scholarly journals Resistance, tolerance and environmental transmission dynamics determine host extinction risk in a load-dependent amphibian disease

2017 ◽  
Vol 20 (9) ◽  
pp. 1169-1181 ◽  
Author(s):  
Mark Q. Wilber ◽  
Roland A. Knapp ◽  
Mary Toothman ◽  
Cheryl J. Briggs
Keyword(s):  
Extinction Risk ◽  
Transmission Dynamics ◽  
Amphibian Disease ◽  
Environmental Transmission ◽  
Host Extinction

scholarly journals Investigating the Role of Environmental Transmission in COVID-19 Dynamics: A Mathematical Model Based Study

2020 ◽  
Author(s):  
Ibrahim M. ELmojtaba ◽  
Fatma Al-Musalhi ◽  
Asma Al-Ghassani ◽  
Nasser Al-Salti
Keyword(s):  
Mathematical Model ◽  
Disease Transmission ◽  
Reproduction Number ◽  
Equilibrium Points ◽  
Transmission Dynamics ◽  
Model Parameters ◽  
Environmental Transmission ◽  
Estimated Parameters ◽  
Existence And Stability

Abstract A mathematical model with environmental transmission has been proposed and analyzed to investigate its role in the transmission dynamics of the ongoing COVID-19 outbreak. Two expressions for the basic reproduction number R0 have been analytically derived using the next generation matrix method. The two expressions composed of a combination of two terms related to human to human and environment to human transmissions. The value of R0 has been calculated using estimated parameters corresponding to two datasets. Sensitivity analysis of the reproduction number to the corresponding model parameters has been carried out. Existence and stability analysis of disease free and endemic equilibrium points have been presented in relation with the obtained expressions of R0. Numerical simulations to demonstrate the effect of some model parameters related to environmental transmission on the disease transmission dynamics have been carried out and the results have been demonstrated graphically.

scholarly journals An Ebola virus disease model with fear and environmental transmission dynamics

2021 ◽  
Author(s):  
M.L. Juga ◽  
F. Nyabadza ◽  
F. Chirove
Keyword(s):  
Disease Transmission ◽  
Ebola Virus ◽  
Virus Disease ◽  
Case Fatality ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Ebola Virus Disease ◽  
Fear Of Death ◽  
List Type ◽  
Environmental Transmission

ABSTRACTRecent Ebola virus disease (EVD) outbreaks have been limited not only to the interactions between humans but also to the complex interplay of the environment, human and socio-economic factors. Changes in human behaviour as a result of fear can also affect disease transmission dynamics. In this paper, a compartmental model is used to study the dynamics of EVD incorporating fear and environmental transmission. We formulate a fear dependent contact rate function to measure the rate of person to person, as well as pathogen to person transmissions. The epidemic threshold and the model equilibria are determined and, their stabilities are analysed. The model is validated by fitting it to data from the 2019 and 2020 EVD outbreaks in the Democratic Republic of Congo. Our results suggest that the fear of death from EVD may reduce the transmission and aid the control of the disease, but it is not sufficient to eradicate the disease. Policymakers need to also implement other control measures such as case finding, media campaigns, Quarantine and increase in the number of beds in the Ebola treatment centers, good laboratory services, safe burials and social mobilisation, to eradicate the disease.HighlightsDue to its high case fatality rate, EVD undoubtedly instills fear in the inhabitants of any affected community.We propose an Ebola model with fear, which considers the pathogens in the environment to quantify the effect of fear and environmental transmission on the EVD disease dynamics.The fear of death from Ebola is proportional to the Ebola disease transmission rate.At high levels of fear, the number of EVD cases decrease.

scholarly journals Assessing host extinction risk following exposure to Batrachochytrium dendrobatidis

2014 ◽  
Vol 281 (1785) ◽  
pp. 20132783 ◽  
Author(s):  
Stilianos Louca ◽  
Margarita Lampo ◽  
Michael Doebeli
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Extinction Risk ◽  
Life Stage ◽  
Adult Life ◽  
Host Population ◽  
Amphibian Conservation ◽  
Relevant Parameter ◽  
Wildlife Diseases ◽  
Host Extinction

Wildlife diseases are increasingly recognized as a major threat to biodiversity. Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungus Batrachochytrium dendrobatidis ( Bd ). Using a mathematical model and simulations, we study its effects on a generic riparian host population with a tadpole and adult life stage. An analytical expression for the basic reproduction quotient, Q o , of the pathogen is derived. By sampling the entire relevant parameter space, we perform a statistical assessment of the importance of all considered parameters in determining the risk of host extinction, upon exposure to Bd . We find that Q o not only gives a condition for the initial invasion of the fungus, but is in fact the best predictor for host extinction. We also show that the role of tadpoles, which in some species tolerate infections, is ambivalent. While tolerant tadpoles may provide a reservoir for the fungus, thus facilitating its persistence or even amplifying its outbreaks, they can also act as a rescue buffer for a stressed host population. Our results have important implications for amphibian conservation efforts.

The environmental transmission of cholera

Waterlines ◽  
1994 ◽  
Vol 12 (4) ◽  
pp. 4-7
Author(s):  
Ann storey
Keyword(s):  
Environmental Transmission

Simulating disease transmission dynamics at a multi-scale level

2007 ◽  
Vol 1 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Moshe B Hoshen ◽  
Anthony H Burton ◽  
Themis J V Bowcock
Keyword(s):  
Disease Transmission ◽  
Transmission Dynamics ◽  
Scale Level ◽  
Multi Scale
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