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Scientific Reports Aug 2023The growing interest in microRNAs (miRNAs) over recent years has led to their characterization in numerous organisms. However, there is currently a lack of data...
The growing interest in microRNAs (miRNAs) over recent years has led to their characterization in numerous organisms. However, there is currently a lack of data available on miRNAs from triatomine bugs (Reduviidae: Triatominae), which are the vectors of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. A comprehensive understanding of the molecular biology of vectors provides new insights into insect-host interactions and insect control approaches, which are key methods to prevent disease incidence in endemic areas. In this work, we describe the miRNome profiles from gut, hemolymph, and salivary gland tissues of the Rhodnius prolixus triatomine. Small RNA sequencing data revealed abundant expression of miRNAs, along with tRNA- and rRNA-derived fragments. Fifty-two mature miRNAs, previously reported in Ecdysozoa, were identified, including 39 ubiquitously expressed in the three tissues. Additionally, 112, 73, and 78 novel miRNAs were predicted in the gut, hemolymph, and salivary glands, respectively. In silico prediction showed that the top eight most highly expressed miRNAs from salivary glands potentially target human blood-expressed genes, suggesting that R. prolixus may modulate the host's gene expression at the bite site. This study provides the first characterization of miRNAs in a Triatominae species, shedding light on the role of these crucial regulatory molecules.
Topics: Animals; Humans; Rhodnius; MicroRNAs; Insect Vectors; Chagas Disease; Trypanosoma cruzi; Triatominae
PubMed: 37573416
DOI: 10.1038/s41598-023-40353-9 -
Frontiers in Physiology 2023(Hemiptera: Reduviidae) is an important vector of , the causative agent of Chagas Disease. This insect is a model for the study of insect physiology, especially...
(Hemiptera: Reduviidae) is an important vector of , the causative agent of Chagas Disease. This insect is a model for the study of insect physiology, especially concerning the digestion of blood. Among the enzymes produced in the midgut of after blood feeding there is a α-L-fucosidase activity. There are very few studies on α-L-fucosidase of insects, and the role of α-L-fucosidase is still not clear. In this work, we tested if the mechanism for production of this enzyme is similar to the observed for proteases, a secretatogue mechanism that respond to the protein contents of the meal. We tested if specific proteins or sugars elicit this response, which may help to understand the nature of the physiological substrate for this enzyme. In general, our results showed that the Anterior Midgut was the only midgut fraction that responds to the blood meal in terms of α-L-fucosidase production. Besides that, this response was not triggered by midgut distension or by ingestion of the blood cell fraction. Conversely, the enzyme was produced after feeding with the plasma fraction. However, the production of α-L-fucosidase was also triggered by different biochemical stimuli, as protein or fucoidan ingestion. This suggested that the production of the enzyme in the anterior midgut was a general physiological response under control of different convergent signals. Besides that, the comparison between different treatments for artificial blood feeding showed that heparinated blood was the choice with minor side effects for the study of the midgut α-L-fucosidase, when compared to defibrinated or citrated blood.
PubMed: 37538373
DOI: 10.3389/fphys.2023.1123414 -
Memorias Do Instituto Oswaldo Cruz 2023Triatoma infestans (Kissing bug) is the main vector of the parasite causative of Chagas disease in Latin-America. This species shows clear activity rhythms easily...
BACKGROUND
Triatoma infestans (Kissing bug) is the main vector of the parasite causative of Chagas disease in Latin-America. This species shows clear activity rhythms easily synchronised to day-night cycles (photic cycle). The haematophagous nature of these insects lead us to think that they may temporally adapt to the particular activity rhythms of potential hosts (non-photic cycle). Our previous data showed that kissing bugs were weakly affected by the activity-inactivity rhythm of a single host.
OBJETIVE
To determine if by increasing the number of individuals of a potential host, T. infestans could increase the likelihood of synchronisation.
METHODS
Individual activity rhythms of experimental insects, maintained in constant darkness in light-tight cabinets, localised in a room with 24 rodents, were continuously monitored. Another insect group that served as control was maintained in the same conditions but in a room without rodents.
FINDINGS
Most of the experimental insects synchronised, expressing a 24 h period coincident with the activity-inactivity rhythms of the rodents, while the controls free ran with a period significantly longer than 24 h.
CONCLUSION
Analogous to what happens with high vs low light intensity in photic synchronisers, a high number of rodents, in contrast to the previous one-rodent experiment, increased the potency of this non-photic zeitgeber.
Topics: Animals; Triatoma; Chagas Disease; Feeding Behavior; Rodentia
PubMed: 37531507
DOI: 10.1590/0074-02760220289 -
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 -
PloS One 2023Ecological Niche Modeling is widely used for animals, but rarely for understanding the parasite ecology. Trypanosoma cruzi is a heterogeneous and widely dispersed...
Ecological Niche Modeling is widely used for animals, but rarely for understanding the parasite ecology. Trypanosoma cruzi is a heterogeneous and widely dispersed multi-host parasite. Didelphis aurita is a generalist species, both in terms of diet and environments. We modeled the D. aurita niche and T. cruzi infection in the Brazilian Atlantic Rainforest, using the models of two common vector species (Triatoma vitticeps and Panstrongylus megistus) as biotic variables, predicting their occurrence. Records of T. cruzi infected and non-infected D. aurita were analyzed through climate and landscape approaches by the Ecoland method. Models for each triatomine species and infected and noninfected D. aurita were produced considering climate and landscape: resolution of ~1km2 selected by Pearson's correlation [-0.7≤α≤0.7]. For modeling, seven algorithms available in ModleR package were used. True Skill Statistic was used to evaluate the models' performance (≥ 0.7). T. vitticeps indicates that there is a spatial dependence with warm areas in the southeastern region while P. megistus presented a distribution with high environmental suitability concentrated in the Southeast. High values of climatic suitability, landscape and potential presence of T. vitticeps and P. megistus were considered necessary, but not sufficient for the presence of D. aurita infected by T. cruzi. Climate models showed an ecological niche with suitability variations homogeneous, and landscape models showed a distribution of habitat conditions along the biome, with a fragmented profile and heterogeneous between locations. Ecoland demonstrated that D. aurita has different degrees of impact on its role in the enzootic cycle in different locations of the Atlantic Rainforest. Associating the models with the Ecoland method allowed the recognition of areas where D. aurita are important T. cruzi reservoirs. Areas of high suitability for the presence of marsupials are a necessary, but not sufficient for D. aurita to act as a reservoir for T. cruzi.
Topics: Animals; Didelphis; Rainforest; Chagas Disease; Trypanosoma cruzi; Triatoma; Brazil
PubMed: 37506103
DOI: 10.1371/journal.pone.0288595 -
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 -
Revista Da Sociedade Brasileira de... 2023Triatominae are vectors of the protozoan Trypanosoma cruzi, the causative agent of Chagas disease. This study aims to report an infestation on Triatominae colonies by a...
BACKGROUND
Triatominae are vectors of the protozoan Trypanosoma cruzi, the causative agent of Chagas disease. This study aims to report an infestation on Triatominae colonies by a beetle, previously identified as a pest.
METHODS
The management of these colonies should be improved to maximize their usefulness, and factors that may cause harm to them should be avoided as much as possible.
RESULTS
This is the first report on a coleopteran infestation on living Triatominae colonies worldwide.
CONCLUSIONS
The present record provides an important warning to researchers who maintain insectaries in general, especially those who rear triatomines, to carry protective measures against such invasions.
Topics: Animals; Triatominae; Reduviidae; Coleoptera; Insect Vectors; Chagas Disease; Trypanosoma cruzi
PubMed: 37493742
DOI: 10.1590/0037-8682-0150-2023 -
Revista Da Sociedade Brasileira de... 2023We report the presence of Triatoma longipennis for the first time in two localities in Hidalgo, Mexico.
BACKGROUND
We report the presence of Triatoma longipennis for the first time in two localities in Hidalgo, Mexico.
METHODS
This study was conducted at Tecozautla municipality, Hidalgo. Collection was performed in April 2022.
RESULTS
We collected eight triatomines from Guadalupe: two fourth-instar nymphs, three fifth-instar nymphs, one female, and two males. In San Miguel Caltepantla, a female was collected inside a dwelling. One sample tested positive for Trypanosoma cruzi.
CONCLUSIONS
These findings suggest the need to investigate the dynamics of this species with respect to the inhabitants of the study area.
Topics: Animals; Male; Female; Triatominae; Triatoma; Chagas Disease; Trypanosoma cruzi; Environment; Mexico
PubMed: 37493734
DOI: 10.1590/0037-8682-0078-2023 -
PloS One 2023Autophagy and the ubiquitin-proteasome system (UPS) are important cellular mechanisms that coordinate protein degradation essential for proteostasis. P62/SQSTM1 is a...
Gene identification and RNAi-silencing of p62/SQSTM1 in the vector Rhodnius prolixus reveals a high degree of sequence conservation but no apparent deficiency-related phenotypes in vitellogenic females.
Autophagy and the ubiquitin-proteasome system (UPS) are important cellular mechanisms that coordinate protein degradation essential for proteostasis. P62/SQSTM1 is a receptor cargo protein able to deliver ubiquitinated targets to the proteasome proteolytic complex and/or to the autophagosome. In the insect vector of Chagas disease, Rhodnius prolixus, previous works have shown that the knockdown of different autophagy-related genes (ATGs) and ubiquitin-conjugating enzymes resulted in abnormal oogenesis phenotypes and embryo lethality. Here, we investigate the role of the autophagy/UPS adaptor protein p62 during the oogenesis and reproduction of this vector. We found that R. prolixus presents one isoform of p62 encoded by a non-annotated gene. The predicted protein presents the domain architecture anticipated for p62: PB1 (N-term), ZZ-finger, and UBA (C-term) domains, and phylogenetic analysis showed that this pattern is highly conserved within insects. Using parental RNAi, we found that although p62 is expressed in the ovary, midgut, and fat body of adult females, systemic silencing of this gene did not result in any apparent phenotypes under in-house conditions. The insects' overall levels of blood meal digestion, lifespan, yolk protein production, oviposition, and embryo viability were not altered when compared to controls. Because it is known that autophagy and UPS can undergo compensatory mechanisms, we asked whether the silencing of p62 was triggering adaptative changes in the expression of genes of the autophagy, UPS, and the unfolded protein response (UPR) and found that only ATG1 was slightly up regulated in the ovaries of silenced females. In addition, experiments to further investigate the role of p62 in insects previously silenced for the E1-conjugating enzyme (a condition known to trigger the upregulation of p62), also did not result in any apparent phenotypes in vitellogenic females.
Topics: Female; Animals; Proteasome Endopeptidase Complex; Rhodnius; Sequestosome-1 Protein; Phylogeny; RNA Interference; Ubiquitin
PubMed: 37486954
DOI: 10.1371/journal.pone.0287488 -
Parasites & Vectors Jul 2023Triatomines are blood-sucking insects capable of transmitting Trypanosoma cruzi, the parasite that causes Chagas disease in humans. Vectorial transmission entails an...
BACKGROUND
Triatomines are blood-sucking insects capable of transmitting Trypanosoma cruzi, the parasite that causes Chagas disease in humans. Vectorial transmission entails an infected triatomine feeding on a vertebrate host, release of triatomine infective dejections, and host infection by the entry of parasites through mucous membranes, skin abrasions, or the biting site; therefore, transmission to humans is related to the triatomine-human contact. In this cross-sectional study, we evaluated whether humans were detected in the diet of three sylvatic triatomine species (Mepraia parapatrica, Mepraia spinolai, and Triatoma infestans) present in the semiarid-Mediterranean ecosystem of Chile.
METHODS
We used triatomines collected from 32 sites across 1100 km, with an overall T. cruzi infection frequency of 47.1% (N = 4287 total specimens) by conventional PCR or qPCR. First, we amplified the vertebrate cytochrome b gene (cytb) from all DNA samples obtained from triatomine intestinal contents. Then, we sequenced cytb-positive PCR products in pools of 10-20 triatomines each, grouped by site. The filtered sequences were grouped into amplicon sequence variants (ASVs) with a minimum abundance of 100 reads. ASVs were identified by selecting the best BLASTn match against the NCBI nucleotide database.
RESULTS
Overall, 16 mammal (including human), 14 bird, and seven reptile species were identified in the diet of sylvatic triatomines. Humans were part of the diet of all analyzed triatomine species, and it was detected in 19 sites representing 12.19% of the sequences.
CONCLUSIONS
Sylvatic triatomine species from Chile feed on a variety of vertebrate species; many of them are detected here for the first time in their diet. Our results highlight that the sylvatic triatomine-human contact is noteworthy. Education must be enforced for local inhabitants, workers, and tourists arriving in endemic areas to avoid or minimize the risk of exposure to Chagas disease vectors.
Topics: Animals; Humans; Ecosystem; Chile; Cross-Sectional Studies; Chagas Disease; Triatoma; Triatominae; Trypanosoma cruzi; High-Throughput Nucleotide Sequencing; Mammals
PubMed: 37415248
DOI: 10.1186/s13071-023-05841-x