Plague Inc. - Lite (Web)

Click a tile to introduce infection. Adjust parameters and observe how infection spreads over time (S = susceptible, I = infected, R = recovered, D = dead).

Model: stochastic SIRD on a grid • Timestep = 1 day

World map

Click a tile to seed infection

Controls

Simulation speed and state

Sim speed: 1x

Epidemiological parameters

Transmissibility (β): 0.30

Higher → infection spreads faster

Recovery rate (γ per day): 0.05

Higher → infected recover faster

Mortality rate (μ per day): 0.01

Higher → more deaths

Mobility (neighbor spread): 0.20

Higher → cross-tile spread easier

Per-tile population (constant):

Changing this resets the world.

Global stats

S: 0

Susceptible (not yet infected)

I: 0

Infected (currently contagious)

R: 0

Recovered (immune)

D: 0

Dead

Controls

Seed infected per click

Vaccinate sets a share to recovered (immune). Lockdown reduces mobility by 80% when ON.

Epidemic curve

Sus

Inf

Rec

Dead

How the model works (short)

S susceptible individuals can become infected when exposed to infected in the same tile or neighbor tiles. Transmission probability per susceptible per day ≈ β * I/N * mobility_factor.
I infected individuals either recover at rate γ (become R) or die at rate μ per day.
Mobility controls cross-tile exposure: higher mobility → more neighbor infections.
Use Vaccinate to convert a fraction of S → R. Use Lockdown to reduce mobility dramatically.

This is a teaching tool — stochastic outcomes vary each run.

Tips to explore

Increase β and watch how fast the epidemic explodes.
Increase γ to simulate faster recovery (shorter infectious period).
Toggle lockdown after an outbreak to see how spread slows.
Try vaccinating early vs late and compare total deaths.