n.传染病；接触传染；蔓延
Tuberculosis is respiratory tract contagion. 肺结核是呼吸道传染病。
Fear spread through the crowd like a contagion. 人们心中的恐惧像瘟疫一样蔓延开来。
Some diseases spread by contagion. 有些疾病藉传染蔓延。
