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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 -
BMC Genomics Nov 2022Hemiptera is one of the most speciose orders of insects, and the most speciose considering Hemimetabola. Through their evolutive history, hemipterans with different...
BACKGROUND
Hemiptera is one of the most speciose orders of insects, and the most speciose considering Hemimetabola. Through their evolutive history, hemipterans with different feeding habits have adapted to deal with different chemical challenges. Three major gene families are involved in xenobiotic detoxification in insects: the cytochromes P450 (CYPs), carboxyl/cholinesterases (CCEs), and glutathione transferases (GSTs). Here we perform a comparative analysis on the complement of these gene superfamilies across five hemipteran species; four heteropterans (the pentatomid plant feeders Nezara viridula and Halyomorpha halys; the hematophagous Cimex lectularius, Cimicidae, and Rhodnius prolixus, Reduviidae), and one Auchenorrhyncha plant feeder (Nilaparvata lugens).
RESULTS
Our results point to an expansion of several enzyme families associated with xenobiotic detoxification in heteropterans with respect to other species and the existence of a dynamic evolution pattern including CYP3 clan, hormone and pheromone processing class in the CCE superfamily, and sigma class in GST superfamily. Other detoxification-related families are reduced in the hemipteran species analyzed here: reduction or even absence of epsilon class and reduced delta class in GST superfamily; absence of mitochondrial CYP12 family; absence of CYP9 family in CYP3 clan; and reduction or even absence of some dietary/detoxification groups of CCEs. Interestingly, the most polyphagous species analyzed here (H. halys) is also the one that presents the largest repertoire of detoxification enzymes. Gene cluster analysis suggests that this could be due to gene duplication events.
CONCLUSIONS
The evolutionary analysis performed here reveals characteristics that are both common and particular for heteropterans. The composition and organization of detoxification-related gene families could shed light on evolutionary forces that shaped their divergence. These families are important for both the detoxification of diet products and for conferring tolerance or resistance to synthetic insecticides. Furthermore, we present the first comprehensive analysis of detoxification gene superfamilies in N. viridula, an understudied species in spite of its economic relevance as a crop pest. The information obtained is of interest for basic insect science as well as for the control of harmful species and the management of insecticide resistance.
Topics: Animals; Xenobiotics; Insecticide Resistance; Insecticides; Rhodnius; Glutathione Transferase; Heteroptera
PubMed: 36396986
DOI: 10.1186/s12864-022-08974-y -
Trends in Parasitology Jan 2017Chagas disease is amongst the ten most important neglected tropical diseases but knowledge on the diversification of its vectors, Triatominae (Hemiptera: Reduviidae), is... (Review)
Review
Chagas disease is amongst the ten most important neglected tropical diseases but knowledge on the diversification of its vectors, Triatominae (Hemiptera: Reduviidae), is very scarce. Most Triatominae species occur in the Americas, and are all considered potential vectors. Despite its amazing ecological vignette, there are remarkably few evolutionary studies of the whole subfamily, and only one genome sequence has been published. The young age of the subfamily, coupled with the high number of independent lineages, are intriguing, yet the lack of genome-wide data makes it a challenge to infer the phylogenetic relationships within Triatominae. Here we synthesize what is known, and suggest the next steps towards a better understanding of how this important group of disease vectors came to be.
Topics: Animals; Biodiversity; Biological Evolution; Chagas Disease; Genome; Insect Vectors; Phylogeny; Triatominae
PubMed: 27986547
DOI: 10.1016/j.pt.2016.11.002 -
Bulletin of Entomological Research Oct 2015Triatomines are vectors that transmit the protozoan haemoflagellate Trypanosoma cruzi, the causative agent of Chagas disease. The aim of the current review is to provide... (Review)
Review
Triatomines are vectors that transmit the protozoan haemoflagellate Trypanosoma cruzi, the causative agent of Chagas disease. The aim of the current review is to provide a synthesis of the immune mechanisms of triatomines against bacteria, viruses, fungi and parasites to provide clues for areas of further research including biological control. Regarding bacteria, the triatomine immune response includes antimicrobial peptides (AMPs) such as defensins, lysozymes, attacins and cecropins, whose sites of synthesis are principally the fat body and haemocytes. These peptides are used against pathogenic bacteria (especially during ecdysis and feeding), and also attack symbiotic bacteria. In relation to viruses, Triatoma virus is the only one known to attack and kill triatomines. Although the immune response to this virus is unknown, we hypothesize that haemocytes, phenoloxidase (PO) and nitric oxide (NO) could be activated. Different fungal species have been described in a few triatomines and some immune components against these pathogens are PO and proPO. In relation to parasites, triatomines respond with AMPs, including PO, NO and lectin. In the case of T. cruzi this may be effective, but Trypanosoma rangeli seems to evade and suppress PO response. Although it is clear that three parasite-killing processes are used by triatomines - phagocytosis, nodule formation and encapsulation - the precise immune mechanisms of triatomines against invading agents, including trypanosomes, are as yet unknown. The signalling processes used in triatomine immune response are IMD, Toll and Jak-STAT. Based on the information compiled, we propose some lines of research that include strategic approaches of biological control.
Topics: Animals; Bacteria; Fungi; Host-Parasite Interactions; Host-Pathogen Interactions; Insect Viruses; Triatominae
PubMed: 26082354
DOI: 10.1017/S0007485315000504 -
Insect Biochemistry and Molecular... Jul 2022The haematophagy process by arthropods has been one of the main targets of studies in the parasite-host interaction, and the kissing-bug Rhodnius prolixus, vector of the... (Review)
Review
The haematophagy process by arthropods has been one of the main targets of studies in the parasite-host interaction, and the kissing-bug Rhodnius prolixus, vector of the protozoan Trypanosoma cruzi, has been one of the main models for such studies. Still in the 1980s, it was identified that among the salivary proteins for disrupting vertebrate host homeostasis, lipocalins were among the most relevant proteins for this process. Since then, 30 lipocalins have been identified in the salivary glands of R. prolixus, that promotes vasodilatation, prevents inflammation, act as anticoagulants and inhibits platelet aggregation. The present work aims to identify new lipocalins from R. prolixus, combining transcriptome and genome data. Identified new genes were mapped and had their structure annotated. To infer an evolutionary relationship between lipocalins, and to support the predicted functions for each lipocalin, all amino acid sequences were used to construct phylogenetic trees. We identified a total of 29 new lipocalins, 3 new bioaminogenic-biding proteins (which act to inhibit platelet aggregation and vasodilation), 9 new inhibitors of platelet aggregation, 7 new apolipoproteins and 10 lipocalins with no putative function. In addition, we observed that several of the lipocalins are also expressed in different R. prolxius tissues, including gut, central nervous system, antennae, and reproductive organs. In addition to newly identified lipocalins and a mapping the new and old lipocalins in the genome of R. prolixus, our study also carried out a review on functional status and nomenclature of some of the already identified lipocalins. Our study reinforces that we are far from understanding the role of lipocalins in the physiology of R. prolixus, and that studies of this family are still of great relevance.
Topics: Animals; Chagas Disease; Insect Vectors; Lipocalins; Phylogeny; Rhodnius
PubMed: 35640811
DOI: 10.1016/j.ibmb.2022.103797 -
Parasites & Vectors Jun 2022Rhodnius robustus and Rhodnius pictipes are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease (CD), that are found in the Brazilian Amazon region....
Infection susceptibility and vector competence of Rhodnius robustus Larrousse, 1927 and R. pictipes Stal, 1872 (Hemiptera, Reduviidae, Triatominae) for strains of Trypanosoma cruzi (Chagas, 1909) (Kinetoplastida, Trypanosomatidae) I, II and IV.
BACKGROUND
Rhodnius robustus and Rhodnius pictipes are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease (CD), that are found in the Brazilian Amazon region. Susceptibility to infection and vector competence depend on the parasite-vector relationship. Our objective was to evaluate the interaction between T. cruzi and these two triatomine vectors in pure and mixed experimental infections of T. cruzi strains from the same or different geographic regions.
METHODS
Fifth-instar nymphs of R. robustus and R. pictipes were fed on mice infected with four T. cruzi strains, namely genotypes TcIAM, TcIMG, TcIIPR, and TcIVAM, respectively, from the Brazilian states of Amazonas, Minas Gerais and Paraná. Over a period of 120 days, excreta were examined every 20 days to assess vector competence, and intestinal contents (IC) were examined every 30 days to determine susceptibility to infection.
RESULTS
The highest positive rate in the fresh examination (%+FE, 30.0%), the highest number of parasitic forms (PF, n = 1969) and the highest metacyclogenesis rate (%MC, 53.8%) in the excreta were recorded for R. robustus/TcIVAM. Examination of the IC of R. pictipes revealed a higher number of PF in infections with TcIAM (22,680 PF) and TcIIPR (19,845 PF) alone or in association (17,145 PF), as well as a %+FE of 75.0% with TcII, in comparison with the other genotypes. The highest %MC (100%) was recorded for the mixed infections of TcIAM with TcIIPR or TcIVAM in the IC of R. pictipes.
CONCLUSIONS
Overall, both species were found to be susceptible to the T. cruzi strains studied. Rhodnius robustus showed vector competence for genotypes TcIVAM and TcIAM+TcIVAM and R. pictipes for TcIAM+TcIVAM and TcIAM+TcIIPR; there was elimination of infective forms as early as at 20 days. Our results suggest that both the genetics of the parasite and its geographic origin influence the susceptibility to infection and vector competence, alone or in association.
Topics: Animals; Chagas Disease; Kinetoplastida; Mice; Rhodnius; Triatominae; Trypanosoma cruzi; Trypanosomatina
PubMed: 35773725
DOI: 10.1186/s13071-022-05350-3 -
Parasites & Vectors Feb 2020Melanic (dark) morphs have been barely reported in peridomestic and sylvatic conditions for Triatoma infestans, the most important vector of Chagas disease in the...
BACKGROUND
Melanic (dark) morphs have been barely reported in peridomestic and sylvatic conditions for Triatoma infestans, the most important vector of Chagas disease in the Southern Cone of South America. Adults with dark and small yellow markings on the connexivum were collected after manual searches conducted by technical personnel in 62 domiciliary units in Cruz del Eje, Córdoba Province, Argentina. The last community-wide insecticide spraying campaign before the study had been conducted three years earlier. We investigated if there was a measurable color morph variation (melanic and non-melanic) in wings and connexivum; we determined infestation, distribution of melanic and non-melanic forms, and correspondence of colorimetric variation with variations in morphology (wing size and shape and body length), development (wing fluctuating asymmetry), physiology (nutritional status) or behaviour (flight initiation).
RESULTS
Forty-nine females, 54 males and 217 nymphs were collected in 24 domiciliary units. House infestation and colonization were 53% and 47%, respectively. Most of the T. infestans individuals (83.2%) were collected in chicken coops; intradomicile infestation was recorded in only one case. The chromatic cluster analysis showed two well-defined groups: melanic and non-melanic. The melanic group included 17 (35%) females and 25 (46%) males. Peridomestic infestation was lower for melanic than for non-melanic adults. Melanic morphs were collected in houses from several localities. Sexual dimorphisms were confirmed by morphometric measurements. Body length was large in melanic adults (P < 0.01 only for males). Differences between groups were significant for wing size and shape, but not for weight or weight/body length ratio. Melanic females and males showed significantly higher fluctuating asymmetry (FA) indices than their non-melanic counterparts.
CONCLUSIONS
This is the second report of melanic forms of T. infestans in domestic and peridomestic habitats in the Dry Chaco region of Argentina. Although non-melanic adults exhibited a higher infestation rate, melanic adults were widespread in the area and were collected in the infested domicile and in most types of peridomestic annexes. Differences in morphometric variables between groups might be due to different ecological adaptations. The higher FA levels observed in melanic individuals suggest a higher developmental instability and a selective advantage of non-melanic individuals in domestic and peridomestic habitats.
Topics: Animals; Chagas Disease; Color; Ecosystem; Humans; Insect Vectors; Melanins; Selection, Genetic; Triatoma
PubMed: 32014037
DOI: 10.1186/s13071-020-3912-y -
Acta Tropica Aug 2022Triatoma guasayana (Hemiptera, Reduviidae), considered a secondary vector of Chagas disease, invades rural dwellings through flight dispersal during the warm season in...
Triatoma guasayana (Hemiptera, Reduviidae), considered a secondary vector of Chagas disease, invades rural dwellings through flight dispersal during the warm season in semi-arid Chaco of Argentina. The objective of this study was to define and compare morphometrics features in the relative body size and wing shape of T. guasayana related to temperature and rainfall between spring, summer and end of summer. A total of 188 adults were collected in rural communities in the northwest of the province of Córdoba (central Argentina). Relative body size [body length (mm) / wing length (mm)] and 11 landmarks on the right wing were recorded. The temperature ( °C) and precipitation (mm) data were extracted from the MODIS sensor and Terra Climate dataset, respectively. Correlations between climatic variables and morphological variation were analyzed using Partial Least Square (PLS). Males at the end of summer were smaller than those at spring or summer (F = 4.48; df = 2; p = 0.01), whereas females were similar in relative body size at all seasons (F = 0.76; df = 2; p = 0.47). The PLS in males showed a correlation between wing shape and temperature (r = 0.48; p = 0.03) and precipitation (r = 0.50; p = 0.02) while in females only the temperature was the correlation significant (r = 0.35; p = 0.03). Triatoma guasayana has elongated and thin wings in spring that become short and wide at the end of summer. The morphotype of early summer could allow sustained long-duration flights, while the morphotype of end of summer would be related to short flights, correlated with the dispersive behavior of the species. The results in this study suggest that wing morphology of T. guasayana has phenotypic plasticity, and that temperature and rainfall could be considered modulator factors during the developmental stage.
Topics: Animals; Argentina; Chagas Disease; Female; Humans; Male; Rural Population; Seasons; Temperature; Triatoma
PubMed: 35533712
DOI: 10.1016/j.actatropica.2022.106488 -
Arthropod Structure & Development Mar 2019Triatomines (Heteroptera: Reduviidae) include around 139 species, widely known as vectors of Chagas disease. Our aim is to review the existing knowledge of the genital... (Review)
Review
Triatomines (Heteroptera: Reduviidae) include around 139 species, widely known as vectors of Chagas disease. Our aim is to review the existing knowledge of the genital morphology and sexual behavior and provide some functional analysis of these traits in triatomines. A complex set of traits comprise genitalia and these are highly variable among species. The components of the phallus and seminal products (secreted by action of testes and two accessory glands) interact to allow successful sperm transfer to the female spermathecae (usually a pair of blind tubes that emerge from the common oviduct). Seminal products may inhibit female physiology and extend mating duration. Mating behavior in triatomines is best characterized as scramble competition. We suggest that males may evaluate female condition prior to copulation, given that female fitness is largely affected by food (blood) source. Although rearing several triatomine species may be difficult and discourage from undertaking studies on this group, any further investigation on sexual behavior and mating interactions may provide data for applicative studies including Chagas disease vectors control.
Topics: Animals; Copulation; Female; Genitalia, Female; Genitalia, Male; Male; Microscopy, Electron, Scanning; Triatominae
PubMed: 30529710
DOI: 10.1016/j.asd.2018.11.012 -
Cutis Jun 2023Members of the Triatoma and Arilus genera (family Reduviidae) often are mistaken as the same arthropod, though their bites have vastly different health implications....
Members of the Triatoma and Arilus genera (family Reduviidae) often are mistaken as the same arthropod, though their bites have vastly different health implications. Bites of the wheel bug (Arilus cristatus) are painful compared to Triatoma bites, which are painless but can cause disease and result in an anaphylactic reaction, posing a risk to human health because these pliable insects commonly infest residential dwellings. A common dermatologic presentation of bites from Triatoma species and A cristatus is an erythematous pruritic papule that can progress to an urticarial wheal, though the presentation can differ from patient to patient. Treatment depends on whether the reaction is localized or systemic, ranging from topicals to systemic agents if anaphylaxis occurs.
Topics: Humans; Animals; Triatoma; Arthropods; Pain; Urticaria
PubMed: 37487132
DOI: 10.12788/cutis.0793