infectious diseases
Smallpox
Introduction
Smallpox is a highly contagious disease caused by the smallpox virus, an orthopoxvirus. Case fatality rate is about 30%. Natural infection has been eradicated. The main concern for outbreaks is from bioterrorism. Severe constitutional symptoms and a characteristic pustular rash develop. Treatment is generally supportive and potentially with antiviral drugs. Prevention involves vaccination, which, because of its risks, is done selectively. No cases of smallpox have occurred in the world since 1977 because of worldwide vaccination. In 1980, the World Health Organization (WHO) recommended discontinuation of routine smallpox vaccination. Routine vaccination in the United States ended in 1972. Because humans are the only natural host of the smallpox virus and because the virus cannot survive>2 days in the environment, WHO has declared natural infection eradicated. Concerns about bioterrorism using smallpox virus from retained research stores or even from synthetically created virus raise the possibility of a recurrence (see Biological Agents as Weapons and 