Anticipating smallpox as a bioterrorist weapon.

The treat of bioterrorism means it is important to be able to diagnose smallpox. The responsibility for the initial recognition of cases lies with clinicians, and early diagnosis is the key to the successful control of an outbreak. Unless rapidly contained, a bioterrorist release of smallpox would constitute not just a national but a global threat to health. This brief review sets smallpox in its modern context as an infection potentially spread by bioterrorists and recommends sources of information from the twentieth century that will assist clinicians in diagnosing the disease.