chagas disease vector
American Journal of Tropical Medicine and Hygiene, 2020Co-Authors: John P. Hanley, Antonieta Rodas, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, Sara Helms Cahan, Leslie A Morrissey, Lucia Orantes, Carlota MonroyAbstract:Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used in tandem to identify sets of risk factor combinations associated with infestation. The optimal model includes 10 risk factors in what is known as a third-order disjunctive normal form (i.e., infested households have chicken coops AND deteriorated bedroom walls OR an accumulation of objects AND dirt floors AND total number of occupants ≥ 5 AND years of electricity ≥ 5 OR poor hygienic condition ratings AND adobe walls AND deteriorated walls AND dogs). Houses with dirt floors and deteriorated walls have been reported previously as risk factors and align well with factors currently targeted by Ecohealth interventions to minimize infestation. However, the tandem evolutionary algorithms also identified two new socioeconomic risk factors (i.e., households having many occupants and years of electricity ≥ 5). Identifying key risk factors may help with the development of new Ecohealth interventions and/or reduce the survey time needed to identify houses most at risk.
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effect of community education in an integrate control for Triatoma dimidiata hemiptera reduviidae
Revista Cubana de Medicina Tropical, 2020Co-Authors: Julio David Soto Lopez, Maria Carlota Monroy, Patricia Dorn, Salvador Castellanos, Raquel Lima, Antonieta RodasAbstract:Introduction: The Mesoamerican endemic specie Triatoma dimidiata is the main vector of Chagas disease in Central America, after the elimination of an introduced vector Rhodnius prolixus . The traditional method of vector control using insecticides results in reinfestation. An integrated Ecohealth approach, including education, house improvements and domestic animal management was shown effective for long-term control of T. dimidiata, and it was applied in several villages in Guatemala. Objective: To evaluate the changes in community practices after an Ecohealth intervention in La Prensa, Olopa Chiquimula. Methods: Through three surveys, we measured risk factors associated with T. dimidiata infestation, the infestation index, blood sources of T. dimidiata , the presence of Trypanosoma cruzi were analyzed using PCR. Statistics analysis included Wilcoxon signed-rank tests, Mc-Nemar test, Chi-square test and Fisher exact test to compare the surveys. Results: Over the years, risk factors associated with the presence of T. dimidiata and population density of the vector were observed. We found a decrease in consumption of human blood and the parasite in the vector population. However, we found the consumption of bird blood meal increased. Conclusions: Our results provide evidence that an ecohealth approach for an endemic Chagas vector has impact on reducing vector-human contact, possibly by influencing people's behavior. Increasing the community knowledge about these risk factors can be an effective strategy to further reduce the risk of house reinfestation and Chagas transmission.
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residual survival and local dispersal drive reinfestation by Triatoma dimidiata following insecticide application in guatemala
Infection Genetics and Evolution, 2019Co-Authors: Sara Helms Cahan, Antonieta Rodas, Patricia L. Dorn, Lori Stevens, Donna M. Rizzo, John P. Hanley, Kimberly F. Wallin, Lucia Orantes, Carlota MonroyAbstract:Abstract Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine insect vectors. In Guatemala, insecticide spraying is an integral part of management of the main vector, Triatoma dimidiata. Spraying typically has low efficacy, which may be due to incomplete elimination from infested houses, within-village dispersal, or influx from other villages or sylvan environments. To evaluate how these mechanisms contribute to reinfestation, we conducted a time-course analysis of T. dimidiata infestation, abundance and household genetic structure in two nearby villages in Jutiapa, Guatemala; houses in the first village were surveyed, treated with insecticide if infested and then re-surveyed at eight and 22 months following spraying, while the second village served as an untreated control to quantify changes associated with seasonal dispersal. Insects were genotyped at 2–3000 SNP loci for kinship and population genetic analyses. Insecticide application reduced overall infestation and abundance, while the untreated village was stable over time. Nevertheless, within two years 35.5% of treated houses were reinfested and genetic diversity had largely recovered. Insects collected from reinfested houses post-spraying were most closely related to pre-spray collections from the same house, suggesting that infestations had not been fully eliminated. Immigration by unrelated insects was also detected within a year of spraying; when it occurred, dispersal was primarily local from neighboring houses. Similar dispersal patterns were observed following the annual dispersal season in the untreated village, with high-infestation houses serving as sources for neighboring homes. Our findings suggest that the efficacy of pyrethroid application is rapidly diminished by both within-house breeding by survivors and annual cycles of among-house movement. Given these patterns, we conclude that house structural improvements, an integral part of the Ecohealth approach that makes houses refractory to vector colonization and persistence, are critical for long-term reduction of T. dimidiata infestation.
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migration and gene flow among domestic populations of the chagas insect vector Triatoma dimidiata hemiptera reduviidae detected by microsatellite loci
Journal of Medical Entomology, 2015Co-Authors: Lori Stevens, Antonieta Rodas, Carlota M Monroy, Robin M Hicks, David E Lucero, Leslie A Lyons, Patricia L. DornAbstract:ABSTRACT Triatoma dimidiata (Latreille, 1811) is the most abundant and significant insect vector of the parasite Trypanosoma cruzi in Central America, and particularly in Guatemala. Tr. cruzi is the causative agent of Chagas disease, and successful disease control requires understanding the geographic distribution and degree of migration of vectors such as T. dimidiata that frequently re-infest houses within months following insecticide application. The population genetic structure of T. dimidiata collected from six villages in southern Guatemala was studied to gain insight into the migration patterns of the insects in this region where populations are largely domestic. This study provided insight into the likelihood of eliminating T. dimidiata by pesticide application as has been observed in some areas for other domestic triatomines such as Triatoma infestans. Genotypes of microsatellite loci for 178 insects from six villages were found to represent five genetic clusters using a Bayesian Markov Chain Mon...
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two distinct Triatoma dimidiata latreille 1811 taxa are found in sympatry in guatemala and mexico
PLOS Neglected Tropical Diseases, 2009Co-Authors: Patricia L. Dorn, Antonieta Rodas, Sergio Melgar, Eric Dumonteil, Barbara Moguel, Claudia I Calderon, Elizabeth Solorzano, Nick De La Rua, Roberto Garnica, Carlota MonroyAbstract:Approximately 10 million people are infected with Trypanosoma cruzi, the causative agent of Chagas disease, which remains the most serious parasitic disease in the Americas. Most people are infected via triatomine vectors. Transmission has been largely halted in South America in areas with predominantly domestic vectors. However, one of the main Chagas vectors in Mesoamerica, Triatoma dimidiata, poses special challenges to control due to its diversity across its large geographic range (from Mexico into northern South America), and peridomestic and sylvatic populations that repopulate houses following pesticide treatment. Recent evidence suggests T. dimidiata may be a complex of species, perhaps including cryptic species; taxonomic ambiguity which confounds control. The nuclear sequence of the internal transcribed spacer 2 (ITS2) of the ribosomal DNA and the mitochondrial cytochrome b (mt cyt b) gene were used to analyze the taxonomy of T. dimidiata from southern Mexico throughout Central America. ITS2 sequence divides T. dimidiata into four taxa. The first three are found mostly localized to specific geographic regions with some overlap: (1) southern Mexico and Guatemala (Group 2); (2) Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica (Group 1A); (3) and Panama (Group 1B). We extend ITS2 Group 1A south into Costa Rica, Group 2 into southern Guatemala and show the first information on isolates in Belize, identifying Groups 2 and 3 in that country. The fourth group (Group 3), a potential cryptic species, is dispersed across parts of Mexico, Guatemala, and Belize. We show it exists in sympatry with other groups in Peten, Guatemala, and Yucatan, Mexico. Mitochondrial cyt b data supports this putative cryptic species in sympatry with others. However, unlike the clear distinction of the remaining groups by ITS2, the remaining groups are not separated by mt cyt b. This work contributes to an understanding of the taxonomy and population subdivision of T. dimidiata, essential for designing effective control strategies.
