scholarly journals Plague metapopulation dynamics in a natural reservoir: the burrow system as the unit of study

2006 ◽  
Vol 135 (5) ◽  
pp. 740-748 ◽  
Author(s):  
S. DAVIS ◽  
N. KLASSOVSKIY ◽  
V. AGEYEV ◽  
B. SULEIMENOV ◽  
B. ATSHABAR ◽  
...  
Keyword(s):  
Host Population ◽  
Metapopulation Dynamics ◽  
Risk Of Infection ◽  
Burrow System ◽  
Host Family ◽  
Natural Reservoir ◽  
System A ◽  
Close Proximity ◽  
Rhombomys Opimus ◽  
Family Groups

SUMMARYThe ecology of plague (Yersinia pestis infection) in its ancient foci in Central Asia remains poorly understood. We present field data from two sites in Kazakhstan where the great gerbil (Rhombomys opimus) is the major natural host. Family groups inhabit and defend burrow systems spaced throughout the landscape, such that the host population may be considered a metapopulation, with each occupied burrow system a subpopulation. We examine plague transmission within and between family groups and its effect on survival. Transmission of plague occurred disproportionately within family groups although not all gerbils became infected once plague entered a burrow system. There were no spatial patterns to suggest that family groups in close proximity to infected burrow systems were more at risk of infection than those far away. At one site, infection increased the chances of burrow-system extinction. Overall, it is useful to consider the burrow system as the unit of study within a much larger metapopulation.

Chronic recurrent infections and immunopathy

Phlebologie ◽  
2016 ◽  
Vol 45 (05) ◽  
pp. 308-309
Author(s):  
A. Miller
Keyword(s):  
Immune System ◽  
Lymphatic System ◽  
Recurrent Infections ◽  
Risk Of Infection ◽  
Central Function ◽  
System A

SummaryIn the immune system the lymphatic system has a central function. Starting with absorption and transport of the antigen to the lymphatic nodes it initiates the production of antibodies. Many substances like fat, proteins and cell detritus can only be absorbed and transported by the lymphatic system. A defect of this systems reduces defence and increase the risk of infection. Any inflammation includes and intensifies lymphoedema. Therefore early and sufficient therapy is important.

scholarly journals How to find natural reservoir hosts from endemic prevalence in a multi-host population: A case study of influenza in waterfowl

Epidemics ◽  
2009 ◽  
Vol 1 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Hiroshi Nishiura ◽  
Bethany Hoye ◽  
Marcel Klaassen ◽  
Silke Bauer ◽  
Hans Heesterbeek
Keyword(s):  
Host Population ◽  
Natural Reservoir ◽  
Reservoir Hosts

scholarly journals Host contact dynamics shapes richness and dominance of pathogen strains

2018 ◽  
Author(s):  
Francesco Pinotti ◽  
Éric Fleury ◽  
Didier Guillemot ◽  
Pierre-Yves Böelle ◽  
Chiara Poletto
Keyword(s):  
Staphylococcus Aureus ◽  
Real World ◽  
Disease Ecology ◽  
Care Facility ◽  
Host Population ◽  
Biological Data ◽  
Contact Dynamics ◽  
Contact Behavior ◽  
Strain Diversity ◽  
Close Proximity

AbstractThe interaction among multiple microbial strains affects the spread of infectious diseases and the efficacy of interventions. Genomic tools have made it increasingly easy to observe pathogenic strains diversity, but the best interpretation of such diversity has remained difficult because of relationships with host and environmental factors. Here, we focus on host-to-host contact behavior and study how it changes populations of pathogens in a minimal model of multi-strain interaction. We simulated a population of identical strains competing by mutual exclusion and spreading on a dynamical network of hosts according to a stochastic susceptible-infectious-susceptible model. We computed ecological indicators of diversity and dominance in strain populations for a collection of networks illustrating various properties found in real-world examples. Heterogeneities in the number of contacts among hosts were found to reduce diversity and increase dominance by making the repartition of strains among infected hosts more uneven, while strong community structure among hosts increased strain diversity. We found that the introduction of strains associated with hosts entering and leaving the system led to the highest pathogenic richness at intermediate turnover levels. These results were finally illustrated using the spread of Staphylococcus aureus in a long-term health-care facility where close proximity interactions and strain carriage were collected simultaneously. We found that network structural and temporal properties could account for a large part of the variability observed in strain diversity. These results show how stochasticity and network structure affect the population ecology of pathogens and warns against interpreting observations as unambiguous evidence of epidemiological differences between strains.Author summaryPathogens are structured in multiple strains that interact and co-circulate on the same host population. This ecological diversity affects, in many cases, the spread dynamics and the efficacy of vaccination and antibiotic treatment. Thus understanding its biological and host-behavioral drivers is crucial for outbreak assessment and for explaining trends of new-strain emergence. We used stochastic modeling and network theory to quantify the role of host contact behavior on strain richness and dominance. We systematically compared multi-strain spread on different network models displaying properties observed in real-world contact patterns. We then analyzed the real-case example of Staphylococcus aureus spread in a hospital, leveraging on a combined dataset of carriage and close proximity interactions. We found that contact dynamics has a profound impact on a strain population. Contact heterogeneity, for instance, reduces strain diversity by reducing the number of circulating strains and leading few strains to dominate over the others. These results have important implications in disease ecology and in the epidemiological interpretation of biological data.

scholarly journals The Visible Burrow System: A behavioral paradigm to assess sociability and social withdrawal in BTBR and C57BL/6J mice strains

2018 ◽  
Vol 344 ◽  
pp. 9-19 ◽  
Author(s):  
Maria Bove ◽  
Kevin Ike ◽  
Adriaan Eldering ◽  
Bauke Buwalda ◽  
Sietse F. de Boer ◽  
...  
Keyword(s):  
Social Withdrawal ◽  
Burrow System ◽  
System A ◽  
Behavioral Paradigm

scholarly journals The visible burrow system: A view from across the hall

2017 ◽  
Vol 178 ◽  
pp. 103-109 ◽  
Author(s):  
James P. Herman ◽  
Kellie L. Tamashiro
Keyword(s):  
Burrow System ◽  
System A

Energy dispersive microprobe analysis of intracellular mineral deposits in rat bone

1978 ◽  
Vol 36 (2) ◽  
pp. 666-667
Author(s):  
D.W. Dempster ◽  
W.A.P. Nicholson ◽  
H.Y. Elder ◽  
D.A.S. Smith ◽  
R.P. Ferrier
Keyword(s):  
Microprobe Analysis ◽  
Detection Efficiency ◽  
Thin Foil ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
Small Areas ◽  
System A ◽  
Transmission Electron ◽  
Close Proximity

The use of an energy dispersive X-ray microanalytical system (EDX) attached to a conventional transmission electron microscope (TEM) allows images of good morphological resolution from ultra-thin specimens and spectra of all detectable elements to be obtained simultaneously at radiation doses which are low compared to wavelength dispersive detectors. For reasons of detection efficiency the solid angle subtended from the specimen to the detector is maximised (∼0.l sterad) in our system, a LINK SYSTEMS 290 with a 30mm2Si(Li) crystal fitted to a JEOL JEM lOOC. However, with this type of system the recorded spectrum has contributions not only from the small areas which can be probed but also from scattered electrons, and X-rays originating in the surrounding specimen, the specimen support system and the microscope environment of the specimen. The problem is particularly acute in projects, such as the present, where it is necessary to detect and determine the ratios of elements (Ca and P) in small quantities in close proximity to relatively massive concentrations of the same elements.Modifications to our system have been described (Nicholson et al., 1977a;Biddlecombe et al., 1977) which greatly improve the peak/background ratios for quantitative analysis and eliminate all of the specific peaks of non-specimen origin. For ease of maintenance the JEOL 100C is fitted with thin foil condenser apertures (10μm thick molybdenum) as standard. At the accelerating voltage used in this study (80 keV) a considerable number of electrons are transmitted by these apertures and with the electron probe placed adjacent to fully mineralized bone the scattered electrons were responsible for generation of sizeable Ca and P signals. We have replaced the standard foils with thick (0.25 mm) molybdenum apertures.

Influence of the semiaquatic habit in determining burrow structure of the star-nosed mole (Condylura cristata)

1983 ◽  
Vol 61 (7) ◽  
pp. 1688-1692 ◽  
Author(s):  
Graham C. Hickman
Keyword(s):  
Food Storage ◽  
Burrow System ◽  
Active Nest ◽  
Nest Chamber ◽  
System A ◽  
Burrow Structure ◽  
Condylura Cristata

Condylura cristata is unique from most talpids in being semiaquatic. This report investigates the effect of a water habitat on burrow structure and is the first description of completely excavated burrow systems of the star-nosed mole, representing reedbed and lakeside habitats. Major features of the burrow structure included lack of surface ridges and mounds, unplugged burrows, along the edge of water, lack of steep vertical shafts to lower levels, deep tunnels not confined to particular areas of burrow system, a single active nest chamber containing dead leaves and freshly chewed pieces of Typha, and absence of special chambers for food storage or defecation. In comparing the influence of aquatic habits on structure of the burrow with terrestrial (Scalopus aquaticus) and aquatic (Desmana moschata) species of Talpidae, the semiaquatic Condylura is intermediate in position.

scholarly journals The Effect of An Emergency Evacuation on the Spread of COVID19

2021 ◽  
Vol 8 ◽  
Author(s):  
Sachit Butail ◽  
Maurizio Porfiri
Keyword(s):  
Built Environment ◽  
Dynamic Model ◽  
Computer Simulations ◽  
Infected Individual ◽  
Emergency Evacuation ◽  
Risk Of Infection ◽  
Potential Threat ◽  
Social Distancing ◽  
Close Proximity ◽  
Respiratory Droplets

In an emergency evacuation, people almost always come in close proximity as they quickly leave a built environment under a potential threat. With COVID19, this situation presents yet another challenge: that of getting unintentionally exposed to an infected individual. To assess the epidemiological consequences of an emergency evacuation, we expanded a popular pedestrian dynamic model to enable social distancing during a normal exit and analyze the effect of possible transmission through respiratory droplets and aerosol. Computer simulations point to a troubling outcome, whereby the benefits of a quick exit could be outweighed by the risk of infection.

Stand-Up Forklift Egress Times as a Function of Operator Compartment Guarding

2014 ◽  
Author(s):  
Ben T. Railsback ◽  
Richard M. Ziernicki ◽  
Ricky L. Nguyen ◽  
Steve D. Knapp ◽  
William H. Pierce
Keyword(s):  
Lower Limb ◽  
Crush Injury ◽  
Lower Limbs ◽  
Safety Standard ◽  
Time Duration ◽  
High Lift ◽  
Open Design ◽  
System A ◽  
Close Proximity ◽  
Additional Protection

A significant hazard related to the use of stand-up lift trucks, or stand-up forklifts, is the hazard of a lower limb crush injury or foot crush due to the opening across the rear of the operator compartment. According to one lift truck manufacturer’s statistics, there have been over 500 accidents that resulted in an injury to the lower limb of the operator in the last 30 years that involved their stand-up lift trucks. [1] Other manufacturers have had similar accidents. The injuries have occurred to the lower limb of the operator due to the close proximity of the operator’s lower limbs to the exterior of the lift truck, and the confined areas that stand-up lift trucks operate in. The operator’s lower limb can become pinned and crushed between the moving lift and another fixed object such as a rack system, a column or another lift truck. Objects, such as a fork tine, can also intrude into the operator compartment, injuring the operator’s lower extremities. The ANSI/ITSDF B56.1, Safety Standard for Low Lift and High Lift Trucks, encourages stand-up lift trucks to be designed with an open compartment to permit easy ingress and egress. [2] According to the standard, the open design allows an operator a free and easy egress from the truck in the event of a tip-over or off-the-dock accident. However, the standard permits the use of additional guarding and enclosure of the operator compartment. Spring loaded doors (or spring assisted closing guards) have been designed, implemented and are available from many manufacturers, but no data has been published regarding the time to open and egress from the operator compartment. Latching doors have also been designed and manufactured, but are not currently available on the market except in the case of trucks equipped with freezer cabs, for operation in refrigerated environments. However, latched doors have been criticized for extending the egress time duration by approximately 1/2 second. This study shows that a spring loaded door can be implemented on a stand-up forklift while only increasing egress time by a negligible amount, 0.05 seconds over an open compartment configuration. Furthermore, this study shows that an optimized latching door, designed by Knott Laboratory engineers, can also be implemented for a stand-up forklift while only increasing egress time by 0.09 seconds. The latching door designed by Knott Laboratory decreases the change in egress time associated with a latched door by a factor of 5. Therefore, the addition of a spring loaded door, or a latching door will not significantly increase operator egress time and provide additional protection to the operator in the event of a collision while still maintaining quick egress.

scholarly journals Host ecotype generates evolutionary and epidemiological divergence across a pathogen metapopulation

2014 ◽  
Vol 281 (1787) ◽  
pp. 20140522 ◽  
Author(s):  
Anna-Liisa Laine ◽  
Jeremy J. Burdon ◽  
Adnane Nemri ◽  
Peter H. Thrall
Keyword(s):  
Host Resistance ◽  
Population Genetic ◽  
Host Population ◽  
Heterogeneous Environments ◽  
Evolutionary Potential ◽  
Pathogen Population ◽  
Melampsora Lini ◽  
Close Proximity ◽  
Pathogen Populations ◽  
Inoculation Study

The extent and speed at which pathogens adapt to host resistance varies considerably. This presents a challenge for predicting when—and where—pathogen evolution may occur. While gene flow and spatially heterogeneous environments are recognized to be critical for the evolutionary potential of pathogen populations, we lack an understanding of how the two jointly shape coevolutionary trajectories between hosts and pathogens. The rust pathogen Melampsora lini infects two ecotypes of its host plant Linum marginale that occur in close proximity yet in distinct populations and habitats. In this study, we found that within-population epidemics were different between the two habitats. We then tested for pathogen local adaptation at host population and ecotype level in a reciprocal inoculation study. Even after controlling for the effect of spatial structure on infection outcome, we found strong evidence of pathogen adaptation at the host ecotype level. Moreover, sequence analysis of two pathogen infectivity loci revealed strong genetic differentiation by host ecotype but not by distance. Hence, environmental variation can be a key determinant of pathogen population genetic structure and coevolutionary dynamics and can generate strong asymmetry in infection risks through space.

Sign in / Sign up

Export Citation Format

Share Document