A scourge is a whip — or anything else that is punishing and dreadful. You could confront "a scourge of corruption" or "a scourge of hunger."
As a verb, scourge means to cause suffering. Not surprisingly, it comes from the old French word meaning "to whip." A dictatorship could scourge and oppress its citizens, and an infectious disease could scourge an entire community. When you see scourge, think "suffering."