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Fronza G, Toloza AC, Mougabure-Cueto GA, Carbajo AE. Pyrethroid resistance distribution in Triatoma infestans and environmental association along the Argentine endemic zone. Acta Trop 2024; 257:107307. [PMID: 38950764 DOI: 10.1016/j.actatropica.2024.107307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/26/2024] [Accepted: 06/26/2024] [Indexed: 07/03/2024]
Abstract
Insecticide resistance is considered a barrier to chemical control of Triatoma infestans, the main vector of Chagas disease in the Southern Cone of South America. Although initiatives to reduce the incidence of the disease in the region have integrated different strategies, they have mainly relied on vector elimination using pyrethroid insecticides such as deltamethrin. Reports of pyrethroid resistance in connection with T. infestans control failures first emerged in northern Argentina and southern Bolivia. Recently, a mosaic pyrethroid-resistant focus has been described in the center of the Argentine Gran Chaco (Department of General Güemes, Chaco Province), characterized by the presence of susceptible and very highly resistant populations in the same area. The involvement of different resistance mechanisms has been proposed, together with the contribution of environmental variables that promote the toxicological heterogeneity described. In the endemic zone of Argentina, however, new questions arise: Are there any other clusters of resistance? Is there a relationship between the distribution of resistance and environmental variables (as has been observed at smaller scale)? We studied toxicological data from insects collected and analyzed at 224 localities between 2010 and 2020 as part of the resistance monitoring conducted by the Chagas National Program. The sites were classified according to the survival rate of insects exposed to a discriminant dose of deltamethrin: 0-0.19 were considered susceptible, 0.2-0.79 low-resistance, and 0.8-1 high-resistance. Localities were georeferenced to describe the spatial distribution of resistance and to identify environmental variables (demographics, land use, urbanization, connectivity, and climate) potentially associated with resistance. We used Generalized Linear Models (GLMs) to examine the association between resistance and environmental predictors, selecting error distributions based on the response variable definition. For the entire period, 197 susceptible localities were distributed across the endemic zone. Localities with different survival rates were found throughout the area; 9 high-resistance localities circled the two previously identified resistant foci, and 18 low-resistance in 6 provinces, highlighting their relevance for control planning. Precipitation variables were linked to resistance in all the GLMs evaluated. Presence/absence models were the most accurate, with precipitation, distance from the capital city, and land use contributing to the distribution of resistance. This information could be valuable for improving T. infestans control strategies in future scenarios characterized by unpredictable changes in land use and precipitation.
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Affiliation(s)
- Georgina Fronza
- Laboratorio de Ecología de Enfermedades Transmitidas Por Vectores, Instituto de Investigaciones e Ingeniería Ambiental, Escuela de Hábitat y Sostenibilidad (2eTV-IIIA-EHyS-UNSAM-CONICET). Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina.
| | - Ariel C Toloza
- Centro de Investigaciones de Plagas e Insecticidas, Unidad de Investigación y Desarrollo Estratégico para la Defensa (CIPEIN-UNIDEF-CONICET), Juan B. de La Salle 4397, Villa Martelli, Buenos Aires, Argentina
| | - Gastón A Mougabure-Cueto
- Laboratorio de Fisiología de Insectos, Departamento de Biodiversidad y Biología Experimental (DBBE), Instituto de Biología y Biodiversidad Experimental y Aplicada (IBBEA-UBA-CONICET), Universidad de Buenos Aires. Intendente Güiraldes, Ciudad Autónoma de Buenos Aires 2160, Argentina
| | - Anibal E Carbajo
- Laboratorio de Ecología de Enfermedades Transmitidas Por Vectores, Instituto de Investigaciones e Ingeniería Ambiental, Escuela de Hábitat y Sostenibilidad (2eTV-IIIA-EHyS-UNSAM-CONICET). Av. 25 de Mayo y Francia, San Martín, Buenos Aires, Argentina
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2
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Schaub GA. Interaction of Trypanosoma cruzi, Triatomines and the Microbiota of the Vectors-A Review. Microorganisms 2024; 12:855. [PMID: 38792688 PMCID: PMC11123833 DOI: 10.3390/microorganisms12050855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 04/15/2024] [Accepted: 04/17/2024] [Indexed: 05/26/2024] Open
Abstract
This review summarizes the interactions between Trypanosoma cruzi, the etiologic agent of Chagas disease, its vectors, triatomines, and the diverse intestinal microbiota of triatomines, which includes mutualistic symbionts, and highlights open questions. T. cruzi strains show great biological heterogeneity in their development and their interactions. Triatomines differ from other important vectors of diseases in their ontogeny and the enzymes used to digest blood. Many different bacteria colonize the intestinal tract of triatomines, but only Actinomycetales have been identified as mutualistic symbionts. Effects of the vector on T. cruzi are indicated by differences in the ability of T. cruzi to establish in the triatomines and in colonization peculiarities, i.e., proliferation mainly in the posterior midgut and rectum and preferential transformation into infectious metacyclic trypomastigotes in the rectum. In addition, certain forms of T. cruzi develop after feeding and during starvation of triatomines. Negative effects of T. cruzi on the triatomine vectors appear to be particularly evident when the triatomines are stressed and depend on the T. cruzi strain. Effects on the intestinal immunity of the triatomines are induced by ingested blood-stage trypomastigotes of T. cruzi and affect the populations of many non-symbiotic intestinal bacteria, but not all and not the mutualistic symbionts. After the knockdown of antimicrobial peptides, the number of non-symbiotic bacteria increases and the number of T. cruzi decreases. Presumably, in long-term infections, intestinal immunity is suppressed, which supports the growth of specific bacteria, depending on the strain of T. cruzi. These interactions may provide an approach to disrupt T. cruzi transmission.
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Affiliation(s)
- Günter A Schaub
- Zoology/Parasitology, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
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Piñanez-Espejo YMG, Munévar A, Schilman PE, Zurita GA. It is hot and cold here: the role of thermotolerance in the ability of spiders to colonize tree plantations in the southern Atlantic Forest. Oecologia 2024; 204:789-804. [PMID: 38561554 DOI: 10.1007/s00442-024-05529-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024]
Abstract
Worldwide, with the decline of natural habitats, species with reduced niche breadth (specialists) are at greater risk of extinction as they cannot colonise or persist in disturbed habitat types. However, the role of thermal tolerance as a critical trait in understanding changes in species diversity in disturbed habitats, e.g., due to forest replacement by tree plantations, is still understudied. To examine the role of thermal tolerance on the responses of specialist and generalist species to habitat disturbances, we measured and compared local temperature throughout the year and thermotolerance traits [upper (CTmax) and lower (CTmin) thermal limits] of the most abundant species of spiders from different guilds inhabiting pine tree plantations and native Atlantic Forests in South America. Following the thermal adaptation hypothesis, we predicted that generalist species would show a wider thermal tolerance range (i.e., lower CTmin and higher CTmax) than forest specialist species. As expected, generalist species showed significantly higher CTmax and lower CTmin values than specialist species with wider thermal tolerance ranges than forest specialist species. These differences are more marked in orb weavers than in aerial hunter spiders. Our study supports the specialisation disturbance and thermal hypotheses. It highlights that habitat-specialist species are more vulnerable to environmental changes associated with vegetation structure and microclimatic conditions. Moreover, thermal tolerance is a key response trait to explain the Atlantic Forest spider's ability (or inability) to colonise and persist in human-productive land uses.
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Affiliation(s)
- Yolanda M G Piñanez-Espejo
- IBS-Instituto de Biología Subtropical (UNaM-CONICET), Puerto Iguazú, Misiones, Argentina.
- Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina.
| | - Ana Munévar
- IBS-Instituto de Biología Subtropical (UNaM-CONICET), Puerto Iguazú, Misiones, Argentina
- Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina
| | - Pablo E Schilman
- Laboratorio de Ecofisiología de Insectos, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
- CONICET-Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), Buenos Aires, Argentina.
| | - Gustavo Andrés Zurita
- IBS-Instituto de Biología Subtropical (UNaM-CONICET), Puerto Iguazú, Misiones, Argentina.
- Facultad de Ciencias Forestales, Universidad Nacional de Misiones, Puerto Iguazú, Misiones, Argentina.
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4
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Pettersen AK, Metcalfe NB. Consequences of the cost of living: is variation in metabolic rate evolutionarily significant? Philos Trans R Soc Lond B Biol Sci 2024; 379:20220498. [PMID: 38186277 PMCID: PMC10772612 DOI: 10.1098/rstb.2022.0498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/14/2023] [Indexed: 01/09/2024] Open
Affiliation(s)
- Amanda K. Pettersen
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
- School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Neil B. Metcalfe
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
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5
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Iltis C, Tougeron K, Hance T, Louâpre P, Foray V. A perspective on insect-microbe holobionts facing thermal fluctuations in a climate-change context. Environ Microbiol 2021; 24:18-29. [PMID: 34713541 DOI: 10.1111/1462-2920.15826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/16/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022]
Abstract
Temperature influences the ecology and evolution of insects and their symbionts by impacting each partner independently and their interactions, considering the holobiont as a primary unit of selection. There are sound data about the responses of these partnerships to constant temperatures and sporadic thermal stress (mostly heat shock). However, the current understanding of the thermal ecology of insect-microbe holobionts remains patchy because the complex thermal fluctuations (at different spatial and temporal scales) experienced by these organisms in nature have often been overlooked experimentally. This may drastically constrain our ability to predict the fate of mutualistic interactions under climate change, which will alter both mean temperatures and thermal variability. Here, we tackle down these issues by focusing on the effects of temperature fluctuations on the evolutionary ecology of insect-microbe holobionts. We propose potentially worth-investigating research avenues to (i) evaluate the relevance of theoretical concepts used to predict the biological impacts of temperature fluctuations when applied to holobionts; (ii) acknowledge the plastic (behavioural thermoregulation, physiological acclimation) and genetic responses (evolution) expressed by holobionts in fluctuating thermal environments; and (iii) explore the potential impacts of previously unconsidered patterns of temperature fluctuations on the outcomes and the dynamic of these insect-microbe associations.
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Affiliation(s)
- Corentin Iltis
- Earth and Life Institute, Biodiversity Research Center, Université catholique de Louvain, Croix du Sud 4-5, Louvain-la-Neuve, 1348, Belgium
| | - Kévin Tougeron
- Earth and Life Institute, Biodiversity Research Center, Université catholique de Louvain, Croix du Sud 4-5, Louvain-la-Neuve, 1348, Belgium.,UMR CNRS 7058 EDYSAN (Ecologie et Dynamique des Systèmes Anthropisés), Université de Picardie Jules Verne, 33 rue St Leu, Amiens, 80039, France
| | - Thierry Hance
- Earth and Life Institute, Biodiversity Research Center, Université catholique de Louvain, Croix du Sud 4-5, Louvain-la-Neuve, 1348, Belgium
| | - Philippe Louâpre
- UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, Dijon, 21000, France
| | - Vincent Foray
- UMR CNRS 7261 Institut de Recherche sur la Biologie de l'Insecte, Université de Tours, Parc Grandmont, Tours, 37200, France
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6
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Schaub GA. An Update on the Knowledge of Parasite-Vector Interactions of Chagas Disease. Res Rep Trop Med 2021; 12:63-76. [PMID: 34093053 PMCID: PMC8169816 DOI: 10.2147/rrtm.s274681] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/15/2021] [Indexed: 11/23/2022] Open
Abstract
This review focusses on the interactions between the etiologic agent of Chagas disease, Trypanosoma cruzi, and its triatomine vector. The flagellate mainly colonizes the intestinal tract of the insect. The effect of triatomines on trypanosomes is indicated by susceptibility and refractoriness phenomena that vary according to the combination of the strains. Other effects are apparent in the different regions of the gut. In the stomach, the majority of ingested blood trypomastigotes are killed while the remaining transform to round stages. In the small intestine, these develop into epimastigotes, the main replicative stage. In the rectum, the population density is the highest and is where the infectious stage develops, the metacyclic trypomastigote. In all regions of the gut, starvation and feeding of the triatomine affect T. cruzi. In the small intestine and rectum, starvation reduces the population density and more spheromastigotes develop. In the rectum, feeding after short-term starvation induces metacyclogenesis and after long-term starvation the development of specific cells, containing several nuclei, kinetoplasts and flagella. When considering the effects of T. cruzi on triatomines, the flagellate seems to be of low pathogenicity. However, during stressful periods, which are normal in natural populations, effects occur often on the behaviour, eg, in readiness to approach the host, the period of time before defecation, dispersal and aggregation. In nymphs, the duration of the different instars and the mortality rates increase, but this seems to be induced by repeated infections or blood quality by the feeding on infected hosts. Starvation resistance is often reduced by infection. Longevity and reproduction of adults is reduced, but only after infection with some strains of T. cruzi. Only components of the surface coat of blood trypomastigotes induce an immune reaction. However, this seems to act against gut bacteria and favours the development of T. cruzi.
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Affiliation(s)
- Günter A Schaub
- Zoology/Parasitology, Ruhr-University Bochum, Bochum, Germany
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Rabinovich JE, Alvarez Costa A, Muñoz IJ, Schilman PE, Fountain-Jones NM. Machine-learning model led design to experimentally test species thermal limits: The case of kissing bugs (Triatominae). PLoS Negl Trop Dis 2021; 15:e0008822. [PMID: 33684127 PMCID: PMC7971882 DOI: 10.1371/journal.pntd.0008822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 03/18/2021] [Accepted: 01/10/2021] [Indexed: 12/18/2022] Open
Abstract
Species Distribution Modelling (SDM) determines habitat suitability of a species across geographic areas using macro-climatic variables; however, micro-habitats can buffer or exacerbate the influence of macro-climatic variables, requiring links between physiology and species persistence. Experimental approaches linking species physiology to micro-climate are complex, time consuming and expensive. E.g., what combination of exposure time and temperature is important for a species thermal tolerance is difficult to judge a priori. We tackled this problem using an active learning approach that utilized machine learning methods to guide thermal tolerance experimental design for three kissing-bug species: Triatoma infestans, Rhodnius prolixus, and Panstrongylus megistus (Hemiptera: Reduviidae: Triatominae), vectors of the parasite causing Chagas disease. As with other pathogen vectors, triatomines are well known to utilize micro-habitats and the associated shift in microclimate to enhance survival. Using a limited literature-collected dataset, our approach showed that temperature followed by exposure time were the strongest predictors of mortality; species played a minor role, and life stage was the least important. Further, we identified complex but biologically plausible nonlinear interactions between temperature and exposure time in shaping mortality, together setting the potential thermal limits of triatomines. The results from this data led to the design of new experiments with laboratory results that produced novel insights of the effects of temperature and exposure for the triatomines. These results, in turn, can be used to better model micro-climatic envelope for the species. Here we demonstrate the power of an active learning approach to explore experimental space to design laboratory studies testing species thermal limits. Our analytical pipeline can be easily adapted to other systems and we provide code to allow practitioners to perform similar analyses. Not only does our approach have the potential to save time and money: it can also increase our understanding of the links between species physiology and climate, a topic of increasing ecological importance.
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Affiliation(s)
- Jorge E. Rabinovich
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE CONICET-CCT La Plata, UNLP), National University of La Plata, La Plata, Argentina
| | - Agustín Alvarez Costa
- Laboratorio de Ecofisiología de Insectos, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET–Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ignacio J. Muñoz
- Laboratorio de Ecofisiología de Insectos, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET–Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Pablo E. Schilman
- Laboratorio de Ecofisiología de Insectos, Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA), CONICET–Universidad de Buenos Aires, Buenos Aires, Argentina
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Rabinovich JE. Morphology, Life Cycle, Environmental Factors and Fitness – a Machine Learning Analysis in Kissing Bugs (Hemiptera, Reduviidae, Triatominae). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.651683] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Populations are permanently evolving and their evolution will influence their survival and reproduction, which will then alter demographic parameters. Several phenotypic, life history and environmental variables are known to be related to fitness measures. The goal of this article was to look into the possible types of those relationships in insects of the subfamily Triatominae, vectors of Trypanosoma cruzi, the causative agent of Chagas disease. After an exhaustive literature review of 7,207 records of publications referring exclusively to all possible features of the triatomines, using 15 keywords those records were reduced to 2,968 publications, that were analyzed individually; after deleting those publications that did not have the data in quantitative form as needed for the objective of this article, I found that 171 papers were adequate for the present analysis. From them I compiled a dataset of 11 variables and 90 cases from 36 triatomine species. Those variables included four environmental, two life cycle, and four morphological variables, and one demographic parameter: a fitness measure (the population intrinsic rate of natural increase, r0), used as dependent variable. However, the relationship between T. cruzi and its vector host was not included in this analysis despite triatomine-T. cruzi interactions constitute an important factor in the evolution of triatomine’s life history. I resorted to the Random Forest method as a machine learning approach for the analysis of this dataset, and found that –in addition to the triatomine species themselves– only the two life cycle variables (mean development time from egg to adult, and mean fecundity, expressed as the average number of female eggs laid per female per day) were statistically significant in determining fitness (r0). The machine learning approach used in the analysis provided a similar but deeper insight into these relationships than classical regression. Except for an analysis on senescence, this is the first study in triatomines addressing these questions. These results will be useful for other theoretical optimization approaches (frequency-dependence, density-dependence, evolutionary game theory, and adaptive dynamics), thus contributing to the theoretical framework for interpreting the succession of stages in insect adaptations, a framework yet to be constructed.
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Clavijo-Baquet S, Cavieres G, González A, Cattan PE, Bozinovic F. Thermal performance of the Chagas disease vector, Triatoma infestans, under thermal variability. PLoS Negl Trop Dis 2021; 15:e0009148. [PMID: 33571203 PMCID: PMC7904210 DOI: 10.1371/journal.pntd.0009148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/24/2021] [Accepted: 01/14/2021] [Indexed: 11/18/2022] Open
Abstract
Vector-borne diseases (VBD) are particularly susceptible to climate change because most of the diseases' vectors are ectotherms, which themselves are susceptible to thermal changes. The Chagas disease is one neglected tropical disease caused by the protozoan parasite, Trypanosoma cruzi. One of the main vectors of the Chagas disease in South America is Triatoma infestans, a species traditionally considered to be restricted to domestic or peridomestic habitats, but sylvatic foci have also been described along its distribution. The infestation of wild individuals, together with the projections of environmental changes due to global warming, urge the need to understand the relationship between temperature and the vector's performance. Here, we evaluated the impact of temperature variability on the thermal response of T. infestans. We acclimated individuals to six thermal treatments for five weeks to then estimate their thermal performance curves (TPCs) by measuring the walking speed of the individuals. We found that the TPCs varied with thermal acclimation and body mass. Individuals acclimated to a low and variable ambient temperature (18°C ± 5°C) exhibited lower performances than those individuals acclimated to an optimal temperature (27°C ± 0°C); while those individuals acclimated to a low but constant temperature (18°C ± 0°C) did not differ in their maximal performance from those at an optimal temperature. Additionally, thermal variability (i.e., ± 5°C) at a high temperature (30°C) increased performance. These results evidenced the plastic response of T. infestans to thermal acclimation. This plastic response and the non-linear effect of thermal variability on the performance of T. infestans posit challenges when predicting changes in the vector's distribution range under climate change.
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Affiliation(s)
- Sabrina Clavijo-Baquet
- Laboratorio de Etología, Ecología y Evolución, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Grisel Cavieres
- Departamento de Ecología, Center of Applied Ecology & Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Avia González
- Departamento de Ecología, Center of Applied Ecology & Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pedro E. Cattan
- Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Francisco Bozinovic
- Departamento de Ecología, Center of Applied Ecology & Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Melo RDFP, Guarneri AA, Silber AM. The Influence of Environmental Cues on the Development of Trypanosoma cruzi in Triatominae Vector. Front Cell Infect Microbiol 2020; 10:27. [PMID: 32154185 PMCID: PMC7046586 DOI: 10.3389/fcimb.2020.00027] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/15/2020] [Indexed: 12/19/2022] Open
Abstract
Trypanosoma cruzi, a hemoflagellate parasite, is the etiological agent of Chagas disease that affects about 6-7 million people worldwide, mostly in Latin America. The parasite life cycle is complex and alternates between an invertebrate host-Triatominae vector-and a mammalian host. The parasite adaptation to the several microenvironments through which it transits is critical to success in establishing infection. Moreover, environmental cues also play an important role on the parasite development, and it can modulate the infection. In the present study, we discussed how the temperature oscillations and the nutritional state of the invertebrate host can affect the parasite development, multiplication, and the differentiation process of epimastigote forms into metacyclic trypomastigotes, called metacyclogenesis. The impact of oxidative imbalance and osmotic stresses on the parasite-vector relationship are also discussed.
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Affiliation(s)
- Raíssa de Fátima Pimentel Melo
- Laboratório de Bioquímica de Tryps (LaBTryps), Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Alessandra Aparecida Guarneri
- Vector Behaviour and Pathogen Interaction Group, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Ariel Mariano Silber
- Laboratório de Bioquímica de Tryps (LaBTryps), Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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11
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Belliard SA, De la Vega GJ, Schilman PE. Thermal Tolerance Plasticity in Chagas Disease Vectors Rhodnius prolixus (Hemiptera: Reduviidae) and Triatoma infestans. JOURNAL OF MEDICAL ENTOMOLOGY 2019; 56:997-1003. [PMID: 30849174 DOI: 10.1093/jme/tjz022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Indexed: 06/09/2023]
Abstract
Temperature is recognized as the most influential abiotic factor on the distribution and dispersion of most insect species including Rhodnius prolixus (Stål, 1859) and Triatoma infestans (Klug, 1834), the two most important Chagas disease vectors. Although, these species thermotolerance range is well known their plasticity has never been addressed in these or any other triatomines. Herein, we investigate the effects of acclimation on thermotolerance range and resistance to stressful low temperatures by assessing thermal critical limits and 'chill-coma recovery time' (CCRT), respectively. We found positive effects of acclimation on thermotolerance range, especially on the thermal critical minimum of both species. In contrast, CCRT did not respond to acclimation in either. Our results reveal the plasticity of these Triatomines thermal tolerance in response to a wide range of acclimation temperatures. This presumably represents a physiological adaptation to daily or seasonal temperature variation with concomitant improvement in dispersion potential.
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Affiliation(s)
- Silvina A Belliard
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada. CONICET-UBA, Buenos Aires, Argentina
| | - Gerardo J De la Vega
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada. CONICET-UBA, Buenos Aires, Argentina
| | - Pablo E Schilman
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada. CONICET-UBA, Buenos Aires, Argentina
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12
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Modelling the association between deltamethrin resistance in Triatoma infestans populations of the Argentinian Gran Chaco region with environmental factors. Acta Trop 2019; 194:53-61. [PMID: 30898614 DOI: 10.1016/j.actatropica.2019.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/26/2019] [Accepted: 03/16/2019] [Indexed: 11/21/2022]
Abstract
In Latin America, Triatoma infestans is the main vector of the protozoan Trypanosoma cruzi, causal agent of Chagas disease. This blood-sucking triatomine is widely distributed in the Gran Chaco ecoregion, where chemical control has failed because of the evolution of resistance to pyrethroid insecticides. Recently, we described a deltamethrin high resistant focus in Güemes Department (Chaco province) characterized by susceptible populations, populations with low resistance (without field control failures) and some of the populations with the highest resistance level detected. This toxicological heterogeneity could be a result of non-homogenous insecticide pressure and be influenced by environmental factors. The present study evaluated the association of deltamethrin resistance ratios (RR50s) of T. infestans populations with explanatory variables extracted from the WorldClim dataset and constructed from information of National Chagas Program actions during 2005-2015. Control actions were distributed throughout the analyzed period, representing a homogeneous selective pressure. The average percentage of total positive houses was 33.66%. Models that included temperature and precipitation indicators presented 65% explanation. When village size variables where added, the explanatory power reached 70%. This observational result suggests that the climate may favor directly or indirectly the development/selection for resistance, representing a valuable tool to understand the occurrence of resistance that could increase the Chagas disease in the Gran Chaco.
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