Limits...
Tactics and strategies for managing Ebola outbreaks and the salience of immunization.

Getz WM, Gonzalez JP, Salter R, Bangura J, Carlson C, Coomber M, Dougherty E, Kargbo D, Wolfe ND, Wauquier N - Comput Math Methods Med (2015)

Bottom Line: We present a stochastic transmission chain simulation model for Ebola viral disease (EVD) in West Africa, with the salutary result that the virus may be more controllable than previously suspected.The ongoing tactics to detect cases as rapidly as possible and isolate individuals as safely as practicable is essential to saving lives in the current outbreaks in Guinea, Liberia, and Sierra Leone.Equally important are educational campaigns that reduce contact rates between susceptible and infectious individuals in the community once an outbreak occurs.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA ; School of Mathematical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.

ABSTRACT
We present a stochastic transmission chain simulation model for Ebola viral disease (EVD) in West Africa, with the salutary result that the virus may be more controllable than previously suspected. The ongoing tactics to detect cases as rapidly as possible and isolate individuals as safely as practicable is essential to saving lives in the current outbreaks in Guinea, Liberia, and Sierra Leone. Equally important are educational campaigns that reduce contact rates between susceptible and infectious individuals in the community once an outbreak occurs. However, due to the relatively low R 0 of Ebola (around 1.5 to 2.5 next generation cases are produced per current generation case in naïve populations), rapid isolation of infectious individuals proves to be highly efficacious in containing outbreaks in new areas, while vaccination programs, even with low efficacy vaccines, can be decisive in curbing future outbreaks in areas where the Ebola virus is maintained in reservoir populations.

Show MeSH

Related in: MedlinePlus

(a) A bar plot of the average weekly incidence rates during outbreaks (i.e., given that immediate fadeout did not occur) over 12 weeks, starting with an index case at the beginning of week 1, as generated from 100 runs of our transmission model, using the baseline parameter set in Table S1 (see SOI for details). (b) Plots of weekly incidence rates in 6 local areas (see Figure S2 for daily rates) that have been shifted to allow us to visually compare the shapes of these bar plots with model output.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4338386&req=5

fig2: (a) A bar plot of the average weekly incidence rates during outbreaks (i.e., given that immediate fadeout did not occur) over 12 weeks, starting with an index case at the beginning of week 1, as generated from 100 runs of our transmission model, using the baseline parameter set in Table S1 (see SOI for details). (b) Plots of weekly incidence rates in 6 local areas (see Figure S2 for daily rates) that have been shifted to allow us to visually compare the shapes of these bar plots with model output.

Mentions: We note that since estimates of R0 for outbreaks in different countries have ranged between 1.5 and 2.5 [8], it makes no sense to estimate model parameters from the data for one country and then apply the model to predict the course of an outbreak in another country. Additionally, the stochastic nature of outbreaks implies, as we demonstrate in our baseline simulation results below, that the same model parameters produce events that may either fadeout or breakout, where, in the latter case, the outbreak sizes may differ by nearly two orders of magnitude. Finally, even within country, as our data (Figure 2) and the data of others show (as discussed below), sufficient spatial structure exists so that a model not accounting for this spatial structure (e.g., rural areas versus towns and cities) cannot accurately forecast the course of any within country epidemic. Thus, the primary value of our model is to investigate, in the context of an ensemble of simulated events, the potential impacts of healthcare responses such as reductions in contact rates of community members with infected individuals or the efficacy of vaccination programs, should a suitable vaccine be released.


Tactics and strategies for managing Ebola outbreaks and the salience of immunization.

Getz WM, Gonzalez JP, Salter R, Bangura J, Carlson C, Coomber M, Dougherty E, Kargbo D, Wolfe ND, Wauquier N - Comput Math Methods Med (2015)

(a) A bar plot of the average weekly incidence rates during outbreaks (i.e., given that immediate fadeout did not occur) over 12 weeks, starting with an index case at the beginning of week 1, as generated from 100 runs of our transmission model, using the baseline parameter set in Table S1 (see SOI for details). (b) Plots of weekly incidence rates in 6 local areas (see Figure S2 for daily rates) that have been shifted to allow us to visually compare the shapes of these bar plots with model output.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4338386&req=5

fig2: (a) A bar plot of the average weekly incidence rates during outbreaks (i.e., given that immediate fadeout did not occur) over 12 weeks, starting with an index case at the beginning of week 1, as generated from 100 runs of our transmission model, using the baseline parameter set in Table S1 (see SOI for details). (b) Plots of weekly incidence rates in 6 local areas (see Figure S2 for daily rates) that have been shifted to allow us to visually compare the shapes of these bar plots with model output.
Mentions: We note that since estimates of R0 for outbreaks in different countries have ranged between 1.5 and 2.5 [8], it makes no sense to estimate model parameters from the data for one country and then apply the model to predict the course of an outbreak in another country. Additionally, the stochastic nature of outbreaks implies, as we demonstrate in our baseline simulation results below, that the same model parameters produce events that may either fadeout or breakout, where, in the latter case, the outbreak sizes may differ by nearly two orders of magnitude. Finally, even within country, as our data (Figure 2) and the data of others show (as discussed below), sufficient spatial structure exists so that a model not accounting for this spatial structure (e.g., rural areas versus towns and cities) cannot accurately forecast the course of any within country epidemic. Thus, the primary value of our model is to investigate, in the context of an ensemble of simulated events, the potential impacts of healthcare responses such as reductions in contact rates of community members with infected individuals or the efficacy of vaccination programs, should a suitable vaccine be released.

Bottom Line: We present a stochastic transmission chain simulation model for Ebola viral disease (EVD) in West Africa, with the salutary result that the virus may be more controllable than previously suspected.The ongoing tactics to detect cases as rapidly as possible and isolate individuals as safely as practicable is essential to saving lives in the current outbreaks in Guinea, Liberia, and Sierra Leone.Equally important are educational campaigns that reduce contact rates between susceptible and infectious individuals in the community once an outbreak occurs.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA ; School of Mathematical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.

ABSTRACT
We present a stochastic transmission chain simulation model for Ebola viral disease (EVD) in West Africa, with the salutary result that the virus may be more controllable than previously suspected. The ongoing tactics to detect cases as rapidly as possible and isolate individuals as safely as practicable is essential to saving lives in the current outbreaks in Guinea, Liberia, and Sierra Leone. Equally important are educational campaigns that reduce contact rates between susceptible and infectious individuals in the community once an outbreak occurs. However, due to the relatively low R 0 of Ebola (around 1.5 to 2.5 next generation cases are produced per current generation case in naïve populations), rapid isolation of infectious individuals proves to be highly efficacious in containing outbreaks in new areas, while vaccination programs, even with low efficacy vaccines, can be decisive in curbing future outbreaks in areas where the Ebola virus is maintained in reservoir populations.

Show MeSH
Related in: MedlinePlus