Bioterrorism

Bioterrorism differs from biowarfare in the sense that the threat comes from terrorist groups and not nation states. Bioterrorism differs also from conventional warfare in that the enemy, circumstances, and probable mode of warfare are not usually officially acknowledged. As a result, terrorism can be more unpredictable, being directed at seemingly random targets with little regard for the lives of civilian victims or the perpetrators themselves.

Biological warfare has its origins in ancient history. For instance, the Greeks and Romans polluted their enemy’s drinking water with animal corpses, additionally:

• The dead bodies of plague victims may have been catapulted by the Tartars at their enemy during the siege of Caffa (now Feodossia, Ukraine) in the 14th century.

• The British may have distributed contaminated blankets from smallpox victims amongst local American Indian populations during the 18th century.

• During World War I, Germany attempted to hinder the enemy's food supply by infecting cattle with anthrax and glanders.

• During World War II, the British developed an anthrax bomb that was tested on the Gruinard Island, and produced five million pieces of cattle feed loaded with anthrax, planning to release them over Germany and reduce its meat supplies by some 30%. However, no chemical or biological agents were used as weapons during World War II.

Bioterrorism can be defined as entailing terrorist attacks involving biological materials such as bacteria, bacterial spores, and viruses. A more inclusive definition would be that it entails terrorists' use of agents that range from classical chemical warfare agents to biologically viable particles, such as bacteria.

Example of a cutaneous anthrax lesion

Biological materials that may be used by terrorists include bacteria such as Bacillus anthracis (anthrax), viruses such as Variola major (smallpox), and biological toxins such as ricin. Ricin was studied extensively as a potential warfare agent during World War II and it is the substance said to have been used in the assassination of the Bulgarian dissident writer Georgi Markov in London in 1978.

Ricin can be obtained in large quantities during the processing of castor oil from Ricinis communis seeds. Ricin is highly toxic, and when injected the lethal dose in an adult may be less than 1 mg. Ricin is especially toxic upon inhalation, causing fever, chest tightness, dyspnoea, and cough within four to eight hours. Only supportive treatment is available for ricin poisoning, and it is believed that death occurs as a result of multiple organ failure.

Cerebrospinal fluid of the first documented anthrax case in 2001

Although Bacillus anthracis occurs commonly in the environment, specific technical expertise is required in order to obtain virulent strains, purify spores, and develop an effective dispersal system. The events of October 2001, when anthrax spores were widely disseminated through the postal service, show that this can be accomplished by terrorists.

The problem with identifying an anthrax attack involving exposure by inhalation is that the early symptoms match those of flu and treatment becomes less effective when delayed. This issue is exacerbated by the lack of clinical trials and the potentiality of resistance to antimicrobial agents. Despite the availability of antibiotics, five of eleven patients who contracted anthrax in the October 2001 incident died. Early identification of anthrax exposure and antimicrobial therapy commenced within the first week significantly improves the treatment prognosis.

The smallpox virus would be much more challenging to obtain as it is known to be kept in only two places in the world, though other sources of it may exist. Stores of the original smallpox vaccine were produced from animal lymph and have been in storage for over twenty years. The employment of these vaccines by Israel and the USA has called attention to some previously expected side effects, most notably myopericarditis.

Example of a smallpox victim

Smallpox may be diagnosed through the polymerase chain reaction (PCR) and electron microscopy methods. Case fatality rate is approximately 30%. Death results from multiple organ failure due to a massive inflammatory response and normally occurs during the second week of illness. Treatment entails supportive care, isolation, and possibly the administration of drugs such as tecovirimat, cidofovir, or brincidofovir (CMX 001).

About 5 to 10 percent of people infected with Variola major develop either a hemorrhagic or a malignant (flat) variant. The rarer hemorrhagic variant has a shorter and more intense prodrome (early symptom), followed by generalized erythema and cutaneous and mucosal hemorrhage, and is usually fatal within five or six days. The malignant form also has a more severe prodrome than the ordinary variant, followed by the development of confluent, flat, nonpustular skin lesions. In survivors, the epidermis tends to desquamate.

The lung is vulnerable to all compounds that can be dispersed as gases or aerosols. Bronchoconstriction and pulmonary oedema are the two major effects caused by the inhalation of chemical compounds, but the absence of specific antidotes makes them difficult to treat. Chlorine and phosgene are widely used industrial chemicals and, although they have been known to be deadly since before their widespread use during World War I, no specific antidotes to their effects have been discovered.

There are multiple definitions of bioterrorism, including those proposed by government agencies such as the Centers for Disease Control and Prevention (CDC) or those contained in federal and state laws. They generally focus on some or all of the following criteria:

• The intentional use or threat of use of any biological agent to cause harm in a human, animal, plant, or other living organism

• The same use or threat of use to degrade the quality of food, air, or water supply
• With the goal of influencing government conduct or policy
• With the goal of intimidating or coercing a civilian population.
• The release of the most dangerous pathogens

The CDC has identified the six most dangerous pathogens that could be used in a bioterrorist attack.

The following list is a timeline of historical events involving biological weapons and bioterrorism:

• <1000 c. BC: Scythian archers tipped arrows with blood, manure, and tissue from dead bodies.
• 5th c. BC: Assyrians poisoned enemy wells with rye ergot (Claviceps purpurea), a fungus containing mycotoxins.
• 590 BC: Athenians poisoned enemy water supplies with hellebore, an herb purgative, during the Siege of Krissa.
• 3rd c. BC: Persian, Greek, and Roman texts describe the use of dead animals being used to contaminate enemy water supplies.
• 184 BC: Carthaginian general Hannibal ordered his sailors to toss clay pots filled with poisonous snakes onto the decks of enemy ships during a naval battle.
• 1155: Emperor Barbarossa poisoned wells with decomposing human bodies.
• 1346: The Tartur army catapulted deceased bodies of plague victims over city walls during the siege of Caffa.
• 1495: The Spanish sold wine mixed with the blood of lepers to their enemies.
• 1763: The British distributed blankets contaminated with the variola virus to Native Americans and caused an outbreak of smallpox.
• 1797: Napoleon flooded fields around Mantua to promote malaria.
• 1915–18: Germans attempted to infect Allied horses with anthrax and glanders.
• 1932–45: Unit 731 of the Japanese Imperial Army in Manchuria conducted experiments that included infecting prisoners with a variety of lethal pathogens.
• 1942: The British army tested anthrax bombs on the Gruinard Island off the coast of Scotland.
• 1950–69: US and USSR developed offensive biological weapons programs.
• 1969: US president Richard Nixon ended the US offensive biological weapons program.
• 1972: US and USSR sign the Biological Weapons Convention agreeing to end offensive programs.
• 1978: Georgi Markov, a Bulgarian exile, is assassinated in London with an injected ricin pellet.
• 1979: Accidental anthrax release from a secret Soviet facility in Sverdlovsk led to the death of 66 people.
• 1984: In The Dalles, Oregon, the Rajneeshee cult contaminated local salad bars with salmonella, causing sickness in 750 people.
• 1990: Japanese Aum Shinrikyo cult unsuccessfully attempted botulinum toxin releases in Tokyo.
• 1991: US troops received anthrax vaccinations.
• 1991: After the Persian Gulf War, UN inspectors commenced inspections of biological weapon capability in Iraq. Iraqi government officials confirmed that they have carried out research related to the use of anthrax and botulism.
• 1993: The Aum Shinrikyo cult unsuccessfully attempted a second botulinum toxin attack on the wedding of the Crown Prince. Later the same month they unsuccessfully attempted to release anthrax from a Tokyo high-rise building.
• 2001: Anthrax-contaminated letters were mailed to US Senate offices and media outlets, causing sickness in 22 and leading to the deaths of five people.
• 2004: Ricin was sent to US Senate Majority Leader Bill Frist’s office.