就像流感一样，一个人的情绪状态是可以传染的。

Like the flu, a person's emotional state can be contagious.

youdao

所以我猜想，笑是可以传染的。

So I guess it's contagious.

youdao

不过，寂寞是可以传染的。

But loneliness can be contagious.

youdao

So, the concern at this time, and still remains a concern, is that infectious agents, particularly very deadly infectious agents like smallpox, could be weaponized in some way, or converted into a weapon.

当时有一些担心,现在还在担心,这些传染源,尤其是像天花非常具有致命性的传染源,可以进行某种程度的武器化,或者转变成武器

耶鲁公开课 - 生物医学工程探索课程节选