scholarly journals Long-term prevalence data reveals spillover dynamics in a multi-host (Artemia), multi-parasite (Microsporidia) community

2018 ◽  
Author(s):  
Eva J.P. Lievens ◽  
Nicolas O. Rode ◽  
Julie Landes ◽  
Adeline Segard ◽  
Roula Jabbour-Zahab ◽  
...  
Keyword(s):  
Host Species ◽  
Natural Variation ◽  
Community Context ◽  
Parasite Transmission ◽  
Prevalence Data ◽  
Cascading Effects ◽  
High Prevalence ◽  
Host Parasite ◽  
Parasite Dynamics

AbstractIn the study of multi-host parasites, it is often found that host species contribute asymmetrically to parasite transmission, with cascading effects on parasite dynamics and overall community structure. Yet, identifying which of the host species contribute to parasite transmission and maintenance is a recurring challenge. Here, we approach this issue by taking advantage of natural variation in the community composition of host species. We studied the horizontally transmitted microsporidians Anostracospora rigaudi and Enterocytospora artemiae in a Southern French metacommunity of their brine shrimp hosts, Artemia franciscana and Artemia parthenogenetica. Within the metacommunity, patches can contain either or both of the Artemia host species, so that long-term prevalence data can provide a direct link between the presence of the two host species and the persistence of the two parasites. First, we show that the microsporidian A. rigaudi is a spillover parasite: it was unable to persist in the absence of its maintenance host A. parthenogenetica. This result was particularly striking in light of A. rigaudi’s high prevalence (in the field) and high infectivity (when tested in the lab) in both hosts. Moreover, A. parthenogenetica’s seasonal presence imposed seasonality on the rate of spillover, causing cyclical pseudo-endemics in the spillover host A. franciscana. Second, while our prevalence data was sufficient to identify E. artemiae as either a spillover or a facultative multi-host parasite, we could not distinguish between the two possibilities. This study supports the importance of studying the community context of multi-host parasites, and demonstrates that in appropriate multi-host systems, sampling across a range of conditions and host communities can lead to clear conclusions about the drivers of parasite persistence.

scholarly journals Potential parasite transmission in multi-host networks based on parasite sharing

2014 ◽  
Author(s):  
Shai Pilosof ◽  
Serge Morand ◽  
Boris R Krasnov ◽  
Charles L Nunn
Keyword(s):  
Host Species ◽  
Single Species ◽  
Individual Characteristics ◽  
Parasite Transmission ◽  
Species Identity ◽  
Transmission Networks ◽  
Single Host ◽  
Transmission Pathways ◽  
Host Parasite ◽  
Parasite Dynamics

Epidemiological networks are commonly used to explore dynamics of parasite transmission among individuals in a population of a given host species. However, many parasites infect multiple host species, and thus multi-host networks may offer a better framework for investigating parasite dynamics. We investigated the factors that influence parasite sharing – and thus potential transmission pathways – among rodent hosts in Southeast Asia. We focused on differences between networks of a single host species and networks that involve multiple host species. In host-parasite networks, modularity (the extent to which the network is divided to subgroups composed of individuals that interact more among themselves than with individuals outside the subgroup) was higher in the multi-species than in the single-species networks. This suggests that phylogeny affects patterns of parasite sharing, which was confirmed in analyses showing that it predicted affiliation of individuals to modules. We then constructed “potential transmission networks” based on the host-parasite networks, in which edges depict the number of parasites shared between a pair of individuals. The centrality of individuals in these networks differed between multi- and single-species networks, with species identity and individual characteristics influencing their position in the networks. Simulations further revealed that parasite dynamics differed between multi- and single-species networks. We conclude that multi-host networks based on parasite sharing can provide new insights into the potential for transmission among hosts in an ecological community. In addition, the factors that determine the nature of parasite sharing (i.e. structure of the host-parasite network) may impact transmission patterns.

scholarly journals Potential parasite transmission in multi-host networks based on parasite sharing

2014 ◽  
Author(s):  
Shai Pilosof ◽  
Serge Morand ◽  
Boris R Krasnov ◽  
Charles L Nunn
Keyword(s):  
Host Species ◽  
Single Species ◽  
Individual Characteristics ◽  
Parasite Transmission ◽  
Species Identity ◽  
Transmission Networks ◽  
Single Host ◽  
Transmission Pathways ◽  
Host Parasite ◽  
Parasite Dynamics

Epidemiological networks are commonly used to explore dynamics of parasite transmission among individuals in a population of a given host species. However, many parasites infect multiple host species, and thus multi-host networks may offer a better framework for investigating parasite dynamics. We investigated the factors that influence parasite sharing – and thus potential transmission pathways – among rodent hosts in Southeast Asia. We focused on differences between networks of a single host species and networks that involve multiple host species. In host-parasite networks, modularity (the extent to which the network is divided to subgroups composed of individuals that interact more among themselves than with individuals outside the subgroup) was higher in the multi-species than in the single-species networks. This suggests that phylogeny affects patterns of parasite sharing, which was confirmed in analyses showing that it predicted affiliation of individuals to modules. We then constructed “potential transmission networks” based on the host-parasite networks, in which edges depict the number of parasites shared between a pair of individuals. The centrality of individuals in these networks differed between multi- and single-species networks, with species identity and individual characteristics influencing their position in the networks. Simulations further revealed that parasite dynamics differed between multi- and single-species networks. We conclude that multi-host networks based on parasite sharing can provide new insights into the potential for transmission among hosts in an ecological community. In addition, the factors that determine the nature of parasite sharing (i.e. structure of the host-parasite network) may impact transmission patterns.

scholarly journals Avian vampire fly (Philornis downsi) mortality differs across Darwin’s finch host species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lauren K. Common ◽  
Petra Sumasgutner ◽  
Rachael Y. Dudaniec ◽  
Diane Colombelli-Négrel ◽  
Sonia Kleindorfer
Keyword(s):  
Host Species ◽  
Larval Mortality ◽  
Fitness Costs ◽  
Small Tree ◽  
Host Nest ◽  
Philornis Downsi ◽  
Time Period ◽  
Specific Mortality ◽  
Host Parasite ◽  
Parasite Dynamics

AbstractIn invasive parasites, generalism is considered advantageous during the initial phase of introduction. Thereafter, fitness costs to parasites, such as host-specific mortality, can drive parasites towards specialism to avoid costly hosts. It is important to determine changes in host specificity of invasive populations to understand host-parasite dynamics and their effects on vulnerable host populations. We examined changes in mortality in the introduced avian vampire fly (Philornis downsi) (Diptera: Muscidae), a generalist myasis-causing ectoparasite, between 2004 and 2020 on Floreana Island (Galápagos). Mortality was measured as the proportion of immature larvae found upon host nest termination. Over the time period, the avian vampire fly was most abundant and had low mortality in nests of the critically endangered medium tree finch (Camarhynchus pauper) and had the highest mortality in nests of hybrid tree finches (Camarhynchus spp.). Low larval mortality was also found in small tree (Camarhynchus parvulus) and small ground finch (Geospiza fuliginosa) nests. Selection could favour avian vampire flies that select medium tree finch nests and/or avoid hybrid nests. Overall, the finding of differences in avian vampire fly survival across host species is parsimonious with the idea that the introduced fly may be evolving towards host specialisation.

scholarly journals Effects of climate change on parasites and disease in estuarine and nearshore environments

PLoS Biology ◽  
2020 ◽  
Vol 18 (11) ◽  
pp. e3000743
Author(s):  
James E. Byers
Keyword(s):  
Climate Change ◽  
Temperature Effects ◽  
Marine Invertebrate ◽  
Research Priorities ◽  
Community Context ◽  
Bottom Line ◽  
Change Factors ◽  
Lethal Limit ◽  
Host Parasite ◽  
Parasite Dynamics

Information on parasites and disease in marine ecosystems lags behind terrestrial systems, increasing the challenge of predicting responses of marine host–parasite systems to climate change. However, here I examine several generalizable aspects and research priorities. First, I advocate that quantification and comparison of host and parasite thermal performance curves is a smart approach to improve predictions of temperature effects on disease. Marine invertebrate species are ectothermic and should be highly conducive to this approach given their generally short generation times. Second, in marine systems, shallow subtidal and intertidal areas will experience the biggest temperature swings and thus likely see the most changes to host–parasite dynamics. Third, for some responses like parasite intensity, as long as the lethal limit of the parasite is not crossed, on average, there may be a biological basis to expect temperature-dependent intensification of impacts on hosts. Fourth, because secondary mortality effects and indirect effects of parasites can be very important, we need to study temperature effects on host–parasite dynamics in a community context to truly know their bottom line effects. This includes examining climate-influenced effects of parasites on ecosystem engineers given their pivotal role in communities. Finally, other global change factors, especially hypoxia, salinity, and ocean acidity, covary with temperature change and need to be considered and evaluated when possible for their contributing effects on host–parasite systems. Climate change–disease interactions in nearshore marine environments are complex; however, generalities are possible and continued research, especially in the areas outlined here, will improve our understanding.

scholarly journals Estimating parasite host range

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171250 ◽  
Author(s):  
Tad Dallas ◽  
Shan Huang ◽  
Charles Nunn ◽  
Andrew W. Park ◽  
John M. Drake
Keyword(s):  
Host Range ◽  
Host Species ◽  
Disease Ecology ◽  
Species Abundance ◽  
Simulated Data ◽  
Host Community ◽  
Estimation Accuracy ◽  
Long Term Ecological Research ◽  
Host Parasite

Estimating the number of host species that a parasite can infect (i.e. host range) provides key insights into the evolution of host specialism and is a central concept in disease ecology. Host range is rarely estimated in real systems, however, because variation in species relative abundance and the detection of rare species makes it challenging to confidently estimate host range. We applied a non-parametric richness indicator to estimate host range in simulated and empirical data, allowing us to assess the influence of sampling heterogeneity and data completeness. After validating our method on simulated data, we estimated parasite host range for a sparsely sampled global parasite occurrence database (Global Mammal Parasite Database) and a repeatedly sampled set of parasites of small mammals from New Mexico (Sevilleta Long Term Ecological Research Program). Estimation accuracy varied strongly with parasite taxonomy, number of parasite occurrence records, and the shape of host species-abundance distribution (i.e. the dominance and rareness of species in the host community). Our findings suggest that between 20% and 40% of parasite host ranges are currently unknown, highlighting a major gap in our understanding of parasite specificity, host–parasite network structure, and parasite burdens.

scholarly journals Long-term condition management for prisoners: improving the processes between community and prison

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
NMJ Wright ◽  
F Hankins ◽  
P Hearty
Keyword(s):  
Qualitative Interviews ◽  
Electronic Record ◽  
Medicines Management ◽  
Long Term Conditions ◽  
Police Custody ◽  
Barriers To Screening ◽  
High Prevalence ◽  
Facilitators And Barriers ◽  
Ongoing Monitoring

Abstract Background Prisoner populations have a disproportionately high prevalence of risk factors for long-term conditions (LTCs), and movement between community and prisons is a period of potential disruption in the ongoing monitoring and management of LTCs. Method Nineteen qualitative interviews with staff, recruited by purposive sampling for professional background, were conducted to explore facilitators and barriers to screening, monitoring and medicines management for LTCs. Results There is variability in prisoner behaviours regarding bringing community GP-prescribed medication to prison following arrest and detention in police custody, which affects service ability regarding seamless continuation of community prescribing actions. Systems for actively inputting clinical data into existing, nationally agreed, electronic record templates for QOF monitoring are under-developed in prisons and such activity is dependent upon individual “enthusiast(s)”. Conclusion There is a pressing need to embed standardised QOF monitoring systems within an integrated community/prison commissioning framework, supported by connectivity between prison and community primary care records, including all activity related to QOF compliance.

scholarly journals Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 71
Author(s):  
Charalampos Dimitriadis ◽  
Ivoni Fournari-Konstantinidou ◽  
Laurent Sourbès ◽  
Drosos Koutsoubas ◽  
Stelios Katsanevakis
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
High Performance ◽  
Marine Protected Area ◽  
Habitat Degradation ◽  
Population Increase ◽  
Rocky Reef ◽  
Cascading Effects ◽  
High Level

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.

Evidence for Early and Regular Physical Therapy and Exercise in Parkinson's Disease

2021 ◽  
Author(s):  
Terry D. Ellis ◽  
Cristina Colón-Semenza ◽  
Tamara R. DeAngelis ◽  
Cathi A. Thomas ◽  
Marie-Hélène Saint Hilaire ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Physical Therapy ◽  
Secondary Prevention ◽  
Medical Management ◽  
Long Term Outcomes ◽  
High Prevalence ◽  
Growing Body ◽  
Prevention Model

AbstractAdvances in medical management of Parkinson's disease (PD) have resulted in living longer with disability. Although disability worsens over the course of the disease, there are signs of disability even in the early stages. Several studies reveal an early decline in gait and balance and a high prevalence of nonmotor signs in the prodromal period that contribute to early disability. There is a growing body of evidence revealing the benefits of physical therapy and exercise to mitigate motor and nonmotor signs while improving physical function and reducing disability. The presence of early disability coupled with the benefits of exercise suggests that physical therapy should be initiated earlier in the disease. In this review, we present the evidence revealing early disability in PD and the effectiveness of physical therapy and exercise, followed by a discussion of a secondary prevention model of rehabilitation to reduce early disability and optimize long-term outcomes.

scholarly journals A Bit of Sex Stabilizes Host–Parasite Dynamics

2001 ◽  
Vol 212 (3) ◽  
pp. 345-354 ◽  
Author(s):  
THOMAS FLATT ◽  
NICOLAS MAIRE ◽  
MICHAEL DOEBELI
Keyword(s):  
Host Parasite ◽  
Parasite Dynamics
Sign in / Sign up

Export Citation Format

Share Document