Melissa Walsh


Salem Press | 2011 | Salem Health: Infectious Diseases & Conditions

Essay title: Bioterrorism Category: Epidemiology Also known as: N/A

Definition Bioterrorism is the intentional release of bacteria and viruses into a civilian population to achieve a political or social end.

Biological Agents

Found in nature, biological agents become a threat to human populations when terrorists engineer them for deliberate release into a target human population. Terrorists cultivate the agents to make them more resistant to medicines and vaccines and more easily transmitted throughout a population. The U.S. Centers for Disease Control and Prevention (CDC) classifies biological terror agents by their likelihood for use by terrorist groups and by risk to a population. The CDC groups bioterrorism agents into the categories A, B, and C.

Category A Agents Cited as highest priority, Category A agents are rare in the United States, easily transmitted, would cause a high death rate, and demand a proactive public health preparedness strategy. Category A agents include Anthrax (Bacillus anthracis), Botulism (Clostridium botulinum toxin), Plague (Yersinia pestis), Smallpox (Variola major), Tularemia (Francisella tolarensis), and Viral Hemorrhagic Fevers — filoviruses, such as Ebola and Marburg, and arena-viruses, such as Lassa and Machupo.

Anthrax An anthrax infection is triggered by Bacillus anthracis, a bacterium that forms spores, or dormant cells that reawaken under certain conditions. There are three types of anthrax infection: in the skin (cutaneous), in the lungs (inhalation), or in the digestive tract (gastrointestinal). Anthrax does not spread from person to person. People contract anthrax by handling or ingesting infected animal products or by falling victim to terrorists using anthrax as a weapon. Anthrax symptoms can appear within seven days. Symptoms for the cutaneous anthrax include the appearance of non-painful skin blisters with a black area in the center. Nausea, loss of appetite, bloody diarrhea, fever and stomach pain are symptoms of gastrointestinal anthrax. Cold symptoms with significant chest congestion and shortness of breath are present with inhalation anthrax.

Botulism Spread by the bacterium known as Clostridium botulinum, botulism is a muscle-paralyzing disease. Botulism is not spread from person to person. People contract botulism from infected food or from an infected wound. Infants can contract the disease from the presence of the bacterium in their digestive tract. The food-borne form of botulism has a potential for becoming a public health emergency, as the toxin can contaminate large amounts of food. After ingesting the toxin, symptoms of double vision, dry mouth, slurred speech, and muscle weakness appear. Gradually, paralysis spreads throughout the body. Though most treated patients recover within weeks, untreated persons can die from paralysis of the breathing muscles.

Plague Caused by the Yersinia pestis bacterium, plague originates with rodents and their fleas. Though bubonic Plague is transmitted through a rodent or flea bite, pneumonic Plague can be transmitted through the air from person to person or via a deliberate aerosol release. Once exposed, an individual experiences symptoms within one to six days, including cough, shortness of breath, chest pain, nausea, and abdominal pain. Plague is treated with antibiotics. Untreated, Plague results in respiratory failure. Plague is diagnosed through blood, sputum, or lymph-node aspirate sampling.

Smallpox The two forms of smallpox are Variola major, which is severe and most common, and the less common and less deadly Variola minor. The four types of Variola major smallpox are ordinary, modified, flat, and hemorrhagic. Ordinary Variola major, causing 90 percent of known cases, has a fatality rate of 30 percent, according to the CDC. The flat and hemorrhagic types are rare and usually fatal. The only known carriers of smallpox, humans spread the disease to others through close personal contact. Following an incubation period of seven to 17 days, an infected person becomes contagious, experiencing fever, head and body aches, and a rash of small red spots, first in the mouth and throat, then over the entire body. The last known case of smallpox in the United States was in 1949, and the last known case worldwide was in Somalia in 1977. The Variola virus exists only in science laboratories.

Tularemia Tularemia is caused by the bacterium Francisella tularensis, which is found in rodents and rabbits. A human contracts the disease upon being bitten by an infected tick or fly, handling an infected carcass, ingesting contaminated food or water, or inhaling the airborne bacteria. Appearing within three to five days after exposure, symptoms include spiked fever, chills, headache, diarrhea, muscle aches, joint pain, dry cough, and weakness. Tularemia is treated with antibiotics.

Viral Hemorrhagic Fevers (VHFs) Filovirus VHFs, such as Ebola and Marburg, and arena-virus VHFs, such as Lassa and Machupo, are known by the CDC as “severe multi-system syndrome” diseases. Multiple systems of the body are attacked, accompanied by bleeding. Patients experience symptoms of fever, achiness, and fatigue, before seeing bleeding under the skin and from the mouth, eyes, and ears. VHF may progress to nervous system damage or kidney failure. Initially transmitted from contact with rodents and their bodily excretions or mosquito or tick bites, some VHFs can spread via human-to-human contact, such as Ebola, Marburg, and Lassa. Though there is no direct treatment for VHFs, the anti-viral drug Ribavirin is sometimes administered to VHF patients.

Category B Agents Ranked by the CDC as second highest priority, Category B agents are moderately easy to transmit and result in lower mortality rates. Category B agents include Brucellosis (Brucella species), Epsilon toxin of Clostridium perfringens, food safety threats (Salmonella, Escherichia coli, and Shigella), Glanders (Burkholderia mallei), Melioidosis (Burkholderia pseudomallei), Psittacosis (Chlamydia psittaci), Q fever (Coxiella burnetii), Ricin toxin from Ricinus communis (castor beans), Staphylococcal enterotoxin B, Typhus fever (Rickettsia prowazekii), Viral encephalitis — alphaviruses, such as Venezuelan equine encephalitis, eastern equine encephalitis, and western equine encephalitis — and water safety threats, such as Vibrio cholerae and Cryptosporidium parvum.

Category C Agents Third highest priority agents are Category C. These include emerging pathogens. Newly discovered infectious diseases such as Nipah virus and hantavirus are in Category C and rated according to availability, ease of production, and potential for inflicting deaths.

Biological Weapons History At the end of the nineteenth century, scientists discovered a link between microorganisms and the outbreak of illness. They began to understand how diseases are spread through air, food and water supplies, person-to-person contact, and insect bites. Upon uncovering these facts, scientists rapidly found ways to protect people against the outbreak of several diseases.

By the early twentieth century, some western governments were beginning to explore the harvesting and use of biological agents for use in weapons. During World War I, Germany undertook the first known state-sponsored biological weapons program, deliberately infecting the horses and mules of enemy forces. During the 1920s, the French conducted research in biological weapon aerosols, ramping up this discipline in the mid-1930s.

In 1942, American biologists Theodor Rosebury and Elvin A. Kabot noted that Bacillus anthracis in its dormant-spore state can be easily used as a biological weapon. The spores can withstand disbursement well in hot or cold environments. Viewing this pathogen as a potential threat, Rosebury and Kabot recommended the development of an anthrax vaccine. They also described how Plague bacillus, if freeze-dried, could also be weaponized into an aerosol. As a result of Rosebury and Kabot’s findings on the potential for use of biological weapons, allied soldiers were administered antibiotics and vaccines during World War II.

The September 11 attacks in the United States by Al Qaeda prompted a surge in support and funding for defending populations against bioterror threats, such as technologies for new methods of air detection and treatment medicines. In the book Biological Weapons, Jeanne Guillemin explains that the establishment of the Department of Homeland Security (DHS) in 2003 “far outweighed the diffuse, decentralized domestic preparedness project of the previous decade.”


The Homeland Security Act of November 25, 2003 incorporated the Federal Emergency Management Agency (FEMA), which immediately dedicated resources into investigating the threat of biological terrorism. FEMA concluded that three groups of biological agents could be used as weapons: bacteria, viruses, and toxins. Though terrorists may choose biological warfare over other tactics, most known agents are difficult to cultivate and are quickly destroyed once exposed to dry air and sunlight. For example, though the airborne spread of Plague is possible, the Yersinia pestis bacteria survive up to only an hour once released. Some agents, like the Smallpox virus, only spread through human contact, while others, like anthrax, only infect those exposed to a primary source of the germs. However, if not directly releasing germs onto human, terrorists could threaten a target population by infecting animals that could carry disease to humans or by contaminating food and water supply.

In December of 2008, a congressionally mandated, bipartisan panel commissioned to analyze the threat of unconventional weapons warned that, unless the international community commits to additional security and preventive moves, “it is more likely than not that a weapon of mass destruction will be used in a terrorist attack somewhere in the world by the end of 2013.” The panel called for the strengthening of international organizations dedicated to preventing unconventional warfare, improvement of rapid-response and bioforensic capabilities, heightened security at research institutions housing biological pathogens, and the formation of an international conference on biosecurity. Notably, the report concluded that weaponizing biological agents is extremely difficult and likely outside the range of capabilities for a rogue, non-state-supported group. Before leaving office in January of 2009, President George Bush signed an executive order on laboratory biosecurity that established an interagency body dedicated to regulating and overseeing research programs and laboratories.

The warning about potential for breaching security of state-sponsored programs relates to lessons learned following events in 2001, when anthrax was spread via an infected powder sent with letters through the U.S. postal system. The anthrax-laced letters were targeted to individuals in media and politics, resulting in 22 documented cases of anthrax infection. Analysis of the infected letters pointed to the Ames strain, the form grown and studied in the American program. An FBI investigation later identified the anthrax source as the lab of Dr. Bruce Ivins of the U.S. Army research facility at Fort Detrick, Maryland.

Federal agencies and politicians continue to incorporate the threat of biological terrorism into national security regulations and policies. The next-generation threat to U.S. security is lax security at labs researching diseases that could be cultivated for biological weapons. At a Chemical, Biological, Radiological and Nuclear (CBRN) Aspects in Combatting Terrorism meeting in mid-October 2010, Ambassador Jacek Bylica, Head of NATO’s Weapons of Mass Destruction Non-Proliferation Centre, Emerging Security Challenges Devision said, “The spread of WMD and their means of delivery, and the possibility that terrorists acquire them, are the principal threats facing the Alliance over the next 10 to 15 years.” In November of 2010, bioterrorism security concerns were again raised when Senator Richard G. Lugar and Pentagon officials visited Uganda’s Ministry of Agricultural, Animals, Industry and Fisheries. They discovered research specimens of anthrax and the Ebola and Marburg viruses being stored in an unlocked refrigerator in a non-secured building.


In response to the threat of bioterrorism, the DHS seeks to understand which agents are easiest to grow and deliberately release and to develop methods for identifying the natural outbreak of a disease from a bioterrorism attack. In 2004, the DHS established the Biodefense Knowledge Center (BKC), part of the Nonproliferation, Homeland and International Security (NHI) Directorate’s Threat Awareness Program. The BKC provides a forum for experts in biological pathogens and political terrorism to share information and assess bioterror threats in a collaborative way.

To prepare people for a bioterrorism attack, the CDC and the American Red Cross provide educational resources and preparedness recommendations through multimedia. They urge families to store supplies for the possible event of a bioterrorism attack, including three gallons of water per person. They also teach people how to detect signs and symptoms of biological terror agents and how to react assertively to alert public authorities. If exposed to a suspicious substance, people are advised to vacate the vicinity of the substance, wash with soap and water, contact the authorities, and seek medical attention. If exposed to a biological agent, the direction is to remove and bag clothing and personal items, wash with soap and water, and seek medical assistance. People should also pay attention to official instructions announced through public emergency alert systems. According to FEMA, optimal prevention against a bioterrorism attack includes installing a High Efficiency Particulate Air (HEPA) filter in furnaces and ensuring that recommended immunizations are up to date and.

Prepared for a possible bioweapon aerosol attack of the pneumonic plague agent or the tularemia agent, national and state health centers have stockpiled antibiotics for administration. Medicines would be administered within 12 hours of an attack, lasting at least seven days. The CDC also maintains an antitoxin to treat the botulism. Though there have been no known cases of smallpox since 1977 and routine vaccination against the disease is discontinued, the United States took precautionary action following the bioterrorism events of 2001 to secure research stockpiles of the Variola virus and to treat the disease should an outbreak occur. As of 2010, no Plague vaccine was available in the United States, but research for such a vaccine was underway.


A June 2010 report from the Center for Biosecurity of the University of Pittsburgh Medical Center stated that, from 2008 through 2010, government spending to support biodefense programs increased. Bioterrorism prevention and intervention are top priority, according to Health and Human Services (HHS) Secretary Kathleen Sebelious, who in early 2010 announced a new U.S. national health security strategy of focusing resources on first-responder teams and frontline healthcare, in addition to beefing up public health leadership on a national level. On October 7, 2010, the National Institute of Allergy and Infectious Diseases (NIAID) announced its investment of $68 million in research projects for the development of vaccines to protect against biological terror: a needle-free dengue vaccine, an orally administered anthrax vaccine, and an anthrax vaccine administered with an adjuvant to stimulate the immune system. On November 5, 2010, the U.S. Department of Health and Human Services’ Biomedical Advanced Research and Development Authority (BARDA) awarded Northrop Grumman with a one-year, $9.6 million contract to develop a bio-defense system to allow first-responders to rapidly screen and triage individuals exposed to a biological agent. Northrup Grumman will develop and test two BioCHAMP-RSP (Confirmation of Harmful Agents by MassTag PCR Co Rapid Screening Platform) prototypes with the capability of identifying over 30 pathogens.


Because there have been few incidents of bioterrorism, there is little historical data on impact. However, scientific predictions about likely effects on populations have impacted response strategies and the investment in prevention and detection technologies.

Melissa Walsh

Further Reading

Guillemin, Jeanne. Biological Weapons. New York: Columbia University Press, 2005. Covers the history of terrorist- and state-sponsored development of biological weapons.

Isikoff, Michael. “The Case Still Isn’t Closed.” Newsweek (Aug. 18, 2008): 152.

Kron, Josh. “Uganda Seen as a Front Line in the Bioterrorism Fight.” New York Times (Nov. 11, 2010): A8.

Miller, Judith, William Broad, et al. Germs: Biological Weapons and America’s Secret War. New York: Simon & Schuster, 2002. An investigation into state-sponsored biological weapons programs.

"NATO Looks at Chemical, Biological, Radiological and Nuclear Aspects in Combatting Terrorism." States News Service (Oct. 14, 2010).

“Northrop Grumman-led Team Wins U.S. Government Contract to Develop Rapid, Integrated Biodefense Response Capability.” Globe Newswire (Nov. 5, 2010).

Rosebury, Theodor. Peace or Pestilence: Biological Warfare and How to Avoid It. New York: McGraw-Hill, 1949. A frequently referenced early work about the weaponization of biological agents.

Sands, David R. “Panel Warns of Risk of an Attack by 2013.” Washington Times (Dec. 3, 2008): A02.

Schmidt, Eric. “Panel Fears Use of Unconventional Weapon.” New York Times (Dec. 1, 2008): A11.

Spiers, Edward M. A History of Chemical and Biological Weapons. London: Reaktion Books, 2010. An examination of the threat posed by the accessibility of chemical and biological weapons since the 2001.

“United States: NIH Funds Advanced Development of Three Biodefense Vaccines.” TendersInfo News (Oct. 7, 2010).

Web Sites of Interest

U.S. Centers for Disease Control and Prevention, United States Food and Drug Administration, and United States Department for Homeland Security, American Red Cross preparedness page,