scholarly journals Dilution effects in disease ecology

2021 ◽  
Author(s):  
Felicia Keesing ◽  
Richard S. Ostfeld
Keyword(s):  
Disease Ecology ◽  
Dilution Effects

scholarly journals Biodiversity loss underlies the dilution effect of biodiversity

2020 ◽  
Author(s):  
Fletcher W. Halliday ◽  
Jason R. Rohr ◽  
Anna-Liisa Laine
Keyword(s):  
Disease Ecology ◽  
Dilution Effect ◽  
Biodiversity Loss ◽  
Host Community ◽  
Scale Dependency ◽  
Risk Of Infection ◽  
Community Competence ◽  
Dilution Effects ◽  
Meta Analyses

AbstractThe dilution effect predicts increasing biodiversity to reduce the risk of infection, but the generality of this effect remains unresolved. Because biodiversity loss generates predictable changes in host community competence, we hypothesized that biodiversity loss might drive the dilution effect. We tested this hypothesis by reanalyzing four previously published meta-analyses that came to contradictory conclusions regarding generality of the dilution effect. In the context of biodiversity loss, our analyses revealed a unifying pattern: dilution effects were inconsistently observed for natural biodiversity gradients, but were commonly observed for biodiversity gradients generated by disturbances causing losses of native biodiversity. Incorporating biodiversity loss into tests of generality of the dilution effect further indicated that scale-dependency may strengthen the dilution effect only when biodiversity gradients are driven by biodiversity loss. Together, these results help to resolve one of the most contentious issues in disease ecology: the generality of the dilution effect.

AIR DILUTION EFFECTS ON TETRADECANE SPRAY AUTOIGNITION IN TRANSCRITICAL AND SUPERCRITICAL REGIMES

1999 ◽  
Vol 9 (2) ◽  
pp. 153-172 ◽  
Author(s):  
M. De Joannon ◽  
Antonio Cavaliere ◽  
Raffaele Ragucci
Keyword(s):  
Dilution Effects

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

scholarly journals Topic modeling of major research themes in disease ecology of mammals

2019 ◽  
Vol 100 (3) ◽  
pp. 1008-1018 ◽  
Author(s):  
Barbara A Han ◽  
Richard S Ostfeld
Keyword(s):  
Topic Modeling ◽  
Disease Ecology ◽  
Major Research ◽  
Research Themes

scholarly journals Impact of the experimental removal of lizards on Lyme disease risk

2011 ◽  
Vol 278 (1720) ◽  
pp. 2970-2978 ◽  
Author(s):  
Andrea Swei ◽  
Richard S. Ostfeld ◽  
Robert S. Lane ◽  
Cheryl J. Briggs
Keyword(s):  
Lyme Disease ◽  
Disease Ecology ◽  
Disease Risk ◽  
Large Fraction ◽  
Host Community ◽  
Deer Mice ◽  
Infection Prevalence ◽  
Alternate Host ◽  
Experimental Removal ◽  
Tick Infection

The distribution of vector meals in the host community is an important element of understanding and predicting vector-borne disease risk. Lizards (such as the western fence lizard; Sceloporus occidentalis ) play a unique role in Lyme disease ecology in the far-western United States. Lizards rather than mammals serve as the blood meal hosts for a large fraction of larval and nymphal western black-legged ticks ( Ixodes pacificus —the vector for Lyme disease in that region) but are not competent reservoirs for the pathogen, Borrelia burgdorferi . Prior studies have suggested that the net effect of lizards is to reduce risk of human exposure to Lyme disease, a hypothesis that we tested experimentally. Following experimental removal of lizards, we documented incomplete host switching by larval ticks (5.19%) from lizards to other hosts. Larval tick burdens increased on woodrats, a competent reservoir, but not on deer mice, a less competent pathogen reservoir. However, most larvae failed to find an alternate host. This resulted in significantly lower densities of nymphal ticks the following year. Unexpectedly, the removal of reservoir-incompetent lizards did not cause an increase in nymphal tick infection prevalence. The net result of lizard removal was a decrease in the density of infected nymphal ticks, and therefore a decreased risk to humans of Lyme disease. Our results indicate that an incompetent reservoir for a pathogen may, in fact, increase disease risk through the maintenance of higher vector density and therefore, higher density of infected vectors.

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