Analogy — Scale of conflict/illness: Skirmish : War :: Disease : ____

Introduction / Context:
A skirmish is a small conflict; war is a large-scale conflict. Likewise, an epidemic is disease on a large/population scale. The mapping is “small-scale instance → large-scale version”.

Why Other Options Are Wrong:

• Medicine/Patient — agent or experiencer, not scale.
• Infection — often the base condition, not necessarily the scaled-up phenomenon.

Final Answer:
Epidemic