He went west by stagecoach and succumbed to the epidemic of gold and silver fever.
句意：他乘驿站马车来到西部，受到当时正流行的淘金热的诱惑。epidemic此处意为极为盛行。flu 流感。rush涌动。inflammation炎症。temptation诱惑。B选项与划线处意义最为接近，故选B。