This model simulates the epidemic dynamics in a human population based on the SEIR model. Students may use the model to explore infectious disease outbreak dynamics in a population influenced by the length of the incubation period, transmission rates, mortality, population mobility, and vaccination coverage. This model allows students to explore the effect of vaccination and the development of herd immunity.
Grades: 9-12;
The model starts with a human population consisting of susceptible (green color)people. Once a carrier (orange color) appears in the population, it will pass the disease to one of the susceptible people nearby (within a radius of 1.5) at the defined transmission rate. The carrier may become sick (infectious red color) after the defined incubation period. The sick people will be isolated, so they do not infect others. The sick people will remain ill for 14 days. By the 15th day of being sick, they die (disappear from the model) at the defined mortality or recover and become immune to the disease (blue color).
Buttons, Sliders, and Switches:
The buttons of Set up/Reset, Default settings, Run/Pause, and Run a day are self-explanatory.
The population density slider determines the number of people in the population.
The Transmission-rate slider determines how likely a susceptible person is infected when s/he is near an exposed person.
The "Incubation-period" define the number of days between a person is infected and becomes sick.
The Mobility slide determines how far the individuals move each time. The greater the mobility, the further they move.
The Vaccination-rate slider determined the vaccination coverage of the population. Use it with the Vaccination button.
The Watch a person button lets you focus on a single person or stop watching the person. You may see if this person progresses through the four stages.
Use the model:
First, choose the factors, such as population-density, transmission rate, etc.
Click on Set up/Reset then Run/Pause. The model is set to stop when there are no infectious people.
Observe the infection changes in the population in the plot and monitor.
Use Run one day to run the model in a controlled way and collect day-by-day data.
First, choose the factors, such as population size, transmission rate, etc.
Click on "Set up/Reset" then "Run/Pause." The model is set to stop when there are no infectious people.
Observe the infection changes in the population in the plot and monitor.
Use "Run one day" to run the model in a controlled way and collect day-by-day data.
THINGS TO TRY
There are so many things you can try in this model. Here are only very a few quick ideas:
Does the total of deaths change differ in a population where all people are susceptible vs. a potion of people are vaccinated? How?
What is the vaccination rate for achieving herd immunity?
How does the length of the incubation period affect the maximum number of daily cases and the total death toll in an epidemic?
Dr. Lin Xiang creates this module at the University of Kentucky. If you mention this model in a publication, we ask that you include the citations below.
Xiang, L. (2021). Infectious Disease Outbreak-SEIR model. Department of STEM Education, University of Kentucky, Lexington, KY.
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