Community-Level Interactions and Disease Dynamics

2021 ◽  
pp. 145-170
Author(s):  
Karen D. McCoy
Keyword(s):  
Local Area ◽  
Community Level ◽  
Disease Dynamics ◽  
Biological Communities ◽  
Natural Systems ◽  
Parasite Communities ◽  
Almost All ◽  
Host Parasite ◽  
Natural Communities ◽  
Over Time

An ecological community includes all individuals of all species that interact within a single patch or local area of habitat. Understanding the outcome of host–parasite interactions and predicting disease dynamics is particularly challenging at this biological scale because the different component species interact both directly and indirectly in complex ways. Current shifts in biodiversity due to global change, and its associated modifications to biological communities, will alter these interactions, including the probability of disease emergence, its dynamics over time, and its community-level consequences. Birds are integral component species of almost all natural communities. Due to their ubiquity and specific life history traits, they are defining actors in the ecology, evolution, and epidemiology of parasitic species. To better understand this role, this chapter examines the relative importance of birds and parasites in natural communities, revisiting basic notions in community ecology. The impact of changes in diversity for disease dynamics, including the debate surrounding dilution and amplification effects are specifically addressed. By considering the intrinsic complexities of natural communities, the importance of combining data from host and parasite communities to better understand how natural systems function over time and space is highlighted. The different elements in each section of the chapter are illustrated with brief, concrete examples from avian species, with a detailed example from marine bird communities in which Lyme disease bacteria circulate.

scholarly journals Molecular Identification and Hidden Diversity of Novel Daphnia Parasites from European Lakes

2009 ◽  
Vol 75 (22) ◽  
pp. 7051-7059 ◽  
Author(s):  
Justyna Wolinska ◽  
Sabine Giessler ◽  
Henrike Koerner
Keyword(s):  
Sequence Variation ◽  
Local Population ◽  
Its Region ◽  
Small Subunit ◽  
Diagnostic Tools ◽  
Rrna Gene ◽  
Natural Systems ◽  
Parasite Communities ◽  
Host Parasite ◽  
Sequence Similarities

ABSTRACT Parasites play important roles in local population dynamics and genetic structure. However, due to insufficient diagnostic tools, detailed host-parasite interactions may remain concealed by hidden parasite diversity in natural systems. Microscopic examination of 19 European lake Daphnia populations revealed the presence of three groups of parasites: fungi, microsporidia, and oomycetes. For most of these parasites no genetic markers have been described so far. Based on sequence similarities of the nuclear small-subunit and internal transcribed spacer (ITS) rRNA gene regions, one fungus, four microsporidian, and nine oomycete taxa were discovered in 147 infected Daphnia (and/or three other zooplankton crustaceans). Additionally, cloning of rRNA gene regions revealed parasite sequence variation within host individuals. This was most pronounced in the ITS region of one microsporidian taxon, where the within-host sequence variation ranged from 1.7% to 5.3% polymorphic sites for parasite isolates from 14 different geographical locations. Interestingly, the parasite isolates from close locations grouped together based on sequence similarities, suggesting that there was parasite dispersal. Taken together, the data obtained in this study revealed hidden diversity of parasite communities in Daphnia lake populations. Moreover, a higher level of resolution for identifying parasite strains makes it possible to test new hypotheses with respect to parasite dispersal, transmission routes, and coinfection.

Globalization and interconfessional communications

2001 ◽  
pp. 13-17
Author(s):  
Serhii Viktorovych Svystunov
Keyword(s):  
21St Century ◽  
Global Economy ◽  
Modern World ◽  
The World ◽  
Target Set ◽  
Almost All ◽  
Over Time ◽  
Rapid Appearance

In the 21st century, the world became a sign of globalization: global conflicts, global disasters, global economy, global Internet, etc. The Polish researcher Casimir Zhigulsky defines globalization as a kind of process, that is, the target set of characteristic changes that develop over time and occur in the modern world. These changes in general are reduced to mutual rapprochement, reduction of distances, the rapid appearance of a large number of different connections, contacts, exchanges, and to increase the dependence of society in almost all spheres of his life from what is happening in other, often very remote regions of the world.

scholarly journals Pyrite (FeS2)-supported ultrafiltration system for removal of mercury (II) from water

2021 ◽  
Author(s):  
Dong Suk Han ◽  
Kawsher M. D. Solayman ◽  
Ho Kyong Shon ◽  
Ahmed Abdel-Wahab
Keyword(s):  
Membrane Filter ◽  
Pyrite Surface ◽  
Ph Change ◽  
Filtration Process ◽  
Sem Images ◽  
Flux Decline ◽  
Cake Layer ◽  
Water Effects ◽  
Almost All ◽  
Over Time

AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.

scholarly journals High parasite diversity in a neglected host: larval trematodes of Bithynia tentaculata in Central Europe

2020 ◽  
Vol 94 ◽  
Author(s):  
J. Schwelm ◽  
O. Kudlai ◽  
N.J. Smit ◽  
C. Selbach ◽  
B. Sures
Keyword(s):  
Central Europe ◽  
Phylogenetic Analyses ◽  
Snail Host ◽  
Morphological Data ◽  
Curonian Lagoon ◽  
Parasite Communities ◽  
Bithynia Tentaculata ◽  
Host Parasite ◽  
Host Families ◽  
High Parasite

Abstract Bithynids snails are a widespread group of molluscs in European freshwater systems. However, not much information is available on trematode communities from molluscs of this family. Here, we investigate the trematode diversity of Bithynia tentaculata, based on molecular and morphological data. A total of 682 snails from the rivers Lippe and Rhine in North Rhine-Westphalia, Germany, and 121 B. tentaculata from Curonian Lagoon, Lithuania were screened for infections with digeneans. In total, B. tentaculata showed a trematode prevalence of 12.9% and 14%, respectively. The phylogenetic analyses based on 55 novel sequences for 36 isolates demonstrated a high diversity of digeneans. Analyses of the molecular and morphological data revealed a species-rich trematode fauna, comprising 20 species, belonging to ten families. Interestingly, the larval trematode community of B. tentaculata shows little overlap with the well-studied trematode fauna of lymnaeids and planorbids, and some of the detected species (Echinochasmus beleocephalus and E. coaxatus) constitute first records for B. tentaculata in Central Europe. Our study revealed an abundant, diverse and distinct trematode fauna in B. tentaculata, which highlights the need for further research on this so far understudied host–parasite system. Therefore, we might currently be underestimating the ecological roles of several parasite communities of non-pulmonate snail host families in European fresh waters.

Consistent differences in macroparasite community composition among populations of three-spined sticklebacks,Gasterosteus aculeatusL.

Parasitology ◽  
2012 ◽  
Vol 139 (11) ◽  
pp. 1478-1491 ◽  
Author(s):  
JOB DE ROIJ ◽  
ANDREW D. C. MacCOLL
Keyword(s):  
Spatial Variation ◽  
Community Composition ◽  
Gasterosteus Aculeatus ◽  
Parasite Community ◽  
Field Studies ◽  
Habitat Characteristics ◽  
Parasite Communities ◽  
Geographical Distances ◽  
Host Parasite ◽  
Relative Differences

SUMMARYParasite ecologists are often interested in the repeatability of patterns in parasite communities in space and/or time, because of implications for the dynamics of host-parasite interactions. Field studies usually examine temporal and spatial variation in isolation or limit themselves to a small number of host populations. Here, we studied the macroparasite communities of 12 populations of three-spined stickleback,Gasterosteus aculeatusL., on North Uist, Scotland, separated by small geographical distances, during the breeding season in 2 consecutive years (2007 and 2008) to determine: (1) the extent of spatial variation in macroparasite communities, (2) whether this variation is consistent across years, and (3) whether habitat characteristics can explain differences in macroparasite community composition among populations. We found substantial variation in parasite communities among populations. Generally, measures of parasite community composition were higher in 2008 than in 2007, but this effect of year was consistent across populations, such that the relative differences in these measures among populations changed little between years. These data suggest that there is short-term stability in the spatial variation in macroparasite communities of North Uist sticklebacks. However, none of the 5 habitat characteristics measured explained spatial variation in any measure of parasite community composition.

scholarly journals Table scraps: inter-trophic food provisioning by pumas

2012 ◽  
Vol 8 (5) ◽  
pp. 776-779 ◽  
Author(s):  
L. Mark Elbroch ◽  
Heiko U. Wittmer
Keyword(s):  
Canis Lupus ◽  
National Park ◽  
Puma Concolor ◽  
Large Carnivores ◽  
Food Provisioning ◽  
Ecological Functions ◽  
Natural Systems ◽  
Food Subsidies ◽  
Vultur Gryphus ◽  
Natural Communities

Large carnivores perform keystone ecological functions through direct predation, or indirectly, through food subsidies to scavengers or trophic cascades driven by their influence on the distributions of their prey. Pumas ( Puma concolor ) are an elusive, cryptic species difficult to study and little is known about their inter-trophic-level interactions in natural communities. Using new GPS technology, we discovered that pumas in Patagonia provided 232 ± 31 kg of edible meat/month/100 km 2 to near-threatened Andean condors ( Vultur gryphus ) and other members of a diverse scavenger community. This is up to 3.1 times the contributions by wolves ( Canis lupus ) to communities in Yellowstone National Park, USA, and highlights the keystone role large, solitary felids play in natural systems. These findings are more pertinent than ever, for managers increasingly advocate controlling pumas and other large felids to bolster prey populations and mitigate concerns over human and livestock safety, without a full understanding of the potential ecological consequences of their actions.

scholarly journals The Scenario of a Pandemic Spread of the Coronavirus SARS-CoV-2 is Based on a Statistical Fallacy

2020 ◽  
Author(s):  
Christof Kuhbandner
Keyword(s):  
Apparent Increase ◽  
Rapid Spread ◽  
Almost All ◽  
Over Time ◽  
Coronavirus Infections

In view of the rapidly increasing numbers of reported new coronavirus infections, many speak of an upcoming pandemic. However, since the number of conducted coronavirus tests has rapidly increased over time as well, the apparent increase in infections may actually reflect increased testing, rather than a rapid spread of the coronavirus. To examine this issue, data from Austria, Belgium, France, Germany, Italy, and USA were analyzed. In all countries, the rapid increase in reported new infections was largely attributable to the rapid increase in conducted tests. Statistically controlling for the increased amount of testing revealed that the increases in reported infections dramatically overestimate the true increases in every country. According to the estimated true courses of new infections, the increases were initially much smaller, and the courses of new infections have already flattened or are even decreasing since the beginning of calendar week 13 (March 23) in almost all countries. The courses of reported new infections and deaths started to increase almost simultaneously in every country, which further confirms that the increases in reported new infections reflect effects of increased testing. These results indicate that the scenario of a coronavirus pandemic is based on a statistical fallacy.<br>

Natural History Wet Collections: Observations on PH Readings from the Use of Different Ethanol and Label Types

2019 ◽  
Vol 33 (1) ◽  
pp. 7-17
Author(s):  
Ximo Mengual ◽  
France Gimnich ◽  
Hannah Petersen ◽  
Jonas J. Astrin
Keyword(s):  
Natural History ◽  
Tissue Samples ◽  
Daily Work ◽  
Starting Point ◽  
Good Starting Point ◽  
Research Questions ◽  
Almost All ◽  
Changes Over Time ◽  
Fluid Preservation ◽  
Over Time

Abstract We examined the effects of different types of specimen labels and tags on pH of different concentrations of ethanol typically used for fluid preservation in natural history collections. Labels were immersed in three different concentrations of ethanol, 96% pure undenatured ethanol (EtOH), 96% EtOH denatured with methyl-ethyl ketone (MEK), and 99.8% pure undenatured EtOH, with or without the presence of insect specimens, and the solutions were evaluated after 26 months for changes over time in pH reading. In general, pH readings of all label trials with 96% and 99.8% ethanol increased over time, except for trials of denatured alcohol, which demonstrated lower pH readings in almost all treatments, regardless of label type. Samples that contained labels with ordinary, nonstandardized, not explicitly acid-free printing paper had higher pH readings compared after the trial. Our observations are a good starting point for further experiments to answer research questions related to chemical interactions with labels in ethanol-preserved specimens, including tissue samples for molecular analyses, which can guide collection staff in their daily work.

Club convergence of crime rates in the United States of America

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kolawole Ogundari
Keyword(s):  
Violent Crime ◽  
Property Crime ◽  
The United States ◽  
Crime Rates ◽  
Community Level ◽  
Club Convergence ◽  
Content Type ◽  
Level Data ◽  
Convergence Club ◽  
Over Time

Purpose The cyclical behavior of US crime rates reflects the dynamics of crime in the country. This paper aims to investigate the US's club convergence of crime rates to provide insights into whether the crime rates increased or decreased over time. The paper also analyzes the factors influencing the probability of states converging to a particular convergence club of crime. Design/methodology/approach The analysis is based on balanced panel data from all 50 states and the district of Columbia on violent and property crime rates covering 1976–2019. This yields a cross-state panel of 2,244 observations with 55 time periods and 51 groups. In addition, the author used a club clustering procedure to investigate the convergence hypothesis in the study. Findings The empirical results support population convergence of violent crime rates. However, the evidence that supports population convergence of property crime rates in the study is not found. Further analysis using the club clustering procedure shows that property crime rates converge into three clubs. The existence of club convergence in property crime rates means that the variation in the property crime rates tends to narrow among the states within each of the clubs identified in the study. Analysis based on an ordered probit model identifies economic, geographic and human capital factors that significantly drive the state's convergence club membership. Practical implications The central policy insight from these results is that crime rates grow slowly over time, as evident by the convergence of violent crime and club convergence of property crime in the study. Moreover, the existence of club convergence of property crime is an indication that policies to mitigate property crime might need to target states within each club. This includes the efforts to use state rather than national crime-fighting policies. Social implications As crimes are committed at the local level, this study's primary limitation is the lack of community-level data on crime and other factors considered. Analysis based on community-level data might provide a better representation of crime dynamics. However, the author hopes to consider this as less aggregated data are available to use in future research. Originality/value The paper provides new insights into the convergence of crime rates using the club convergence procedure in the USA. This is considered an improvement to the methods used in the previous studies.

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