scholarly journals Food for contagion: synthesis and future directions for studying host–parasite responses to resource shifts in anthropogenic environments

2018 ◽  
Vol 373 (1745) ◽  
pp. 20170102 ◽  
Author(s):  
Sonia Altizer ◽  
Daniel J. Becker ◽  
Jonathan H. Epstein ◽  
Kristian M. Forbes ◽  
Thomas R. Gillespie ◽  
...  
Keyword(s):  
Regional Scale ◽  
Population Level ◽  
Food Resources ◽  
Resource Subsidies ◽  
Conservation Implications ◽  
Contact Rates ◽  
Animal Aggregation ◽  
Infection Processes ◽  
Host Parasite ◽  
Future Work

Human-provided resource subsidies for wildlife are diverse, common and have profound consequences for wildlife–pathogen interactions, as demonstrated by papers in this themed issue spanning empirical, theoretical and management perspectives from a range of study systems. Contributions cut across scales of organization, from the within-host dynamics of immune function, to population-level impacts on parasite transmission, to landscape- and regional-scale patterns of infection. In this concluding paper, we identify common threads and key findings from author contributions, including the consequences of resource subsidies for (i) host immunity; (ii) animal aggregation and contact rates; (iii) host movement and landscape-level infection patterns; and (iv) interspecific contacts and cross-species transmission. Exciting avenues for future work include studies that integrate mechanistic modelling and empirical approaches to better explore cross-scale processes, and experimental manipulations of food resources to quantify host and pathogen responses. Work is also needed to examine evolutionary responses to provisioning, and ask how diet-altered changes to the host microbiome influence infection processes. Given the massive public health and conservation implications of anthropogenic resource shifts, we end by underscoring the need for practical recommendations to manage supplemental feeding practices, limit human–wildlife conflicts over shared food resources and reduce cross-species transmission risks, including to humans. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.

scholarly journals Winter feeding of elk in the Greater Yellowstone Ecosystem and its effects on disease dynamics

2018 ◽  
Vol 373 (1745) ◽  
pp. 20170093 ◽  
Author(s):  
Gavin G. Cotterill ◽  
Paul C. Cross ◽  
Eric K. Cole ◽  
Rebecca K. Fuda ◽  
Jared D. Rogerson ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Population Level ◽  
Research Management ◽  
Natural Food ◽  
Past Century ◽  
Winter Mortality ◽  
Animal Testing ◽  
Resource Subsidies ◽  
The Right ◽  
Host Parasite

Providing food to wildlife during periods when natural food is limited results in aggregations that may facilitate disease transmission. This is exemplified in western Wyoming where institutional feeding over the past century has aimed to mitigate wildlife–livestock conflict and minimize winter mortality of elk ( Cervus canadensis ). Here we review research across 23 winter feedgrounds where the most studied disease is brucellosis, caused by the bacterium Brucella abortus . Traditional veterinary practices (vaccination, test-and-slaughter) have thus far been unable to control this disease in elk, which can spill over to cattle. Current disease-reduction efforts are being guided by ecological research on elk movement and density, reproduction, stress, co-infections and scavengers. Given the right tools, feedgrounds could provide opportunities for adaptive management of brucellosis through regular animal testing and population-level manipulations. Our analyses of several such manipulations highlight the value of a research–management partnership guided by hypothesis testing, despite the constraints of the sociopolitical environment. However, brucellosis is now spreading in unfed elk herds, while other diseases (e.g. chronic wasting disease) are of increasing concern at feedgrounds. Therefore experimental closures of feedgrounds, reduced feeding and lower elk populations merit consideration. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.

Forecast of COVID-19 Trend Following Countrywide Movement Control Order in Malaysia: SEIR Model Approach (Preprint)

2020 ◽  
Author(s):  
Aidalina Mahmud ◽  
Poh Ying Lim ◽  
Hayati Kadir Shahar
Keyword(s):  
Mathematical Model ◽  
Incidence Rate ◽  
Movement Control ◽  
Seir Model ◽  
Infection Incidence ◽  
Contact Rates ◽  
Exposed Population ◽  
Control Order ◽  
Future Work ◽  
Model Approach

BACKGROUND On March 18, 2020, the Malaysian government implemented Movement Control Order (MCO) to limit the contact rates among the population and infected individuals. OBJECTIVE The objective of this study was to forecast the trend of the COVID-19 epidemic in Malaysia in terms of its magnitude and duration. METHODS Data for this analysis was obtained from publicly available databases, from March 17 until March 27, 2020. By applying the Susceptible, Exposed, Infectious and Removed (SEIR) mathematical model and several predetermined assumptions, two analyses were carried out: without and with MCO implementation. RESULTS Without MCO, it is forecasted that it would take 18 days to reach the peak of infection incidence. The incidence rate would plateau at day 80 and end by day 94, with 43% of the exposed population infected. With the implementation of the MCO, it is forecasted that new cases of infection would peak at day 25, plateau at day 90 and end by day 100. At its peak, the infection could affect up to about 40% of the exposed population. CONCLUSIONS It is forecasted that the COVID-19 epidemic in Malaysia will subside soon after the mid-year of 2020. Although the implementation of MCO can flatten the epidemiological curve, it also prolongs the duration of the epidemic. The MCO can result in several unfavorable consequences in economic and psychosocial aspects. A future work of an exit plan for the MCO should also be devised and implemented gradually. The exit plan raises several timely issues of re-infection resurgence after MCO are lifted.

scholarly journals The Evolution of Gambling-Related Harm Measurement: Lessons from the Last Decade

2021 ◽  
Vol 18 (9) ◽  
pp. 4395
Author(s):  
Matthew Browne ◽  
Vijay Rawat ◽  
Catherine Tulloch ◽  
Cailem Murray-Boyle ◽  
Matthew Rockloff
Keyword(s):  
Public Health ◽  
Population Level ◽  
Health Utility ◽  
Health And Wellbeing ◽  
Recent Developments ◽  
Psychometric Evidence ◽  
Future Work ◽  
Utility Metrics ◽  
Gambling Harms ◽  
Related Harm

Jurisdictions around the world have a self-declared mandate to reduce gambling-related harm. However, historically, this concept has suffered from poor conceptualisation and operationalisation. However, recent years have seen swift advances in measuring gambling harm, based on the principle of it being a quantifiable decrement to the health and wellbeing of the gambler and those connected to them. This review takes stock of the background and recent developments in harm assessment and summarises recent research that has validated and applied the Short Gambling Harms Screen and related instruments. We recommend that future work builds upon the considerable psychometric evidence accumulated for the feasibility of direct elicitation of harmful consequences. We also advocate for grounding harms measures with respect to scalar changes to public health utility metrics. Such an approach will avoid misleading pseudo-clinical categorisations, provide accurate population-level summaries of where the burden of harm is carried, and serve to integrate gambling research with the broader field of public health.

scholarly journals Assessing the direct and indirect effects of food provisioning and nutrient enrichment on wildlife infectious disease dynamics

2018 ◽  
Vol 373 (1745) ◽  
pp. 20170101 ◽  
Author(s):  
David J. Civitello ◽  
Brent E. Allman ◽  
Connor Morozumi ◽  
Jason R. Rohr
Keyword(s):  
Nutrient Enrichment ◽  
Management Strategies ◽  
Wildlife Disease ◽  
Host Population ◽  
Food Provisioning ◽  
Resource Subsidies ◽  
Predator Species ◽  
Interacting Species ◽  
Integrative View ◽  
Host Parasite

Anthropogenic resource supplementation can shape wildlife disease directly by altering the traits and densities of hosts and parasites or indirectly by stimulating prey, competitor or predator species. We first assess the direct epidemiological consequences of supplementation, highlighting the similarities and differences between food provisioning and two widespread forms of nutrient input: agricultural fertilization and aquatic nutrient enrichment. We then review an aquatic disease system and a general model to assess whether predator and competitor species can enhance or overturn the direct effects of enrichment. All forms of supplementation can directly affect epidemics by increasing host population size or altering parasite production within hosts, but food provisioning is most likely to aggregate hosts and increase parasite transmission. However, if predators or competitors increase in response to supplementation, they could alter resource-fuelled outbreaks in focal hosts. We recommend identifying the traits of hosts, parasites or interacting species that best predict epidemiological responses to supplementation and evaluating the relative importance of these direct and indirect mechanisms. Theory and experiments should examine the timing of behavioural, physiological and demographic changes for realistic, variable scenarios of supplementation. A more integrative view of resource supplementation and wildlife disease could yield broadly applicable disease management strategies. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.

scholarly journals The role of host phenology for parasite transmission

2020 ◽  
Author(s):  
Hannelore MacDonald ◽  
Erol Akçay ◽  
Dustin Brisson
Keyword(s):  
Species Interactions ◽  
Activity Period ◽  
Parasite Transmission ◽  
Nymphal Stage ◽  
Mouse Population ◽  
Tick Activity ◽  
Contact Rates ◽  
Wide Range ◽  
Host Phenology ◽  
Host Parasite

Abstract Phenology is a fundamental determinant of species distributions, abundances, and interactions. In host–parasite interactions, host phenology can affect parasite fitness due to the temporal constraints it imposes on host contact rates. However, it remains unclear how parasite transmission is shaped by the wide range of phenological patterns observed in nature. We develop a mathematical model of the Lyme disease system to study the consequences of differential tick developmental-stage phenology for the transmission of B. burgdorferi. Incorporating seasonal tick activity can increase B. burgdorferi fitness compared to continuous tick activity but can also prevent transmission completely. B. burgdorferi fitness is greatest when the activity period of the infectious nymphal stage slightly precedes the larval activity period. Surprisingly, B. burgdorferi is eradicated if the larval activity period begins long after the end of nymphal activity due to a feedback with mouse population dynamics. These results highlight the importance of phenology, a common driver of species interactions, for the fitness of a parasite.

Bidirectional interactions between host social behaviour and parasites arise through ecological and evolutionary processes

Parasitology ◽  
2020 ◽  
pp. 1-15
Author(s):  
Dana M. Hawley ◽  
Amanda K. Gibson ◽  
Andrea K. Townsend ◽  
Meggan E. Craft ◽  
Jessica F. Stephenson
Keyword(s):  
Social Interactions ◽  
Social Behaviour ◽  
Population Level ◽  
Parasite Infection ◽  
Evolutionary Processes ◽  
Ecological Patterns ◽  
Ecological Feedbacks ◽  
Host Parasite ◽  
Bidirectional Interactions ◽  
Social Behaviours

Abstract An animal's social behaviour both influences and changes in response to its parasites. Here we consider these bidirectional links between host social behaviours and parasite infection, both those that occur from ecological vs evolutionary processes. First, we review how social behaviours of individuals and groups influence ecological patterns of parasite transmission. We then discuss how parasite infection, in turn, can alter host social interactions by changing the behaviour of both infected and uninfected individuals. Together, these ecological feedbacks between social behaviour and parasite infection can result in important epidemiological consequences. Next, we consider the ways in which host social behaviours evolve in response to parasites, highlighting constraints that arise from the need for hosts to maintain benefits of sociality while minimizing fitness costs of parasites. Finally, we consider how host social behaviours shape the population genetic structure of parasites and the evolution of key parasite traits, such as virulence. Overall, these bidirectional relationships between host social behaviours and parasites are an important yet often underappreciated component of population-level disease dynamics and host–parasite coevolution.

scholarly journals Conservation implications of spatial genetic structure in two species of oribatid mites from the Antarctic Peninsula and the Scotia Arc

2018 ◽  
Vol 30 (2) ◽  
pp. 105-114 ◽  
Author(s):  
Bettine Jansen van Vuuren ◽  
Jennifer E. Lee ◽  
Peter Convey ◽  
Steven L. Chown
Keyword(s):  
Genetic Structure ◽  
Antarctic Peninsula ◽  
Sequence Data ◽  
Spatial Genetic Structure ◽  
Complex Structure ◽  
Regional Scale ◽  
Terrestrial Invertebrates ◽  
Conservation Implications ◽  
Scotia Arc ◽  
The Antarctic

AbstractMitochondrial and nuclear sequence data from two Antarctic ameronothroid mites, Halozetes belgicae and Alaskozetes antarcticus, were used to address three key questions important for understanding both the evolution of biodiversity and its future conservation in the Antarctic Peninsula Region: i) Do populations of mites across the Antarctic Peninsula and Scotia Arc constitute distinct genetic lineages? ii) What implications does the spatial genetic structure in these species have for current understanding of the region’s glacial history? iii) What are the conservation implications of these findings? Our results indicate that both mite species have been present in the Antarctic since at least the Pliocene. At the regional scale, both species are comprised of a number of divergent, but sympatric, lineages that are genetically as distinct as some species within the genera Halozetes and Alaskozetes. At the local scale, complex structure suggests limited and stochastic post-Holocene dispersal. For both species, considerable spatial genetic structure exists across the region, similar to that found in other terrestrial invertebrates. These results support the implementation of stringent biosecurity measures for moving between the Scotia Arc islands and the Antarctic Peninsula, and throughout the latter, to conserve both evolutionary history and future evolutionary trajectories.

scholarly journals Toward a synthetic understanding of the role of phenology in ecology and evolution

2010 ◽  
Vol 365 (1555) ◽  
pp. 3101-3112 ◽  
Author(s):  
Jessica Forrest ◽  
Abraham J. Miller-Rushing
Keyword(s):  
Climate Change ◽  
Population Level ◽  
Annual Cycles ◽  
Biological Phenomena ◽  
Ecosystem Level ◽  
Modelling Techniques ◽  
Evolutionary Consequences ◽  
Future Work ◽  
The Relationship

Phenology affects nearly all aspects of ecology and evolution. Virtually all biological phenomena—from individual physiology to interspecific relationships to global nutrient fluxes—have annual cycles and are influenced by the timing of abiotic events. Recent years have seen a surge of interest in this topic, as an increasing number of studies document phenological responses to climate change. Much recent research has addressed the genetic controls on phenology, modelling techniques and ecosystem-level and evolutionary consequences of phenological change. To date, however, these efforts have tended to proceed independently. Here, we bring together some of these disparate lines of inquiry to clarify vocabulary, facilitate comparisons among habitat types and promote the integration of ideas and methodologies across different disciplines and scales. We discuss the relationship between phenology and life history, the distinction between organismal- and population-level perspectives on phenology and the influence of phenology on evolutionary processes, communities and ecosystems. Future work should focus on linking ecological and physiological aspects of phenology, understanding the demographic effects of phenological change and explicitly accounting for seasonality and phenology in forecasts of ecological and evolutionary responses to climate change.

scholarly journals Modelling tree shape and structure in viral phylodynamics

2013 ◽  
Vol 368 (1614) ◽  
pp. 20120208 ◽  
Author(s):  
Simon D. W. Frost ◽  
Erik M. Volz
Keyword(s):  
Population Structure ◽  
Common Ancestor ◽  
Population Level ◽  
Structured Populations ◽  
Evolutionary System ◽  
Epidemiological Models ◽  
Evolutionary Time ◽  
Contact Rates ◽  
Measure Of Asymmetry ◽  
Hiv 1

Epidemiological models have highlighted the importance of population structure in the transmission dynamics of infectious diseases. Using HIV-1 as an example of a model evolutionary system, we consider how population structure affects the shape and the structure of a viral phylogeny in the absence of strong selection at the population level. For structured populations, the number of lineages as a function of time is insufficient to describe the shape of the phylogeny. We develop deterministic approximations for the dynamics of tips of the phylogeny over evolutionary time, the number of ‘cherries’, tips that share a direct common ancestor, and Sackin's index, a commonly used measure of phylogenetic imbalance or asymmetry. We employ cherries both as a measure of asymmetry of the tree as well as a measure of the association between sequences from different groups. We consider heterogeneity in infectiousness associated with different stages of HIV infection, and in contact rates between groups of individuals. In the absence of selection, we find that population structure may have relatively little impact on the overall asymmetry of a tree, especially when only a small fraction of infected individuals is sampled, but may have marked effects on how sequences from different subpopulations cluster and co-cluster.

scholarly journals Central Himalayan rivers record the topographic signature of erosion by glacial lake outburst floods

2021 ◽  
Author(s):  
Maxwell P. Dahlquist ◽  
A. Joshua West
Keyword(s):  
Regional Scale ◽  
Glacial Lake ◽  
River Channels ◽  
Nepal Himalaya ◽  
River Incision ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Bedrock Erosion ◽  
River Valleys ◽  
Future Work

Abstract. In steep landscapes, river incision sets the pace of landscape evolution. Transport of coarse sediment controls incision by evacuating material delivered to river channels by landslides. However, large landslide-derived boulders that impede bedrock erosion are immobile even in major runoff-driven floods. Glacial lake outburst floods (GLOFs) mobilize these boulders and drive incision, yet their role in regional-scale erosion is poorly understood, largely because of their rarity. Here, we find a topographic signature consistent with widespread GLOF erosion in the Nepal Himalaya. In rivers with glaciated headwaters that generate GLOFs, valleys stay narrow and relatively free of sediment, with bedrock often exposed to erosion. In turn, tributaries to these valleys are steep, allowing less efficient erosional regimes to keep pace with GLOF-driven incision. Where GLOFs are less frequent, valleys are more alluviated and incision stalls. Our results suggest the extent of headwater glaciation may play an important role in erosion of Himalayan river valleys and deserves more attention in future work.

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