November 2000

Note: Because some of the information in this article may be outdated, it has been archived.

What is bioterrorism?

A wanted poster in Japan, with photos of people wanted in connection with the sarin gas attack on the Tokyo subway on March 20, 1995. Source: Creative Commons.

Henderson: Bioterrorism is the dissemination of biological agents such as Anthrax, Smallpox, or chemicals such as Sarin gas (which was used by the Aum Shinryko Cult in Tokyo in 1995 killing 12 people and injuring hundreds), into the population by an individual or group intended to cause illness, injury or death. Since the specific diseases and chemicals used by terrorist groups could potentially cause significant diseases or injuries, they are the focus of national planning efforts to prepare for and respond to acts of bioterrorism. Keep in mind that bioterrorism is seen as a “High Consequence - Low Probability” event.

How significant a threat is it?

Henderson: We think bioterrorism poses a very serious threat to the population in general. Although, we in public health are not privy to intelligence information that would provide significant details regarding terrorist groups and their intentions, we do know that if one of these agents was introduced into the population it could cause considerable damage.

What kind of biological agents could be used by terrorists?

Henderson: The CDC has three categories for critical biological agents:

Category A: Smallpox, Anthrax, Plague, Botulism, Tularaemia, Filoviruses (e.g., Ebola), and Arenaviruses (e.g., Lassa fever). These organisms are grouped into the A list because they:

• can be easily disseminated or transmitted person-to-person
• cause high mortality, with potential for major public health impact
• might cause public panic and social disruption
• require special action for public health preparedness

Category B:

Q fever, Brucellosis, Glanders, Alphaviruses (e.g., Equine Encephalomyelitis), Ricin toxin from castor beans, Epsilon toxin, Staph enterotoxin B, and food/water-borne pathogens. The organisms in this group:

• are moderately easy to disseminate
• cause moderate morbidity and low mortality
• require specific diagnostic capacity and enhanced disease surveillance

Category C:

Tick-borne encephalitis (TBE) is a viral infection of the central nervous system affecting humans and most other mammals. It is caused by ixodes ricinus. TBE could be used for bioterrorism. Photo: Roxirras Blogg.

Nipah virus, Hantaviruses, tickborne Hemorrhagic Fever viruses, tickborne Encephalitis viruses, Yellow Fever, and multidrug-resistant Tuberculosis. These organisms fall into the third group because of:

• availability
• ease of production and dissemination
• potential for high morbidity and mortality and major health impact

Smallpox and Anthrax at are at the top of your list. Why?

Henderson: Anthrax and Smallpox along with Viral Hemorrhagic Fevers, Tularemia, Botulism toxins, and Plague top our list of critical diseases because they:

• can be easily transmitted person-to-person
• cause high mortality, with potential for major public health impact
• might cause public panic and social disruption
• require special action for public health preparedness

Anthrax and Smallpox have potential for casualties on a large scale. Both are highly lethal. For example, the death rate for inhaled Anthrax, if untreated before serious symptoms develop, exceeds 90% and in the case of Smallpox, up to 30% for people who are not immunized for the disease. In addition, both agents can survive for a long time under the right conditions. Availability of vaccines for either of these infectious diseases is limited.

In the case of Smallpox, we know that there still are quantities of the live virus in the United States and we believe some quantities may exist in the old Soviet Union. In addition, we only have a limited supply of Smallpox vaccine currently available but we have signed a contract with OraVax out of Cambridge, MA to begin developing a new Smallpox vaccine.

Can an ordinary person obtain information easily about chemical or biological agents?

Henderson: I think so. The Internet provides a vast amount of information on these diseases. Even though we recognize the Internet as being a valuable tool for finding information this can be used for both good and bad purposes when it comes to bioterrorism. I don’t think the process would be that easy for someone to find information but if enough time was spent on the Internet I think they could find a substantial amount of information pertaining to infectious diseases and chemical agents.

How well is the U.S. prepared for a bioterrorist attack?

Henderson: We are much better prepared today than we were two years ago thanks in large part to the funds appropriated by Congress to support federal, state, and local bioterrorism preparedness and response efforts.

Last May, CDC participated in a national exercise sponsored by the Department of Justice and the Federal Emergency Management Agency called Top Off for top officials.

• The intent of this exercise was to see how cabinet level officials collaborated to respond to weapons of mass destruction event.
• For this exercise, CDC focused most of our resources on the simulated Plague outbreak in Denver, CO although we were also involved in a simulated mustard gas release in Portsmouth, NH and a simulated radiological incident in the greater Washington, D.C. area.
• We learned many lessons from this exercise that has resulted in significant improvements to CDC’s internal response capacities.

We now have a national training plan for bioterrorism preparedness and response that will enhance our own staff competencies, the recognition that we need to establish an emergency operations center for infectious diseases control here at CDC, and a process for alerting state and local health agencies about bioterrorist events or other public health emergencies.

However, we have a considerable amount of work yet to be completed at the state and local public health levels of government. I believe that the work we will embark on in this coming year will help continue to build this needed public health infrastructure. Keep in mind that we still need additional funding to build this infrastructure but we are on the right path.

Is our government concerned about bioterrorism and what is it doing about the threat?

Henderson: The President and Congress have been and continue to be extremely concerned about this threat. Over the past two years a considerable amount of money has been appropriated by Congress and passed by the President to support weapons of mass destruction. Anti-terrorism is a significant component of this activity and therefore so is bioterrorism. Along with the work being done at the Centers for Disease Control, the Department of Health and Human Services is also supporting these efforts by ensuring the medical care delivery system can handle the increased caseload should a bioterrorist event occur. Other departments such as DOJ and Federal Emergency Management Agency are also working hard to ensure bioterrorism preparedness and response fits into their larger preparedness planning efforts.

What can an individual do in the event of a bioterrorist threat?

Henderson: This really depends on the agent that has been used. The most important thing is not to panic but to wait for information before making a decision. It may take a day - 24 hours - before information can be given to the public through the media. A lot of information that we are compiling at the CDC to make available to the public in the event of a threat is actually pretty basic information. Most of the things you can do if you are trying to deal with a particular organism will fit on two pages of paper.

Is our health care system prepared for a bioterrorist attack?

Henderson: I don’t think they are well prepared. In fact, the health care system is the weakest link in the chain. As a first step they need to contact local public health authorities to determine what their role should be in the context of larger local planning efforts. The challenge here is to get hospitals and other healthcare providers to understand that a large outbreak of an infectious disease will place a huge burden on them and they really need to be prepared. We learned during the Top Off exercise how fast the health care system would become saturated with a plague outbreak. The only way to resolve the problems we encountered during Top Off is to start preparing now.

How do you determine if an infectious disease is the result of terrorism or a natural outbreak?

Henderson: In public health, the source is of no consequence. We would activate our resources to control and contain public suffering the same way regardless. The difference is that we see bioterrorist events as being potentially large-scale outbreaks of a magnitude we are not accustomed to. Again, how it started is not the issue but how we control and contain it is. Keep in mind that the FBI will be very interested in how these incidents start so that they can work to ensure it doesn’t reoccur.

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