That`s what they do their blood sucking.

这就是他们吸血的原因。

And many animals in addition to countryside livestock serve as hosts for the bacterium and blood sucking pests.

除了农村牲畜外，许多动物也是细菌和吸血害虫的宿主。

However, whether the fleas were of the human or rat variety, it is blood sucking pests of one kind or another that likely passed it on successfully and so very quickly.

然而， 无论跳蚤是人类跳蚤还是老鼠跳蚤，很可能是一种或另一种吸血害虫成功地、非常迅速地传播了它。