NOVA Online | Bioterror | Ask the Expert Responses, 11/21/01

Ask the Expert
Responses from Dr. Jonathan Tucker
Set 3
Posted November 21, 2001
Previous set of responses

Q: My impression after watching NOVA's program "Bioterror" is that the U.S. is largely responsible for the proliferation of potentially deadly agents worldwide through private sector market outlets. What do you think the domestic, political, and legal implications will be if it is proven that international terrorists are purchasing materials from businesses and agencies right here at home?

Edward Inouye

A: The challenge in preventing the spread of biological weapons is that most of the necessary materials and production equipment are "dual-use," meaning that they have legitimate commercial applications as well as potential military uses. This fact makes the relevant technology extremely difficult to keep out of the wrong hands. Nevertheless, the United States is a member of the Australia Group, an informal forum of 33 industrialized countries that seek to harmonize their national controls on exports of dual-use materials and equipment to countries believed to be pursuing chemical and/or biological weapons.

Q: In the program it was mentioned that Bacillus anthracis is very similar to Bacillus thurengensis, the active agent in some GMO corn. Is it possible that terrorists could use the same technology to genetically modify crops to produce anthrax to be carried in their pollen and other plant parts? Has the corn genome been mapped well enough to know where to look if such was suspected?

Adrian Plapp
Malta, IL

A: Even if terrorists had the technical sophistication to incorporate genes for anthrax toxins into genetically modified corn, which is unlikely, they would have little reason to do so. Cooking would presumably inactivate the protein toxins. Even if it did not, the ingestion of contaminated food would result in gastrointestinal anthrax, which is considerably less deadly than the inhalational form of the disease.

Q: For about the last two weeks I have been opening my mail out of doors and disposing of the envelopes in a trash container outside of my home. Once having opened my mail I wash my hands. I have been doing this to reduce possible exposure to residual traces of anthrax that could be passed by cross contamination in the postal system. Is this a prudent precaution to take until irradiation of postal content becomes commonplace? Thank you.

Steve
Michigan

A: Although there is no harm in taking reasonable precautions when handling mail, the risk that letters sent to your home in Michigan could be cross-contaminated with anthrax spores is extremely low. To date, all of the anthrax-tainted letters were sent to prominent individuals in politics or the media, and only postal workers in New York, New Jersey, and Washington, D.C. have been exposed by cross-contamination. (The one exception is the mysterious case of inhalation anthrax in New York, which does not appear to have involved exposure to mail.)

Q: I understand that the U.S. government keeps tight security on its chemical and biological weapons, but what about foreign powers like the former Soviet Union? Do they have the security necessary to keep the weapons out of terrorist hands or from having them sold to the terrorists to pay for the country's debt?

John

A: The U.S. government is concerned about the physical security of chemical weapons and biological pathogens stored in former Soviet states, such as Russia, Kazakhstan, and Uzbekistan. Although the Pentagon is providing assistance to these countries to upgrade their security measures, much more needs to be done.

Q: What exactly does it mean to "weaponize" a biological agent. How do weaponized and nonweaponized anthrax differ?

If the terrorists in the recent anthrax attack wanted to maximize the loss of life in our population, what prevented them from using some sort of aerosol to spread the anthrax spores over a wider area than a mail room?

Kevin
Arcata, California

A: "Weaponization" refers to a variety of activities aimed at rendering a biological pathogen more virulent, enhancing its stability and shelf-life, and processing it so that it can be more readily delivered as a fine-particle aerosol capable of infecting the targeted population through the air. Non-weaponized anthrax would be in the vegetative (non-spore) form, which would die off rapidly after dispersal. Weaponized anthrax would be in the spore form and probably dried and milled to a fine powder, with chemicals added to reduce clumping and to enhance aerosolization. It is possible that the perpetrators of the recent anthrax attacks had only a few grams of weaponized anthrax, making delivery through the mail the only practical means of delivery. Alternative explanations are that they do not want to kill indiscriminately but simply to terrorize the U.S. population, or that they plan to escalate gradually to more extensive attacks.

Q: I first saw the movie "The Andromeda Strain" when just a kid in the '70s, and I have always wondered if the book/movie has any basis in fact. Has our government or other world governments sought out space-born biological agents? Also, do we have "Wildfire" facilities to combat new disease organisms?

William

A: Michael Crichton's novel The Andromeda Strain appears to have no basis in historical fact. Nevertheless, the Centers for Disease Control and Prevention (CDC) in Atlanta and the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) at Fort Detrick, Maryland, do have maximum-containment (Biosafety Level 4) laboratories for working with deadly pathogens that resemble the "Wildfire" facility portrayed in the book.

Q: This may be a microbiologist question: If a bacteria or viral germ can mutate to become contagious via the host by acquiring the genetic makeup, then why could it not be a realistic possibility that anthrax or other such agents that can become infectious through microbes also mutate to become contagious?

Also, how unlikely would it be for "terrorists" or groupings of them already in the United States in various employment positions to taint our supplies of food, water, etc. (such as individuals working on-site at large factories that would have direct access to processing, packaging, or bottling facilities) with anthrax or other viral/bacterial/chemical toxic agents?

Angel Franks
Salisbury, NC

A: I am not a microbiologist, but it appears to me extremely unlikely that a non-contagious agent could mutate spontaneously into a contagious one. The reason is that multiple genes are involved in the transmissibility of a disease. As for contamination of water or food supplies with a biological agent, the former is unlikely because of the combined effects of dilution, chlorination, and filtration in water treatment plants. Food contamination could be a problem, however, particularly at large plants that process hamburger meat. For this reason, the U.S. government should substantially increase the number of inspectors for meat and produce while consolidating the various agencies with overlapping food-inspection responsibilities.

Q: In the offices and post offices where anthrax was found, is it possible that some of the substance went home with people on their clothes, in their lunch bags, etc.? If that happened, can the anthrax find a place to multiply, such as in the soil of house plants? If someone unknowingly brought home a very small amount from a contaminated site before the anthrax was discovered there, can his or her home or car be a place where the anthrax can increase? Could it later cause illness in family members and pets?

Chris
Boston, MA

A: Small numbers of anthrax spores that were carried home on a person's clothes would not germinate or multiply spontaneously. They could, however, cause a cutaneous anthrax infection if an individual came in direct contact with the spores and had a cut or abrasion on the skin.

Q: The NOVA program mentioned that both the U.S. and USSR had developed agricultural weapons for purposes of disrupting economies. Is there any evidence suggesting that an attack (w/foot and mouth, BSE, VEE, or others) on our food supply could be a future move of any group?

Anonymous

A: The U.S. Department of Agriculture is very concerned about the possibility that terrorists could deliberately release an anti-crop or anti-livestock agent as a means of harming the U.S. economy. For example, an outbreak of foot-and-mouth disease would be devastating for cattle ranchers and meat packers.

Q: I noticed that the detection time for B. anthracis (airborne form) is about four to seven days and that by that time the person with the infection is too far along for antibiotics to help. If that's true, is anyone working to find a quicker method of detection? After all, it seems as though the first 24 to 48 hours is crucial after inital contact with this particular bacteria.

Ed Johnson
Adamsville, Tennessee

A: More rapid methods exist for detecting the presence of anthrax bacteria, but they are prone to false-positive results. For this reason, all initial detections must be confirmed by culturing the bacteria, which can take several days.

Q: I am very suspicious that AIDS was a product of experiments to modify viruses for bioterror. Did it ever occur to people studying the disease that we didn't have such a disease until the same era that Sergei Popov and others (including Americans, to be fair to him) were involved with "genetic tweaking?" The Australian government used such a sexually transmitted disease to eliminate rabbits from the entire continent. What is the probability of statistics that such a disease would come into being on its own or cross over from one species to another?

Anonymous

A: Absolutely no evidence suggests that the HIV/AIDS virus was developed as a biological warfare agent. In fact, the virus would make an exceedingly poor weapon because it generally takes about a decade to cause serious illness. It is certainly possible that HIV/AIDS originated as a disease of monkeys that jumped the species barriers to humans. Indeed, many so-called "zoonotic" pathogens cause illness in both animals and people.

Q: What is the difference between Pasternella pestis and Yersia pestis? How many people in the U.S. and how many people in the world die from bubonic plague? Is there an antidote? Is there an inoculation against it? Thank you.

Anonymous

A: Pasteurella pestis is the old name for Yersinia pestis (bubonic plague). According to the U.S. Centers for Disease Control and Prevention, the last epidemic of plague in the United States took place in Los Angeles in 1924-25. Since then, scattered cases of human plague have occurred in rural areas, with an average of 10 to 15 cases per year. The disease is endemic in wild rodents in parts of the western United States (the Four Corners region, California, and Nevada) and occasionally spreads to humans, sometimes via domestic cats that hunt infected rodents. Plague is also present in parts of Africa, Asia, and South America. Worldwide, the World Health Organization reports 1,000 to 3,000 cases of plague each year.

Q: I am a 10th grader in high school , and I am doing a report on bioterrorism. An email from you answering some of my questions would greatly aid my grade. Plus it would cure some of my curiosity.

People are taking medicine to protect them from anthrax and smallpox. If they get one of these diseases, and they already took the medicine, wouldn't the germs just mutate and eventually become immune to the medicines?

What would be the targets if the terrorists would have gotten hold of some germs? (I live in Lockport, a small town south of Chicago, 35 miles away.) Would it be possible to drop the germs on the south side of Chicago, and some would actually cover my town?

I heard that anthrax is more deadly and cheaper than nuclear warheads. Is this true?

If you have any really vital information about germ warfare or some astonishing fact, it would be greatly appreciated. Thank you in advance.

Robert Dunn
Lockport, Illinois

A: (1) People who have not been exposed to anthrax should not self-administer antibiotics such as Cipro for two reasons: the risk of serious side-effects, and the fact that inappropriate use of antibiotics will hasten the evolution of antibiotic-resistant strains of anthrax and other bacteria, making these life-saving drugs ineffective when they are really needed. (2) Large quantities (kilograms) of dried anthrax spores would have to be disseminated into the air, probably from an aircraft, to cover an urban area. Depending on the method of dissemination, the time of day, and the weather and atmospheric conditions, a light wind might carry the "plume" of aerosolized anthrax several miles downwind. (3) If roughly 100 kilograms of anthrax spores were disseminated over a densely populated city under optimal weather and atmospheric conditions, and the resulting cases of inhalation anthrax were left untreated, they could potentially kill as many people as an atomic bomb. Because an anthrax weapon would be much cheaper than a nuclear device, biological weapons have been termed "the poor man's atom bomb."

Q: I don't believe any longer that this anthrax problem in the U.S. was the act of a "loner." I believe it was the act of a well-organized group. Well, anyway since we now know that bioterriorists have anthrax as a potential weapon, what are the other possible deadly "bioattacks" that could occur? What is your best guess as to what will be the next bioattack?

Also, what do you recommend that "ordinary" people have in their medical supplies at home? What is the best and least expensive informational source and possibly free places where one can get up-to-date pamphlets etc.?

Lora Handiboe
Glen Burnie, MD

A: It seems hard to imagine that an individual working alone would have the know-how and resources to acquire or produce the high-grade anthrax used in the letter attacks. What the perpetrator(s) will do next depends on their motivations and their technical capabilities, which remain unknown. Thus, we must be prepared for a range of contingencies. Accurate scientific information on bioterrorism is available from the Web site of the U.S. Centers for Disease Control and Prevention at the following address: http://www.bt.cdc.gov

Q: What is the real danger to the American public from airborne and waterborne infectious diease?

Anonymous

A: In addition to the threat of bioterrorism, a variety of natural infectious disease agents threaten the health of U.S. citizens. A subset of these pathogens are transmissible through the air (e.g., measles, influenza) or water (e.g., E. coli, Shigella, Giardia).

Q: I am particularily interested in a concept that was introduced during the last NOVA broadcast. The concept explained that it is currently possible through the melting of DNA, that DNA from myelin-producing cells can be attached within plasmids of certain infectious bacteria such as pneumococcus. The condition created is one in which the host's body will overcome the bacteria but then turn its immunoresponse to its own myelin, therefore killing the host by destroying its neurological system.

To your knowledge, has this been done, and what is the process at the DNA level? The reason for my question is that I am currently working towards a masters of science and in one of my classes we used PCR to melt and study DNA. I wondered if the processes learned in an intermediate class could be used to this end.

Concerned Student

A: Recombinant DNA technologies, such as those taught in your class, could potentially be used to develop more deadly pathogens for malicious purposes, although doing so would require a high level of expertise as well as considerable trial and effort. Molecular biologists need to be aware of the potential misuse of these powerful technologies and to do everything in their power to prevent it.

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