Multiple choice general knowledge science & technology Small Pox is caused by Rubeola Virus Variola Virus Varicella Myxovirus Reveal answer Fill a bubble to check yourself B Correct answer Explanation Smallpox is caused by the Variola virus, specifically Variola major and Variola minor. Rubeola virus causes measles (also called rubeola), while Varicella causes chickenpox. Myxovirus is an older term for influenza viruses.