From Wikipedia: Tetralogy of Fallot (TOF) is a congenital heart defect which is classically understood to involve four anatomical abnormalities (although only three of them are always present). It is the most common cyanotic heart defect, representing 55-70%, and the most common cause of blue baby syndrome..
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.They are larger than some bacteria and contain double-stranded DNA. Poxviruses are the only viruses that do not need a cell's nucleus to replicate inside the cell. The variola virus is the only known cause of smallpox.The disease affects only humans.oxviruses are the only viruses that do not need a cell's nucleus to replicate inside the cell. The variola virus is the only known cause of smallpox. The disease affects only humans.
Smallpox is an ancient disease caused by the variola virus. Early symptoms include high fever and fatigue. The virus then produces a characteristic rash, particularly on the face, arms and legs.he virus which causes smallpox is contagious and spreads through person-to-person contact and saliva droplets in an infected personâs breath. It has an incubation period of between 7 and 17 days after exposure and only becomes infectious once the fever develops. A distinctive rash appears two to three days later.