What is anthrax?
Anthrax is an acute infectious disease caused by a spore-forming bacterium - Bacillus anthracis.  Anthrax most commonly causes disease in wild and domestic herbivores, e.g., cattle, sheep, goats, camels, and antelope.  Humans become incidentally infected when in contact with infected animals or their products.  Symptoms of disease vary depending on how the disease was contracted.

What are anthrax spores?
The bacterium, Bacillus anthracis, that causes anthrax can exist in two states - a spore form and a vegetative form.  As a spore, the bacterium is in a dormant or resting state and is surrounded by a tough protective coat.  Anthrax spores are odorless, colorless, and tasteless.  The anthrax spores can survive in the soil for decades.  The anthrax spore can also survive for a prolonged time on animal products - hides, fur, wool, or goat hair. 

The characteristics of the spores have allowed their use as biological weapons.  At any time, the spores can germinate and turn into viable, vegetative forms that multiply and produce toxins.

How is anthrax transmitted?
Anthrax has three modes of transmission.  First, people can get anthrax through a break in the skin by direct contact with the spores - cutaneous or skin anthrax.
Second, people can ingest or eat inadequately cooked contaminated meat - gastrointestinal anthrax.
Third, the bacteria or spores can be inhaled - respiratory anthrax, the most deadly form.
Direct person-to-person spread of anthrax is extremely unlikely, if it occurs at all.  Thus, household contacts, friends, or coworkers should not be at risk unless they were also exposed to the same source of infection.

Who gets infected with anthrax?
Animals and people get anthrax disease.  Cattle, sheep, goats, camels, or other plant-eating animals ("herbivores") who are not vaccinated are at risk.  When anthrax affects humans, it is usually due to an occupational exposure to infected animals or their products.  Occupational risk groups include veterinarians, animal handlers, abattoir workers, and laboratorians.

Where is anthrax usually found?
Anthrax is found around the globe.  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.  It is rare to find infected domestic animals in the United States because of the animal vaccination program.

What are the symptoms of anthrax?
Symptoms of anthrax vary depending on how the disease was contracted.  Symptoms usually occur within 7 days.  Most anthrax infections are cutaneous (about 95%).

Cutaneous: Skin infection begins as a raised itchy bump.  A vesicle develops within 1-2 days, then a painless ulcer, usually 1-3 cm in diameter, with a black necrotic (dying) area in the center.  About 20% of untreated cases of cutaneous anthrax will result in death.  Deaths are rare with appropriate antimicrobial therapy.

Gastrointestinal:  Initial signs of nausea, loss of appetite, vomiting, and fever are followed by abdominal pain, vomiting of blood, and severe diarrhea.  Gastrointestinal anthrax results in death in 25% to 60% of cases.

Respiratory (Inhalation):  Initial symptoms may resemble a common cold with malaise, low-grade fever, and dry cough.  After 1 to 3 days, this is followed by a second phase that progresses to severe breathing problems and shock.  Without antibiotic therapy, inhalation anthrax is usually fatal.  With antibiotic treatment, the fatality rate is estimated to be at least 75%.

Is there a treatment for anthrax?
Doctors can prescribe effective antibiotics - Penicillin G or ciprofloxacin - for cutaneous anthrax.  Despite appropriate antimicrobial therapy, inhalation anthrax is fatal in the majority of patients.
Antibiotics - ciprofloxacin, levofloxacin, or doxycycline- may protect people without symptoms after a known exposure to aerosolized anthrax spores.  However, they may be ineffective following a large dose, unrecognized exposures, or exposures recognized only after symptoms appear.

Is there an anthrax vaccine for humans?
Yes, an anthrax vaccine has been licensed for use in humans.  It is relatively safe and 93% effective in protecting against anthrax.  Persons who should be vaccinated against anthrax are listed in the CDC web site.

Can I acquire anthrax through the mail?
Yes, anthrax spores can be sent through the mail in packages or letters. The CDC web site provides a CDC Health Advisory on "how to identify suspicious packages and letters" and what to do in the event this would happen. 

For more information, visit the following:
Bioterrorism
CDC Bioterrorism site:  http://www.bt.cdc.gov  
Information on anthrax vaccine:  http://www.anthrax.osd.mil
What to do with a suspicious letter or package: http://www.co.douglas.ne.us/dept/health/Biohealth.