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Frontiers in Endocrinology 2021(the kissing bug and a major vector of Chagas disease) is an obligate blood feeder that in the case of the fifth instar consumes up to 10 times its unfed body weight in... (Review)
Review
(the kissing bug and a major vector of Chagas disease) is an obligate blood feeder that in the case of the fifth instar consumes up to 10 times its unfed body weight in a single 20-minute feed. A post-prandial diuresis is initiated, within minutes of the start of gorging, in order to lower the mass and concentrate the nutrients of the meal. Thus, rapidly excretes a fluid that is high in NaCl content and hypo-osmotic to the hemolymph, thereby eliminating 50% of the volume of the blood meal within 3 hours of gorging. In , as with other insects, the Malpighian tubules play a critical role in diuresis. Malpighian tubules are not innervated, and their fine control comes under the influence of the neuroendocrine system that releases amines and neuropeptides as diuretic or antidiuretic hormones. These hormones act upon the Malpighian tubules a variety of G protein-coupled receptors linked to second messenger systems that influence ion transporters and aquaporins; thereby regulating fluid secretion. Much has been discovered about the control of diuresis in , and other model insects, using classical endocrinological studies. The post-genomic era, however, has brought new insights, identifying novel diuretic and antidiuretic hormone-signaling pathways whilst also validating many of the classical discoveries. This paper will focus on recent discoveries into the neuroendocrine control of the rapid post-prandial diuresis in , in order to emphasize new insights from a transcriptome analysis of Malpighian tubules taken from unfed and fed bugs.
Topics: Animals; Body Fluids; Diuresis; Diuretics; Gene Expression Profiling; Insect Hormones; Malpighian Tubules; Neurosecretory Systems; Postprandial Period; Rhodnius; Transcriptome; Vasopressins
PubMed: 34512553
DOI: 10.3389/fendo.2021.722487 -
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 -
Acta Tropica Jan 2023Triatoma rubrovaria subcomplex consists of T. carcavalloi, T. circummaculata, T. klugi, T. limai, T. oliveirai, T. pintodiasi, T. rubrovaria, T. patagonica and T....
Triatoma rubrovaria subcomplex consists of T. carcavalloi, T. circummaculata, T. klugi, T. limai, T. oliveirai, T. pintodiasi, T. rubrovaria, T. patagonica and T. guasayana, which can be vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease. In this study, morphological, morphometric, and genetic characters of T. circummaculata, T. pintodiasi, T. carcavalloi, T. klugi, and T. rubrovaria were analyzed in view of the integrative taxonomy and phylogeny of the T. rubrovaria subcomplex. Molecular studies were carried out through the sequencing and analysis of the mitochondrial genes COI and CytB, nuclear genes ITS I, ITS 2, 16S, and 28S from rDNA and rescued a monophyletic group. Furthermore, differential morphological characters were found among the five species in the pronotum, scutellum, stridulatory sulcus, male genitalia, and external female genitalia. Finally, morphometric analyses made it possible to differentiate the five species. Phylogenetic analyzes rescued the relationship of T. pintodiasi with members of the T. rubrovaria subcomplex and demonstrated that this subcomplex is a monophyletic group composed of the species T. carcavalloi, T. circummaculata, T. klugi, T. guasayana, T. limai, T. oliveirai, T. patagonica, T. pintodiasi, and T. rubrovaria. Furthermore, through integrative taxonomy, it was possible to confirm the specific status of the species T. carcavalloi, T. circummaculata, T. pintodiasi, T. klugi, and T. rubrovaria, offering new useful morphological characters for the differentiation and characterization of these potential vectors and distributed in Southern Brazil.
Topics: Animals; Male; Female; Triatoma; Triatominae; Phylogeny; Chagas Disease; Brazil
PubMed: 36309107
DOI: 10.1016/j.actatropica.2022.106699 -
Biology Letters Apr 2023Tool-use in animals is a complex and rare phenomenon, particularly in insects. Tool-use in assassin bugs has been suggested as several species apply adhesive plant...
Tool-use in animals is a complex and rare phenomenon, particularly in insects. Tool-use in assassin bugs has been suggested as several species apply adhesive plant resins to their body, which has been hypothesized to function in enhancing prey capture. Here, we staged predatory interactions of resin-deprived and resin-equipped assassin bugs ( sp.) and discovered that applying resin as a tool conveys a clear predatory advantage to the assassin bugs. sp. can thus be considered a tool-user, and since this behaviour was present in all individuals, including newly hatched nymphs, tool-use can be considered to be stereotyped. Our study, along with others, suggests that, when compared with other insects, tool-use is disproportionately common within the assassin bugs.
Topics: Animals; Reduviidae; Insecta; Predatory Behavior; Resins, Plant; Nymph
PubMed: 37122198
DOI: 10.1098/rsbl.2022.0608 -
Acta Tropica Nov 2020A widely accepted idea in parasite-host relationships is that the former manipulates the latter so that it increases its own success. In the case of complex life cycles,...
A widely accepted idea in parasite-host relationships is that the former manipulates the latter so that it increases its own success. In the case of complex life cycles, this means that the parasite is able to manipulate the first host which allows its transmission to the second host. In this paper, I formalize the idea that this may be the case for the Trypanosoma cruzi parasite and its vectors, bugs of the subfamily Triatominae. I discuss the sources of existing evidence and propose some types of manipulation. This manipulation could also occur in the second host, that is, a vertebrate. Here, I emphasize humans and domesticated animals. I also discuss how global change and insecticide resistance may drive the arms race between both, triatomines and T. cruzi, and host manipulation.
Topics: Animals; Animals, Domestic; Chagas Disease; Host-Parasite Interactions; Humans; Insect Vectors; Life Cycle Stages; Triatominae; Trypanosoma cruzi
PubMed: 32592685
DOI: 10.1016/j.actatropica.2020.105600 -
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 -
Acta Tropica Jan 2023Autogeny, the ability to develop eggs without a meal in the adult stage, has been described in several groups of arthropods, especially hematophagous Diptera Nematocera....
Autogeny, the ability to develop eggs without a meal in the adult stage, has been described in several groups of arthropods, especially hematophagous Diptera Nematocera. In obligate hematophagous hemimetabolous insects that feed on blood in all their instars, such as Triatominae, this concept gives rise to species with apparently facultative autogeny, such as Triatoma infestans. Generalized linear models were applied to explain egg production by the predictor variables molting weight as a proxy of nymphal accumulated reserves and digested blood weight as an indicator of adult reserve in fasted, incompletely fed and engorged at repletion females. The relationship between these indicators of nutritional status and egg development turned out to be a continuous function in which, with molting weights greater than 254 mg, the insects are autogenic, but for the first batch of eggs with molting weights between 132 and 253 mg, they require one adult meal of at least 202 mg, and with molting weights less than 131 mg at least two meals are required. Both molting weight and blood intake could determine oocyte production in an additive manner, thus the concept of autogeny as a switch on-off phenomenon is not directly applicable to Triatominae. Nevertheless, autogenic ability would allow Triatominae with relatively long cycles to accelerate population growth under favorable or low competition conditions during colonization or recovery after a control intervention.
Topics: Animals; Female; Triatoma; Triatominae; Nymph; Feeding Behavior; Nutritional Status
PubMed: 36273538
DOI: 10.1016/j.actatropica.2022.106727 -
Parasites & Vectors Dec 2019The identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is important to assess the potential risk of Chagas disease transmission. We...
BACKGROUND
The identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is important to assess the potential risk of Chagas disease transmission. We identified T. cruzi infection and blood-meal sources of triatomines caught in and around houses in the state of Bahia, northeastern Brazil, and mapped the occurrence of infected triatomines that fed on humans and domestic animals.
METHODS
Triatominae bugs were manually captured by trained agents from the Epidemiologic Surveillance team of Bahia State Health Service between 2013 and 2014. We applied conventional PCR to detect T. cruzi and blood-meal sources (dog, cat, human and bird) in a randomized sample of triatomines. We mapped triatomine distribution and analyzed vector hotspots with kernel density spatial analysis.
RESULTS
In total, 5906 triatomines comprising 15 species were collected from 127 out of 417 municipalities in Bahia. The molecular analyses of 695 triatomines revealed a ~10% T. cruzi infection rate, which was highest in the T. brasiliensis species complex. Most bugs were found to have fed on birds (74.2%), and other blood-meal sources included dogs (6%), cats (0.6%) and humans (1%). Trypanosoma cruzi-infected triatomines that fed on humans were detected inside houses. Spatial analysis showed a wide distribution of T. cruzi-infected triatomines throughout Bahia; triatomines that fed on dogs, humans, and cats were observed mainly in the northeast region.
CONCLUSIONS
Synanthropic triatomines have a wide distribution and maintain the potential risk of T. cruzi transmission to humans and domestic animals in Bahia. Ten species were recorded inside houses, mainly Triatoma sordida, T. pseudomaculata, and the T. brasiliensis species complex. Molecular and spatial analysis are useful to reveal T. cruzi infection and blood-meal sources in synanthropic triatomines, identifying areas with ongoing threat for parasite transmission and improving entomological surveillance strategies.
Topics: Animals; Animals, Domestic; Brazil; Cats; Dogs; Feeding Behavior; Humans; Insect Vectors; Triatominae; Trypanosoma cruzi
PubMed: 31878960
DOI: 10.1186/s13071-019-3849-1 -
Genetics May 2022Pigmentation in insects has been linked to mate selection and predator evasion, thus representing an important aspect for natural selection. Insect body color is...
Pigmentation in insects has been linked to mate selection and predator evasion, thus representing an important aspect for natural selection. Insect body color is classically associated to the activity of tyrosine pathway enzymes, and eye color to pigment synthesis through the tryptophan and guanine pathways, and their transport by ATP-binding cassette proteins. Among the hemiptera, the genetic basis for pigmentation in kissing bugs such as Rhodnius prolixus, that transmit Chagas disease to humans, has not been addressed. Here, we report the functional analysis of R. prolixus eye and cuticle pigmentation genes. Consistent with data for most insect clades, we show that knockdown for yellow results in a yellow cuticle, while scarlet and cinnabar knockdowns display red eyes as well as cuticle phenotypes. In addition, tyrosine pathway aaNATpreto knockdown resulted in a striking dark cuticle that displays no color pattern or UV reflectance. In contrast, knockdown of ebony and tan, that encode N-beta-alanyl dopamine hydroxylase branch tyrosine pathway enzymes, did not generate the expected dark and light brown phenotypes, respectively, as reported for other insects. We hypothesize that R. prolixus, which requires tyrosine pathway enzymes for detoxification from the blood diet, evolved an unusual strategy for cuticle pigmentation based on the preferential use of a color erasing function of the aaNATpreto tyrosine pathway branch. We also show that genes classically involved in the generation and transport of eye pigments regulate red body color in R. prolixus. This is the first systematic approach to identify the genes responsible for the generation of color in a blood-feeding hemiptera, providing potential visible markers for future transgenesis.
Topics: Animals; Pigmentation; Rhodnius; Tyrosine
PubMed: 35445704
DOI: 10.1093/genetics/iyac064 -
Vector Borne and Zoonotic Diseases... Sep 2022The objective of this study was to evaluate the effectiveness of selective and community-wide house insecticide spraying in controlling triatomines in the subtropical...
The objective of this study was to evaluate the effectiveness of selective and community-wide house insecticide spraying in controlling triatomines in the subtropical areas of Loja Province, Ecuador. We designed a quasi-experimental pre-post-test without a control group to compare entomological levels before and after spraying. The baseline study was conducted in 2008. Second, third, and fourth visits were conducted in 2010, 2011, and 2012 in three rural communities. Out of the 130 domestic units (DU) visited, 41 domestic units were examined in each of the four visits. Selective and community-wide insecticide interventions included spraying with 5% deltamethrin at 25 mg/m active ingredient. At each visit, a questionnaire was administered to identify the characteristics of households, and DUs were searched for triatomine bugs. In addition, parasitological analysis was carried out in life triatomines. One and two rounds of selective insecticide spraying decreased the probability of infestation by 62% (pairwise odds ratios [POR] 0.38, 95% confidence interval [CI] 0.17-0.89, = 0.024) and 51% (POR 0.49, 95% CI 0.23-1.01, = 0.054), respectively. A similar effect was observed after one round of community-wide insecticide application in Chaquizhca and Guara (POR 0.55, CI 0.24-1.25, = 0.155) and Bellamaria (POR 0.62, CI 0.22-1.79, = 0.379); however, it was not statistically significant. infection in triatomines ( = 483) increased overtime, from 2008 (42.9% and 8.5% for and , respectively) to 2012 (79.5% and 100%). Neither of the two spraying methodologies was effective for triatomine control in this area and our results point to a high likelihood of reinfestation after insecticide application. This underscores the importance of the implementation of physical barriers that prevent invasion and colonization of triatomines in households, such as home improvement initiatives, accompanied by a concerted effort to address the underlying socioeconomic issues that keep this population at risk of developing Chagas disease.
Topics: Animals; Chagas Disease; Disease Vectors; Ecuador; Insecticides; Triatoma; Trypanosoma cruzi
PubMed: 36044033
DOI: 10.1089/vbz.2021.0089