Poxvirus is the biggest virion in nature, of which the most notorious member is Variola virus that had caused disasters 痘病毒是自然界最大的病毒，其中最著名的成员是曾给人类带来深重灾难的天花病毒，属于痘病毒科正痘病毒属。
Variola virus belongs to the genus of orthopoxvirus, and there are some other infectious members, such as Vaccinia 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。