Disease
Diseases are long-term, harmful effects that worsen over time. They can be contracted from infected animal bites or random events.
Infection
The infection spread from infected individuals to nearby units. The speed of infection and the spread radius vary depending on the disease.
Disease
Disease severity is separate from infection. Once fully infected, a unit develops worsening symptoms. Fatal diseases such as plague and rabies kill at 100% disease progress, not 100% infection.
Immunity
Once immunity reaches 100%, the disease will recede. After the disease is cured (at 0%), this immunity will slowly fade, but the unit remains protected from that specific disease until it's completely gone.
Tip
Compare disease severity with immunity progress. Rest, treatment and a medical room help immunity develop. Disease spread is limited to nearby susceptible units in the same room, or outdoors together. A sick unit in a medical room does not spread disease through this proximity mechanism.