Smallpox Causes. Variola (the virus that causes smallpox) is a member of the orthopoxvirus genus, which also includes viruses that cause cowpox, monkeypox, orf, and molluscum contagiosum.Poxviruses are the largest animal viruses, visible with a light microscope.urvivors of smallpox often have severely deformed skin from the pustules. 1  Types: Variola major, or smallpox, has a death rate of 30%. 2  Variola minor, or alastrim, is a milder form of the virus with a death rate of 1%. 3  Four types of variola exist: classic, hemorrhagic, malignant, and modified.
This means that even when condoms are used properly, syphilis can still be spread if the sore is located in an area not covered by the condom. Because sores can be located on the lips and mouth as well as the external genitals, vagina, anus, and rectum, there are many possibilities for transmission. [5].
Causes and Risk Factors. Syphilis is caused by the bacterium Treponema pallidum. Syphilis is passed from one person to another through contact with a syphilis sore. The sores are usually painless and can go unnoticed.Sores can be found on the external genitals, vagina, penis or in the anus.. Late or Latent Stage. In this stage, syphilis typically has no symptoms at all. If left untreated a person can remain in this stage of the condition for the rest of his or her life, or the disease can progress to the next stage.