Biological warfare

Biological warfare is the use of living organisms (e.g., bacteria , virus ) or biochemical agents (e.g., chemical neurotoxins) as strategic military weapons to cause harm in humans, animals, or plants. In contrast to bioterrorism , biological warfare is considered the governmentsanctioned use of biological weapons to attack a clearly defined military force or civilian population. These agents can be classified into six distinct groups; bacteria, viruses, rickettsiae, chlamydia, fungi , and biological toxins.

Bacteria (by itself or genetically engineered) can be used to produce disease that often can be treated with antibiotics . These are small organisms that can be easily grown on solid supports or liquid media. Viruses, however, require a living host in which to reproduce and are dependent on the cells they infect. Viruses sometimes can be destroyed using antiviral compounds, however, there is a limited supply of these compounds and only a few types available. Rickettsiae are organisms with similar characteristics common to bacteria, as they are susceptible to antibiotics, require oxygen , and have cell membranes. Rickettsiae are also similar to viruses in that they require a host to grow and reproduce. Chlamydia are parasites that cannot produce their own energy sources. Fungi can live without oxygen, are non-photosynthetic species , utilize decaying vegetable matter as their food source, and form spores. Toxins can be synthetic (chemical agents) or derived from poisonous substances produced by living plants, animals, or microorganisms . Toxins have an important advantage over pathogens as they are not alive and, therefore, they are more stable and easier to produce and distribute.

The degree at which these biological weapons become threatening involves several characteristics such as the level of infectiousness, toxicity, virulence, pathogenicity (ability to cause infectious disease), stability, and how easily they are transmitted from one species to the next.

Historical perspective of biological warfare

Biological weapons have been used as part of an arsenal during warfare for centuries. For example, ancient battle records suggest that diseased human remains and cattle that had died of microbial diseases were used to poison wells. In the spring of 1346, after a Mongol army attempted an overtake of the Crimean city of Caffa for three years without success, the Mongols gathered a number of their own people who had died of the plague, laid them on their catapults, and hurled them into the town. Eventually, the plague spread through Caffa causing residents to flee. It is quite possible that the successful conquest of the town by the Mongols may have resulted in the most damaging attack using biological weapons in world history. In the 1760s, a rebellion among Native Americans was countered when Lord Jeffrey Amherst, then commander-in-chief of British forces, suggested grinding pox scabs (pustule scabs) into blankets intended for distribution to members of an Ohio tribe. The disease broke out among the Native Americans, ending the rebellion.

During the twentieth century, a trend of designer biological weapons targeted for larger, more defined military objectives became more prevalent. Research projects aimed at developing anthrax-based biological weapon programs during World War II were initiated by Canada, the United States, and Britain. Britain produced anthrax-based weapons at the United Kingdom Chemical and Biological Defense Establishment at the Porton Down facility that were intended to be dropped on Germany to infect their food supply (reportedly, they were never used). Prisoners in Nazi Germany concentration camps were infected with pathogens, such as hepatitis A, Plasmodium falciparum, as well as other types of a bacteria for unclear research objectives. Countries such as Japan also conducted extensive biological weapons research during World War II while occupying part of China. Prisoners were infected with a variety of bacterial pathogens, including Neisseria meningitis, Bacillus anthracis (anthrax ), and Yersinia pestis. It has been estimated that over 10,000 prisoners died as a result of either infection or execution following infection. In addition, biological agents contaminated the food and water supply. It is also thought that approximately 15 million potentially plague-infected fleas were released from Japanese aircrafts, affecting many Chinese cities with an estimated 10,000 illnesses and 1,700 deaths.

The development of airborne biological weapons make biological warfare particularly dangerous. For example, British open-air testing of anthrax weapons in 1941 on Gruinard Island in Scotland rendered the island uninhabitable for five decades. The United States Army conducted a study in 1951–52 called Operation Sea Spray to study how wind currents might effect the dispersion of bioagents. As part of the project design, balloons were filled with Serratia marcescens (then thought to be relatively harmless) and exploded over San Francisco. Reportedly, there was a corresponding significant increase in the number of pneumonia and urinary tract infections. In 1979, an accidental release of anthrax spores (approximately a gram for several minutes) at a bioweapons facility near the Russian city of Sverdlovsk, infected 77 and killed 66 people that were approximately 2.5 mi (4 km) downwind of the facility. Sheep and cattle up to 31 mi (50 km) downwind also became ill. From these events, anthrax is considered one of the most deadly biological weapons. A dose of 10,000 spores, or one millionth of a gram, is fatal within days after exposure in 90–100% of the population. According to the U.S. Congress Office of Technology Assessment, an aircraft that drops 220 lb (100 kg) of anthrax over a city under normal weather conditions would be lethal for approximately one to three million people. Skin contact with spores can also produce a less lethal, but dangerous cutaneous anthrax infection. Without antibiotic treatment, the mortality rate for cutaneous anthrax is 10–20% and with treatment, the mortality rate falls to less than 1%.

The first diplomatic effort to reduce biological warfare was initiated by the international community in 1925 and called the Geneva Protocol, a treaty prohibiting the development and use of any form of biological weapon in war. During the 1950s and 1960s, the United States constructed research facilities to develop antisera, vaccines, and equipment for protection against a possible biological attack as well as the use of microorganisms as offensive weapons. Since then, other initiatives to ban the use of biological warfare and/or destroy the stockpiles of biological weapons have been attempted. Despite the international prohibitions, the existence of biological weapons remains an impending and growing threat. In 1972, 87 nations, including the United States, signed the Biological Weapons Convention Treaty, which banned the development, testing, and storage of such weapons. For a time, it appeared that the world agreed to ban biological weapons. By the 1980s, the political mood had changed. In 1982, President Ronald Reagan declared that world politics justified research on biological and chemical weapons and that the United States would return to a more ambitious program.

Over the last decade, an emphasis on the development of chemical toxins and the development of genetically engineered biological weapons emerged due to international political instability in several countries, along with the uprising of extremist groups and disestablishmentarianism in the Middle East. During the Persian Gulf War, U.S. troops were exposed to an uncertain source of biological weapons leading to what are called the Gulf War Illnesses. In Iraq, five hidden laboratories were discovered that were designed to refine and stockpile several biological weapons including anthrax, botulism , and gas gangrene bacteria. In 1997, Secretary of Defense William Cohen pinpointed Libya, Iraq, Syria, and Iran as countries that were launching aggressive biological weapon development programs. In 1998, several scientists that were part of the former Soviet Union's biological and chemical weapons programs were reported to have been recruited to develop biological warfare in Libya. Not long after the terrorist attacks on the U.S. World Trade Center and Pentagon in 2001, the postal service was used by terrorists (possibly unrelated to World Trade Center and Pentagon attacks) to deliver anthrax by mail to several locations within the U.S. On October 4, 2001, a 63-year-old man was reported to have contracted the first known intentionally inflicted case of inhalation anthrax in the U.S. By the time the outbreak was contained, the U.S. Centers for Disease Control reported 23 cases of inhaled or cutaneous anthrax (19 confirmed, 4 suspected), including five deaths.

Genetically engineered weapons and other biological weapons

Since about 1960, the development of genetic engineering has greatly expanded the possibilities of biological warfare. Genetic engineering is the process by which an organism's genetic properties are manipulated so that they acquire desired characteristics. In the case of biological warfare, the desired characteristics are harmful to mankind. Several issues arise when tampering with the genetic makeup of microorganisms such as the development of new diseases for which there is no treatment available for either opponent. Genetic engineering can also be applied for the purposes of making existing pathogens more pathogenic (disease-causing).

Other known biological agents that are considered biological weapons and might be used during biological warfare are botulism, brucellosis , Q fever, smallpox, saxitoxin, ebola hemorrhagic fever, tularemia, and staphylococcus enterotoxin.

Like most potential biological weapons, brucellosis occurs naturally among domestic and wild animals. It is spread by one of three varieties of the Brucella bacterium. It is seldom fatal, but causes a long-term, debilitating illness characterized by fever, loss of weight, general lassitude, and depression . Brucellosis is a biological weapon that does not kill people, but renders them so ill that they are unable to fight effectively. The disease can be treated with tetracycline.

Q fever is a biological agent that is not particularly harmful but is highly infectious. It is caused by a bacterial strain of the rickettsial organism Coxiella burnetii and produces headache, fever, chills, sweats, and a loss of appetite. Scientists believe that the condition is often mistaken for the flu. Like brucellosis, the value of Q fever is not in its toxicity, but in its ability to be easily spread. No more than a dozen microbes are needed to initiate an infection. It represents a particularly noxious biological weapon in its potential to be modified to cause disease or death.

From time to time, coastal waters in various parts of the world develop a reddish tinge because of a unicellular organisms called dinoflagellates. These so-called red tides are a warning that seafood from these waters are potentially unsafe. The dinoflagellates release a variety of toxins including saxitoxin. Some of these toxins quickly cause a type of paralysis that can cause death in humans in less than an hour. U.S. scientists prepared and tested shellfish toxins, including saxitoxin, for possible use as a biological weapon after World War II.

Many forms of Staphylococcus exist, some harmless and some quite dangerous. They are often responsible for specific forms of food poisoning and, in rare instances, exposure to these microorganisms can lead to toxic shock syndrome within hours. A person infected with Staphylococcus contaminated food experiences severe nausea, vomiting, diarrhea, and is essentially incapacitated for two or three days. Staphylococcus has a practical advantage in that it can be dried and stored for up to a year without losing its toxicity.

Tularemia is a plague-like disease caused by the bacterium Francisella tularensis. After an incubation period of about a week, a person infected with the bacterium begins to develop a fever accompanied by chills and headaches. If the bacterium is inhaled, symptoms also include chest pain and difficulty in breathing. The death rate is relatively low when exposure occurs through the skin, but much higher when inhaled. Delivery of a genetically modified form of the bacteria by aerosolization would cause a disease that is expected to have a case fatality rate which may be higher compared to the 5–10% seen when disease is acquired naturally.

See also Anthrax; Poisons and toxins.

Resources

books

Frist, William. When Every Moment Counts: What You Need toKnow About Bioterrorism from the Senate's Only Doctor. Lanham, MD: Rowman and Littlefield, 2002.

McCuen, Gary E. Poison in the Wind: The Spread of Chemical and Biological Weapons. Hudson: GEM Publications, Inc., 1992.

Tucker, Jonathan B. Scourge: The Once and Future Threat ofSmallpox. New York: Atlantic Monthly Publishers, 2001.

periodicals

Drotman, D. Peter, et al. "Bioterrorism-Related Anthrax." Emerging Infectious Diseases 8, no. 10 (October, 2002).

Inglesby, T.V., D.T. Dennis, D.A. Henderson, et al., for the Working Group on Civilian Biodefense. "Plague as a Biological Weapon: Medical and Public Health Management." Journal of the American Medical Association 283 (2000): 2281–90.

other

United States Centers for Disease Control. "Bioterrorism and Public Health Preparedness." [cited October 20, 2002]. <http://www.cdc.gov/od/oc/media/presskit/bio.htm>.

Brian R. Cobb

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Epidemic

—A situation in which a particular infection is experienced by a very large percentage of the people in a given community within a given time frame.

Microorganism

—An organism so small that it can be seen only with the aid of a microscope.

Pathogen

—Any organism capable of causing a disease.

Plague

—A highly contagious disease that spreads rapidly through a population.

Toxin

—A poisonous substance.