I sometimes use the mantra like just breathing in the breath of God and breathing out the breath of God.

我又是也会吟颂咒语,就好像吸入上帝之气,呼出上帝之气。

普林斯顿公开课 - 人性课程节选

But it can be acquired in the air, from patients that are from- from other individuals that are infected.

天花会通过空气传播,通过病人和其他感染者呼出的空气传播

耶鲁公开课 - 生物医学工程探索课程节选