scholarly journals Community disassembly and disease: realistic—but not randomized—biodiversity losses enhance parasite transmission

2019 ◽  
Vol 286 (1902) ◽  
pp. 20190260 ◽  
Author(s):  
Pieter T. J. Johnson ◽  
Dana M. Calhoun ◽  
Tawni Riepe ◽  
Travis McDevitt-Galles ◽  
Janet Koprivnikar
Keyword(s):  
Species Composition ◽  
Host Species ◽  
Host Community ◽  
Trematode Species ◽  
Parasite Transmission ◽  
Field Surveys ◽  
Larval Amphibians ◽  
Experimental Approaches ◽  
The Individual ◽  
The Relationship

Debates over the relationship between biodiversity and disease dynamics underscore the need for a more mechanistic understanding of how changes in host community composition influence parasite transmission. Focusing on interactions between larval amphibians and trematode parasites, we experimentally contrasted the effects of host richness and species composition to identify the individual and joint contributions of both parameters on the infection levels of three trematode species. By combining experimental approaches with field surveys from 147 ponds, we further evaluated how richness effects differed between randomized and realistic patterns of species loss (i.e. community disassembly). Our results indicated that community-level changes in infection levels were owing to host species composition, rather than richness. However, when composition patterns mirrored empirical observations along a natural assembly gradient, each added host species reduced infection success by 12–55%. No such effects occurred when assemblages were randomized. Mechanistically, these patterns were due to non-random host species assembly/disassembly: while highly competent species predominated in low diversity systems, less susceptible hosts became progressively more common as richness increased. These findings highlight the potential for combining information on host traits and assembly patterns to forecast diversity-mediated changes in multi-host disease systems.

scholarly journals Host community assembly modifies the relationship between host and parasite richness

2019 ◽  
Author(s):  
Fletcher W. Halliday ◽  
Robert W. Heckman ◽  
Peter A. Wilfahrt ◽  
Charles E. Mitchell
Keyword(s):  
Community Assembly ◽  
Host Species ◽  
Phylogenetic Diversity ◽  
Host Community ◽  
Parasite Transmission ◽  
Host Diversity ◽  
Parasite Richness ◽  
The Stability ◽  
The Relationship ◽  
Exotic Host

AbstractHost and parasite richness are generally positively correlated, but the stability of this relationship during community assembly remains untested. The composition of host communities can alter parasite transmission, and the relationship between host and parasite richness is sensitive to parasite transmission. Thus, changes in composition during host community assembly could strengthen or weaken the relationship between host and parasite richness. Host community assembly, in turn, can be driven by many processes, including resource enrichment. To test the hypothesis that host community assembly can alter the relationship between host and parasite richness, we experimentally crossed host diversity and resource supply to hosts, then allowed communities to assemble. As previously shown, initial host diversity and resource supply determined the trajectory of host community assembly, altering post-assembly host species richness, richness-independent host phylogenetic diversity, and colonization by exotic host species. Throughout community assembly, host richness predicted parasite richness. As predicted, this effect was moderated by exotic abundance: communities dominated by exotic species exhibited a stronger positive relationship between post-assembly host and parasite richness. Ultimately, these results suggest that, by modulating parasite transmission, community assembly can modify the relationship between host and parasite richness, providing a novel mechanism to explain contingencies in this relationship.

scholarly journals Vector-borne parasite invasion in communities across space and time

2019 ◽  
Vol 286 (1917) ◽  
pp. 20192614
Author(s):  
John E. Vinson ◽  
Andrew W. Park
Keyword(s):  
Host Species ◽  
Species Abundance ◽  
Host Community ◽  
Parasite Transmission ◽  
Community Size ◽  
Parasite Invasion ◽  
Space And Time ◽  
Invasion Potential ◽  
Novel Host ◽  
Vector Borne

While vector-borne parasite transmission often operates via generalist-feeding vectors facilitating cross-species transmission in host communities, theory describing the relationship between host species diversity and parasite invasion in these systems is underdeveloped. Host community composition and abundance vary across space and time, generating opportunities for parasite invasion. To explore how host community variation can modify parasite invasion potential, we develop a model for vector-borne parasite transmission dynamics that includes a host community of arbitrary richness and species' abundance. To compare invasion potential across communities, we calculate the community basic reproductive ratio of the parasite. We compare communities comprising a set of host species to their subsets, which allows for flexible scenario building including the introduction of novel host species and species loss. We allow vector abundance to scale with, or be independent of, community size, capturing regulation by feeding opportunities and non-host effects such as limited oviposition sites. Motivated by equivocal data relating host species competency to abundance, we characterize plausible host communities via phenomenological relationships between host species abundance and competency. We identify an underappreciated mechanism whereby changes to communities simultaneously alter average competency and the vector to host ratio and demonstrate that the interaction can profoundly influence invasion potential.

Ectoparasites and endoparasites of fish form networks with different structures

Parasitology ◽  
2015 ◽  
Vol 142 (7) ◽  
pp. 901-909 ◽  
Author(s):  
S. BELLAY ◽  
E. F. DE OLIVEIRA ◽  
M. ALMEIDA-NETO ◽  
M. A. R. MELLO ◽  
R. M. TAKEMOTO ◽  
...  
Keyword(s):  
Species Composition ◽  
Host Species ◽  
Parasite Species ◽  
Parasite Fauna ◽  
Interaction Patterns ◽  
Host Fish ◽  
Ecological Processes ◽  
Fauna Composition ◽  
The Relationship ◽  
Interaction Intensity

SUMMARYHosts and parasites interact with each other in a variety of ways, and this diversity of interactions is reflected in the networks they form. To test for differences in interaction patterns of ecto- and endoparasites we analysed subnetworks formed by each kind of parasites and their host fish species in fish–parasite networks for 22 localities. We assessed the proportion of parasite species per host species, the relationship between parasite fauna composition and host taxonomy, connectance, nestedness and modularity of each subnetwork (n = 44). Furthermore, we evaluated the similarity in host species composition among modules in ecto- and endoparasite subnetworks. We found several differences between subnetworks of fish ecto- and endoparasites. The association with a higher number of host species observed among endoparasites resulted in higher connectance and nestedness, and lower values of modularity in their subnetworks than in those of ectoparasites. Taxonomically related host species tended to share ecto- or endoparasites with the same interaction intensity, but the species composition of hosts tended to differ between modules formed by ecto- and endoparasites. Our results suggest that different evolutionary and ecological processes are responsible for organizing the networks formed by ecto- and endoparasites and fish.

Patterns ofClinostomum marginatuminfection in fishes and amphibians: integration of field, genetic, and experimental approaches

2019 ◽  
Vol 94 ◽  
Author(s):  
D.M. Calhoun ◽  
K. L. Leslie ◽  
T.B. Riepe ◽  
T.J. Achatz ◽  
T. McDevitt-Galles ◽  
...  
Keyword(s):  
Host Species ◽  
Large Scale ◽  
Life Stage ◽  
Exposure Dose ◽  
Molecular Evidence ◽  
Intermediate Hosts ◽  
Species Identity ◽  
Field Surveys ◽  
Pseudacris Regilla ◽  
Experimental Approaches

AbstractDigenetic trematodes of the genusClinostomumare cosmopolitan parasites infecting fishes, amphibians, reptiles, and snails as intermediate hosts. Despite the broad geographical distribution of this genus, debate about the number of species and how they vary in host use has persisted. To better understand patterns of infection among host species and across life stages, we used large-scale field surveys and molecular tools to examine five species of amphibians and seven species of fishes from 125 California ponds. Among the 12,360 examined hosts, infection was rare, with an overall prevalence of 1.7% in amphibians and 9.2% in fishes. Molecular evidence indicated that both groups were infected withClinostomum marginatum. Using generalized linear mixed effects models, host species identity and host life stage had a strong influence on infection status, such thatLepomis cyanellus(green sunfish) (49.3%) andTaricha granulosa(rough skinned newt) (9.2%) supported the highest overall prevalence values, whereas adult amphibians tended to have a higher prevalence of infection relative to juveniles (13.3% and 2.5%, respectively). Experimentally, we tested the susceptibility of two amphibian hosts (Pseudacris regilla[Pacific chorus frog] andAnaxyrus boreas[western toad]) to varying levels of cercariae exposure and measured metacercariae growth over time.Pseudacris regillawas 1.3× more susceptible to infection, while infection success increased with cercariae exposure dose for both species. On average, metacarcariae size increased by 650% over 20 days. Our study highlights the importance of integrating field surveys, genetic tools, and experimental approaches to better understand the ecology of host–parasite interactions.

Species and site contributions toβ-diversity in fleas parasitic on the Palearctic small mammals: ecology, geography and host species composition matter the most

Parasitology ◽  
2018 ◽  
Vol 146 (5) ◽  
pp. 653-661 ◽  
Author(s):  
Boris R. Krasnov ◽  
Georgy I. Shenbrot ◽  
Elizabeth M. Warburton ◽  
Luther van der Mescht ◽  
Elena N. Surkova ◽  
...  
Keyword(s):  
Life History ◽  
Species Composition ◽  
Small Mammals ◽  
Host Species ◽  
Host Community ◽  
Life History Trait ◽  
Environmental Predictors ◽  
Factors Affecting ◽  
Spatial Variables ◽  
Moderate Scale

AbstractTheβ-diversity of fleas parasitic on small mammals in 45 regions of the Palearctic was partitioned into species [species contributions toβ-diversity (SCBD)] and site ( = assemblage) contributions [local contributions toβ-diversity (LCBD)]. We asked what are the factors affecting SCBD and LCBD and tested whether (a) variation in ecological, morphological, life history and geographic traits of fleas can predict SCBD and (b) variation in flea and host community metrics, off-host environmental factors, host species composition of flea assemblages can predict LCBD. We used spatial variables to describe geographic distribution of flea assemblages with various LCBD values. SCBD significantly increased with an increase in abundance and a decrease in phylogenetic host specificity of a flea as well as with size and latitude of its geographic range, but was not associated with any morphological/life history trait. LCBD of flea assemblages did not depend on either flea or host species richness or environmental predictors, but was significantly affected by compositional uniqueness ( = LCBD) of regional host assemblages and variables describing their species composition. In addition, variation in LCBD was also explained by broad-to-moderate-scale spatial variables. We conclude that SCBD of fleas could be predictedviatheir ecological and geographic traits, whereas LCBD of their assemblages could be predictedviahost composition.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Investigating the Relationship Between Self-Esteem and Stigma Among Young Adults With History of Suicide Attempts

Crisis ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Meshan Lehmann ◽  
Matthew R. Hilimire ◽  
Lawrence H. Yang ◽  
Bruce G. Link ◽  
Jordan E. DeVylder
Keyword(s):  
Young Adults ◽  
Suicide Attempts ◽  
Self Esteem ◽  
High Risk Population ◽  
High Functioning ◽  
People With Mental Illness ◽  
History Of ◽  
The Individual ◽  
The Impact ◽  
The Relationship

Abstract. Background: Self-esteem is a major contributor to risk for repeated suicide attempts. Prior research has shown that awareness of stigma is associated with reduced self-esteem among people with mental illness. No prior studies have examined the association between self-esteem and stereotype awareness among individuals with past suicide attempts. Aims: To understand the relationship between stereotype awareness and self-esteem among young adults who have and have not attempted suicide. Method: Computerized surveys were administered to college students (N = 637). Linear regression analyses were used to test associations between self-esteem and stereotype awareness, attempt history, and their interaction. Results: There was a significant stereotype awareness by attempt interaction (β = –.74, p = .006) in the regression analysis. The interaction was explained by a stronger negative association between stereotype awareness and self-esteem among individuals with past suicide attempts (β = –.50, p = .013) compared with those without attempts (β = –.09, p = .037). Conclusion: Stigma is associated with lower self-esteem within this high-functioning sample of young adults with histories of suicide attempts. Alleviating the impact of stigma at the individual (clinical) or community (public health) levels may improve self-esteem among this high-risk population, which could potentially influence subsequent suicide risk.

Tourism awareness as a tourism development strategy: status of the issue

2020 ◽  
Vol 13 (9) ◽  
Author(s):  
M.I. Rosas-Jaco ◽  
S.X. Almeraya-Quintero ◽  
L.G. Guajardo-Hernández
Keyword(s):  
Development Strategy ◽  
Design Methodology ◽  
Local Development ◽  
Local Population ◽  
Host Community ◽  
Government Policies ◽  
Training Manual ◽  
Environmental Development ◽  
Main Engine ◽  
The Relationship

Objective: Tourism has become the main engine of economic, social and environmental development in several countries, so promoting tourism awareness among tourists and the local population should be a priority. The present study aims to suggest a status of the research carried out on the topic of tourism awareness. Design / methodology / approach: The type of analysis is through a retrospective and exploratory bibliometric study. The analysis materials were scientific articles and a training manual published between 2000 and 2020, registered by Scopus, Emerald insight and Dialnet, using “tourism awareness” as the keyword. Results: When considering the three senses in which tourism awareness ought to operate, it is concluded that studies are more focused on the relationship and contact of the host community with the tourist. It is observed that four out of six articles in this sense consider that education, training, and government policies around tourism awareness should be developed in a better way in the destinations, in order to be an element that contributes to the development of communities and reduces poverty in developing countries. Study limitations / implications: It is considered a limitation not to include thesis dissertations. Findings / conclusions: It is necessary to make visible the importance of tourism awareness as a local development strategy for communities, in addition to including tourism awareness on the part of tourists.

Virginia Woolf and Being-in-the-world

2017 ◽  
Author(s):  
Emma Simone
Keyword(s):  
Virginia Woolf ◽  
Historical Context ◽  
The Political ◽  
Cartesian Dualism ◽  
Self And Other ◽  
The World ◽  
Binary Oppositions ◽  
The Individual ◽  
The Relationship ◽  
Existential Perspective

Virginia Woolf and Being-in-the-world: A Heideggerian Study explores Woolf’s treatment of the relationship between self and world from a phenomenological-existential perspective. This study presents a timely and compelling interpretation of Virginia Woolf’s textual treatment of the relationship between self and world from the perspective of the philosophy of Martin Heidegger. Drawing on Woolf’s novels, essays, reviews, letters, diary entries, short stories, and memoirs, the book explores the political and the ontological, as the individual’s connection to the world comes to be defined by an involvement and engagement that is always already situated within a particular physical, societal, and historical context. Emma Simone argues that at the heart of what it means to be an individual making his or her way in the world, the perspectives of Woolf and Heidegger are founded upon certain shared concerns, including the sustained critique of Cartesian dualism, particularly the resultant binary oppositions of subject and object, and self and Other; the understanding that the individual is a temporal being; an emphasis upon intersubjective relations insofar as Being-in-the-world is defined by Being-with-Others; and a consistent emphasis upon average everydayness as both determinative and representative of the individual’s relationship to and with the world.

The importance and significance of gene polymorphisms in preeclampsia

2016 ◽  
pp. 45-49
Author(s):  
P.N. Veropotvelyan ◽  
◽  
I.S. Tsehmistrenko ◽  
N.P. Veropotvelyan ◽  
N.S. Rusak ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Systematic Review ◽  
Early Diagnosis ◽  
Gene Polymorphisms ◽  
Individual Risk ◽  
Extended Study ◽  
Stress Genes ◽  
Detoxification System ◽  
The Individual ◽  
The Relationship

Was to conduct a systematic review of data on the relationship between polymorphisms genes of detoxification system and development of preeclampsia (РЕ). Рresents the main genes of detoxification system (GSTPI, GSTМI, GSTТI, GРХI, ЕРНХI, SOD-2, SOD-3, CYPIAL, MTHЕR, MTR) and their functions. Of interest is the possibility of calculating the individual risk of PE based on the results about the presence of a combination of different polymorphisms in the genotype of the female. Question about early diagnosis of РЕ remains controversial and not fully understood. It is necessary to conduct further in-depth, extended study of this problem. Key words: preeclampsia, oxidative stress, genes of the detoxification system.

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