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Insects Jul 2023The assassin bug genus Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian...
The assassin bug genus Stål, 1861 (Hemiptera: Reduviidae: Stenopodainae) has a disjunct distribution in Sub-Saharan Africa and Asia. In the present study, the Asian species of are revised. Two species are recognized, redescribed, and illustrated, with the following new subjective synonyms and new combination proposed: Stål, 1861 = Distant, 1909, = Distant, 1919, ; (Reuter, 1882) = Distant, 1919, = Livingstone & Ravichandran, 1989, ; (Distant, 1909), (transferred from ) = Hsiao, 1977, Lectotypes for , , and are designated. A key to separate the two Asian species of is provided. The sexual dimorphism, systematic relationships, and distribution of are discussed. is newly recorded from Laos, Pakistan, and Vietnam.
PubMed: 37623389
DOI: 10.3390/insects14080680 -
Molecular Biology and Evolution Aug 2023Though the phylogenetic signal of loci on sex chromosomes can differ from those on autosomes, chromosomal-level genome assemblies for nonvertebrates are still relatively...
Though the phylogenetic signal of loci on sex chromosomes can differ from those on autosomes, chromosomal-level genome assemblies for nonvertebrates are still relatively scarce and conservation of chromosomal gene content across deep phylogenetic scales has therefore remained largely unexplored. We here assemble a uniquely large and diverse set of samples (17 anchored hybrid enrichment, 24 RNA-seq, and 70 whole-genome sequencing samples of variable depth) for the medically important assassin bugs (Reduvioidea). We assess the performance of genes based on multiple features (e.g., nucleotide vs. amino acid, nuclear vs. mitochondrial, and autosomal vs. X chromosomal) and employ different methods (concatenation and coalescence analyses) to reconstruct the unresolved phylogeny of this diverse (∼7,000 spp.) and old (>180 Ma) group. Our results show that genes on the X chromosome are more likely to have discordant phylogenies than those on autosomes. We find that the X chromosome conflict is driven by high gene substitution rates that impact the accuracy of phylogenetic inference. However, gene tree clustering showed strong conflict even after discounting variable third codon positions. Alternative topologies were not particularly enriched for sex chromosome loci, but spread across the genome. We conclude that binning genes to autosomal or sex chromosomes may result in a more accurate picture of the complex evolutionary history of a clade.
Topics: Animals; Phylogeny; Reduviidae; Biological Evolution; Genome; X Chromosome
PubMed: 37494292
DOI: 10.1093/molbev/msad168 -
Insect Biochemistry and Molecular... Aug 2023Trypanosoma rangeli is a protozoan parasite that infects triatomines and mammals in the Americas, producing mixed infections with Trypanosoma cruzi, the etiological...
Trypanosoma rangeli is a protozoan parasite that infects triatomines and mammals in the Americas, producing mixed infections with Trypanosoma cruzi, the etiological agent of Chagas disease. The former parasite is not pathogenic to humans, but has different levels of pathogenicity, as well as causing physiological and behavioral alterations, to its invertebrate hosts. In this study, we measured locomotory activity, and the glyceride accumulation profile in the hemolymph and fat body, as well as the expression of key genes related to triglyceride metabolism, of Rhodnius prolixus nymphs infected with T. rangeli. We found that the locomotory activity of the insects was correlated with the amount of triglycerides in the fat body. Infected nymphs had increased activity when starved, and also had an accumulation of glycerides in the fat body and hemolymph. These alterations were also associated with a higher expression of the diacylglycerol acyltransferase, lipophorin and lipophorin receptor genes in the fat body. We infer that T. rangeli is able to alter the energetic processes of its invertebrate host, in order to increase the availability of lipids to the parasite, which, in turn modifies the activity levels of the insect. These alterations are discussed with regard to their potential to increase the transmission rate of the parasite.
Topics: Humans; Animals; Trypanosoma rangeli; Rhodnius; Host-Parasite Interactions; Insect Vectors; Nymph; Energy Metabolism; Mammals
PubMed: 37429385
DOI: 10.1016/j.ibmb.2023.103987 -
Lipid metabolism dynamic in Triatomine Rhodnius prolixus during acute Trypanosoma rangeli infection.Acta Tropica Dec 2023During its life cycle, Trypanosoma rangeli invades the hemolymph of its invertebrate host and colonizes hemocytes and salivary glands. The parasite cannot synthesize...
During its life cycle, Trypanosoma rangeli invades the hemolymph of its invertebrate host and colonizes hemocytes and salivary glands. The parasite cannot synthesize some lipid classes, and during its cycle, it depends on the uptake of these molecules from its vertebrate and invertebrate hosts to meet growth and differentiation requirements. However, until now, knowledge on how the parasite affects the lipid physiology of individual insect organs has been largely unknown. Herein, the biochemical and molecular dynamics of triatomine R. prolixus lipid metabolism in response to acute T. rangeli infection were investigated. Biochemical and microscopic assays revealed the lipid droplet profile and the levels of the different identified lipid classes. In addition, a qRT‒PCR approach was used to determine the expression profile of 6 protein-coding genes involved in the R. prolixus lipid physiology. We observed that triacylglycerol (TAG), monoacylglycerol (MAG), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) levels in the fat body decreased in infected insects. On the other hand, high levels of free fatty acids were observed in the hemolymph during infection. Analysis by confocal microscopy revealed a decrease in lipid droplets size from infected fat bodies, and investigations by scanning electron microscopy revealed a significant number of parasites adhered to the surface of the organ. T. rangeli infection upregulated the transcript levels of the protein-coding gene for the acetyl-CoA carboxylase, the first enzyme in the de novo fatty acid synthesis pathway, responsible for the production of malonyl-CoA. On the other hand, downregulation of lipophorin receptor was observed. In conclusion, this study reveals a new set of molecular events that occur within the vector in response to the challenge imposed by the parasite.
Topics: Animals; Trypanosoma rangeli; Rhodnius; Lipid Metabolism; Salivary Glands; Lipids; Trypanosoma
PubMed: 37838024
DOI: 10.1016/j.actatropica.2023.107032 -
Journal of Inorganic Biochemistry Sep 2023The nitrophorins (NPs) comprise an unusual group of heme proteins with stable ferric heme iron nitric oxide (Fe-NO) complexes. They are found in the salivary glands of...
The nitrophorins (NPs) comprise an unusual group of heme proteins with stable ferric heme iron nitric oxide (Fe-NO) complexes. They are found in the salivary glands of the blood-sucking kissing bug Rhodnius prolixus, which uses the NPs to transport the highly reactive signaling molecule NO. Nuclear resonance vibrational spectroscopy (NRVS) of both isoform NP2 and a mutant NP2(Leu132Val) show, after addition of NO, a strong structured vibrational band at around 600 cm, which is due to modes with significant Fe-NO bending and stretching contribution. Based on a hybrid calculation method, which uses density functional theory and molecular mechanics, it is demonstrated that protonation of the heme carboxyl groups does influence both the vibrational properties of the Fe-NO entity and its electronic ground state. Moreover, heme protonation causes a significant increase of the gap between the highest occupied and lowest unoccupied molecular orbital by almost one order of magnitude leading to a stabilization of the Fe-NO bond.
Topics: Animals; Heme; Carrier Proteins; Nitric Oxide; Salivary Proteins and Peptides; Hemeproteins; Iron; Rhodnius
PubMed: 37352657
DOI: 10.1016/j.jinorgbio.2023.112281 -
Journal of Vector Ecology : Journal of... Dec 2023Triatominae are associated with various Brazilian habitats, including bird nests, animal burrows, and peridomestic structures. Despite extensive studies on triatomines...
Triatominae are associated with various Brazilian habitats, including bird nests, animal burrows, and peridomestic structures. Despite extensive studies on triatomines in domiciliary environments in Ceará, Brazil, there has been limited research on their presence in the wild. This study focuses on the municipality of Morrinhos in Ceará, which is characterized by a Caatinga biome and riparian forests along the Acaraú River. During the study, a total of 185 nests of were analyzed in rural locations and triatomines were collected in 26 nests from 12 different locations. A total of 117 triatomines was collected, belonging to three species: , , and . was the only species found in a nest inhabited by . Nests of serve as shelters for various animals, providing an ideal environment for triatomines to establish colonies due to their proximity to food sources and their generalist feeding habits. The incorporation of anthropogenic materials by birds in nest construction can indirectly affect the presence of other animals that may serve as food sources for triatomines. Understanding the interactions between triatomines, birds, and their habitats is essential for assessing the risks associated with triatomine infestation in wild ecosystems.
Topics: Animals; Triatominae; Brazil; Ecosystem; Insect Vectors; Triatoma; Rhodnius; Birds; Chagas Disease; Trypanosoma cruzi
PubMed: 37843454
DOI: 10.52707/1081-1710-48.2.124 -
Acta Tropica Sep 2023In vector control terms, insecticide resistance is the development of the capacity, of an insect population, to tolerate doses of an insecticide that are lethal to most...
In vector control terms, insecticide resistance is the development of the capacity, of an insect population, to tolerate doses of an insecticide that are lethal to most individuals in a typical population of the same species. The genetic changes that determine resistance may have adaptive costs in the resistant phenotype or, conversely, may result in an adaptive advantage when compared to susceptible insects in the environment without insecticides. Triatoma infestans is one of the main vectors of Trypanosoma cruzi in the southern cone of South America. High insecticide resistance in T. infestans was detected in Argentina in Salta and Chaco provinces. The objective of this study was to determine the possible morphometric changes in wings, heads, and the antennal phenotype of deltamethrin-resistant T. infestans (RR) males and females compared to susceptible insects (SS), evaluating its implication in adaptive processes such as olfactory capacity, dispersion, and probability of colonizing new habitats, among others. Nine type I landmarks were marked on wings, 5 type II landmarks on heads, and 10 antennal sensilla were counted on 106 adults of both sexes (resistant and susceptible from first and second laboratory generations). Morphological divergence was observed between the two groups (RR and SS). The RR insects showed smaller sizes of wings and heads and shape compatible with lower dispersal potential and different active dispersal behaviors. Antennae also revealed sensory simplification in RR and divergence between RR and SS, although more marked in females. This study characterizes for the first time T. infestans RR and SS through wings, heads, and antennae. The results suggest a lower dispersive potential in resistant insects and the differences described lay the foundations for the identification of a resistance biomarker in triatomines.
Topics: Male; Animals; Female; Triatoma; Pyrethrins; Insecticides; Nitriles; Insecticide Resistance; Argentina; Phenotype; Chagas Disease
PubMed: 37352997
DOI: 10.1016/j.actatropica.2023.106976 -
PLoS Neglected Tropical Diseases Oct 2023Vector-borne diseases remain a significant public health threat in many regions of the world. Traditional vector surveillance and control methods have relied on active...
Vector-borne diseases remain a significant public health threat in many regions of the world. Traditional vector surveillance and control methods have relied on active and passive surveillance programs, which are often costly and time-consuming. New internet-based vector surveillance systems have shown promise in removing some of the cost and labor burden from health authorities. We developed and evaluated the effectiveness of a new internet-based surveillance system, "AlertaChirimacha", for detecting Triatoma infestans (known locally by its Quechua name, Chirimacha), the Chagas disease vector, in the city of Arequipa, Peru. In the first 26 months post-implementation, AlertaChirimacha received 206 reports of residents suspecting or fearing triatomines in their homes or neighborhoods, of which we confirmed, through pictures or inspections, 11 (5.3%) to be Triatoma infestans. After microscopic examination, none of the specimens collected were infected with Trypanosoma cruzi. AlertaChirimacha received 57% more confirmed reports than the traditional surveillance system and detected 10% more infested houses than active and passive surveillance approaches combined. Through in-depth interviews we evaluate the reach, bilateral engagement, and response promptness and efficiency of AlertaChirimacha. Our study highlights the potential of internet-based vector surveillance systems, such as AlertaChirimacha, to improve vector surveillance and control efforts in resource-limited settings. This approach could decrease the cost and time horizon for the elimination of vector-mediated Chagas disease in the region.
Topics: Animals; Humans; Chagas Disease; Triatoma; Trypanosoma cruzi; Insect Vectors; Peru
PubMed: 37844066
DOI: 10.1371/journal.pntd.0011694 -
Parasites & Vectors Aug 2023The Gran Chaco region is a major hotspot of Chagas disease. We implemented a 9-year program aimed at suppressing house infestation with Triatoma infestans and stopping...
The Pampa del Indio project: sustainable vector control and long-term declines in the prevalence and abundance of Triatoma infestans infected with Trypanosoma cruzi in the Argentine Chaco.
BACKGROUND
The Gran Chaco region is a major hotspot of Chagas disease. We implemented a 9-year program aimed at suppressing house infestation with Triatoma infestans and stopping vector-borne transmission to creole and indigenous (Qom) residents across Pampa del Indio municipality (Argentine Chaco). The aim of the present study was to assess the intervention effects on parasite-based transmission indices and the spatial distribution of the parasite, and test whether house-level variations in triatomine infection with Trypanosoma cruzi declined postintervention and were influenced by household ethnicity, persistent infestation linked to pyrethroid resistance and other determinants of bug infection.
METHODS
This longitudinal study assessed house infestation and bug infection with T. cruzi before and after spraying houses with pyrethroids and implemented systematic surveillance-and-response measures across four operational areas over the period 2007-2016. Live triatomines were individually examined for infection by optical microscopy or kinetoplast DNA (kDNA)-PCR and declared to be infected with T. cruzi when assessed positive by either method.
RESULTS
The prevalence of infection with T. cruzi was 19.4% among 6397 T. infestans examined. Infection ranged widely among the study areas (12.5-26.0%), household ethnicity (15.3-26.9%), bug ecotopes (1.8-27.2%) and developmental stages (5.9-27.6%), and decreased from 24.1% (baseline) to 0.9% (endpoint). Using random-intercept multiple logistic regression, the relative odds of bug infection strongly decreased as the intervention period progressed, and increased with baseline domestic infestation and bug stage and in Qom households. The abundance of infected bugs and the proportion of houses with ≥ 1 infected bug remained depressed postintervention and were more informative of area-wide risk status than the prevalence of bug infection. Global spatial analysis revealed sharp changes in the aggregation of bug infection after the attack phase. Baseline domestic infestation and baseline bug infection strongly predicted the future occurrence of bug infection, as did persistent domestic infestation in the area with multiple pyrethroid-resistant foci. Only 19% of houses had a baseline domestic infestation and 56% had ever had ≥ 1 infected bug.
CONCLUSIONS
Persistent bug infection postintervention was closely associated with persistent foci generated by pyrethroid resistance. Postintervention parasite-based indices closely agreed with human serosurveys at the study endpoint, suggesting transmission blockage. The program identified households and population subgroups for targeted interventions and opened new opportunities for risk prioritization and sustainable vector control and disease prevention.
Topics: Animals; Humans; Triatoma; Trypanosoma cruzi; Prevalence; Longitudinal Studies; Insect Vectors; Chagas Disease; Pyrethrins; DNA, Kinetoplast; Argentina
PubMed: 37528423
DOI: 10.1186/s13071-023-05861-7 -
Journal of Medical Entomology Jun 2024Predicting the potential distribution and coexistence of suitable geographic areas for Chagas disease vectors in the Americas is a crucial task for understanding the...
Predicting the potential distribution and coexistence of suitable geographic areas for Chagas disease vectors in the Americas is a crucial task for understanding the eco-epidemiological dynamics of this disease. The potential distribution and coexistence of 3 species-Rhodnius prolixus (Hemiptera: Reduviidae), Cavernicola pilosa (Hemiptera: Reduviidae), and Rhodnius pictipes (Hemiptera: Reduviidae) were modeled. Presence records were obtained and environmental variables were selected based on correlation analysis, Jackknife analysis and knowledge of the biology and natural history of the species. The MaxEnt algorithm included in the kuenm package of R software was used for modeling the potential distribution, and various scenarios of the BAM diagram (Biotic, Abiotic, and Movement variables) were evaluated. The variables contributing to the final models were different for each species. Rhodnius pictipes showed a potential distribution in South America, particularly in Brazil, Bolivia, Peru, Colombia, Venezuela, Guyana, and Suriname. Areas with environmentally suitable conditions for R. prolixus were located in southern Brazil, Peru, Colombia, southern Mexico, Guatemala, El Salvador, and Honduras, whereas for C. pilosa they were in southeastern Brazil, southeastern Central America, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, and French Guiana. Co-occurrence analysis revealed distinct patterns in the neotropical region, with some areas indicating the potential distribution of 1 or more species. In Brazil, occurrence and co-occurrence areas were concentrated in the northwest and southeast regions. Overall, this study provides valuable information on the potential distribution and coexistence of vectors, which can inform targeted vector control strategies and contribute to global efforts in combating Chagas disease.
PubMed: 38941237
DOI: 10.1093/jme/tjae077