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The American Journal of Tropical... Nov 2023To assess the attracting capacity of aliphatic and aromatic aldehydes to Triatoma infestans, the Chagas disease vector, laboratory tests were conducted using individual...
To assess the attracting capacity of aliphatic and aromatic aldehydes to Triatoma infestans, the Chagas disease vector, laboratory tests were conducted using individual compounds and mixtures to evaluate their potential use in baited traps for intradomicile population dynamics analysis. Commercial samples of hexanal, nonanal, and benzaldehyde were used at 95% purity. The experiments were performed at 25°C and 65% relative humidity using two procedures: a glass arena with filter papers impregnated with 1, 5, and 10 μL of the tested compounds and a double-choice olfactometer. Attraction was scored positively if the insect remained more than 30 seconds on one of the surfaces. The results of the study showed that hexanal was attractive to females at higher concentrations (5-10 μL; P < 0.0001), and IV instar nymphs were only attracted at the highest concentration (10 μL; P < 0.01). Nonanal was attractive to IV instar nymphs at 1 and 5 μL (P < 0.0001), whereas males and females were more attracted at 1 μL (P < 0.01 and P < 0.05, respectively). Benzaldehyde showed significant differences with respect to controls, attracting females at low concentrations (1 μL; P < 0.0001) and IV instar nymphs at 5 and 10 μL (P < 0.0001 and P < 0.001, respectively). In the olfactometer, the 60:40 hexanal/nonanal mixture was the most effective. In conclusion, this study demonstrated that the aliphatic and aromatic aldehydes studied here, both individually and in mixtures, could be used as effective attractants for T. infestans in intradomicile-baited traps. These results suggest that mixtures of these compounds could be implemented in field trials for Chagas disease surveillance.
Topics: Humans; Male; Animals; Female; Triatoma; Benzaldehydes; Chagas Disease
PubMed: 37696519
DOI: 10.4269/ajtmh.23-0277 -
Pharmaceuticals (Basel, Switzerland) Aug 2023Chagas disease, caused by the parasitic protozoan, is a neglected tropical disease (NTD) of significant incidence in Latin America. Transmission to humans and other... (Review)
Review
Chagas disease, caused by the parasitic protozoan, is a neglected tropical disease (NTD) of significant incidence in Latin America. Transmission to humans and other mammals is mainly via the vector insect from the Reduviidae family, popularly known as the kissing bug. There are other transmission means, such as through congenital transmission, blood transfusions, organ transplantations, and the consumption of contaminated food. For more than 50 years, the disease has been treated with benznidazole and nifurtimox, which are only effective during the acute phase of the disease. In addition to their low efficacy in the chronic phase, they cause many adverse effects and are somewhat selective. The use of nanocarriers has received significant attention due to their ability to encapsulate and release therapeutic agents in a controlled manner. Generally, their diameter ranges from 100 to 300 nanometers. The objective of this scoping review was to perform a search of the literature for the use of nanocarriers as an alternative for improving the treatment of Chagas disease and to suggest future research. Bibliographic searches were carried out in the Web of Science and PubMed scientific databases from January 2012 to May 2023, using the "Chagas disease and and nanoparticles" keywords, seeking to gather the largest number of articles, which were evaluated using the inclusion and exclusion criteria. After analyzing the papers, the results showed that nanocarriers offer physiological stability and safety for the transport and controlled release of drugs. They can increase solubility and selectivity against the parasite. The in vitro assays showed that the trypanocidal activity of the drug was not impaired after encapsulation. In the in vivo assays, parasitemia reduction and high survival and cure rates in animals were obtained during both phases of the disease using lower doses when compared to the standard treatment. The scoping review showed that nanocarriers are a promising alternative for the treatment of Chagas disease.
PubMed: 37631078
DOI: 10.3390/ph16081163 -
Microbiology Spectrum Aug 2023The importance of gut microbiomes has become generally recognized in vector biology. This study addresses microbiome signatures in North American species of public...
The importance of gut microbiomes has become generally recognized in vector biology. This study addresses microbiome signatures in North American species of public health significance (vectors of Trypanosoma cruzi) linked to their blood-feeding strategy and the natural habitat. To place the -associated microbiomes within a complex evolutionary and ecological context, we sampled sympatric populations, related predatory reduviids, unrelated ticks, and environmental material from vertebrate nests where these arthropods reside. Along with five species, we have characterized microbiomes of five reduviids (Stenolemoides arizonensis, Ploiaria hirticornis, Zelus longipes, and two species), a single soft tick species, Ornithodoros turicata, and environmental microbiomes from selected sites in Arizona, Texas, Florida, and Georgia. The microbiomes of predatory reduviids lack a shared core microbiota. As in triatomines, microbiome dissimilarities among species correlate with dominance of a single bacterial taxon. These include , , " Midichloria," and , which are often accompanied by known symbiotic genera, i.e., , " Lariskella," , , and We have further identified a compositional convergence of the analyzed microbiomes in regard to the host phylogenetic distance in both blood-feeding and predatory reduviids. While the microbiomes of the two reduviid species from the Emesinae family reflect their close relationship, the microbiomes of all species repeatedly form a distinct monophyletic cluster highlighting their phylosymbiosis. Furthermore, based on environmental microbiome profiles and blood meal analysis, we propose three epidemiologically relevant and mutually interrelated bacterial sources for microbiomes, i.e., host abiotic environment, host skin microbiome, and pathogens circulating in host blood. This study places microbiomes of blood-feeding North American vectors (Reduviidae) into a broader evolutionary and ecological context provided by related predatory assassin bugs (Reduviidae), another unrelated vector species (soft tick ), and the environment these arthropods coinhabit. For both vectors, microbiome analyses suggest three interrelated sources of bacteria, i.e., the microbiome of vertebrate nests as their natural habitat, the vertebrate skin microbiome, and the pathobiome circulating in vertebrate blood. Despite an apparent influx of environment-associated bacteria into the arthropod microbiomes, microbiomes retain their specificity, forming a distinct cluster that significantly differs from both predatory relatives and ecologically comparable ticks. Similarly, within the related predatory Reduviidae, we found the host phylogenetic distance to underlie microbiome similarities.
Topics: Animals; Phylogeny; Triatoma; Trypanosoma cruzi; Microbiota; Bacteria
PubMed: 37289079
DOI: 10.1128/spectrum.01681-23 -
Frontiers in Endocrinology 2023Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such...
Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such as feeding, diuresis, and reproduction. Rhopr-CRF/DH plays a key role in feeding and diuresis in , a blood-gorging insect and a vector for human Chagas disease. Here, we extend our understanding on the role of this neurohormone in reproduction in adult female . Double-label immunohistochemistry displays co-localized staining of CRF-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in the same neurosecretory cells (NSCs) in the mesothoracic ganglionic mass (MTGM) and in their neurohemal sites in adult female , suggesting these peptides could work together to regulate physiological processes. qPCR analysis reveals that the transcript for Rhopr-CRF/DH receptor 2 () is expressed in reproductive tissues and fat body (FB) in adult female , and its expression increases post blood meal (PBM), a stimulus that triggers diuresis and reproduction. Using RNA interference, transcript expression of was knocked down, and egg production monitored by examining the major yolk protein, vitellogenin (Vg), the number and quality of eggs laid, and their hatching ratio. Injection of dsCRFR2 into adult females reduces transcript expression, accelerates oogenesis, increases the number of eggs produced, and reduces hatching rate in female . Downregulation of leads to an increase in the transcript expression of in the fat body and ovaries, and increases the transcript level for the Vg receptor, , in the ovaries. A significant increase in Vg content in the fat body and in the hemolymph is also observed. Incubation of isolated tissues with Rhopr-CRF/DH leads to a significant decrease in transcript expression of in the fat body and in the ovaries. In addition, Rhopr-CRF/DH reduces transcript expression of the ecdysteroid biosynthetic enzymes and reduces ecdysteroid titer in the culture medium containing isolated ovaries. These results suggest the involvement of the CRF-signaling pathway in reproduction, and that Rhopr-CRF/DH acts as a gonad-inhibiting hormone in the adult female , as previously shown for the colocalized glycoprotein, GPA2/GPB5.
Topics: Animals; Female; Adult; Humans; Corticotropin-Releasing Hormone; Diuretics; Rhodnius; Ecdysteroids; Gonadal Hormones; Glycoproteins; Gonads
PubMed: 37842303
DOI: 10.3389/fendo.2023.1279929 -
Current Research in Parasitology &... 2023Triatomines (Hemiptera: Reduviidae: Triatominae), commonly called "kissing bugs", are blood-sucking pests and vectors of the protozoan parasite , the causative agent of... (Review)
Review
Triatomines (Hemiptera: Reduviidae: Triatominae), commonly called "kissing bugs", are blood-sucking pests and vectors of the protozoan parasite , the causative agent of Chagas disease (CD). Eleven species of kissing bugs occur throughout the southern half of the USA, four of which are well known to invade human dwellings. Certain kissing bugs in the USA are known to transmit to humans and other animals and their bites can also lead to serious allergic reactions, including anaphylaxis. In Florida, the kissing bug frequently invades homes, bites residents, and has been found infected with , placing humans and companion animals at risk for CD. This review outlines integrated pest management (IPM) strategies for minimizing human exposure to and CD. A comprehensive IPM plan for kissing bugs includes detailed inspections, removal of vertebrate host nesting areas, and kissing bug harborage, home improvements to exclude kissing bugs from entering structures, pest removal, and judicious use of pesticides. This approach can limit or eliminate kissing bug entry into residential structures, thereby preventing kissing bug bites, and CD infections in humans and companion animals.
PubMed: 37841307
DOI: 10.1016/j.crpvbd.2023.100144 -
Acta Tropica Nov 2023Genetic and morphological structure of vector populations are useful to identify panmictic groups, reinfestation sources and minimal units for control interventions....
Genetic and morphological structure of vector populations are useful to identify panmictic groups, reinfestation sources and minimal units for control interventions. Currently, no studies have integrated genetic and morphometric data in Triatoma infestans (Hemiptera: Reduviidae), one of the main vectors of Trypanosoma cruzi. We characterized the genetic and phenotypic structure of T. infestans at a small spatial scale (2-8 km), identified potential migrants and compared flight-related traits among genetic groups and between migrant and non-migrant insects in a well-defined area without insecticide spraying in the previous 12 years. We obtained microsatellite genotypes (N = 303), wing shape and size (N = 164) and body weight-to-length ratios (N = 188) in T. infestans from 11 houses in Pampa del Indio, Argentine Chaco. The uppermost level of genetic structuring partially agreed with the morphological groups, showing high degrees of substructuring. The genetic structure showed a clear spatial pattern around Route 3 and one genetic group overlapped with an area of persistent infestation and insecticide resistance. Females harboured more microsatellite alleles than males, which showed signs of isolation-by-distance. Wing shape discriminant analyses of genetic groups revealed low reclassification scores whereas wing size differed among genetic groups for both sexes. Potential migrants (8%) did not differ from non-migrants in sex, ecotope, wing shape and size. However, male migrants had lower W/L than non-migrants suggesting poorer nutritional state. Our findings may contribute to the understanding of population characteristics, dispersal dynamics and ongoing elimination efforts of T. infestans.
Topics: Female; Animals; Male; Triatoma; Alleles; Discriminant Analysis; Genotype; Insecticide Resistance
PubMed: 37666351
DOI: 10.1016/j.actatropica.2023.107010 -
Frontiers in Insect Science 2023The fall armyworm (FAW), , an invasive pest originating from the Americas is a serious pest threatening cereal production and food security in Zambia. We studied the...
The fall armyworm (FAW), , an invasive pest originating from the Americas is a serious pest threatening cereal production and food security in Zambia. We studied the prevalence and abundance of natural enemies of FAW in three Agroecological regions (AERs I, II, and III) to identify those that could potentially serve as bio-control agents. Sampling of FAW parasitoids and predators was done along trunk roads at intervals of 10 km. Molecular sequence analysis and morphological characterization were used to identify natural enemies. Over 11 species of FAW natural enemies, including egg, egg-larval, and larval parasitoids, and predators, were identified in Zambia. The mean number of natural enemies and species richness was higher in AER I and IIa. Consequently, egg parasitism was highest in those two regions, at 24.5% and 12.2%, respectively. Larvae parasitism was highest in AER I (4.8%) and AER III (1.9), although no significant differences were observed. The most abundant and widely distributed parasitoid was sp. (Diptera: Tachinidae), while (Germar) (Hemiptera: Reduviidae) and sp. (Hymenoptera: Vespidae) were the most prevalent predators. Our study reveals the presence of two natural enemies belonging to the genus and , uncommon to FAW. Significant differences in the number of parasitoids were observed in polycropping, with the highest recovery of 12 ± 10% from maize + cowpeas + pumpkin and watermelon mixed cropping. The higher the rainfall, the lower the number of natural enemies recorded. Variations in rainfall patterns which affect FAW availability, cropping systems and the three AERs may explain natural enemies' species diversity in Zambia. The information provided in this study can aid the development of a national biological control programme for sustainable management of fall armyworm.
PubMed: 38469517
DOI: 10.3389/finsc.2023.1091084 -
Pediatric Annals Oct 2023Chagas disease, also known as , is caused by , a parasite transmitted by hematophagous triatomine insects (subfamily Triatominae) belonging to the Reduviidae family,...
Chagas disease, also known as , is caused by , a parasite transmitted by hematophagous triatomine insects (subfamily Triatominae) belonging to the Reduviidae family, order Hemiptera. Infection occurs through contact with the feces of the infected vector at the site of its bite or on intact mucosa. .
Topics: Animals; Humans; Cellulitis; Insect Vectors; Chagas Disease; Triatominae; Trypanosoma cruzi
PubMed: 37820707
DOI: 10.3928/19382359-20230829-02 -
Journal of Medical Entomology Dec 2023Triatomine species (kissing bugs) infected with Trypanosoma cruzi are found across the southern United States. The northern limits of Trypanosoma cruzi infected kissing...
The distribution of triatomine (Hemiptera: Reduviidae) vectors of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) in Illinois and Missouri: historical records and specimen submissions from community science programs.
Triatomine species (kissing bugs) infected with Trypanosoma cruzi are found across the southern United States. The northern limits of Trypanosoma cruzi infected kissing bugs are less understood. The objective of this work was to describe the locations of kissing bugs from Illinois and Missouri based on historical records, submissions to Texas A&M University's (TAMU) Kissing Bug Community Science Program and the Centers for Disease Control and Prevention (CDC), and records from online platforms (iNaturalist, BugGuide, and GBIF) up to and including 2022. A total of 228 records were discovered, including 186 from historical or observation platforms and 42 specimens submitted to TAMU or CDC. Species included Triatoma sanguisuga (221 total records, 9 nymphs) and Triatoma lecticularia (7 records). Notably, nearly all (24/26) records submitted to TAMU were collected indoors. Twelve of the 30 (40%) specimens tested were positive for the presence of T. cruzi, including parasite discrete taxonomic units TcI and TcIV. One triatomine sample had been found in a bed feeding on the submitter; this bug was positive for T. cruzi and had evidence of human blood in its gut. Records suggest a ubiquitous distribution in Missouri and potentially to the northernmost border in Illinois. Further investigations into triatomine distribution and infection status are needed within states assumed to be northern limits in order to create public health and veterinary health messaging and baseline distributional maps from which to measure future range shifts in relation to a changing climate.
PubMed: 38070198
DOI: 10.1093/jme/tjad124 -
Archives of Insect Biochemistry and... Apr 2024Kissing bugs do not respond to host cues when recently molted and only exhibit robust host-seeking several days after ecdysis. Behavioral plasticity has peripheral...
Kissing bugs do not respond to host cues when recently molted and only exhibit robust host-seeking several days after ecdysis. Behavioral plasticity has peripheral correlates in antennal gene expression changes through the week after ecdysis. The mechanisms regulating these peripheral changes are still unknown, but neuropeptide, G-protein coupled receptor, nuclear receptor, and takeout genes likely modulate peripheral sensory physiology. We evaluated their expression in antennal transcriptomes along the first week postecdysis of Rhodnius prolixus 5th instar larvae. Besides, we performed clustering and co-expression analyses to reveal relationships between neuromodulatory (NM) and sensory genes. Significant changes in transcript abundance were detected for 50 NM genes. We identified 73 sensory-related and NM genes that were assigned to nine clusters. According to their expression patterns, clusters were classified into four groups: two including genes up or downregulated immediately after ecdysis; and two with genes with expression altered at day 2. Several NM genes together with sensory genes belong to the first group, suggesting functional interactions. Co-expression network analysis revealed a set of genes that seem to connect with sensory system maturation. Significant expression changes in NM components were described in the antennae of R. prolixus after ecdysis, suggesting that a local NM system acts on antennal physiology. These changes may modify the sensitivity of kissing bugs to host cues during this maturation interval.
Topics: Animals; Rhodnius; Neuropeptides; Transcriptome; Triatoma; Molting
PubMed: 38597092
DOI: 10.1002/arch.22106