Rumors are like a bacillus that spreads quietly through the community.

bacillus 是名词，来自拉丁语，指"杆菌"或"芽孢杆菌"这类杆状的细菌。在医学和生物学中特指某些致病细菌，这里用作比喻，形容谣言像细菌一样具有传播性和危害性。