Key strategies for reducing spread of avian influenza among commercial poultry holdings: lessons for transmission to humans
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A mathematical model based on stochastic farm-to-farm transmission that incorporates flock size and spatial contacts is presented that suggests an immediate depopulation of infected flocks following an accurate and quick diagnosis would have a greater impact than simply depopulating surrounding flocks.Abstract:
Recent avian flu epidemics (A/H5N1) in Southeast Asia and case reports from around the world have led to fears of a human pandemic. Control of these outbreaks in birds would probably lead to reduced transmission of the avian virus to humans. This study presents a mathematical model based on stochastic farm-to-farm transmission that incorporates flock size and spatial contacts to evaluate the impact of control strategies. Fit to data from the recent epidemic in the Netherlands, we evaluate the efficacy of control strategies and forecast avian influenza dynamics. Our results identify high-risk areas of spread by mapping of the farm level reproductive number. Results suggest that an immediate depopulation of infected flocks following an accurate and quick diagnosis would have a greater impact than simply depopulating surrounding flocks. Understanding the relative importance of different control measures is essential for response planning.read more
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Journal ArticleDOI
Risk Maps for the Spread of Highly Pathogenic Avian Influenza in Poultry
G.J. Boender,Thomas J. Hagenaars,Annemarie Bouma,Gonnie Nodelijk,A.R.W. Elbers,Mart C.M. de Jong,Michiel van Boven +6 more
TL;DR: The analyses provide an estimate of the spatial range over which highly pathogenic avian influenza viruses spread between farms, and emphasize that control measures aimed at controlling such outbreaks need to take into account the local density of farms.
Journal ArticleDOI
Transmission of the Highly Pathogenic Avian Influenza Virus H5N1 within Flocks during the 2004 Epidemic in Thailand
Thanawat Tiensin,Thanawat Tiensin,Mirjam Nielen,Hans Vernooij,Thaweesak Songserm,Wantanee Kalpravidh,Sirikan Chotiprasatintara,Arunee Chaisingh,Surapong Wongkasemjit,Karoon Chanachai,Weerapong Thanapongtham,Thinnarat Srisuvan,Arjan Stegeman +12 more
TL;DR: This present study is the first to quantify the transmission of avian influenza virus H5N1 within flocks during the 2004 epidemic in Thailand and indicates that a critical proportion of the susceptible poultry population in a flock needs to be vaccinated.
Journal ArticleDOI
Optimal control strategy for prevention of avian influenza pandemic.
TL;DR: It is revealed that an optimal strategy to reduce the number of total infected humans might increase a chance of invadability of the mutant influenza.
Journal ArticleDOI
The effect of network mixing patterns on epidemic dynamics and the efficacy of disease contact tracing.
TL;DR: Stochastic simulations are used to investigate the effects of mixing patterns on epidemic dynamics and contact-tracing efficacy, finding that for small epidemics, contact tracing is more effective on disassortative networks due to the greater resilience of assortative Networks to link removal.
Journal ArticleDOI
Optimal isolation control strategies and cost-effectiveness analysis of a two-strain avian influenza model.
TL;DR: In this paper, optimal control theory is applied to a system of ordinary differential equation describing a two-strain avian influenza transmission via the Pontryagin's Maximum Principle, and a pair of control variables representing the isolation strategies for individuals with avian and mutant strains were incorporated into the transmission model.
References
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Infectious Diseases of Humans: Dynamics and Control
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Strategies for containing an emerging influenza pandemic in Southeast Asia
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TL;DR: A simulation model of influenza transmission in Southeast Asia is used and it is shown that elimination of a nascent pandemic may be feasible using a combination of geographically targeted prophylaxis and social distancing measures, if the basic reproduction number of the new virus is below 1.8.
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