Anthrax

• 1. Introduction

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  Anthrax is an infection caused by Bacillus anthracis, a bacterium whose spores can lie dormant in soil for decades, waiting. In 2016, a heat wave in the Arctic thawed a carcass that had been frozen for 75 years, and the spores inside came back to life, triggering an outbreak in reindeer. Russian researchers estimate the Arctic permafrost holds around 1.5 million anthrax-infected reindeer carcasses, each one a potential time capsule of disease. That single fact reframes what anthrax is: not a relic of the past, not merely a chapter in Cold War bioweapons history, but something genuinely alive in the world right now. How did scientists come to understand this bacterium? How did a disease of wool workers and cattle farmers become a weapon capable of closing United States Senate offices? And what does it mean that a warming planet may be quietly thawing one of nature's oldest killers back into circulation?

• 2. The Name and Its Shadows

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  The English word "anthrax" comes from the ancient Greek for coal, a reference to the characteristic black skin lesions the disease leaves behind. The first recorded use of the word in English appears in a 1398 translation of Bartholomaeus Anglicus's work De proprietatibus rerum, written originally in 1240. Before the bacterium was identified, the disease accumulated names like layers of fear: Siberian plague, Cumberland disease, charbon, splenic fever, malignant edema, woolsorter's disease, la maladie de Bradford. Each name marks a geography, an occupation, a population that knew this illness too well. The first clinical descriptions of cutaneous anthrax, the skin form of the disease, were given by Maret in 1752 and by Fournier in 1769. Before those accounts, anthrax appeared only in historical narratives, unnamed and only partially understood.

• 3. What the Bacterium Does

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  Bacillus anthracis is a rod-shaped bacterium about 1 by 9 micrometers in size. It kills not by overwhelming the body directly but through a sophisticated chemical attack. Once inside a host, the bacterium releases three proteins: lethal factor, edema factor, and protective antigen. None of the three is toxic by itself. Protective antigen combines with lethal factor to form lethal toxin, and combines with edema factor to form edema toxin. These toxins destroy tissue, cause massive fluid accumulation, and ultimately kill the host. The mechanism is particularly cruel in the inhalation form. Spores travel into the lungs, where immune cells called macrophages engulf them and carry them to the lymph nodes in the central chest cavity. There the spores germinate, the bacteria multiply, and eventually burst the macrophages. Released into the bloodstream, they spread throughout the body, producing toxins at lethal concentrations. By the time the fulminant phase of inhalation anthrax begins, marked by high fever, extreme shortness of breath, and shock, death in fatal cases follows within 48 hours. Even if antibiotics arrive in time to kill the bacteria, patients can still die from toxemia, because the toxins already released remain in the body at lethal doses.

• 4. Forms of the Disease

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  Cutaneous anthrax accounts for more than 95 percent of all human cases. The infection begins as an itchy blister, darkens, and forms a painless ulcer with a black center called an eschar, somewhat resembling bread mold at the site of infection. Without treatment, the risk of death from this skin form is 23.7 percent. With treatment, it is rarely fatal. Inhalation anthrax initially mimics influenza, with fever, chills, and fatigue, making it difficult to distinguish from community-acquired pneumonia in its early prodromal phase. It does not infect the lungs directly at first but the lymph nodes around them, a condition called hemorrhagic mediastinitis, which causes bloody fluid to accumulate in the chest cavity. Before 2001, the fatality rate for inhalation anthrax was 90 percent. Since then, with improved treatment, it has fallen to 45 percent, though those who reach the fulminant stage nearly always die. A study placed that late-stage death rate at 97 percent. Gastrointestinal anthrax, caused by consuming infected meat, carries a fatality rate of 25 to 60 percent depending on how quickly treatment begins. In December 2009, an unusual form emerged among injecting heroin users in the Glasgow and Stirling areas of Scotland, resulting in 14 deaths. The source was believed to be bone meal used to dilute the heroin in Afghanistan.

• 5. Koch, Pasteur, and the Science of Prevention

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  Robert Koch, a German physician working in Wollstein, now called Wolsztyn in Poland, first identified Bacillus anthracis as the cause of anthrax disease in 1875. His method was direct: he took blood from an infected cow, isolated the bacteria, and introduced them into a mouse. His work helped settle the debate still raging at the time between spontaneous generation and cell theory, providing evidence that specific microbes cause specific diseases. Koch went on to win the 1905 Nobel Prize in Physiology or Medicine for identifying the bacterium behind tuberculosis. In Britain, a doctor named John Henry Bell, based in Bradford, made a separate crucial connection in 1878, demonstrating that the mysterious and deadly woolsorter's disease and anthrax were the same illness. The practical question of prevention fell to Louis Pasteur. In May 1881, at Pouilly-le-Fort, Pasteur and his assistants including Emile Roux conducted a public experiment. Twenty-five sheep, one goat, and several cattle were vaccinated with Pasteur's anthrax preparation. A matching control group received no vaccine. Thirty days after the first injection, all animals were exposed to live anthrax bacteria. Every animal in the unvaccinated group died. Every animal in the vaccinated group survived. Pasteur then sent his nephew, Adrien Loir, to Australia in 1888 to introduce the vaccine in New South Wales, but the formula proved unsuitable for the climate and was replaced by a version developed by local researchers John Gunn and John McGarvie Smith. The human vaccine arrived in 1954 as a cell-free formulation, with an improved version following in 1970. The current FDA-approved American vaccine, BioThrax, was formulated in the 1960s and was administered in a six-dose series until 2008, when the FDA approved dropping the week-2 dose, reducing it to five doses.

• 6. From Weapon to Terror

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  Anthrax has been used in biowarfare and bioterrorism since 1916, when Nordic rebels supplied by the German General Staff used it against the Imperial Russian Army in Finland. Unit 731 of the Japanese Kwantung Army tested anthrax as a biological agent in Manchuria during the 1930s, with thousands of prisoners of war dying in the process. In 1942, British scientists at Porton Down developed Operation Vegetarian, a plan to drop five million animal feed pellets infected with anthrax spores over Nazi Germany. The pellets were built, but the operation was scrapped after the Allied liberation of France, and all pellets were destroyed in 1945. That same year, tests at Gruinard Island in the Scottish Highlands established how lethal anthrax could be against sheep. The Vollum strain used in those tests was first isolated in 1935 from a cow in Oxfordshire. A variation called Vollum 1B is believed to have been isolated from William A. Boyles, a 46-year-old scientist at the US Army Biological Warfare Laboratories at Camp Detrick, Maryland, who died in 1951 after accidental infection. The Soviet Union created the particularly virulent Strain 836 in the 1980s, described by the Los Angeles Times as the most virulent and vicious strain of anthrax known. The Biological Weapons Convention of 1975 prohibited the development, production, and stockpiling of biological weapons, but the Soviet Union continued its program in secret. On the 2nd of April 1979, an accidental release from a biological weapons facility in Sverdlovsk infected at least 94 people and killed at least 68. Soviet authorities blamed tainted meat; Boris Yeltsin admitted the truth only in 1992. Cleaning the Hart Senate Office Building after the 2001 anthrax letter attacks cost $27 million. Cleaning the Brentwood postal facility in Washington cost $130 million and took 26 months.

• 7. The Letters of 2001

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  In October 2001, letters containing concentrated anthrax spores were mailed to several news media offices and to two Democratic senators: Tom Daschle of South Dakota and Patrick Leahy of Vermont. The Ames strain of anthrax, which carries two virulence plasmids encoding the three-protein toxin and a polyglutamic acid capsule, was used in the attacks. Twenty-two people were infected and five died. Only a few grams of material were used. In August 2008, the US Department of Justice announced it believed the attacks were carried out by Bruce Ivins, a senior biodefense researcher employed by the United States government. In response to the attacks and subsequent hoaxes, the US Postal Service installed biohazard detection systems at its major mail processing centers. A high school student later published research in the Journal of Medical Toxicology suggesting that a domestic electric iron at its hottest setting, at least 400 degrees Fahrenheit, applied for at least five minutes, could destroy all anthrax spores in a standard postal envelope. As of 2020, none of the postal detection systems had triggered a positive alert.