Agents of Bioterror
While highly infectious, smallpox carries clear signs that may prevent the spread of an epidemic.
incubation period |
how it would spread |
Through natural epidemics, smallpox has likely claimed more lives than any
other infectious disease. In the 20th century alone, before it was eradicated
by universal vaccination, smallpox killed up to 500 million people.
In 1980, the same year that the World Health Assembly announced smallpox had
been eradicated and recommended that vaccination programs cease, the Soviet
Union launched a program to mass-produce the virus as a bioweapon. Russia may
still maintain a research program to produce virulent and contagious strains,
ostensibly as a defensive measure.
The only confirmed repositories of smallpox are at the Centers for Disease
Control and Prevention in Washington D.C. and at the Institute of Virus
Preparations in Moscow, but Iraq and North Korea are suspected to have stocks.
Smallpox has no natural reservoirs other than humans. While the chance of
terrorists obtaining smallpox is remote, it is considered a grave bioterrorism
threat because the disease is highly contagious and deadly. The most lethal
natural form of smallpox, caused by the Variola major virus, has a
fatality rate of roughly 30%.
Incubation period before symptoms
- high fever
- headache, backache, and vomiting
- rash (pox) on the face and arms that spreads to the trunk
How it would be spread
Aerosol or person-to-person, potentially by a terrorist-"martyr." It is highly
contagious. However, smallpox victims show clear signs of the disease, and
anyone who came in contact with them could be vaccinated post-exposure.
There is no current treatment against the smallpox virus. Vaccination given 3-5
days post-exposure can prevent the disease.
Vaccine exists but is currently not recommended for the general public.
Stockpiles of vaccine are being increased. No one in the U.S. has been
vaccinated since 1972, and people vaccinated before then have likely lost
Chart of the 8 agents
Photo: Corbis Images
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