America At War:
Bioterrorism: Anthrax
With Jonathan B. Tucker, Ph.D.
Monterey Institute of International Studies
Wednesday, Oct. 17, 2001; 2 p.m. EDT

Jonathan B. Tucker, Ph.D., an expert on chemical and biological weapons in the Washington, D.C. office of the Monterey Institute of International Studies and the author of "Scourge: The Once and Future Threat of Smallpox," was online Wednesday, Oct. 17 at 2 p.m. EDT to talk about bioterrorism and anthrax.

"Congressional leaders announced today that the Capitol and office buildings for the House of Representatives will be closed from Thursday through Monday following the discovery that more than 20 members of Sen. Thomas A. Daschle's (D-S.D.) office staff were exposed to anthrax when a contaminated letter was opened there Monday." Read the article House to Shut Doors After Apparent Anthrax Outbreak (Post, Oct. 17, 2001)

Tucker directs the Chemical and Biological Weapons Nonproliferation Program at the Center for Nonproliferation Studies (CNS) of the Monterey Institute of International Studies, a private graduate school in Monterey, California.

Before joining CNS, Tucker worked as an arms control fellow at the Department of State, an analyst in the international security program at the Congressional Office of Technology Assessment, and a foreign affairs specialist in the office of chemical/biological policy at the Arms Control and Disarmament Agency. He also served as senior policy analyst on the staff of the Presidential Advisory Committee on Gulf War Veterans' Illnesses. In February 1995, he was a biological weapons inspector in Iraq under the auspices of the United Nations Special Commission.

A transcript follows.

Editor's Note: Washingtonpost.com moderators retain editorial control over Live Online discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions.

Chattanooga, Tenn.: Is is possible that the smallpox virus could be effectively distributed by contaminating mail as we have seen with the recent anthrax incidents?

If so, is there any way to detect or defend against that kind of attack?

Dr. Jonathan Tucker: Unlike anthrax, smallpox cannot infect people through cuts or abrasions in the skin, but only by being inhaled. Thus, the virus would have to be disseminated through the air to cause infection. It is known that before smallpox was eradicated, laundry-workers who handled the sheets and blankets of smallpox patients could aerosolize the virus and become infected. Perhaps if the smallpox virus was sent through the mail as a dried powder, it might be infectious, but it would be extremely difficult to produce the virus in this form.

Washington, D.C.: Is there any speculation on why there is a return address of "4th grade" on the envelope sent to Sen. Daschle?

Dr. Jonathan Tucker: One can only speculate as to the motive, but perhaps the sender sought to mislead the recipient into thinking that the letter was harmless.

Tampa, Fla.: Is it possible to be infected with small pox, then receive the vaccine and be cured?

Dr. Jonathan Tucker: The smallpox vaccine (vaccinia virus) is unique among vaccines in that it works extremely rapidly. Protective immunity results in about 10 days after vaccination. The vaccine can also prevent smallpox, or at least reduce its severity, if administered within four days of infection with the virus. (Smallpox has an incubation period of roughly 12-14 days before symptoms appear.) Once the skin rash has developed, however, no treatment is available.

Waldorf, Md.: With so many exposed to the Anthrax bacteria at the House, it seems likely that at least one of them regularly rides Metro. Are the people who ride public transportation at risk of having been contaminated by these staffers? If so, where can lower-income people go to be tested and, if necessary, receive treatment? And finally, just how accurate is the testing process, and how quickly are results turned around?

Dr. Jonathan Tucker: Anthrax is not contagious from person to person, so there is no risk of secondary exposure from an ill person. Moreover, once anthrax spores have settled onto a surface, they tend to adhere tightly and are extremely difficult to reaerosolize. Thus, it is highly unlikely that a person who had been contaminated with a small amount of anthrax spores could pose a secondary contamination threat to others. With respect to testing, the initial rapid screening test is not 100 percent accurate, but all screening tests are confirmed with more reliable tests involving the culture of the anthrax bacteria. Such tests take at least 48 hours to complete.

Reston, Va.: What is Mousepox? Is it more dangerous or contagious than Smallpox?

Dr. Jonathan Tucker: Mousepox, or ectromelia, is a poxvirus that infects mice. It is distantly related to the smallpox virus but is harmless to humans.

Arlington, Va/: Dr. Tucker: Does the fact that the anthrax in Sen. Daschle's office is probably "weapons-grade" suggest to you that the terrorists who sent it could disseminate it more widely, using more effective methods than the mail? If so, how should individuals react? Avoid subways? Move away from big cities? Thank you.

Dr. Jonathan Tucker: The dried anthrax sent to Sen. Daschele's office was of high quality, meaning that the particles had been finely milled to microscopic dimensions. This physical form makes it easier to aerosolize the spores and hence poses a greater threat of causing inhalation anthrax, the most deadly form of the disease. Because producing dried anthrax in this form is beyond the capabilities of most, if not all, terrorist groups, the perpetrators appear to have had outside technical assistance, either from a state-sponsor or from scientists formerly employed with a state-level offensive biological weapons program. Roughly a dozen countries are suspected of having biowarfare programs, including Egypt, Iraq, Iran, Israel, Libya, Syria, and North Korea. Russia and South Africa are known to have had such programs in the past and may retain a residual capability. Nevertheless, just because the terrorists managed to acquire a small amount of "weapons-grade" anthrax does not necessarily mean that they have the large (multi-kilogram) quantities needed to launch a mass-casualty attack.

Bethesda, Md.: I'm a federal employee and I work about 6 blocks from the Capitol. Other than being careful about mail, what -- if any -- precautions should I be taking these days? And should I be wary of attending social events in public places? I don't want to be an alarmist, but I also don't want to be taking foolish chances. Thanks.

Dr. Jonathan Tucker: Beyond taking reasonable precautions with mail, the current level of threat does not warrant panic or avoiding public places. You should, however, remain vigilant and report any suspicious behavior -- such as an individual spraying a fine mist or powder -- to the police. Although the anthrax attacks are certainly disturbing, it is important to keep them in perspective. The letter attacks thus far have inflicted only one fatality, and the form of the disease appears to respond well to antibiotics. Thus, the primary impact to date has been psychological.

Washington, D.C.: Dear Dr. Tucker,
We were assured in the immediate aftermath of the terror attacks that bioterrorism, while possible, was a fairly remote possibility because dispersion of germs is difficult. As it turns out, dispersing anthrax is not so very difficult and has been done. What about smallpox? Is there a "real" story and a "public" story about that too? Is that as easily dispersed or sent as anthrax? Is the public getting the information it needs to cope with the threat?
Thank you.

Dr. Jonathan Tucker: Bioterrorism experts (including myself) have long warned that "low-tech" attacks with biological agents were possible and even likely, including delivery by mail or contamination of food. In contrast, mass-casualty biological attacks involving the production of large quantities of anthrax or some other microbial agent and its dissemination as an aerosol cloud over populated areas would require overcoming major technical hurdles, probably with the assistance of a state-sponsor or former bioweapons scientists. In my view, this threat assessment continues to hold, despite the recent anthrax mail attacks.

Washington, D.C.: Dr. Tucker,
What kinds of knowledge and facilities and resources would an organization need to produce the "good quality" anthrax apparently found in Sen. Daschle's office? Might it have come from old Russian stockpiles?

Dr. Jonathan Tucker: It is possible that the "weapons-grade" anthrax sent to Sen. Daschle's office was produced by a state with a biological weapons program (such as several countries in the Middle East) and then provided to the perpetrators. The anthrax spores might also have been smuggled out of Russia or Kazakhstan by former Soviet bioweapons scientists and sold on the international black market. Of course, this is pure speculation. It will be important to characterize the strain and serotype of the anthrax used in the various letter attacks to obtain clues as to the source of the material.

Ashburn, Va.: Should I have my family vaccinated against smallpox right away?

What are the risks of having a smallpox vaccination?

Dr. Jonathan Tucker: Vaccination of the general population against smallpox at this time would be a very bad idea. Back before 1972, when smallpox vaccination of American children before school entry was mandatory, about one in every 1 million people who received the vaccine developed severe complications, including death or encephalitis resulting in permanent brain damage. Today, the rate of complications from vaccination would be substantially higher because of the increased number of people with immune-system impairments, including people with eczema, transplant recipients, people who are HIV-positive, and those receiving cancer chemotherapy. Thus, it is important to weigh the risk of exposure to smallpox against the risk of vaccination. At present, the chances that terrorists will get their hands on the smallpox virus remain low, because the disease was eradicated in the late 1970s and stocks of the virus only exist in a few laboratories. Because the risk is more than zero, we need to acquire more smallpox vaccine and keep it on the shelf, for use in the unlikely event that one or more cases of smallpox are detected. At this time, however, the current level of threat does not warrant mass vaccination, with the associated risks of complications and death.

Damascus, Md.: I've read that small pox and be transmitted from one person to another. Is it possible for a person to avoid infection? What precautions can the average person take to remain uninfected?

Dr. Jonathan Tucker: It's true that smallpox, unlike anthrax, can spread from person to person. However, the disease only becomes contagious after the first appearance of the facial rash, which initially appears as red spots on the skin similar to chickenpox. You would also need to come into fairly close proximity to person with active smallpox -- say, four or five feet -- to become infected. Thus, I would advise you to avoid anyone with a facial rash. That having been said, the probability that terrorists would obtain smallpox and use it as a weapon remains low.

Washington, D.C.: The terrorists, whoever they are, chose to send anthrax bacteria by mail. Can a regular paper envelope securely contain the spores, which are then released when the envelope is opened, or can the spores "transpire" through the paper, which would mean that many more people would be at risk?

Dr. Jonathan Tucker: No, the spores would be contained within the envelope, unless it was not sealed properly or had small holes or tears in it.

Arlington, Va.: How possible is it for terrorists to distribute the inhalable, fine powder form of anthrax over a city?

Dr. Jonathan Tucker: Terrorists wishing to disseminate anthrax spores as an inhalable aerosol cloud over a city would have to disseminate the material from a rooftop, a moving vehicle, or an aircraft. This effort would be technically challenging, however, and could well be foiled by atmospheric turbulence and other environmental factors.

Triadelphia, W.Va.: My overriding concern these days, as is that of most Americans, is the public safety from bioterrorism. How real is the threat to Americans? Do doctors even have the vaccine for smallpox anymore? I was vaccinated as a child, but my children were not. More than antrhax, smallpox has my attention regarding bioterrorism. Thank you.

Dr. Jonathan Tucker: Although smallpox would be a potentially catastrophic threat, it no longer exists in nature and hence is much less likely to be employed as a biological agent by terrorists than more common diseases such as anthrax. Still, acquiring more smallpox vaccine is prudent, so that health officials could prevent the spread of the disease were it ever to reappear. The smallpox vaccine was taken off the market in 1983 because of its relatively high rate of complications and is no longer available to the general public. In the event of a terrorist attack with the virus, the Centers for Disease Control would distribute the vaccine in a targeted manner to contain the outbreak or outbreaks.

Washington, D.C.: Thanks for taking questions. These news stories about the anthrax terrorism are getting scarier by the day.

I've read that the greatest bioterrorism threat involves the use of "aerosolized" biological agents, including aerosolized anthrax; but that there is no reason to get panicky about it because it is technically very difficult to aerosolize anthrax.

Is there more reason to worry about aerosolization than a few days ago, now that we know the anthrax in Sen. Daschle's office was virulent, refined, and very small? Does that suggest that whoever is doing this can aerosolize anthrax?

Dr. Jonathan Tucker: The fact that the anthrax sent to Sen. Daschle's office was "weapons grade" is troubling because it suggests that the perpetrators were able to overcome some of the technical hurdles involved in producing it. Alternatively, they may have obtained the dried anthrax pre-made from an outside source. Still, we have no indication that the perpetrators have access to large quantities of weapons-grade material. Kilogram quantities of dried anthrax would be required to stage a large-scale attack against a city. Moreover, disseminating the agent effectively would be technically challenging.

Falls Church, Va: Thanks for participating in the discussion. I find I have had a shift in mind set.I have followed the virus hunters and others involved in identifying outbreaks of disease in all areas of the world. I now find myself responding to recent news that the anthrax identified here in the last few days with a sigh of relief that it is not the genetically altered variety that would be resistant to antibiotics. I keep having to remember that anthrax is Level 4 lab stuff and there is no "good" kind to get. Any comment? Thanks

Dr. Jonathan Tucker: Thus far, all of the strains of anthrax used in the letter attacks have responded well to antibiotic therapy. It is known, however, that the Soviet Union developed antibiotic-resistant strains of anthrax, as well as a genetically engineered strain designed to be resistant to the anthrax vaccine. If terrorists were to gain access to such "engineered" strains, the threat would be considerably greater. Fortunately, this does not appear to be the case.

Arlington, Va.: What are the different strains of anthrax? What was the strain in Daschle's office? How do you differentiate the strains and the danger levels? Also, how do you "fingerprint" the different forms of anthrax?

Dr. Jonathan Tucker: Strains of anthrax vary in their level of virulence, or ability to cause disease. Full virulence requires the presence of a "capsule" that renders the bacteria resistant to ingestion by certain white blood cells, as well as the ability to produce three toxin components (protective antigen, lethal factor, and edema factor). It is the anthrax toxins, and not the bacteria themselves, that cause the tissue injury and death associated with the disease. Thus, once the bacteria have released the toxins into the bloodstream, the disease is no longer treatable with antibiotics. Different strains of anthrax are "fingerprinted" by extracting their DNA, cutting the DNA molecule with bacterial enzymes into fragments of different lengths, and running the snippets on a gel under an electric field, a technique known as "electrophoresis." The resulting pattern of DNA fragments is characteristic of each strain, and hence provides a unique "fingerprint."

Alexandria, Va.: Let's say you spot something suspicious in your mailbox. What should you do?

Dr. Jonathan Tucker: If you see a suspicious letter or package in your mailbox that could be contaminated, do not touch it with your bare hands. Instead, put on a pair of gloves and, holding your breath, place the letter in a sealable plastic bag. After sealing the bag, examine the letter closely. If you are still suspicious, call 911.

Chicago, Ill.: I read in the newspaper that the threat of smallpox bioterrorism is very small. This is because only the US and the former Soviet Union have reserves of the virus and unlike anthrax, there is no other reservoir for the virus in nature. My question is a 2-part question:
Do US officials know today the status of the smallpox reserves once held in the former Soviet Union, meaning know which of the new nations currently hold it and if yes, do thye know how the officials of the new nations view their responsibility for its safekeeping? I realize that it would be imprudent to announce the whereabouts of it, but it would be very re-assuring to know that US officials know where it is and that its safekeepers share US views on safeguarding it.

Dr. Jonathan Tucker: Smallpox was eradicated as a human disease by a global vaccination campaign in the 1960s and '70s, and the last human case was reported in 1978. Since then, the smallpox virus has only existed in a few laboratories. There are two labs that have been authorized by the World Health Organization to store the virus, the CDC in Atlanta and a Russian laboratory called Vector (in Koltsovo, near Novosibirsk). It is rumored, however, that undeclared stocks of smallpox virus may exist in countries such as Iraq and North Korea, both of which are assessed to have offensive biological warfare programs and are suspected of sponsoring terrorism. Although the evidence is circumstantial (such as the fact that both countries continue to vaccinate their troops against smallpox), it is sufficiently compelling for the U.S. government to be concerned about the potential threat. The government is therefore taking prudent steps, such as increasing the available U.S. stockpile of smallpox vaccine. As for Russia, in addition to the official WHO stocks of the virus at Vector, it is suspected that undeclared stocks of smallpox may exist at the Center of Virology, a Ministry of Defense facility in Sergiev Posad that was involved with the Soviet biowarfare program. This facility remains top secret and off-limits to Western scientists, and hence continues to arouse concern.

Mt. Lebanon, PA: Tommy Thompson and the rest of the government boys have been spinning like a top trying to assure us they're in charge and in control and therefore the American public isn't in any real danger from anthrax, smallpox, and god knows what else. Other than spouting the party line, what are the real threats we face from these agents of death and the real likelihood that we can effectively counter them? What're the chances the government will take prompt, effective action and drop the denial they seem to be into now? Thanks much.

Dr. Jonathan Tucker: Secretary Thompson has aroused skepticism from Congress and the public by claiming that the U.S. government is fully prepared to deal with bioterrorism. In fact, the situation is more complex. Federal agencies such as the CDC are well-equipped to address the problem, and cities such as New York have responded well to the current anthrax crisis, which remains relatively small-scale. Nevertheless, a number of serious gaps in defenses against biological attack exist in many cities, counties, and states around the country. These deficiencies include the current inability of primary-care doctors to recognize unusual diseases such as anthrax, of clinical laboratories to diagnose them accurately, and of public health departments to detect that an unusual outbreak is underway and take appropriate measures while the disease is still treatable. These gaps in our public health infrastructure need to be addressed promptly if the country is to be prepared for a large-scale incident of bioterrorism in the future.

Worcester, Mass.: How vulnerable are we to the threat of a smallpox epidemic, and what is the incubation period for the disease?

Dr. Jonathan Tucker: The incubation period of smallpox is about 12 to 14 days, occasionally longer. At present, the U.S. stockpile of smallpox vaccine is conservatively estimated at about 7.5 million doses. The U.S. government is currently undertaking two parallel efforts to increase the supply. First, tests are under way to determine if the existing vaccine can be diluted five- or even ten-fold and still produce effective immunity. If successful, this could increase the existing supply to up to 75 million doses. In addition, a new contract has been issued to the pharmaceutical industry to produce 40 million doses of smallpox vaccine, and the delivery date was recently moved up from mid-2004 to late 2002. Secretary Thompson indicated today that the government may ultimately seek to acquire as many as 300 million doses.

Montgomery Village, Md.: I don't understand why its the Capitol and the House offices that will be closing for a security sweep when the Anthrax was discovered in the Senate offices. I actually have a meeting in one of the Senate Office Buildings tomorrow and wonder if I should go. It doesn't seem like they are taking the threat seriously there. What are your thoughts?

Dr. Jonathan Tucker: The Capitol and the House offices appear to be erring on the side of caution by shutting down for inspection, even though there is no evidence that these buildings have been contaminated. The Senate, for its part, wants to demonstrate that it has not been cowed by the anthrax attacks and is continuing to address the nation's business. Although the Senate is taking the threat seriously, they don't want to hand the terrorists a moral victory.

Capitol Hill: Hi Dr. Tucker-

I work in one of the House office buildings. Is there any reason at all why I should get screened for anthrax exposure? I'm not too worried about it, but I'm also from the "better safe than sorry" school.

Thanks.

Dr. Jonathan Tucker: There is no reason to be medically screened for anthrax unless an inspection of the House office buildings turns up evidence of contamination.

Annandale, Va.: Can the anthrax found in the senator's office be spread throughout the DC/VA/MD area through the air?

Dr. Jonathan Tucker: The anthrax spores contaminating Sen. Daschle's office are contained in the building and hence do not pose a threat to the surrounding area.

Virginia: What's the difference between biological warfare and bioterrorism? Anthrax comes under which one?

Dr. Jonathan Tucker: Biological warfare involves the use of germ weapons by states, either on the battlefield (which is unlikely because of their delayed effects) or as a strategic weapon for attacks against enemy population centers. Bioterrorism involves the release of a biological agent by a sub-national group, with the intent of inflicting casualties or instilling terror.

Washington, D.C.: What do we know about Iraq's capacity to produce anthrax, smallpox and other biological weapons? Would there be signatures to such material that would enable us to identify it as having been generated by Iraq or related parties? If not Iraq, who else are possible suspects in producing this material?

Dr. Jonathan Tucker: Shortly before the 1991 Gulf War, Iraq produced large quantities of three biological warfare agents: anthrax spores (as a liquid slurry), botulinum toxin, and aflatoxin. In addition, it is believed that the Iraqis produced smaller quantities of three other agents: Clostridium perfringens toxin ("gas gangrene"), brucellosis bacteria, and ricin toxin. The UN weapons inspectors managed to uncover a number of production facilities involved in the program, and destroyed the largest one, called Al Hakam. Nevertheless, the UN was unable to uncover the full extent of the program. Ever since the UN weapons inspectors were forced to leave Iraq in December 1998, it is believed that Baghdad has reconstituted its biological weapons program, and may now have a significant arsenal of germ weapons, including anthrax in dried powder form. Still, there is no evidence to date -- at least in the public domain -- that Iraq has made these weapons available to terrorists. Indeed, such a step would be inconsistent with the past behavior of Saddam Hussein, who has sought to retain tight control over his arsenal of mass-destruction weapons.

Washington, D.C.: Just how scared should an ordinary citizen be?

Dr. Jonathan Tucker: Although recent developments are worrisome, it is important to put the anthrax threat in perspective. Only one person has died, and although dozens have been exposed to anthrax, only four have so far been infected. Most of the cases involve skin anthrax, which is eminently treatable with antibiotics, and all of the cases but one (the Florida man who died) have responded to drug therapy. The main impact of the attacks thus far has been to frighten rather than kill, and the risk to the average citizen remains extremely low.

Los Angeles, Calif.: I think in the time of anthrax threat, it would be better for everyone to take some kind of "injection" which would prevent anthrax to grow if someone gets it. Will it not serve as precautionary measure? Why does the government wait until the anthrax hits public and then distribute the vaccine/injection/tablets/medicine? Why can't we do something like when young childrens are given polio drops. Similarly, the public can take tablets/injection as a precautionary measure. How far is this feasible?

Dr. Jonathan Tucker: Although an anthrax vaccine exists, it is currently in very short supply and is only available to the military, who are at far greater risk of attack. Moreover, the current vaccine requires six injections over a period of 18 months to induce protective immunity, and also involves some risk of side effects, making it poorly suited for the civilian population. Fortunately, all of the strains of anthrax used in the letter attacks have responded well to antibiotic therapy. Thus, at least for now, vaccination of the civilian population against anthrax is not warranted, even if it were possible.

Dr. Jonathan Tucker: Many thanks for your excellent questions. Although current developments are clearly troubling, there is no reason to panic. The authorities appear to have the situation well in hand, and all those exposed to anthrax are being treated with antibiotics and are unlikely to develop clinical illness. Moreover, it is not recommended for individuals to hoard Cipro and other antibiotics, or to self-medicate with these powerful drugs. Not only do antibiotics have potential side effects, but taking them in the absence of anthrax exposure increases the risk of making a variety of harmful bacteria genetically resistant to these drugs, reducing their effectiveness in the future.

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