Variola virus belongs to the genus of orthopoxvirus, and there are some other infectious members, such as Vaccinia virus, cowpox virus, and monkeypox virus.

在正痘病毒属还有另外几种病毒对人具有一定的感染性，如痘苗病毒、牛痘病毒和猴痘病毒。

youdao

But variola, which causes smallpox in humans, and vaccinia, which causes a disease called cowpox in cattle, turned out to be, we now know, viruses that are molecularly very similar.

但是导致天花的人痘病毒,和导致牛痘,的牛痘病毒,后来发现其实是,我们现在知道,这两种病毒在分子水平上十分相似

耶鲁公开课 - 生物医学工程探索课程节选