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Modeling the effect of transient populations on epidemics in Washington DC.

Parikh N, Youssef M, Swarup S, Eubank S - Sci Rep (2013)

Bottom Line: We find that there are significantly more infections when transients are considered.Surprisingly, closing museums has no beneficial effect.However, promoting healthy behavior at the museums can both reduce and delay the epidemic peak.

View Article: PubMed Central - PubMed

Affiliation: Networks Dynamics and Simulation Science Laboratory, Virginia Bioinformatics Institute, Virginia Tech, USA.

ABSTRACT
Large numbers of transients visit big cities, where they come into contact with many people at crowded areas. However, epidemiological studies have not paid much attention to the role of this subpopulation in disease spread. We evaluate the effect of transients on epidemics by extending a synthetic population model for the Washington DC metro area to include leisure and business travelers. A synthetic population is obtained by combining multiple data sources to build a detailed minute-by-minute simulation of population interaction resulting in a contact network. We simulate an influenza-like illness over the contact network to evaluate the effects of transients on the number of infected residents. We find that there are significantly more infections when transients are considered. Since much population mixing happens at major tourism locations, we evaluate two targeted interventions: closing museums and promoting healthy behavior (such as the use of hand sanitizers, covering coughs, etc.) at museums. Surprisingly, closing museums has no beneficial effect. However, promoting healthy behavior at the museums can both reduce and delay the epidemic peak. We analytically derive the reproductive number and perform stability analysis using an ODE-based model.

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Related in: MedlinePlus

Evaluation of the reproductive number Ro in eqn.1 as a function of the resident reproductive number  and transient reproductive number  while the competing reproductive number  equals its estimated value 0.5359.The reproductive number is evaluated by sweeping the infection rates values βr→r and βt→t between 0 and 2 and changing  and  accordingly.
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f7: Evaluation of the reproductive number Ro in eqn.1 as a function of the resident reproductive number and transient reproductive number while the competing reproductive number equals its estimated value 0.5359.The reproductive number is evaluated by sweeping the infection rates values βr→r and βt→t between 0 and 2 and changing and accordingly.

Mentions: The first case is shown in Figures 7 and 8 and the other four cases are shown in the Supplementary Information. In Figure 7, even if the reproductive numbers and are less than 1, the overall reproductive number Ro can be greater than 1 and the epidemic spreads in the two populations. This observation is consistent with the non-endemic disease equilibrium point where there is no endemic equilibrium for the transient population. The endemic equilibrium point is observed for and the corresponding attack rate becomes high (~0.45). Also the two figures show that the transient reproductive number changes slower than the resident reproductive number when their infection rates are changed similarly between 0 and 2.


Modeling the effect of transient populations on epidemics in Washington DC.

Parikh N, Youssef M, Swarup S, Eubank S - Sci Rep (2013)

Evaluation of the reproductive number Ro in eqn.1 as a function of the resident reproductive number  and transient reproductive number  while the competing reproductive number  equals its estimated value 0.5359.The reproductive number is evaluated by sweeping the infection rates values βr→r and βt→t between 0 and 2 and changing  and  accordingly.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3818653&req=5

f7: Evaluation of the reproductive number Ro in eqn.1 as a function of the resident reproductive number and transient reproductive number while the competing reproductive number equals its estimated value 0.5359.The reproductive number is evaluated by sweeping the infection rates values βr→r and βt→t between 0 and 2 and changing and accordingly.
Mentions: The first case is shown in Figures 7 and 8 and the other four cases are shown in the Supplementary Information. In Figure 7, even if the reproductive numbers and are less than 1, the overall reproductive number Ro can be greater than 1 and the epidemic spreads in the two populations. This observation is consistent with the non-endemic disease equilibrium point where there is no endemic equilibrium for the transient population. The endemic equilibrium point is observed for and the corresponding attack rate becomes high (~0.45). Also the two figures show that the transient reproductive number changes slower than the resident reproductive number when their infection rates are changed similarly between 0 and 2.

Bottom Line: We find that there are significantly more infections when transients are considered.Surprisingly, closing museums has no beneficial effect.However, promoting healthy behavior at the museums can both reduce and delay the epidemic peak.

View Article: PubMed Central - PubMed

Affiliation: Networks Dynamics and Simulation Science Laboratory, Virginia Bioinformatics Institute, Virginia Tech, USA.

ABSTRACT
Large numbers of transients visit big cities, where they come into contact with many people at crowded areas. However, epidemiological studies have not paid much attention to the role of this subpopulation in disease spread. We evaluate the effect of transients on epidemics by extending a synthetic population model for the Washington DC metro area to include leisure and business travelers. A synthetic population is obtained by combining multiple data sources to build a detailed minute-by-minute simulation of population interaction resulting in a contact network. We simulate an influenza-like illness over the contact network to evaluate the effects of transients on the number of infected residents. We find that there are significantly more infections when transients are considered. Since much population mixing happens at major tourism locations, we evaluate two targeted interventions: closing museums and promoting healthy behavior (such as the use of hand sanitizers, covering coughs, etc.) at museums. Surprisingly, closing museums has no beneficial effect. However, promoting healthy behavior at the museums can both reduce and delay the epidemic peak. We analytically derive the reproductive number and perform stability analysis using an ODE-based model.

Show MeSH
Related in: MedlinePlus