scholarly journals The Fine-Scale Landscape of Immunity and Parasitism in a Wild Ungulate Population

2019 ◽  
Vol 59 (5) ◽  
pp. 1165-1175 ◽  
Author(s):  
Gregory F Albery ◽  
Daniel J Becker ◽  
Fiona Kenyon ◽  
Daniel H Nussey ◽  
Josephine M Pemberton

Abstract Spatial heterogeneity in susceptibility and exposure to parasites is a common source of confounding variation in disease ecology studies. However, it is not known whether spatial autocorrelation acts on immunity at small scales, within wild animal populations, and whether this predicts spatial patterns in infection. Here we used a well-mixed wild population of individually recognized red deer (Cervus elaphus) inhabiting a heterogeneous landscape to investigate fine-scale spatial patterns of immunity and parasitism. We noninvasively collected 842 fecal samples from 141 females with known ranging behavior over 2 years. We quantified total and helminth-specific mucosal antibodies and counted propagules of three gastrointestinal helminth taxa. These data were analyzed with linear mixed models using the Integrated Nested Laplace Approximation, using a Stochastic Partial Differentiation Equation approach to control for and quantify spatial autocorrelation. We also investigated whether spatial patterns of immunity and parasitism changed seasonally. We discovered substantial spatial heterogeneity in general and helminth-specific antibody levels and parasitism with two helminth taxa, all of which exhibited contrasting seasonal variation in their spatial patterns. Notably, Fasciola hepatica intensity appeared to be strongly influenced by the presence of wet grazing areas, and antibody hotspots did not correlate with distributions of any parasites. Our results suggest that spatial heterogeneity may be an important factor affecting immunity and parasitism in a wide range of study systems. We discuss these findings with regards to the design of sampling regimes and public health interventions, and suggest that disease ecology studies investigate spatial heterogeneity more regularly to enhance their results, even when examining small geographic areas.

2018 ◽  
Author(s):  
Gregory F. Albery ◽  
Daniel J. Becker ◽  
Fiona Kenyon ◽  
Daniel H. Nussey ◽  
Josephine M. Pemberton

AbstractSpatial heterogeneity in parasite susceptibility and exposure is a common source of confounding variation in disease ecology studies. However, it is not known whether spatial autocorrelation acts on immunity in particular at small scales, within wild animal populations, and whether this predicts spatial patterns in infection. Here we used a well-mixed wild population of individually recognised red deer (Cervus elaphus) inhabiting a heterogeneous landscape to investigate fine-scale spatial patterns of immunity and parasitism. We noninvasively collected 842 faecal samples from 141 females with known ranging behaviour over two years. We quantified total and helminth-specific mucosal antibodies and counted propagules of three gastrointestinal helminth taxa. These data were analysed with linear mixed models using the Integrated Nested Laplace Approximation (INLA), using a Stochastic Partial Differentiation Equation approach (SPDE) to control for and quantify spatial autocorrelation. We also investigated whether spatial patterns of immunity and parasitism changed seasonally. We discovered substantial spatial heterogeneity in general and helminth-specific antibody levels and parasitism with two helminth taxa, all of which exhibited contrasting seasonal variation in their spatial patterns. Notably, strongyle nematode intensity did not align with density hotspots, while Fasciola hepatica intensity appeared to be strongly influenced by the presence of wet grazing. In addition, antibody hotspots did not correlate with distributions of any parasites. Our results suggest spatial heterogeneity may be an important factor affecting immunity and parasitism in a wide range of study systems. We discuss these findings with regards to the design of sampling regimes and public health interventions, and suggest that disease ecology studies investigate spatial heterogeneity more regularly to enhance their results, even when examining small geographic areas.


2018 ◽  
Vol 50 (1) ◽  
pp. 215-230
Author(s):  
Dedi Liu ◽  
Qin Zhao ◽  
Shenglian Guo ◽  
Pan Liu ◽  
Lihua Xiong ◽  
...  

Abstract Spatial interpolation of precipitation data is an essential input for hydrological modelling. At present, the most frequently used spatial interpolation methods for precipitation are based on the assumption of stationary in spatial autocorrelation and spatial heterogeneity. As climate change is altering the precipitation, stationary in spatial autocorrelation and spatial heterogeneity should be first analysed before spatial interpolation methods are applied. This study aims to propose a framework to understand the spatial patterns of autocorrelation and heterogeneity embedded in precipitation using Moran's I, Getis–Ord test, and semivariogram. Variations in autocorrelation and heterogeneity are analysed by the Mann–Kendall test. The indexes and test methods are applied to the 7-day precipitation series which are corresponding to the annual maximum 7-day flood volume (P-AM7FV) upstream of the Changjiang river basin. The spatial autocorrelation of the P-AM7FV showed a statistically significant increasing trend over the whole study area. Spatial interpolation schemes for precipitation may lead to better estimation and lower error for the spatial distribution of the areal precipitation. However, owing to the changing summer monsoons, random variation in the spatial heterogeneity analysis shows a significant increasing trend, which reduces the reliability of the distributed hydrological model with the input of local or microscales.


2020 ◽  
Author(s):  
Gregory F Albery ◽  
Amy R Sweeny ◽  
Daniel J Becker ◽  
Shweta Bansal

AbstractAll pathogens are heterogeneous in space, yet little is known about the prevalence and scale of this spatial variation, particularly in wild animal systems. To address this question, we conducted a broad literature search to identify datasets involving diseases of wild mammals in spatially distributed contexts. Across 31 such final datasets featuring 89 replicates and 71 host-parasite combinations, only 51% had previously been used to test spatial hypotheses. We analysed these datasets for spatial dependence within a standardised modelling framework using Bayesian linear models. We detected spatial autocorrelation in 44/89 model replicates (54%) across 21/31 datasets (68%), spread across parasites of all groups and transmission modes. Surprisingly, although larger sampling areas more easily detected spatial patterns, even some very small study areas (under 0.01km2) exhibited substantial spatial heterogeneity. Parasites of all transmission modes had easily detectable spatial patterns, implying that structured contact networks and susceptibility effects are likely as important in spatially structuring disease as are environmental drivers of transmission efficiency. Our findings imply that fine-scale spatial patterns of infection often manifest in wild animal systems, whether or not the aim of the study is to examine environmentally varying processes. Given the widespread nature of these findings, studies should more frequently record and analyse spatial data, facilitating development and testing of spatial hypotheses in disease ecology.


2019 ◽  
Vol 6 (10) ◽  
pp. 190682
Author(s):  
S. M. Rodríguez ◽  
J. C. Uribe ◽  
S. A. Estay ◽  
M. Palacios ◽  
R. Pinochet ◽  
...  

Cottage cheese disease is caused by microsporidian parasites that infect a wide range of animal populations. Despite its potential to affect economically important activities, the spatial patterns of prevalence of this disease are still not well understood. Here, we analyse the occurrence of the microsporidian Areospora rohanae in populations of the king crab Lithodes santolla over ca 800 km of the southeastern Pacific shore. In winter 2011, conical pots were deployed between 50 and 200 m depth to capture crabs of a wide range of sizes. The infection was widely distributed along the region, with a mean prevalence of 16%, and no significant association between prevalence and geographical location was detected. Males, females and ovigerous females showed similar prevalence values of 16.5 (13–18.9), 15 (9.2–15) and 16.7% (10–19%), respectively. These patterns of prevalence were consistent across crab body sizes, despite the ontogenetic and sex-dependent variations in feeding behaviour and bathymetric migrations previously reported for king crabs. This study provided the first report of the geographical distribution of A. rohanae infecting southern king crabs.


2017 ◽  
Vol 114 (24) ◽  
pp. E4744-E4752 ◽  
Author(s):  
Xiaoli Dong ◽  
Albert Ruhí ◽  
Nancy B. Grimm

Nutrients in freshwater ecosystems are highly variable in space and time. Nevertheless, the variety of processes contributing to nutrient patchiness, and the wide range of spatial and temporal scales at which these processes operate, obfuscate how this spatial heterogeneity is generated. Here, we describe the spatial structure of stream nutrient concentration, quantify the relative importance of the physical template and biological processes, and detect and evaluate the role of self-organization in driving such patterns. We examined nutrient spatial patterns in Sycamore Creek, an intermittent desert stream in Arizona that experienced an ecosystem regime shift [from a gravel/algae-dominated to a vascular plant-dominated (hereafter, “wetland”) system] in 2000 when cattle grazing ceased. We conducted high-resolution nutrient surveys in surface water along a 10-km stream reach over four visits spanning 18 y (1995–2013) that represent different successional stages and prewetland stage vs. postwetland state. As expected, groundwater upwelling had a major influence on nutrient spatial patterns. However, self-organization realized by the mechanism of spatial feedbacks also was significant and intensified over ecosystem succession, as a resource (nitrogen) became increasingly limiting. By late succession, the effects of internal spatial feedbacks and groundwater upwelling were approximately equal in magnitude. Wetland establishment influenced nutrient spatial patterns only indirectly, by modifying the extent of surface water/groundwater exchange. This study illustrates that multiple mechanisms interact in a dynamic way to create spatial heterogeneity in riverine ecosystems, and provides a means to detect spatial self-organization against physical template heterogeneity as a dominant driver of spatial patterns.


2001 ◽  
Vol 268 (1468) ◽  
pp. 711-717 ◽  
Author(s):  
P. P. Pomeroy ◽  
J. Worthington Wilmer ◽  
W. Amos ◽  
S. D. Twiss

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Rubayet Elahi ◽  
Ausraful Islam ◽  
Mohammad Sharif Hossain ◽  
Khaja Mohiuddin ◽  
Andrea Mikolon ◽  
...  

The parasites of generaHaemoproteus, Plasmodium,andLeucocytozoonare well-known avian haematozoa and can cause declined productivity and high mortality in wild birds. The objective of the study was to record the prevalence of haematozoan parasites in a wide range of wetland birds in Bangladesh. Six species ofHaemoproteus, seven species ofPlasmodium, one unidentified species ofLeucocytozoon, and one unidentified microfilaria of the genusParonchocercawere found. Data on the morphology, size, hosts, prevalence, and infection intensity of the parasites are provided. The overall prevalence among the birds was 29.5% (95 out of 322 birds). Of those, 13.2% (42 of 319) of birds were infected withHaemoproteusspp., 15.1% withPlasmodiumspp. (48 of 319) and 0.6% withLeucocytozoonspp. (2 of 319). Two birds were positive for bothHaemoproteussp. andPlasmodiumsp. A single resident bird,Ardeola grayii, was found positive for an unidentified microfilaria. Prevalence of infection varied significantly among different bird families. Wild birds of Bangladesh carry several types of haematozoan parasites. Further investigation with a larger sample size is necessary to estimate more accurately the prevalence of haematozoan parasites among wild birds as well as domestic ducks for better understanding of the disease ecology.


2021 ◽  
Author(s):  
Shane Stoner ◽  
Carlos Sierra ◽  
Marion Schrumpf ◽  
Sebastian Dötterl ◽  
Susan Trumbore

<p>Soil organic matter (SOM) is a complex collection of organic molecules of varying origin, structure, chemical activity, and mineral association. A wide array of laboratory methods exists to separate SOM based on qualitative, biological, chemical, and physical characteristics. However, all present conceptual and logistical limitations, including the requirement of a substantial amount soil material.</p><p>An newly applied alternative method of fractionation relies on a conceptual analogue between biochemical stability in soil and thermal stability, e.g. more persistent SOM will require higher temperatures (greater energy inputs) to decompose than less persistent SOM. This accounts for both chemical complexity and mineral association as main factors in determining SOM persistence.</p><p>In this method, carbon is released by heating SOM to 900°C at a constant rate. The peaks of carbon release are grouped into activation energy pools, CO<sub>2 </sub>is collected, and analyzed for <sup>13</sup>C and <sup>14</sup>C. We seek to describe in finer detail the distribution of soil radiocarbon by adding another fractionation step following a different paradigm of SOM stability, and explore mineralogical effects on SOM quality and stability using thermal analysis, radiocarbon, and gas chromatography.</p><p>Here, we analyzed bulk soil and soil fractions derived from density separation and chemical oxidation, as well as mineral horizons dominated by diverse mineralogies. Density fractions contained a wide range of radiocarbon activities and that young SOM is stabilized across multiple fractions, likely due to organomineral complexation. Initial results showed that soil minerals with limited stabilization potential released C at lower temperatures than those with diverse stabilization mechanisms. High-temperature sub-fractions contained the oldest carbon across fractions and minerals, thus supporting the assumption that thermal stability can be used as a limited analogue for stability in soil. We present a fine-scale distribution of radiocarbon in SOM and discuss the potential of this method for comparison with other fractionation techniques.</p>


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