Some Basic Information on Anthrax (Modified from Bexar County Document)
For more information go to CDC and choose anthrax. The FBI has has also released an advisory for suspicious packages in PDF format.


The US has experienced a rash of anthrax letter threats in recent days which has raised public concern about the risks posed by these threats. The good news is that most all of these incidents have been hoaxes. The bad news is that we will likely have more incidents. The public safety agencies have plans to deal with these threats quickly and efficiently. The following guidelines are offered to you in the event you receive an anthrax threat letter.


Staff responsible for incoming mail should maintain an awareness of the possibility of anthrax threat letters. This checklist outlines common features of anthrax threat letters.

No return address

Excessive postage

Hand written or poorly typed addresses

Misspelling of common words

Restrictive markings such as "Confidential", "Personal", etc.

Excessive weight and/or a feel of a powdery substance


RELAX AND REMAIN CALM - Although any threatened use of biological agent must be treated as thought it is real, experience has demonstrated that these are likely to be a HOAX.   If the suspected biological agent is reported as Anthrax, be assured that it is NOT contagious, and that treatment is readily available if administered before the onset of symptoms.


1.      If it is a letter that you have opened, set it down gently at the location where you first read it.      Then move to an area that will minimize your exposure to others.  Avoid contact with others when possible, and remain in the area.  Public Safety and Health responders will come to you.

2.      If it is a note that you happen to find, LEAVE IT ALONE.

3.      Advise a coworker in the immediate area what has happened and ask them to call 911.

4.      If possible, have the buildings ventilation system shut down and turn off any fans in the area.

5.      Do not allow others into the area.  If anyone enters, they should stay until instructed to leave by Public Safety or Health responders.

6.      Remain calm.  Exposure does not mean that you will become sick.   Public Health responders will provide specific information and instructions about the symptoms and effective treatment to prevent illness.


  1. Do not pass the letter or note to others to look at.
  2. Do not disturb any contents in the letter or note.  Handling the letter may only spread the and substance inside and increase the chances of it getting into the air.
  3. Do not ignore the threat.  It must be treated as real until properly evaluated.



  1. Call 911 immediately.
  2. If possible, have the buildings ventilation system shut down.
  3. Remain calm, similar threats have all proven false and this is likely to be a hoax as well.


  1. Do not ignore the threat.  It must be treated as real until properly evaluated.
  2. Do not argue with or antagonize the caller.
  3. Listen carefully to the caller so you can recall the details later.   Listen for background noises.


Health Department will respond with the jurisdictional law enforcement and fire service.  People will be asked to cooperate by waiting in the area until an appropriate evaluation of the incident is made.   You will be given information as soon as it is available.  There may be a decontamination  (washing/rinsing) process performed on the persons exposed and/or the area.  There are several ways to accomplish decontamination and the method used will be based upon the conditions present at the scene.  The scene will be photographed and the letter and any product taken into custody as evidence and to determine the nature of any product.  Statements will be taken from those involved. 

Even in the event of a substance being real anthrax, infection is unlikely and treatment is extremely effective. Stay calm and proceed slowly with the above instructions. For more information please contact the Centers for Centers for Disease Control and Prevention


What is anthrax?

Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Anthrax most commonly occurs in wild and domestic lower vertebrates (cattle, sheep, goats, camels, antelopes, and other herbivores), but it can also occur in humans when they are exposed to infected animals or tissue from infected animals.

Why has anthrax become a current issue?

Because anthrax is considered to be a potential agent for use in biological warfare, the Department of Defense (DoD) has begun mandatory vaccination of all active duty military personnel who might be involved in conflict.

How common is anthrax and who can get it?

Anthrax is most common in agricultural regions where it occurs in animals. These include South and
Central America, Southern and Eastern Europe, Asia, Africa, the Caribbean, and the Middle East. When anthrax affects humans, it is usually due to an occupational exposure to infected animals or their products. Workers who are exposed to dead animals and animal products from other countries where anthrax is more common may become infected with B. anthracis (industrial anthrax). Anthrax in wild livestock has occurred in the United States.

How is anthrax transmitted?

Anthrax infection can occur in three forms: cutaneous (skin), inhalation, and gastrointestinal. B. anthracis spores can live in the soil for many years, and humans can become infected with anthrax by handling products from infected animals or by inhaling anthrax spores from contaminated animal products. Anthrax can also be spread by eating undercooked meat from infected animals. It is rare to find infected animals in the
United States.

What are the symptoms of anthrax?

Symptoms of disease vary depending on how the disease was contracted, but symptoms usually occur within 7 days.

Cutaneous: Most (about 95%) anthrax infections occur when the bacterium enters a cut or abrasion on the skin, such as when handling contaminated wool, hides, leather or hair products (especially goat hair) of infected animals. Skin infection begins as a raised itchy bump that resembles an insect bite but within 1-2 days develops into a vesicle and then a painless ulcer, usually 1-3 cm in diameter, with a characteristic black necrotic (dying) area in the center. Lymph glands in the adjacent area may swell. About 20% of untreated cases of cutaneous anthrax will result in death. Deaths are rare with appropriate antimicrobial therapy.

Inhalation: Initial symptoms may resemble a common cold. After several days, the symptoms may progress to severe breathing problems and shock. Inhalation anthrax is usually fatal.

Intestinal: The intestinal disease form of anthrax may follow the consumption of contaminated meat and is characterized by an acute inflammation of the intestinal tract. Initial signs of nausea, loss of appetite, vomiting, fever are followed by abdominal pain, vomiting of blood, and severe diarrhea. Intestinal anthrax results in death in 25% to 60% of cases.

Where is anthrax usually found?

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.

Can anthrax be spread from person-to-person?

Direct person-to-person spread of anthrax is extremely unlikely to occur. Communicability is not a concern in managing or visiting with patients with inhalational anthrax.

Is there a way to prevent infection?

In countries where anthrax is common and vaccination levels of animal herds are low, humans should avoid contact with livestock and animal products and avoid eating meat that has not been properly slaughtered and cooked. Also, an anthrax vaccine has been licensed for use in humans. The vaccine is reported to be 93% effective in protecting against anthrax.

What is the anthrax vaccine?

The anthrax vaccine is manufactured and distributed by BioPort, Corporation, Lansing, Michigan. The vaccine is a cell-free filtrate vaccine, which means it contains no dead or live bacteria in the preparation. The final product contains no more than 2.4 mg of aluminum hydroxide as adjuvant. Anthrax vaccines intended for animals should not be used in humans.

Who should get vaccinated against anthrax?

The Advisory Committee on Immunization Practices has recommend anthrax vaccination for the following groups:

Pregnant women should be vaccinated only if absolutely necessary.

What is the protocol for anthrax vaccination?

The immunization consists of three subcutaneous injections given 2 weeks apart followed by three additional subcutaneous injections given at 6, 12, and 18 months. Annual booster injections of the vaccine are recommended thereafter.

Are there adverse reactions to the anthrax vaccine?

Mild local reactions occur in 30% of recipients and consist of slight tenderness and redness at the injection site. Severe local reactions are infrequent and consist of extensive swelling of the forearm in addition to the local reaction. Systemic reactions occur in fewer than 0.2% of recipients.

How is anthrax diagnosed?

Anthrax is diagnosed by isolating B. anthracis from the blood, skin lesions, or respiratory secretions or by measuring specific antibodies in the blood of persons with suspected cases.

Is there a treatment for anthrax?

Doctors can prescribe effective antibiotics. To be effective, treatment should be initiated early. If left untreated, the disease can be fatal.

Where can I get more information about the recent Department of Defense decision to require men and women in the Armed Services to be vaccinated against anthrax?

The Department of Defense recommends that servicemen and women contact their chain of command on questions about the vaccine and its distribution. The anthrax Vaccine Immunization Program in the U.S. Army Surgeon General's Office can be reached at

Clinical Features

Human anthrax has three major clinical forms: cutaneous, inhalation, and gastrointestinal. Cutaneous anthrax is a result of introduction of the spore through the skin; inhalation anthrax, through the respiratory tract; and gastrointestinal anthrax, by ingestion.

Etiologic Agent

Bacillus anthracis, the etiologic agent of anthrax, is a large, gram-positive, nonmotile, spore-forming bacterial rod. The three virulence factors of B. anthracis are edema toxin, lethal toxin and a capsular antigen. B. anthracis is considered to be a likely agent for use in acts of biological terrorism.


In the United States, incidence is extremely low. Gastrointestinal anthrax is rare but may occur as explosive outbreaks associated with ingestion of infected animals. Worldwide, the incidence is unknown, though B. anthracis is present in most of the world.


If untreated, anthrax in all forms can lead to septicemia and death. Early treatment of cutaneous anthrax is usually curative, and early treatment of all forms is important for recovery. Patients with gastrointestinal anthrax have reported case- fatality rates ranging from 25% to 75%. Case-fatality rates for inhalational anthrax are thought to approach 90 to 100%.


For humans, the source of infection in naturally acquired disease is infected livestock and wild animals or contaminated animal products. Human-to-human transmission is extremely rare and only reported with cutaneous anthrax.

Risk Groups

Cutaneous anthrax is the most common manifestation of infection with B. anthracis. Inhalation (pulmonary) anthrax occurs in persons working in certain occupations where spores may be forced into the air from contaminated animal products, such as animal hair processing. Occupational risk groups include those coming into contact with livestock or products from livestock, e.g., veterinarians, animal handlers, abattoir workers, and laboratorians.


For both livestock and humans, anthrax is a notifiable disease in the United States.


Among humans, there has been no increase in naturally acquired infection in the United States. Recently, considerable attention has been focused on the potential for B. anthracis to be used in acts of biologic terrorism.


Because B. anthracis has a high probability for use as an agent in biologic terrorism, CDC is expanding epidemiologic and diagnostic laboratory capacities and technologies. This capacity building, includes local and state health department training. In addition, there are gaps in our understanding of the immunology of anthrax and protection against anthrax via vaccination. Also, post-exposure prophylaxis against anthrax requires further investigation.


Identify, transfer to CDC laboratories, test, and improve as needed, rapid diagnostic technologies developed for rapid identification of B. anthracis in Department of Defense (DoD) laboratories.


December 2000