Preparing for Invisible Killers

Smallpox and Anthrax Could Be Put to Work in Biological Warfare

Washington Post/February 23, 1999
By Susan Okie

In a hotel ballroom here last week, a rapt audience of doctors and public health officials gazed at the image of a child's face studded with smallpox blisters. D.A. Henderson, the doctor who led the successful global campaign to eradicate that deadly disease, paused as he prepared to teach them how to recognize a killer most of them had never seen.

"I thought I had given my last presentation on the [symptoms and appearance] of smallpox," he said. "But here we go."

The smallpox virus, along with the anthrax bacillus and a few other dreaded microorganisms, is among the most potentially devastating agents of biological warfare. Although the world's last official stocks of the virus (stored in Atlanta and Russia) are scheduled to be destroyed this June, Henderson told the audience at a national symposium on bioterrorism that there is evidence that at least two additional Russian laboratories have stores of smallpox virus, some of which was produced for biological warfare.

In addition, according to Henderson, intelligence experts fear that samples of the virus may have been secretly obtained by some other countries, particularly North Korea and Iran and perhaps Libya and Syria. If so, it's possible that smallpox might someday be deliberately released by terrorists.

If that ever happens, the nation's doctors, nurses and lab technicians--not its military weapons experts--will be the ones on the front lines. They will be called upon to recognize cases of an unfamiliar disease, consider the possibility of biological terrorism and move with breathtaking speed to avert a medical catastrophe. Smallpox is highly infectious, spreads rapidly and kills 30 percent of its victims. There is no treatment, and the world's countries stopped vaccinating against the disease by about 1980, after it was eradicated.

Experts at last week's conference warned that even though the chances of a terrorist release of smallpox or anthrax are small, the nation's public health community must be ready for the possibility--as well as for the much more likely scenario that terrorist groups or individuals may use more conventional microbes to trigger a smaller-scale disease outbreak. Health and Human Services Secretary Donna E. Shalala said that preparing for such a threat will require increased government funding to train health-care workers, improve laboratory testing, develop and produce vaccines and drugs, and expand hospitals' capacity to deal with a large influx of sick people. Her department is spending almost $159 million this year for such purposes and has asked Congress for $230 million in next year's budget.

"We're responding to something that we don't know a lot about. We need substantial investment," Shalala said at the meeting, which was sponsored by the recently established Johns Hopkins Center for Civilian Biodefense Studies, headed by Henderson. "It's only in movies like 'Outbreak' that we can save the world from a deadly virus in just 24 hours."

Attacks With Biological Weapons Hoaxes involving biological threats--particularly anthrax--have increased dramatically in recent months, including several anthrax hoaxes this month in Washington. However, the actual use of disease-causing organisms by terrorists has been rare. In the United States, the biggest such incident occurred in 1984, when followers of Bhagwan Shree Rajneesh, a commune leader, used salmonella bacteria to contaminate salad bars in Oregon. More than 750 people got food poisoning.

But some terrorist groups have tried to use biological weapons in recent years, including the Japanese cult Aum Shinrikyo, whose members attempted several times to release anthrax and botulism toxin (a poison produced by bacteria) before launching their 1995 nerve gas attack on the Tokyo subway system. That episode awakened health officials throughout the world to the threat of chemical and biological terrorism. In addition, at least five countries known to sponsor international terrorism now have acquired the capability to produce biological weapons, said Gerald Parker, the commander of the U. S. Army Medical Research Institute of Infectious Diseases (USAMRIID), which conducts most military research on defending against biological weapons. He said a terrorist attack on the United States using a highly lethal agent, such as smallpox or anthrax, would be a "low-probability but high-consequence event."

Anthrax bacteria are found in soil. They frequently cause disease in grazing animals, but less commonly in people. However, under certain conditions, the bacteria produce spores that drift on the breeze and that can be inhaled into the lungs, producing a devastating blood infection. Between 50 and 80 percent of those infected in this manner die, and experts at the conference said a few kilograms of anthrax spores would be enough to infect half of the population in a four-square-mile area. The accidental release in 1979 of a small quantity of anthrax from a biological weapons plant in the Soviet Union caused at least 77 cases of illness and at least 66 deaths.

Fortunately, getting the bacteria to produce spores of the proper size is technically complicated, and ordinary anthrax bacteria don't cause this type of illness.

In a scenario presented at the conference by Thomas V. Inglesby, a Hopkins infectious disease specialist, a truck releases anthrax spores into the air outside a packed football stadium in a city of 2 million. Two days later, several hundred people show up at area emergency rooms with symptoms of flu, but doctors don't initially suspect anything out of the ordinary. It's only on the fourth day, when previously healthy people begin to die, that they become alarmed. A laboratory identifies anthrax on the fifth day and efforts begin to treat tens of thousands of potentially exposed people with antibiotics--too late to save many of them. Ultimately, according to this scenario, 20,000 people are exposed to the spores and 4,000 die. Anthrax Diagnosis Might Be Delayed

Inglesby said recognition of the disease would likely be delayed because doctors are unfamiliar with anthrax and laboratories don't test for it. "Almost no lab in the country would make a diagnosis of anthrax by its routine processing of blood cultures," he said.

To get the death rate below 80 percent, those exposed would need to receive antibiotics promptly. "Even though you may only need to treat those 20,000 [who have been exposed], you don't know who those 20,000 are," Inglesby said. Members of the armed forces are vaccinated against anthrax, but vaccine supplies are insufficient for the civilian population.

A smallpox outbreak could be even more devastating because, unlike anthrax, smallpox spreads rapidly from person to person, with each victim infecting as many as 10 to 20 others. There is no drug treatment, and the only way to halt an outbreak is to quarantine infected patients and to conduct a mass vaccination campaign, Henderson said. Routine smallpox vaccination of schoolchildren in the United States was halted in 1972 and by now, Americans vaccinated before that time have probably lost their immunity to the disease. Currently, no company is manufacturing smallpox vaccine and the federal Centers for Disease Control and Prevention has only enough to vaccinate about 7 million people. "This is only marginally sufficient for small emergency needs," Henderson said.

Health and Human Services officials said the government's plan for strengthening the nation's defenses against biological terrorism includes arranging for production of additional smallpox vaccine and funding additional research on vaccines for anthrax and other diseases, as well as on treatments. The smallpox vaccine is made not from smallpox virus, but from vaccinia, a related virus that doesn't usually cause disease in healthy people.

Shalala said federal officials are also reconsidering their position on whether existing stocks of smallpox virus should be destroyed on schedule in June. A vote on the question is expected in May at the World Health Organization's annual assembly.

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