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 disease is a serious, highly contagious, and often life-threatening infection marked by a rash of round pox (blisters) on the face, arms, and legs. It is caused by the Variola virus.es. Smallpox is highly contagious (spread from person to person). A person with smallpox is most contagious when the smallpox rash is present, but may also be contagious before the rash appears, when the only sign is fever.