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origins of house reinfestation with triatoma infestans after insecticide spraying in the argentine chaco using wing geometric morphometry.identifying the origins of insect vectors collected after community-wide residual insecticide applications is a relevant challenge in the gran chaco region where the main vector of chagas disease triatoma infestans usually reinfests human dwellings. wing geometric morphometry was used to compare the right wings of 63 males and 54 females collected at 4 months post-spraying (mps) with those from 165 males and 111 females collected before full-coverage spraying with pyrethroids in a well-defined r ...201323557838
fine-scale genetic structure in populations of the chagas' disease vector triatoma infestans (hemiptera, reduvidae).fine scale patterns of genetic structure and dispersal in triatoma infestans populations from argentina was analysed. a total of 314 insects from 22 domestic and peridomestic sites from the locality of san martín (capayán department, catamarca province) were typed for 10 polymorphic microsatellite loci. the results confirm subdivision of t. infestans populations with restricted dispersal among sampling sites and suggest inbreeding and/or stratification within the different domestic and peridomes ...201323467902
variation in mitochondrial nadh dehydrogenase subunit 5 and nadh dehydrogenase subunit 4 genes in the chagas disease vector triatoma infestans (hemiptera: reduviidae).variation in mitochondrial nadh dehydrogenase subunit 5 (nd5) and nadh dehydrogenase subunit 4 (nd4) genes was surveyed in triatoma infestans from 24 localities of argentina. the dna sequence comparisons of 2,183 basepairs of the mitochondrial genome, which include the complete sequence of nd5 (1,712 basepairs) and 401 basepairs of nd4 genes, showed 19 haplotypes determined by 48 variable sites and a nucleotide diversity value of 0.292%. twenty-six (65%) substitutions were synonymous, and there ...201323400572
population structure of the chagas disease vector, triatoma infestans, at the urban-rural interface.the increasing rate of biological invasions resulting from human transport or human-mediated changes to the environment has had devastating ecological and public health consequences. the kissing bug, triatoma infestans, has dispersed through the peruvian city of arequipa. the biological invasion of this insect has resulted in a public health crisis, putting thousands of residents of this city at risk of infection by trypanosoma cruzi and subsequent development of chagas disease. here, we show th ...201324103030
risk of transmission of trypanosoma cruzi by wild triatoma infestans (hemiptera: reduviidae) in bolivia supported by the detection of human blood meals.we analyzed the food sources of bolivian wild triatoma infestans (the main vector of chagas disease in this country), to assess the role of these populations in the epidemiological context of chagas disease. ninety-eight blood meals were identified by heteroduplex assay and sequencing. most of them were from wild mammals but surprisingly 27 were from humans. this brings to light the occurrence of human-vector contacts at risk of trypanosoma cruzi transmission in the wild environment by highly in ...201323856437
evaluation of nifurtimox treatment of chronic chagas disease by means of several parasitological methods.currently, evaluation of drug efficacy for chagas disease remains a controversial issue with no consensus. in this work, we evaluated the parasitological efficacy of nifurtimox treatment in 21 women with chronic chagas disease from an area of endemicity in chile who were treated according to current protocols. under pre- and posttherapy conditions, blood (b) samples and xenodiagnosis (xd) samples from these patients were subjected to analysis by real-time pcr targeting the nuclear satellite dna ...201323836179
phenotypic plasticity in response to food source in triatoma infestans (klug, 1834) (hemiptera, reduviidae: triatominae).in the gran chaco region of argentina, bolivia, and paraguay, vector transmission of trypanosoma cruzi, the etiological agent of chagas disease, is still a severe problem because, among other causes, houses are reinfested with triatoma infestans, the main vector of t. cruzi in southern south america. a better understanding of adaptation and evolution of t. infestans populations may contribute to the selection of appropriate vector control strategies in this region. phenotypic plasticity is essen ...201323831637
american trypanosomiasis.american trypanosomiasis is a parasitic disease caused by the flagellate protozoan trypanosoma cruzi. chagas disease is endemic in latin america, where an estimated 10-14 million people are infected, and an emerging disease in europe and the usa. trypanosoma cruzi is transmitted by blood-sucking bugs of the family reduviidae. rhodnius prolixus, panstrongylus megistus, triatoma infestans, and t. dimidiata are the main vectors in the sylvatic cycle. non vector-borne transmission includes blood tra ...201323829903
microsatellite loci-based distribution of trypanosoma cruzi genotypes from chilean chronic chagas disease patients and triatoma infestans is concordant with a specific host-parasite association hypothesis.the objective of this study was to investigate if there is specific host-parasite association in chilean populations of trypanosoma cruzi. for this purpose, two groups of parasites were analyzed, one from chronic chagasic patients, and the other from triatoma infestans triatomines in three regions of the country. the first group consisted of four types of samples: parasites from peripheral blood of non-cardiopathic t. cruzi infected patients (nb); parasites from their corresponding xenodiagnosis ...201323666648
differential expression profiles in the midgut of triatoma infestans infected with trypanosoma cruzi.chagas disease, or american trypanosomiasis, is a parasitic disease caused by the protozoan trypanosoma cruzi and is transmitted by insects from the triatominae subfamily. to identify components involved in the protozoan-vector relationship, we constructed and analyzed cdna libraries from rna isolated from the midguts of uninfected and t. cruzi-infected triatoma infestans, which are major vectors of chagas disease. we generated approximately 440 high-quality expressed sequence tags (ests) from e ...201323658688
trypanosoma cruzi genotypes in mepraia gajardoi from wild ecotopes in northern chile.we evaluated trypanosoma cruzi infection in 397 wild mepraia gajardoi specimens from five coastal localities in northern chile by detection of minicircle dna by polymerase chain reaction. the wild capture sites were classified into two ecotopes: a fully wild ecotope (ecotope 1) and a wild ecotope near human dwellings (ecotope 2). infection rates varied between 11% and 27%. minicircle hybridization assays showed that t. cruzi lineages tc ii and tc vi were commonly detected in ecotope 1 and ecotop ...201323249691
novel adipokinetic hormones in the kissing bugs rhodnius prolixus, triatoma infestans, dipetalogaster maxima and panstrongylus megistus.peptides of the adipokinetic hormone (akh)/red pigment-concentrating hormone (rpch) family were isolated and sequenced from the retrocerebral corpora cardiaca of four kissing bugs which are all vectors of the protozoan trypanosoma cruzi responsible for chagas' disease. the sequence of three novel akhs were deduced from the multiple ms(n) electrospray mass data: the octapeptide pglu-leu-thr-phe-ser-thr-asp-trp amide (denoted rhopr-akh) in rhodnius prolixus and panstrongylus megistus, the nonapept ...201323137850
predominance of hybrid discrete typing units of trypanosoma cruzi in domestic triatoma infestans from the bolivian gran chaco region.in the gran chaco region the reinfestation by triatoma infestans remains a major problem for control of chagas disease. trypanosoma cruzi the agent of the illness presents a broad genetic intraspecific variability which is poorly documented in the bolivian gran chaco. this work presents the identification of the discrete typing units (dtus) currently recognized for t. cruzi in t. infestans populations collected before and after residual insecticide spraying in four villages in this region. befor ...201323047136
new structures for goat corrals to control peridomestic populations of triatoma infestans (hemiptera: reduviidae) in the gran chaco of argentina.goat production is an important economic activity for rural communities in the gran chaco of argentina. goat corrals are important for the survival of peridomestic populations of triatoma infestans. this study evaluated the impact of modifying the traditional structure of goat corrals on t. infestans populations and goat productivity in the region of los llanos (la rioja). thirty-nine experimental corrals were constructed and 57 traditional corrals were used as controls. we evaluated the infesta ...201323778656
improved chemical control of chagas disease vectors in the dry chaco region.the effectiveness of two doses of suspension concentrate (sc) pyrethroid insecticides in suppressing peridomestic populations of triatoma infestans (klug) was evaluated in 28 rural communities located in santiago del estero province, northwestern argentina, including 388 houses and 1,516 identified sites. four treatments were randomly assigned to peridomiciles within each community: 5% sc beta-cypermethrin at standard (s, 50 mg active ingredient [ai]/m2) and double dose (2s), and 2.5% sc deltame ...201323540129
potential sources of triatoma infestans reinfesting peridomiciles identified by morphological characterization in los llanos, la rioja, argentina.the presence of triatoma infestans in habitats treated with insecticides constitutes a frequent problem in endemic areas. basing our study on the hypothesis that descendants of a residual population should be more similar to the pre-treatment population than to any other, we compared the indications of two quantitative morphological approaches. this study seeks to find the origin of 247 t. infestans from three populations found in two chicken coops and a goat corral after treatment with insectic ...201323440121
putative panmixia in restricted populations of trypanosoma cruzi isolated from wild triatoma infestans in bolivia.trypanosoma cruzi, the causative agent of chagas disease, is subdivided into six discrete typing units (dtus; tci-tcvi) of which tci is ubiquitous and genetically highly variable. while clonality is the dominant mode of propagation, recombinant events play a significant evolutive role. recently, foci of wild triatoma infestans have been described in bolivia, mainly infected by tci. hence, for the first time, we evaluated the level of genetic exchange within tci natural potentially panmictic popu ...201324312410
metabolic signatures of triatomine vectors of trypanosoma cruzi unveiled by metabolomics.chagas disease is a trypanosomiasis whose causative agent is the protozoan parasite trypanosoma cruzi, which is transmitted to humans by hematophagous insects known as triatomines and affects a large proportion of south america. the digestive tract of the insect vectors in which t. cruzi develops constitutes a dynamic environment that affects the development of the parasite. thus, we set out to investigate the chemical composition of the triatomine intestinal tract through a metabolomics approac ...201324204787
a country bug in the city: urban infestation by the chagas disease vector triatoma infestans in arequipa, peru.interruption of vector-borne transmission of trypanosoma cruzi remains an unrealized objective in many latin american countries. the task of vector control is complicated by the emergence of vector insects in urban areas.201324171704
dislodgement effect of natural semiochemicals released by disturbed triatomines: a possible alternative monitoring tool.the quick detection of domestic and peridomestic triatomines in their environments becomes difficult without the use of dislodgement substances that flush them out from their shelters. at present, tetramethrin 0.2% is being widely used in control programs. although it is an efficient dislodging agent, its toxicity might affect the health of captured triatomines, of other insects and, to a lesser extent, of other animals, including humans. here, we tested if semiochemicals released by disturbed a ...201324581366
the main component of an alarm pheromone of kissing bugs plays multiple roles in the cognitive modulation of the escape response.innate responses in animals can be modulated by experience. disturbed adults of the triatomine bug triatoma infestans release an alarm pheromone (ap) that elicits an escape response in conspecific larvae. the main component of this ap, the isobutyric acid (isoac), alone has already shown to generate an escape response in this species. however, not much is known about the modulation of this behavior by non-associative and associative cognitive processes. we present here evidences of the cognitive ...201323847483
analysing deltamethrin susceptibility and pyrethroid esterase activity variations in sylvatic and domestic triatoma infestans at the embryonic stage.the aim of the present work was to study the deltamethrin susceptibility of eggs from triatoma infestans populations and the contribution of pyrethroid esterases to deltamethrin degradation. insects were collected from sylvatic areas, including veinte de octubre and kirus-mayu (bolivia) and from domiciliary areas, including el palmar (bolivia) and la pista (argentina). deltamethrin susceptibility was determined by dose-response bioassays. serial dilutions of deltamethrin (0.0005-1 mg/ml) were to ...201324402155
toxicological and biochemical analysis of the susceptibility of sylvatic triatoma infestans from the andean valley of bolivia to organophosphate insecticide.to increase our knowledge of the natural susceptibility of triatoma infestans to an organophosphate insecticide, we performed toxicological and biochemical studies on three sylvatic populations from bolivia and two populations from domestic dwellings from bolivia and argentina. fifty-per-cent lethal doses (ld50) were determined based on the topical application of fenitrothion on first instar nymphs and mortality was assessed at 24 h. both type of populations exhibited ld50ratios significantly hi ...201324037203
niche invasion, competition and coexistence amongst wild and domestic bolivian populations of chagas vector triatoma infestans (hemiptera, reduviidae, triatominae).the model developed for human parasites by bottomley et al. (2007) has been adapted to the dynamics of triatomines to better understand the processes of niche invasion, competition among species and coexistence. in bolivia, both wild and domestic populations of triatoma infestans exist. their ecological niches are normally separated and the two populations do not interbreed, behaving as two distinct species. however, it has been suggested that the two populations may compete, highlighting theref ...201323849721
the central projection of cephalic mechanosensory axons in the haematophagous bug triatoma infestans.the projections of mechanosensory hairs located on the dorsal and lateral head of the adult haematophagous bug triatoma infestans were analyzed by means of cobalt filling. axons run into the anterior and posterior tegumentary nerve and project through the brain to the ventral nerve cord. the fibres are small in diameter and run as a fascicle. some branches run into suboesophageal and prothoracic centres; others run as far as to the mesothoracic ganglion. these sensory projections resemble that o ...201310800197
heme crystallization in the midgut of triatomine insects.hemozoin (hz) is a heme crystal produced by several blood-feeding organisms in order to detoxify free heme released upon hemoglobin (hb) digestion. here we show that heme crystallization also occurs in three species of triatomine insects. ultraviolet-visible and infrared light absorption spectra of insoluble pigments isolated from the midgut of three triatomine species triatoma infestans, dipetalogaster maximus and panstrongylus megistus indicated that all produce hz. morphological analysis of t ...201317254848
cytogenetic study in a mutant of triatoma infestans (hemiptera: reduviidae) carrying a spontaneous autosomal fusion and an extra chromosome.triatomainfestans (2n = 20 a + xy, male) is a blood-sucking bug and the most important vector of chagas disease in the southern cone countries. a cytogenetic analysis of 14 individuals from the argentine gran chaco has revealed the presence of a naturally heterozygous for an autosomal fusion. the fusion heterozygote (2n = 19 a + 1 extra chromosome + xy, male) presented an autosomal trivalent, 8 bivalents, the x and y sex univalents, and a minute extra chromosome at meiosis i. the autosomal triva ...201323037941
triatomicidal effect of new spot-on formulations applied to poultry in semi-field conditions.chagas disease is an endemic disease affecting ten million people in the american continent. produced by a parasite transmitted by triatomine insects, the main actions for reducing the incidence of this disease are focused on the control of insect vectors. this type of control has produced highly effective results within rural homes, but not in peridomestic areas (kitchens, warehouses, hen houses and other buildings not attached to the houses). the object of the present study was to assess the t ...201323001549
salivary antigen-5/cap family members are cu2+-dependent antioxidant enzymes that scavenge o₂₋. and inhibit collagen-induced platelet aggregation and neutrophil oxidative burst.the function of the antigen-5/cap family of proteins found in the salivary gland of bloodsucking animals has remained elusive for decades. antigen-5 members from the hematophagous insects dipetalogaster maxima (dmav) and triatoma infestans (tiav) were expressed and discovered to attenuate platelet aggregation, atp secretion, and thromboxane a2 generation by low doses of collagen (<1 μg/ml) but no other agonists. dmav did not interact with collagen, glycoprotein vi, or integrin α2β1. this inhibit ...201323564450
hemi-nested pcr and rflp methodologies for identifying blood meals of the chagas disease vector, triatoma infestans.trypanosoma cruzi, the etiologic agent of chagas disease, is transmitted by hematophagous reduviid bugs within the subfamily triatominae. these vectors take blood meals from a wide range of hosts, and their feeding behaviors have been used to investigate the ecology and epidemiology of t. cruzi. in this study we describe two pcr-based methodologies that amplify a fragment of the 16s mitochondrial rdna, aimed to improve the identification of blood meal sources for triatoma infestans: a.--sequence ...201324040328
molecular techniques for dicistrovirus detection without rna extraction or purification.dicistroviridae is a new family of small, nonenveloped, and +ssrna viruses pathogenic to both beneficial arthropods and insect pests as well. triatoma virus (trv), a dicistrovirus, is a pathogen of triatoma infestans (hemiptera: reduviidae), one of the main vectors of chagas disease. in this work, we report a single-step method to identify trv, a dicistrovirus, isolated from fecal samples of triatomines. the identification method proved to be quite sensitive, even without the extraction and puri ...201323710438
inoculation of triatoma virus (dicistroviridae: cripavirus) elicits a non-infective immune response in mice.dicistroviridae is a new family of small, non-enveloped, +ssrna viruses pathogenic to both beneficial arthropods and insect pests. little is known about the dicistrovirus replication mechanism or gene function, and any knowledge on these subjects comes mainly from comparisons with mammalian viruses from the picornaviridae family. due to its peculiar genome organization and characteristics of the per os viral transmission route, dicistroviruses make good candidates for use as biopesticides. triat ...201323497610
the effects of city streets on an urban disease vector.with increasing urbanization vector-borne diseases are quickly developing in cities, and urban control strategies are needed. if streets are shown to be barriers to disease vectors, city blocks could be used as a convenient and relevant spatial unit of study and control. unfortunately, existing spatial analysis tools do not allow for assessment of the impact of an urban grid on the presence of disease agents. here, we first propose a method to test for the significance of the impact of streets o ...201323341756
daily variations in the glycerol-3-phosphate dehydrogenase isoforms expression in triatoma infestans flight muscles.triatoma infestans, the main vector of chagas disease, is a blood-sucking insect. flight dispersal of adults is the most important mechanism for reinfestation of houses after insecticide spraying. flight muscles have two glycerol-3-phosphate dehydrogenase (gpdh) isoforms: gpdh-1 is involved in flight metabolism and gpdh-2 provides lipid precursors. in this study, we explored the profile of gpdh expression in females and males adult flight muscles under light/dark cycle, constant light, and const ...201424914000
toxicological and biochemical response of the entomopathogenic fungus beauveria bassiana after exposure to deltamethrin.the chemical control of the chagas disease vector triatoma infestans is endangered by the emergence of pyrethroid resistance. an effective alternative control tool is the use of the entomopathogenic fungus beauveria bassiana. the effect of deltamethrin on fungal growth, gene expression and enzyme activity in relation to detoxification, antioxidant response and oxidative stress levels was studied to evaluate fungal tolerance to deltamethrin.201423716386
triatominae in furnariid nests of the argentine gran chaco.triatomines (hemiptera, reduviidae) are bloodsucking insects involved in the transmission of trypanosoma cruzi, the causative agent of chagas disease, an important public health problem in latin america. the triatomine species found in sylvatic habitats generally play a limited epidemiological role compared to domestic species, but they may act as a reinfestation source of dwellings after insecticide spraying and have to be carefully considered in control strategies of chagas disease transmissio ...201424820557
an updated insight into the sialotranscriptome of triatoma infestans: developmental stage and geographic variations.triatoma infestans is the main vector of chagas disease in south america. as in all hematophagous arthropods, its saliva contains a complex cocktail that assists blood feeding by preventing platelet aggregation and blood clotting and promoting vasodilation. these salivary components can be immunologically recognized by their vector's hosts and targeted with antibodies that might disrupt blood feeding. these antibodies can be used to detect vector exposure using immunoassays. antibodies may also ...201425474469
characterization of guinea pig antibody responses to salivary proteins of triatoma infestans for the development of a triatomine exposure marker.salivary proteins of triatoma infestans elicit humoral immune responses in their vertebrate hosts. these immune responses indicate exposure to triatomines and thus can be a useful epidemiological tool to estimate triatomine infestation. in the present study, we analyzed antibody responses of guinea pigs to salivary antigens of different developmental stages of four t. infestans strains originating from domestic and/or peridomestic habitats in argentina, bolivia, chile and peru. we aimed to ident ...201424699441
domestic animal hosts strongly influence human-feeding rates of the chagas disease vector triatoma infestans in argentina.the host species composition in a household and their relative availability affect the host-feeding choices of blood-sucking insects and parasite transmission risks. we investigated four hypotheses regarding factors that affect blood-feeding rates, proportion of human-fed bugs (human blood index), and daily human-feeding rates of triatoma infestans, the main vector of chagas disease.201424852606
variations in time and space of an andean wild population of t. infestans at a microgeographic scale.wild populations of triatoma infestans are now believed to be the source of reinfestation of dwellings in some andean areas and could impede the full achievement of vector control campaigns in this region. given the poor knowledge of these populations in natural conditions, their basic biology traits, such as monthly demographic variations and movements of individuals, were explored.201424708673
fenitrothion: an alternative insecticide for the control of deltamethrin-resistant populations of triatoma infestans in northern argentina.deltamethrin-based campaigns to control triatoma infestans (klug) (hemiptera: reduviidae) have decreased in success as a result of the development of insecticide resistance. we compared the in vitro effects of the pyrethroid deltamethrin and two doses of the organophosphate fenitrothion, presented on different materials, on t. infestans from la esperanza, argentina. laboratory tests demonstrated a decrease in susceptibility to deltamethrin in the field population [ld50 : 30.32 nanograms per inse ...201423668748
circadian entrainment by light and host in the chagas disease vector, triatoma infestans.triatoma infestans (reduviidae: triatominae, "kissing bug") is the main insect vector of trypanosoma cruzi, the causative agent of chagas disease, a chronic trypanosomiasis infecting 10 million people world-wide. this hematophagous bug feeds on diurnal and nocturnal species during each host's quiescent time. as the hosts are also its major predators, kissing bugs are subjected to dual selective pressures from a single source. therefore, synchronization of feeding with the host's behavior is crit ...201424156522
the peri-urban interface and house infestation with triatoma infestans in the argentine chaco: an underreported process?peri-urban infestations with triatomine bugs, their sources and their dynamics have rarely been investigated. here, we corroborated the reported occurrence of triatoma infestans in a peri-urban area and in neighbouring rural houses in pampa del indio, in the argentine chaco, and identified its putative sources using spatial analysis and demographic questionnaires. peri-urban householders reported that 10% of their premises had triatomines, whereas t. infestans was collected by timed manual searc ...201425410997
susceptibility to deltamethrin of wild and domestic populations of triatoma infestans of the gran chaco and the inter-andean valleys of bolivia.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 b ...201425394392
the peri-urban interface and house infestation with triatoma infestans in the argentine chaco: an underreported process?peri-urban infestations with triatomine bugs, their sources and their dynamics have rarely been investigated. here, we corroborated the reported occurrence of triatoma infestans in a peri-urban area and in neighbouring rural houses in pampa del indio, in the argentine chaco, and identified its putative sources using spatial analysis and demographic questionnaires. peri-urban householders reported that 10% of their premises had triatomines, whereas t. infestans was collected by timed manual searc ...201425338153
effect of feeding frequency on the reproductive efficiency of two species of triatoma with different epidemiological importance.in triatominae, reproductive efficiency is an important factor influencing population dynamics, and a useful parameter in measuring a species' epidemiological significance as a vector of trypanosoma cruzi (chagas, 1909). the reproductive efficiency of triatomines is affected by food availability; hence, we measured and compared the effects of feeding frequency on the reproductive parameters of triatoma patagonica (del ponte, 1929) and triatoma infestans (klug, 1934), and the effects of starvatio ...201425229282
geographic variation of trypanosoma cruzi discrete typing units from triatoma infestans at different spatial scales.we assessed the diversity and distribution of trypanosoma cruzi discrete typing units (dtu) in triatoma infestans populations and its association with local vector-borne transmission levels at various geographic scales. at a local scale, we found high predominance (92.4%) of tcvi over tcv in 68 microscope-positive t. infestans collected in rural communities in santiago del estero province in northern argentina. tcv was more often found in communities with higher house infestation prevalence comp ...201425090650
evolutionary and dispersal history of triatoma infestans, main vector of chagas disease, by chromosomal markers.chagas disease, one of the most important vector-borne diseases in the americas, is caused by trypanosoma cruzi and transmitted to humans by insects of the subfamily triatominae. an effective control of this disease depends on elimination of vectors through spraying with insecticides. genetic research can help insect control programs by identifying and characterizing vector populations. in southern latin america, triatoma infestans is the main vector and presents two distinct lineages, known as ...201425017654
urbanization, land tenure security and vector-borne chagas disease.modern cities represent one of the fastest growing ecosystems on the planet. urbanization occurs in stages; each stage characterized by a distinct habitat that may be more or less susceptible to the establishment of disease vector populations and the transmission of vector-borne pathogens. we performed longitudinal entomological and epidemiological surveys in households along a 1900 × 125 m transect of arequipa, peru, a major city of nearly one million inhabitants, in which the transmission of t ...201424990681
assessing the vulnerability of brazilian municipalities to the vectorial transmission of trypanosoma cruzi using multi-criteria decision analysis.despite the dramatic reduction in trypanosoma cruzi vectorial transmission in brazil, acute cases of chagas disease (cd) continue to be recorded. the identification of areas with greater vulnerability to the occurrence of vector-borne cd is essential to prevention, control, and surveillance activities. in the current study, data on the occurrence of domiciliated triatomines in brazil (non-amazonian regions) between 2007 and 2011 were analyzed. municipalities' vulnerability was assessed based on ...201424857942
heterogeneities in the ecoepidemiology of trypanosoma cruzi infection in rural communities of the argentinean chaco.we conducted a cross-sectional survey of trypanosoma cruzi infection of triatoma infestans as well as dogs and cats in 327 households from a well-defined rural area in northeastern argentina to test whether the household distribution of infection differed between local ethnic groups (tobas and creoles) and identify risk factors for host infection. overall prevalence of infection of bugs (27.2%; 95% confidence interval = 25.3-29.3%), dogs (26.0%; 95% confidence interval = 23.3-30.1%), and cats ex ...201424732461
high levels of trypanosoma cruzi dna determined by qpcr and infectiousness to triatoma infestans support dogs and cats are major sources of parasites for domestic transmission.the competence of reservoir hosts of vector-borne pathogens is directly linked to its capacity to infect the vector. domestic dogs and cats are major domestic reservoir hosts of trypanosoma cruzi, and exhibit a much higher infectiousness to triatomines than seropositive humans. we quantified the concentration of t. cruzi dna in the peripheral blood of naturally-infected dogs and cats (a surrogate of intensity of parasitemia), and evaluated its association with infectiousness to the vector in a h ...201424732410
a multi-species bait for chagas disease vectors.triatomine bugs are the insect vectors of trypanosoma cruzi, the etiological agent of chagas disease. these insects are known to aggregate inside shelters during daylight hours and it has been demonstrated that within shelters, the aggregation is induced by volatiles emitted from bug feces. these signals promote inter-species aggregation among most species studied, but the chemical composition is unknown.201424587457
origin and distribution of at-rich repetitive dna families in triatoma infestans (heteroptera).triatoma infestans, one of the most important vectors of trypanosoma cruzi, is very interesting model, because it shows large interpopulation variation in the amount and distribution of heterochromatin. this polymorphism involved the three large pairs up to almost all autosomal pairs, including the sex chromosomes. to understand the dynamics of heterochromatin variation in t. infestans, we isolated the at-rich satdna portion of this insect using reassociation kinetics (c0t), followed by cloning, ...201424524986
first report of aprostocetus asthenogmus (hymenoptera: eulophidae) in south america and parasitizing eggs of triatominae vectors of chagas disease.we report for the first time the parasitism of eggs of two triatomine chagas disease vectors, triatoma infestans and t. vitticeps, by the microhymenopterous parasitoid aprostocetus asthenogmus. we also describe the first identification of this parasitoid in south america. a. asthenogmus were captured near unparasitized triatomine colonies in the municipality of vitória, state of espírito santo, brazil, and placed into pots with recently laid triatomine eggs. after 24 days, we observed wasps emer ...201424575298
l925i mutation in the para-type sodium channel is associated with pyrethroid resistance in triatoma infestans from the gran chaco region.chagas' disease is an important public health concern in latin america. despite intensive vector control efforts using pyrethroid insecticides, the elimination of triatoma infestans has failed in the gran chaco, an ecoregion that extends over argentina, paraguay, bolivia and brazil. the voltage-gated sodium channel is the target site of pyrethroid insecticides. point mutations in domain ii region of the channel have been implicated in pyrethroid resistance of several insect species.201424466362
distribution and evolution of repeated sequences in genomes of triatominae (hemiptera-reduviidae) inferred from genomic in situ hybridization.the subfamily triatominae, vectors of chagas disease, comprises 140 species characterized by a highly homogeneous chromosome number. we analyzed the chromosomal distribution and evolution of repeated sequences in triatominae genomes by genomic in situ hybridization using triatoma delpontei and triatoma infestans genomic dnas as probes. hybridizations were performed on their own chromosomes and on nine species included in six genera from the two main tribes: triatomini and rhodniini. genomic prob ...201425478792
filling dynamics of the brindley's glands in the blood-sucking bug triatoma infestans (hemiptera: reduviidae).the filling dynamics of exocrine defensive glands is an important component of the defensive capacity of an insect in its natural environment. we studied the filling state and reloading rate of the brindley's glands in the haematophagous chagas disease vector triatoma infestans (hemiptera: reduviidae). quantitative analyses of isobutyric acid, the main secretion component, were carried out with glands dissected from adults under different scenarios of development, number of discharging events an ...201425450424
residual infestation and recolonization during urban triatoma infestans bug control campaign, peru.chagas disease vector control campaigns are being conducted in latin america, but little is known about medium-term or long-term effectiveness of these efforts, especially in urban areas. after analyzing entomologic data for 56,491 households during the treatment phase of a triatoma infestans bug control campaign in arequipa, peru, during 2003-2011, we estimated that 97.1% of residual infestations are attributable to untreated households. multivariate models for the surveillance phase of the cam ...201425423045
biological cycle and preliminary data on vectorial competence of triatoma boliviana in laboratory conditions.with more than 140 potential vectors of chagas disease, it is important to better know the biology and especially the vectorial capacity of the triatomine species which live in the surroundings of human dwellings. in bolivia where 17 triatomine species are reported, the principal vector is triatoma infestans. in some valleys of the department of la paz where t. infestans is not present, a new species (triatoma boliviana) was described in 2007. this species lives in a sylvatic environment not far ...201425151046
is imidacloprid an effective alternative for controlling pyrethroid-resistant populations of triatoma infestans (hemiptera: reduviidae) in the gran chaco ecoregion?the prevention of chagas disease is based primarily on the chemical control of triatoma infestans (klug) using pyrethroid insecticides. however, high resistance levels, correlated with control failures, have been detected in argentina and bolivia. a previous study at our laboratory found that imidacloprid could serve as an alternative to pyrethroid insecticides. we studied the delayed toxicity of imidacloprid and the influence of the blood feeding condition of the insect on the toxicity of this ...201425141281
[urbanization of chagas disease in peru: experiences in prevention and control].in peru, chagas disease has an epidemiological significance in three macro-regions, one of them is the southern macro-region formed by the departments of arequipa, moquegua and tacna. in 1965 a successful control was performed by house spraying insecticides, however, the persistence of the vector made it necessary for a second control plan that was implemented in 2000 and followed the guidelines of conal plan, based on the elimination of triatoma infestans and screening in blood banks.this plan ...201425123876
genetic variability and geographical diversity of the main chagas' disease vector panstrongylus megistus (hemiptera: triatominae) in brazil based on ribosomal dna intergenic sequences.studies were made on the ribosomal dna intergenic region, comprising complete internal transcribed spacer (its)-1, 5.8s, and its-2 sequences, of populations of the triatomine panstrongylus megistus, the most important vector of chagas' disease in brazil since triatoma infestans eradication. specimens were from 26 localities of rio grande do sul, santa catarina, paraná, são paulo, minas gerais, bahia, and sergipe states. in total, 21 its-1 and 12 its-2 haplotypes were found. nucleotide difference ...201424897854
chagas disease vector control in a hyperendemic setting: the first 11 years of intervention in cochabamba, bolivia.chagas disease has historically been hyperendemic in the bolivian department of cochabamba. in the early 2000s, an extensive vector control program was implemented; 1.34 million dwelling inspections were conducted to ascertain infestation (2000-2001/2003-2011), with blanket insecticide spraying in 2003-2005 and subsequent survey-spraying cycles targeting residual infestation foci. here, we assess the effects of this program on dwelling infestation rates (dirs).201424699407
cdna isolation and characterization of two vitellogenin genes in the chagas' disease vector triatoma infestans (hemiptera, reduviidae).two vitellogenin genes (vg1 and vg2) were identified in the chagas' disease vector triatoma infestans. the putative coding sequence corresponding to vg2 was found to be 5553bp long, encoding 1851 amino acids in a single open reading frame. the comparative analysis of the deduced amino acid sequences from vg1 and vg2 cdna fragments of t. infestans revealed 58.94% of identity with 76.43% of homology. the phylogenetic tree based on the complete vg amino acid sequences of hemimetabolous insects unam ...201424685521
amines from vertebrates guide triatomine bugs to resources.most triatomine bugs (heteroptera: reduviidae) are nest-living insects that require vertebrate blood or invertebrate haemolymph to complete their life cycle. vertebrates accumulate excretory products in or near their nesting sites and we hypothesize that triatomines use emanations from such host wastes when searching for resources. here we recount how triatomine bugs increase upwind locomotion on a servosphere in response to volatile amine constituents of vertebrate excretions. fresh chicken fae ...201425260571
control of experimental triatoma infestans populations: effect of pour-on cypermethrin applied to chickens under natural conditions in the argentinean chaco region.among peridomestic structures, chicken coops are sites of major importance for the domestic ecology of triatoma infestans (hemiptera: reduviidae). the aim of this study was to evaluate in an experimental context the effects of a cypermethrin pour-on formulation applied to chickens on blood intake, moulting and mortality in t. infestans, under the natural climatic conditions of a region endemic for chagas' disease. experimental chicken huts were made of bricks and covered with plastic mosquito ne ...201424191962
key source habitats and potential dispersal of triatoma infestans populations in northwestern argentina: implications for vector control.triatoma infestans -the principal vector of the infection that causes chagas disease- defies elimination efforts in the gran chaco region. this study identifies the types of human-made or -used structures that are key sources of these bugs in the initial stages of house reinfestation after an insecticide spraying campaign.201425299653
description of a newly discovered triatoma infestans (hemiptera: reduviidae) foci in ibipeba, state of bahia, brazil.chagas disease transmitted by the triatoma infestans was eradicated from brazil in 2006. however, reports of triatomine foci threaten the control of chagas disease. the goal of this study was to determine t. infestans foci in the city of ibipeba, state of bahia.201425229295
where do these bugs come from? phenotypic structure of triatoma infestans populations after control interventions in the argentine chaco.house re-invasion by native triatomines after insecticide-based control campaigns represents a major threat for chagas disease vector control. we conducted a longitudinal intervention study in a rural section (area iii, 407 houses) of pampa del indio, northeastern argentina, and used wing geometric morphometry to compare pre-spray and post-spray (re-infestant bugs) triatoma infestans populations. the community-wide spraying with pyrethroids reduced the prevalence of house infestation by t. infes ...201525946158
population structure of the chagas disease vector triatoma infestans in an urban environment.chagas disease is a vector-borne disease endemic in latin america. triatoma infestans, a common vector of this disease, has recently expanded its range into rapidly developing cities of latin america. we aim to identify the environmental features that affect the colonization and dispersal of t. infestans in an urban environment. we amplified 13 commonly used microsatellites from 180 t. infestans samples collected from a sampled transect in the city of arequipa, peru, in 2007 and 2011. we assesse ...201525646757
experimental control of triatoma infestans in poor rural villages of bolivia through community participation.triatoma infestans is the main vector of chagas disease in the southern cone countries. present control strategies based on indoor and outdoor residual insecticide spraying are not sufficient to control disease transmission, particularly in bolivia. techniques based on the management of the human environment may be good alternatives or supplements.201525604766
life history traits and demographic parameters of triatoma infestans (hemiptera: reduviidae) fed on human blood.triatoma infestans (klug, 1834) (hemiptera: reduviidae), the main vector of chagas disease in south america, feeds primarily on humans, but ethical reasons preclude carrying out demographical studies using people. thus, most laboratory studies of t. infestans are conducted using bird or mammal live hosts that may result in different demographic parameters from those obtained on human blood. therefore, it is of interest to determine whether the use of an artificial feeder with human blood would b ...201526373893
examining mechanisms of pyrethroid resistance in eggs of two populations of the chagas' disease vector triatoma infestans (hemiptera: reduviidae).chagas disease is a zoonosis transmitted to man by blood-sucking triatomine bugs found in the americas. triatoma infestans (klug, 1834) is the main vector of chagas' disease in argentina. the control of this illness relies heavily on vector control through the use of insecticide. however, resistance to pyrethroid insecticides associated with ineffective field treatments has been increasingly reported in t. infestans from argentina and bolivia. there are few reports on the expression and causes o ...201526336218
reproductive and developmental costs of deltamethrin resistance in the chagas disease vector triatoma infestans.effective chemical control relies on reducing vector population size. however, insecticide selection pressure is often associated with the development of resistant populations that reduce control success. in treated areas, these resistant individuals present an adaptive advantage due to enhanced survival. resistance can also lead to negative effects when the insecticide pressure ceases. in this study, the biological effects of deltamethrin resistance were assessed in the chagas disease vector tr ...201526047184
spatiotemporal analysis of reported cases of acute chagas disease in the state of pernambuco, brazil, from 2002 to 2013.control strategies to eliminate the transmission of chagas disease by insect vectors have significantly decreased the number of reported acute cases in brazil. however, data regarding the incidence and distribution of acute chagas disease cases in the state of pernambuco are unavailable in the literature.201525992933
transferability of trypanosoma cruzi from mixed human host infection to triatoma infestans and from insects to axenic culture.the etiologic agent of chagas disease is trypanosoma cruzi, a protozoan whose life cycle involves obligatory passage through vertebrate and invertebrate hosts in a series of stages. the aim of this study was to explore the transferability of mixed discrete typing units (dtus) of t. cruzi present in chronic chagasic patients when passed through an invertebrate host during xenodiagnosis (xd) and then when transferred to axenic cultures to obtain t. cruzi isolates. dtus of t. cruzi present in these ...201525240699
migration and gene flow among domestic populations of the chagas insect vector triatoma dimidiata (hemiptera: reduviidae) detected by microsatellite loci.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 collec ...201526334816
an entomological and seroepidemiological study of the vectorial-transmission risk of chagas disease in the coast of northern chile.four species of triatomines are known from chile: triatoma infestans klug, mepraia spinolai porter, m. gajardoi frías, henry & gonzález, and m. parapatrica frías (hemiptera: reduviidae), the last three are endemic. the geographical distribution of m. gajardoi includes the coastal areas in the north of chile between 18° and 21°s, an area with both a resident workforce and summer-season visitors. a study was developed to assess the risk of vectorial transmission of chagas disease by m. gajardoi in ...201526208149
the importance of the multidisciplinary approach to deal with the new epidemiological scenario of chagas disease (global health).there are currently two major factors that have modified the epidemiology of chagas disease in the last decades: climate change and migration flows. in this new scenario, there are new challenges to control and prevent trypanosoma cruzi infection in endemic countries, such as the control of a wider distribution of triatomine vectors or the reinforcement of vertical transmission programs. in non-endemic areas, few countries are aware of the emergence of this new disease and have established chang ...201526187358
bottlenecks in domestic animal populations can facilitate the emergence of trypanosoma cruzi, the aetiological agent of chagas disease.faeces-mediated transmission of trypanosoma cruzi (the aetiological agent of chagas disease) by triatomine insects is extremely inefficient. still, the parasite emerges frequently, and has infected millions of people and domestic animals. we synthesize here the results of field and laboratory studies of t. cruzi transmission conducted in and around arequipa, peru. we document the repeated occurrence of large colonies of triatomine bugs (more than 1000) with very high infection prevalence (more t ...201526085582
insecticide resistance in vector chagas disease: evolution, mechanisms and management.chagas disease is a chronic parasitic infection restricted to america. the disease is caused by the protozoa trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomi ...201526003952
the potential of canine sentinels for reemerging trypanosoma cruzi transmission.chagas disease, a vector-borne disease transmitted by triatomine bugs and caused by the parasite trypanosoma cruzi, affects millions of people in the americas. in arequipa, peru, indoor residual insecticide spraying campaigns are routinely conducted to eliminate triatoma infestans, the only vector in this area. following insecticide spraying, there is risk of vector return and reinitiation of parasite transmission. dogs are important reservoirs of t. cruzi and may play a role in reinitiating tra ...201525962956
control of rural house infestation by triatoma infestans in the bolivian chaco using a microencapsulated insecticide formulation.triatoma infestans, the main vector of trypanosoma cruzi (causative agent of chagas disease) has been successfully eliminated over much of its original geographic distribution over the southern cone countries of south america. however, populations of the species are still infesting houses of rural communities of the gran chaco region of argentina and bolivia. this study reports for the first time a large-scale effect of a vector control intervention using a microencapsulated formulation of organ ...201525928071
the impact of climate change on the geographical distribution of two vectors of chagas disease: implications for the force of infection.chagas disease, caused by the parasite trypanosoma cruzi, is the most important vector-borne disease in latin america. the vectors are insects belonging to the triatominae (hemiptera, reduviidae), and are widely distributed in the americas. here, we assess the implications of climatic projections for 2050 on the geographical footprint of two of the main chagas disease vectors: rhodnius prolixus (tropical species) and triatoma infestans (temperate species). we estimated the epidemiological implic ...201525688019
eco-bio-social research on community-based approaches for chagas disease vector control in latin america.this article provides an overview of three research projects which designed and implemented innovative interventions for chagas disease vector control in bolivia, guatemala and mexico. the research initiative was based on sound principles of community-based ecosystem management (ecohealth), integrated vector management, and interdisciplinary analysis. the initial situational analysis achieved a better understanding of ecological, biological and social determinants of domestic infestation. the ke ...201525604759
host-seeking behavior and dispersal of triatoma infestans, a vector of chagas disease, under semi-field conditions.chagas disease affects millions of people in latin america. the control of this vector-borne disease focuses on halting transmission by reducing or eliminating insect vector populations. most transmission of trypanosoma cruzi, the causative agent of chagas disease, involves insects living within or very close to households and feeding mostly on domestic animals. as animal hosts can be intermittently present it is important to understand how host availability can modify transmission risk to human ...201525569228
the main sceneries of chagas disease transmission. the vectors, blood and oral transmissions--a comprehensive review.this review deals with transmission of trypanosoma cruzi by the most important domestic vectors, blood transfusion and oral intake. among the vectors, triatoma infestans, panstrongylus megistus, rhodnius prolixus, triatoma dimidiata, triatoma brasiliensis, triatoma pseudomaculata, triatoma sordida, triatoma maculata, panstrongylus geniculatus, rhodnius ecuadoriensis and rhodnius pallescens can be highlighted. transmission of chagas infection, which has been brought under control in some countrie ...201525466622
microcavia australis (caviidae, rodentia), a new highly competent host of trypanosoma cruzi i in rural communities of northwestern argentina.rodents are well-known hosts of trypanosoma cruzi but little is known on the role of some caviomorph rodents. we assessed the occurrence and prevalence of t. cruzi infection in microcavia australis ("southern mountain, desert or small cavy") and its infectiousness to the vector triatoma infestans in four rural communities of tafí del valle department, northwestern argentina. parasite detection was performed by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region ...201525447830
evidence of selection on phenotypic plasticity and cost of plasticity in response to host-feeding sources in the major chagas disease vector triatoma infestans.phenotypic plasticity is the ability of a genotype to display alternative phenotypes in different environments. understanding how plasticity evolves and the factors that favor and constrain its evolution have attracted great interest. we investigated whether selection on phenotypic plasticity and costs of plasticity affect head and wing morphology in response to host-feeding sources in the major chagas disease vector triatoma infestans. full-sib families were assigned to blood-feeding on either ...201526433077
effect of the urease-derived peptide jaburetox on the central nervous system of triatoma infestans (insecta: heteroptera).triatoma infestans is the main vector of chagas'disease in southern cone countries. in triatomines, symptoms suggesting neurotoxicity were observed after treatment with jaburetox (jbtx), the entomotoxic peptide obtained from jackbean urease. here, we study its effect in the central nervous system (cns) of this species.201525445710
host-feeding sources and habitats jointly affect wing developmental stability depending on sex in the major chagas disease vector triatoma infestans.fluctuating asymmetry (fa), a slight and random departure from bilateral symmetry that is normally distributed around a 0 mean, has been widely used to infer developmental instability. we investigated whether habitats (ecotopes) and host-feeding sources influenced wing fa of the hematophagous bug triatoma infestans. because bug populations occupying distinct habitats differed substantially and consistently in various aspects such as feeding rates, engorgement status and the proportion of gravid ...201526318543
can body traits, other than wings, reflect the flight ability of triatominae bugs?insects of the subfamily triatominae are vectors of trypanosoma cruzi , the chagas disease parasite, and their flying behavior has epidemiological importance. the flying capacity is strikingly different across and within triatominae species, as well as between sexes or individuals. many triatoma infestans individuals have wings but no flying muscles. in other triatominae species, no clear relationships were found between wing length and flying behavior. if wing presence or size is not reflective ...201526676492
inheritance and heritability of deltamethrin resistance under laboratory conditions of triatoma infestans from bolivia.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, t ...201526572249
deltamethrin binding to triatoma infestans (hemiptera: reduviidae) lipoproteins. analysis by solvent bar microextraction coupled to gas chromatography.the binding of deltamethrin (dlm) to the hemipteran triatoma infestans (klug) hemolymph lipoproteins was evaluated in vitro. after dlm incubation with the insect hemolymph, lipoproteins were fractioned by ultracentrifugation. dlm binding was analyzed by a microextractive technique-solvent bar microextraction-a solventless methodology to extract dlm from each lipoprotein fraction. this is a novel use of the technique applied to extract an insecticide from an insect fluid. capillary gas chromatogr ...201526378097
susceptibility characterization of residual brazilian populations of triatoma infestans klug, 1834 (hemiptera: reduviidae) to deltamethrin pyrethroid.despite years of efforts towards the elimination of triatoma infestans in brazil, residual foci still persist in some areas of the states of bahia and rio grande do sul. the persistence of these t. infestans populations in the country has two different origins of equal concern: operational failures or insecticide resistance. thus, the objective of this study was to characterize the susceptibility profile of the residual brazilian populations of t. infestans to deltamethrin.201525992929
vital statistics of triatominae (hemiptera: reduviidae) under laboratory conditions: iv. panstrongylus geniculatus.a cohort of 100 eggs of panstrongylus geniculatus (latreille) was reared in the laboratory under constant conditions (temperature 26 ± 1°c, 60 ± 10% rh), with mortality and fecundity data recorded weekly. we calculated stage-specific development times, age-specific mortality and fecundity (18.4 eggs/♀/wk), and stage-specific and total preadult mortality (31.6%), and the weekly intrinsic rate of natural increase (r(o) = 0.096), the finite population growth rate (λ = 1.109), the net reproductive r ...201526336251
fine-scale genetic structure of triatoma infestans in the argentine chaco.the patterns of genetic structure in natural populations provide essential information for the improvement of pest management strategies including those targeting arthropod vectors of human diseases. we analyzed the patterns of fine-scale genetic structure in triatoma infestans in a well-defined rural area close to pampa del indio, in the argentine arid-humid chaco transition, where a longitudinal study on house infestation and wing geometric morphometry is being conducted since 2007. a total of ...201526027923
ecological and sociodemographic determinants of house infestation by triatoma infestans in indigenous communities of the argentine chaco.the gran chaco ecoregion, a hotspot for chagas and other neglected tropical diseases, is home to >20 indigenous peoples. our objective was to identify the main ecological and sociodemographic determinants of house infestation and abundance of triatoma infestans in traditional qom populations including a creole minority in pampa del indio, northeastern argentina.201525785439
antigenic components in triatoma infestans haemolymph. 20154561728
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