Anthrax is a zoonotic disease (one shared by animals and humans) whose causative organism is Bacillus anthracis. Primarily a disease of herbivorous animals, humans become naturally infected through contact with infected animals. Anthrax appears in humans in several different forms: cutaneous anthrax, pulmonary anthrax, and intestinal anthrax with meningeal anthrax being a complication of inhalation, gastrointestinal or cutaneous anthrax. Gastrointestinal and meningeal anthrax are extremely rare and have never been documented in the United States. Anthrax forms spores that are extremely sturdy, heat-resistant, and can survive in soil for more than 70 years.
Although anthrax has been known since antiquity, it was not always clearly distinguished from other diseases with similar manifestations. Scholars speculate that in 1500 BCE, the boils that appeared on the Egyptian Pharaoh's cattle were anthrax symptoms. Scholars also have characterized the 5th and 6th biblical plagues as well as the "burning plague" described in Homer's Iliad as anthrax. However, it was Virgil (70-19 BCE) who provided one of the earliest and most detailed descriptions of an anthrax epidemic in his Georgics. Virgil also noted that the disease could spread to humans.
Anthrax was a widespread disease throughout Europe. In 1769 Jean Fournier classified the disease as anthrax or charbon malin, a name undoubtedly derived from the black lesions characteristic of cutaneous anthrax. Fournier also noted a link between those who worked with raw animal hair or wool and susceptibility to anthrax. In 1876, Robert Koch, a Prussian physician considered one of the founders of bacteriology, isolated the anthrax bacillus and recorded that the bacillus could form spores which remained viable for long periods of time in hostile environments. According to Koch, "this remove[d] all doubt that Bacillus anthracis is the actual cause and contagium of anthrax." Anthrax was the first disease for which a microbial origin was definitively established. Shortly after this, John Bell linked anthrax with "woolsorter disease" and developed a procedure to disinfect wool.
William Greenfield was the first to immunize livestock successfully against anthrax in 1880. However, credit for the use of a live vaccine against anthrax is usually given to Louis Pasteur who tested a heat-cured vaccine on sheep in 1881.
During World War I and World War II, anthrax was developed into a biological weapon. After the war in the US, throughout the 1950s, the Communicable Disease Center (later re-named The Centers for Disease Control and Prevention) investigated nature anthrax outbreaks in Pennsylvania, Colorado, North Carolina, New Hampshire, and Louisiana. Center for Disease Control's (CDC's) goal was fivefold: first, to discover the cause of anthrax among workers in wool and animal hair industries; second, to determine the particle size of anthrax-contaminated aerosols in industry; third, to assess the effectiveness of an anthrax vaccine for humans; fourth, to study the epidemiology and epizootiology of anthrax in selected outbreaks and fifth, to collect and study different strains of Bacillus anthracis.
In 1970, the Food and Drug Administration licensed an anthrax vaccine (the first human vaccine, a live spore vaccine, had been developed in the Soviet Union in 1943).
According to CDC, the last case of inhalation anthrax in the United States before 2001 occurred in 1976. A craftsman working with imported and infected yarn in California died as a result of the disease. Before 2001, the last case of cutaneous anthrax in the United States occurred in 2000. A 67 year old resident of North Dakota who participated in the disposal of five cows infected with anthrax contracted the cutaneous form of the disease. Upon being treated with antibiotics, the individual recovered.
Anthrax as a Biological Weapon
Anthrax remains an attractive biological agent because of its infectiousness, its stability in the spore form, the respiratory route of aerosol infection, and the high mortality of inhalation anthrax.
During World War I, German agents were sent to five neutral countries (Romania, Spain, Norway, the United States and Argentina) with instructions to infect animal shipments sent to the Allies. Targeted animals included sheep, cattle, horses, mules, and, in Norway, reindeer. Animals were infected either by having anthrax injected directly into their blood or by being fed sugar laced with anthrax.
In the inter-war period, attention shifted to human anthrax and its potential as a biological weapon. Although the Geneva Protocol of 1925 prohibited biological weapons, several nations, including the United States, experimented with anthrax during the 1930s and 1940s. In the late 1930s, the Japanese Imperial Army performed covert experiments on anthrax and began deploying biological weapons in Manchuria. Hitler had forbidden biological weapons research; however, the Nazis did conduct anthrax and biological weapons research at a small secret facility in Poland.
During World War II, American, British and Canadian laboratories began developing biological weapons, especially anthrax. By 1944, the Allies had developed thousands of anthrax bombs. During the war, the British, under the direction of Sir Paul Fildes who ran Britain's Porton Down facilities, made millions of linseed cakes with anthrax bacteria spores for potential use against German livestock. The British tested weaponized anthrax on Gruinard Island near Scotland to determine the best method of dispersal for the biological agent. An anthrax outbreak among sheep on the coast of Scotland that faced the Gruinard Islands demonstrated that biological weapons like anthrax were hard to contain even in experimental sites.
Following World War II, the Americans and British continued to research anthrax and its potential for biological warfare, with the American program, which started in 1942, was centered at Fort Detrick, Maryland. Anthrax was known as Agent N. In 1969, Richard Nixon limited biological weapons research to defensive purposes, saying "mankind already carries in its own hands too many of the seeds of its own destruction."
The Soviet Union continued its biological weapons program. In April 1979, an anthrax outbreak occurred in the Soviet city of Sverdlovsk (now Yekaterinburg). Soviet officials insisted that the outbreak was caused by tainted meat and that fatalities were limited to sixty-four people. American intelligence sources claim the death toll reached a thousand and that the aerosolized anthrax originated in a military compound. Records from this outbreak were destroyed in 1990 but the consensus was that the outbreak resulted from biological weapons research. In addition, reports suggested that the Soviets may have developed antibiotic-resistant strains and strains of anthrax resistant to US vaccines.
South Africa experimented with anthrax as a possible biological weapons agent through Project Coast under the direction of Colonel Wouter Basson between 1981 and 1994.
In the 1980s, Iraq bought anthrax from the American Type Culture Collection (Maryland). The 1995 defection and debriefing of a key Iraqi official provided western intelligence experts with evidence of Iraq's biological weapons program and its production of 8,500 liters of anthrax. In December 1990, Iraq had stockpiled 50 R400 bombs and 10 Ah-Hussein SCUDS, and these were deployed in January 1991 to four different locations. Since the Gulf War, American troops have been vaccinated against anthrax.
In September 2001, following the 11 September attacks, anthrax spores were sent through the US postal system. Four letters containing white powder were discovered addressed to Tom Brokaw, the New York Post, Senator Patrick Leahy and Senator Tom Daschle. The first two letters were postmarked 18 September and the later was dated 9 October containing a more deadly strain of anthrax. Anthrax infections were also discovered at American Media Inc. offices in Florida, and the New York offices of CBS and ABC. According to the Center for Disease Control (CDC), 23 suffered symptoms from anthrax. Five victims died from anthrax infections. Authorities speculated that the letters originated in the Trenton, New Jersey area. As of mid-2007, the investigation remains open and unsolved.
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