D.A. Henderson, one of the nation's leading authorities on threats to the public's health and the man credited with the success of the smallpox eradication project a quarter century ago, says the virus is once again a threat to the United States and the world--this time as a weapon of bioterrorists.

Writing in the Feb. 26 issue of Science, Henderson, the director of the Johns Hopkins Center for Civilian Biodefense Studies and former dean of the School of Public Health, says recent disclosures of a massive bioweapons industry in the former Soviet Union, a smaller but equally disconcerting Iraqi program and expanding bioweapons research in 10 other countries should focus particular attention on U.S. cities as targets for bioweapons.

While planning by the military and intelligence communities to predict and forestall biological weapons attacks has been under way, such efforts have generally excluded the front line and "first responders"--namely physicians, hospitals and public health workers. They, too, Henderson says, are ill-prepared to deal with anthrax and smallpox, identified by experts as the top two bioweapon threats. "There are three kinds of weapons of mass destruction," Henderson notes, "nuclear, chemical and biological. The biological weapons are most feared, but the country is least equipped to deal with them."

In his Science report, Henderson calls on the private sector; federal, state and local governments; and medical and public health authorities to provide resources for training emergency room doctors and nurses to recognize symptoms caused by biological weapons; to improve diagnostic techniques; to develop, produce and stockpile improved vaccines and treatments; to rebuild the infrastructure of public health agencies; and to develop communications and health care delivery guidelines specifically related to biological terrorism. Unlike a chemical attack, the release of a bioweapon would be invisible, silent, odorless and "almost certainly" undetected, writes Henderson.

But in a few days or a week, patients would appear in emergency rooms and doctors' offices with rarely or never-before-seen symptoms. Without any experience dealing with smallpox, eradicated in the late 1970s, or any other possible bioweapon, doctors may not realize the extent of the problem until lives are unnecessarily lost.

"Just as in the 1980s the medical community rallied to educate policy-makers about the dread reality of a nuclear winter, the same needs to be done for the remote--but real--threat biological weapons pose," says Henderson.

Henderson's Science report follows a conference held Feb. 16 and 17 to grapple with these issues. Nearly a thousand doctors, public health workers, military officers and policy-makers attended. The conference was presented by the Hopkins Center for Civilian Biodefense Studies and co-sponsored by the U.S. Department of Health and Human Services, the Infectious Diseases Society of America and the American Society for Microbiology. The center's Web site, which features a full Netcast of the conference, is http://www.hopkins-biodefense.org.