What do we know about the origin of this outbreak and the human to human transmission?

关于这次爆发的起源和人与人之间的传播，我们知道什么？

Pig viruses are similar to human viruses and that allows human to human transmission to happen quicker.

猪病毒类似于人类病毒，它使人与人之间的传播变得更快。

It's carried most extensively by mosquitoes, though human to human transmission is possible.

它由蚊子传播最广泛，但人与人之间的传播是可能的。