Smallpox: the disease and strategies for its control.

Smallpox was once one of the most severe infectious diseases and was endemic throughout the world for most of recorded history. It no longer exists in nature, having been declared extinct in 1980 following a global eradication campaign led by the World Health Organization. However, recent news reports on the vaccination of key health workers in the event of deliberate release of smallpox as part of a biological attack, and the deployment of Regional Smallpox Diagnosis and Response Teams, are stimulating demand for knowledge of the disease. This article provides an overview of the smallpox virus, including signs and symptoms, treatment and transmission, and vaccination and control in the event of deliberate release.