The world is free of smallpox.
The last case of naturally occurring smallpox was detected in Somalia in 1977. The last recorded case in humans, which was due to an accidental laboratory infection, was reported in England in 1978. The WHO in 1980 declared that smallpox was eradicated from the world. At present, the only remaining known virus isolates are stocked in the laboratories at the Center for Disease Control and Prevention (CDC) in the United States and at the Vektor Institute in Russia. However, during 1990s, it was learned that the smallpox virus has been used by some countries in their biological warfare program. It is not known how many countries still possess the virus in their laboratories.
Smallpox was a highly infectious disease. Respiratory secretions and exudates of the skin lesions were the most common sources of infection. The disease was most commonly transmitted by inhalation of respiratory droplets from smallpox patients. The patients were highly infectious during the first week of rash, once fever had started. The features of the smallpox that con-tributed to its total eradication are summarized.