ATLANTA - The government has begun taking steps to cope with the possibility of a terrorist attack involving smallpox by training doctors to recognize the disease and by vaccinating small teams of experts who would rush to any part of the country to contain and treat a suspected outbreak.
Officials at the Centers for Disease Control and Prevention, which is taking the steps, say they have no evidence that anyone is readying a terrorist attack using smallpox, a disease that was eradicated worldwide 21 years ago. But they say smallpox is so deadly that it is important to prepare for any attack.
The smallpox virus is known to exist only in laboratories in the United States and Russia. But germ warfare experts suspect that other countries, including North Korea and Iraq, might have secretly obtained stocks.
It is greatly feared as a weapon because it is contagious and has a high death rate. And much of the world's population is susceptible.
Training, vaccinating teams
Last week, the disease centers vaccinated about 140 members of epidemiologic teams that can be summoned at a moment's notice to examine a suspected case anywhere in the country.
This week, the centers will begin a series of training courses in smallpox for some of its employees and state and local health workers. Additional courses will be held over the next several weeks at the federal agency's headquarters here.
The vaccinations and course are part of a broader effort by health officials to respond quickly to any new bioterrorism threats that might follow the recent deliberate spread of anthrax through the mail.
"Our concerns are not limited to anthrax," said Dr. James M. Hughes, who directs the federal agency's center for infectious diseases. Those concerns include diseases such as botulism, plague, tularemia and smallpox.
Smallpox is of particular concern because of its potential to spread quickly. In a military exercise this past summer called Dark Winter, researchers conducted a simulated smallpox attack on Oklahoma City. The epidemic quickly soared out of control, spreading to 25 states and millions of people.
Tens of millions of Americans under the age of 30 are susceptible to smallpox because they were never vaccinated; the United States stopped smallpox immunizations in 1972.
Tens of millions of older people who were vaccinated decades ago are thought to have decreased protection because the vaccine might have worn off.
Another major concern is that generations of American doctors have never seen a case of smallpox. The only ones who have are a few hundred doctors who participated in the World Health Organization's smallpox eradication program decades ago.
Smallpox patients are usually quite sick. The infection is characterized by a rash and a fever of at least 102 degrees. The rash and symptoms begin to develop 11 or 12 days after a person is exposed to the virus.
The characteristic lesions can occur anywhere on the body, but they usually appear on the face first, and they tend to appear more on the arms and legs and less on the chest, abdomen and back. Palms and soles are favorite areas.
The earliest lesions tend to appear as raised bumps that often contain fluid.
Over a period that can last as long as 19 days, the lesions become firm, filled with pus, and then form scabs. The illness can leave its victims blind and scarred.
Smallpox can be confused with chickenpox. In making the diagnosis, a doctor touches the skin. Smallpox lesions tend to feel as if they are deep in the skin, in contrast to the lesions of chickenpox, which feel superficial. Chickenpox itches; smallpox lesions can be very painful.
But because the earliest stage of smallpox can resemble rashes caused by many other diseases besides chickenpox, identification can be difficult without laboratory tests.