What Is Anthrax?

Anthrax is an acute infectious disease caused by the bacteria Bacillus anthracis and is highly lethal in its most virulent form. Anthrax most commonly occurs in wild and domestic herbivores, but it can also occur in humans when they are exposed to infected animals, tissue from infected animals, or high concentrations of anthrax spores. Still there are no case of people who got sick through contact with a diseased person. Anthrax means "coal" in Greek, and is used because victims develop black skin lesions.

Bacillus anthracis is a rod-shaped Gram-positive bacterium of size about 1 by 6 micrometres, and is the cause of the disease known as anthrax. B. anthracis was the first bacterium ever to be shown to cause disease, by Robert Koch in 1877. The specific name anthracis originates from the Greek word anthrax (ἄνθραξ), meaning coal, referring to the black skin lesions on the victims. The bacteria normally rest in spore form in the soil, and can survive for decades in this state. Once taken in by a herbivore, the bacteria start multiplying inside the animal and eventually kill it, then continue to reproduce in the carcass. Once they run out of nutrients there, they revert back to the dormant spore state.

Anthrax infection is rare but not remarkable in herbivores such as cattle, sheep, goats, camels, and antelopes. Anthrax can be found globally. It is more common in developing countries or countries without veterinary public health programs. Certain regions of the world (South and Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East) report more anthrax in animals than others.

When anthrax affects humans, it is usually due to an occupational exposure to infected animals or their products (such as skin and meat). Workers who are exposed to dead animals and animal products from countries where anthrax is more common may become infected with B. anthracis, and anthrax in wild livestock has occurred in the United States. Although many such workers are routinely exposed to significant levels of anthrax spores, most are not sufficiently exposed to develop symptoms.

Anthrax can enter the human body through the intestines, lungs (inhalation), or skin (cutaneous). Anthrax is non-contagious, and is unlikely to spread from person to person.

Pulmonary (pneumonic, respiratory, inhalation) anthrax infection initially presents with cold or flu-like symptoms for several days, followed by severe (and often fatal) respiratory problems. If not treated soon after exposure, before symptoms appear, inhalation infection is the most deadly, with a nearly 100% mortality rate. A lethal case of anthrax is reported to result from inhaling 10,000-20,000 spores. This form of the disease has also been known as Woolsorters' disease. Other routes have included the slicing up of animal horns for the manufacture of buttons, and handling bristles used for the manufacturing of brushes.

Gastrointestinal (gastroenteric) anthrax infection often presents with serious gastrointestinal difficulty, vomiting of blood, and severe diarrhea. Untreated, intestinal infection results in a 25-60% death rate.

Cutaneous (skin) anthrax infection presents with a large, painless necrotic ulcer (beginning as an irritating and itchy skin lesion or blister which is dark in color, usually concentrated as a black dot, somewhat resembling bread mold) at the site of infection, forming about a week or two after exposure. Unlike bruises or most other lesions, cutaneous anthrax does not cause pain. Cutaneous infection is the least deadly; without treatment, approximately 20% of all skin infection cases are fatal. Treated cutaneous anthrax is rarely fatal.

Treatment for anthrax infections includes large doses of intravenous and oral antibiotics, such as penicillin, ciprofloxacin, erythromycin, and vancomycin. For inhalation cases, antibiotic treatment is not very effective unless initiated within a day of exposure, before any symptoms appear. Antibiotic prophylaxis is crucial in cases of pulmonary anthrax to save lives. Some antibiotic-resistant strains are known.

A vaccine, produced from one component of the toxin of a non-virulent strand, is also available. The vaccine must be given at least four weeks before exposure to anthrax; annual booster injections are required to maintain immunity.

The spores can be trapped with a simple HEPA or P100 filter. Anthrax as an airborne threat can be prevented with a full-face mask. Unbroken skin is decontaminated simply with soap and water.

Bacillus anthracis is a rod-shaped gram-positive bacterium of size about 1 by 6 micrometres. It was the first bacterium ever to be shown to cause disease, by Robert Koch in 1877. The bacteria normally rest in spore form in the soil, and can survive for decades in this state. Once taken in by an herbivore, the bacteria start multiplying inside the animal and eventually kill it, then continue to reproduce in the carcass. Once they run out of nutrients there, they revert back to the dormant spore state.

The infection of herbivores (and humans) proceeds as follows: the spore is located and engulfed by scavenger cells of the immune system specialized to deal with invaders. Inside the scavenger cell, the spore turns into a bacillus, multiplies, and eventually bursts the cell, releasing bacilli into the bloodstream. There they release a protein toxin which has macrophages as its principal target. The toxin has two components: edema factor and lethal factor. Edema factor inactivates macrophages so that they cannot participate in the fight against the infection; lethal factor causes the macrophage to make TNF-alpha and interleukin-1-beta, both normal components of the immune system used to induce an inflammatory reaction. The excessive inflammation throughout the body ultimately leads to septic shock and death.

The virulence of a strain of anthrax is dependent on its enclosing capsule and its toxin; the two are determined by different genes.

Spores of this bacteria can be used in biological warfare. US Army personnel are now routinely vaccinated prior to active service in places where biological attacks are considered a threat. The anthrax vaccine, produced by BioPort Corporation, contains no live bacteria, and is approximately 93% effective in preventing infection. Anthrax vaccination is one of many factors suspected of causing Gulf War syndrome.

British tests in 1942 contaminated Gruinard Island in Scotland with anthrax spores, and rendered it unusable for the following 48 years. An accidental release of anthrax in a research lab at Fort Detrick in Frederick, Maryland in the United States led to the permanent sealing of a building with plastics and glues.

The simplest method of obtaining an anthrax sample would be to get it from an animal killed by anthrax; this source is rare in developed countries but common in underdeveloped countries.

Cultivating anthrax spores takes minimal equipment and about a first-year collegiate microbiological education. However, to make an aerosol form of anthrax suitable for biological warfare requires extensive training and highly developed equipment.

The 2001 anthrax attacks occurred over the course of several weeks beginning on September 18, 2001. Letters containing anthrax bacteria were sent to five media offices and two US Senators. Five people died as a result. To date, no individual or group has been charged with the attacks themselves.

After the devastating September 11, 2001 attacks there was immediate speculation of linkage between the two events. It is alleged that a "skin lesion" found on Ahmed al-Haznawi, one of the September 11 hijackers who sought treatment in Fort Lauderdale, Florida, was cutaneous anthrax. However, the anthrax letters were mailed after September 11. It is difficult to see how the hijackers were responsible for the anthrax attacks unless there were surviving comrades who continued their terrorist campaign.

The FBI claims the anthrax attack was a result of domestic terrorism. The Justice Department has labeled a former government scientist Dr. Steven Hatfill as a "person of interest" in the case, but has not brought charges. Hatfill has maintained his innocence and is suing the government and the news media for ruining his life.

The letters that were mailed contain at least two different grades of anthrax material. However, all of the anthrax within the letters were of the same strain. This strain, known as the Ames strain, was first researched at the Army's Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland. The Ames strain was then distributed to at least fifteen bio-research labs within the US and six overseas.

The first set of anthrax letters are believed to have been mailed from Trenton NJ on September 18, 2001, exactly one week from the attacks on September 11. Five letters are thought to have been mailed at this time and addressed to media outlets, mostly in the New York City area. The recipients of these letters were ABC News, CBS News, NBC News, and the New York Post — all located in New York City. The other letter believed to have been mailed around this time was addressed to The National Enquirer's old mailing address and later forwarded to their new offices at American Media Inc. in Florida. AMI also publishes a tabloid called Sun where one of the anthrax victims, Robert Stevens, died.

A note was found in the New York Post letter which read, "09-11-01, THIS IS NEXT, TAKE PENACILIN NOW, DEATH TO AMERICA, DEATH TO ISRAEL, ALLAH IS GREAT." Some believe this note represented a benign form of bio-terrorism since medical advice was included in the misspelled precaution: "take penacilin now." It has been suggested the mailer of the New York media anthrax really did not want to harm anyone. A more convincing argument points to the fact that the anthrax in the New York media letters consisted of coarse brown granules and could have caused only skin infections, cutaneous anthrax, and not death.

The second group of anthrax letters were mailed three weeks later on October 9 from Trenton NJ and addressed to two Democrat Senators, Tom Daschle of South Dakota, and Patrick Leahy of Vermont. The two letters had identical notes which read, "09-11-01, YOU CAN NOT STOP US. WE HAVE THIS ANTHRAX. YOU DIE NOW. ARE YOU AFRAID? DEATH TO AMERICA. DEATH TO ISRAEL. ALLAH IS GREAT." The anthrax in the Daschle letter was described as fine powder. In comparison, the Daschle material was ten times denser in anthrax spores when compared to the retrieved New York Post sample. The Daschle anthrax consisted of nearly pure spores, with a concentration of a trillion spores per gram.

The anthrax material in the Leahy letter was similar to the powder found in Daschle letter. However, the Leahy anthrax powder had particles that were smaller and more uniform in size when compared to the Daschle anthrax. Bio-defense experts are having difficulty in reverse engineering the anthrax material found in the Senate letters.