Questions & Answers
Anthrax - Countering the Threat
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Anthrax -- The Disease

  1. What is anthrax?

    Anthrax is a rapidly progressing acute infection caused by spore-forming bacteria called Bacillus anthracis. Anthrax most commonly occurs in warm-blooded animals, especially goats, cattle, and sheep, but it can also infect humans. Anthrax spores can be easily produced in a dry form for biological weapons. Spores can survive many years in adverse conditions and still remain capable of causing disease. When inhaled by humans, these spores cause respiratory failure that can lead to death within a week.

    Anthrax can make an excellent weapon of mass destruction. The spores may be used as a weapon in a variety of delivery systems. They can be produced in large quantities without sophisticated equipment. All it takes is a single breath of aerosolized anthrax to inhale enough spores to cause the disease. Then, if serious symptoms occur, it kills 99% of unprotected people. Even if a person with symptoms receives antibiotics, the death rate is still about 50%. Anthrax spores are odorless, colorless, and tasteless.

  2. Who gets infected with anthrax?
    Animals and people can get anthrax disease. Anthrax is most commonly found in agricultural regions where goats, sheep, cattle or other plant-eating animals have not been vaccinated. When anthrax infects humans, it is usually due to an occupational exposure to infected animals or their products, especially hides, hair, wool, bones or bone products. Less commonly, ingesting undercooked, contaminated meat can infect humans.

  3. What are the symptoms of anthrax?
    • Fever (over 100 degrees F). The fever may be accompanied by chills or night sweats.
    • Flu-like symptoms.
    • Cough, usually a non-productive cough, chest discomfort, shortness of breath, fatigue, muscle aches, sore throat followed by difficulty swallowing, enlarged lymph nodes, headache, nausea, loss of appetite, abdominal distress, vomiting or diarrhea.
    • A sore, especially on the face, arms or hands, that starts as a raised bump and develops into a painless ulcer with a black area in the center.

  4. How can I know my cold or flu is not anthrax?
    Many human illnesses begin with what are commonly referred to as “flu-like” symptoms, such as fever and muscle aches. However, in most cases anthrax can be distinguished from the flu because the flu has additional symptoms. In previous reports of anthrax cases, early symptoms usually did not include a runny nose, which is typical of the flu and common cold.

  5. Where is anthrax usually found?
    Anthrax is found around the globe. It is more often a risk in countries that do not vaccinate their livestock, or that have substandard or ineffective public-health programs.

  6. What are the types of anthrax infection? How is anthrax transmitted?
    There are three forms of anthrax disease, varying by the route of infection. People can get anthrax in the following three ways:
    1. Through a break in the skin (cutaneous anthrax). 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. About 20% of untreated cases of cutaneous anthrax will result in death and less than 1% resulting in death with antibiotic treatment
    2. By eating inadequately cooked contaminated meat (gastrointestinal anthrax). 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 about 25% to 60% of cases.
    3. By breathing in bacteria or spores (inhalational anthrax). Inhalational anthrax does not typically spread from person to person. Inhalational anthrax is usually fatal. Although case-fatality estimates for inhalational anthrax are based on incomplete information, the rate is extremely high even with all possible supportive care including appropriate antibiotics.
    Because anthrax spores can live in the soil for many years, animals can get anthrax by grazing or drinking water in contaminated areas. Weaponized anthrax could be used against people in almost any location, and in many different ways. The greatest threat with the most deadly consequences comes from inhaled anthrax.

  7. Can people spread anthrax to each other?
    Direct person-to-person spread of inhalational anthrax is "very rare," according to the American Public Health Association’s Control of Communicable Diseases Manual. Presumably, person-toperson spread would require contact with contaminated skin lesions.

  8. Can anthrax be transmitted by insects?
    One report suggested that black flies may have transmitted anthrax from animals to humans, where there was a large outbreak in the animal population. Insects are not a major factor in the spread of anthrax.

  9. How is anthrax diagnosed?
    Anthrax is diagnosed by isolating the bacteria, Bacillus anthracis, from the blood, skin, or cerebral spinal fluid, or by measuring specific antibodies in the blood of suspected cases. Generally, diagnosis by antibodies is done weeks or months after the infection occurs, too late to aid in treatment. The best protection is vaccination before exposure, combined with the appropriate Mission-Oriented Protective Posture (MOPP), including protective clothing and detection equipment.

  10. Can I get screened or tested to find out whether I have been exposed to anthrax?
    There is no screening test for anthrax; there is no test that a doctor can do for you that says you have been exposed to or carry it. The only way exposure can be determined is through a public health investigation.

  11. What is a nasal swab test?

    A nasal swab involves placing a swab inside the nostrils and taking a culture. The CDC and the U.S. Department of Health and Human Services do not recommend the use of nasal swab testing by clinicians to determine whether a person has been exposed to Bacillus anthracis, the bacteria responsible for anthrax, or as a means of diagnosing anthrax. At best, a positive result may be interpreted only to indicate exposure; a negative result does not exclude the possibility of exposure. Also, the presence of spores in the nose does not mean that the person has inhalational anthrax. The nose naturally filters out many things that a person breathes, including bacterial spores. To have inhalational anthrax, a person must have the bacteria deep in the lungs, and also have symptoms of the disease.

    Another reason not to use nasal swabs is that most hospital laboratories cannot fully identify anthrax spores from nasal swabs. They are only able to tell that bacteria that resemble anthrax bacteria are present.

  12. If patients are suspected of being exposed to anthrax, should they be quarantined or should other family members be tested?
    Anthrax is not known to spread from one person to another person. Therefore, there is no need to quarantine individuals suspected of being exposed to anthrax or to immunize or treat contacts of persons ill with anthrax, such as household contacts, friends, or coworkers, unless they also were also exposed to the same source of infection. For more information on laboratory testing, go to

  13. Why vaccinate at all? Why not treat with antibiotics after exposure?
    There is no better round-the-clock protection against anthrax infection than the anthrax vaccine. Antibiotics are effective when started immediately or very soon after exposure. However, not all exposures can be predicted in advance or even determined in very early stages, particularly in certain military situations. In such situations, the consequences for military personnel and their mission could be very unfavorable. This is not a risk we can afford to take.

  14. For More Information:
    Advisory Committee on Immunization Practices. Use of anthrax vaccine in the United States. MMWR-Morbidity & Mortality Weekly Report 2000;49(RR-15, Dec 15):1-20.

    Brachman PS. Anthrax. Annals of the NY Academy of Sciences 1970;46:577-82.

    Brachman PS. Inhalation anthrax. Ann NY Acad Sci 1980;56:83-93.

    Brachman PS, Friedlander AM, Grabenstein JD. Anthrax. In: Plotkin SA, Orenstein WA, ed. Vaccines, 4th ed. Philadelphia: W. B. Saunders, 2003.

    Brachman PS, Gold H, Plotkin SA, Fekety FR, Werrin M, Ingraham NR. Field evaluation of a human anthrax vaccine. American Journal of Public Health 1962;52:432-45.

    Emerging Infectious Diseases specialty issue, Proceedings of the Symposium on Bioterrorism: July/August 1999.

    Food and Drug Administration. Biological products; Bacterial vaccines and toxoids; Implementation of efficacy review. Federal Register 1985;50:51002-117.

    Food and Drug Administration. Biological products; Bacterial vaccines and toxoids; Implementation of efficacy review. Federal Register 2004;29:78281-93.

    Franz DR, Jahrling PB, Friedlander AM, McClain DJ, Hoover DL, Bryne WR, Pavlin JA, Christopher GW, Eitzen EM Jr. Clinical recognition and management of patients exposed to biological warfare agents. Journal of the American Medical Association 1997;278(Aug 6):399-411.

    Hambleton P, Carman JA, Melling J. Anthrax: The disease in relation to vaccines. Vaccine 1984;2:125-32.

    Inglesby TV, O'Toole T, Henderson DA, Bartlett JG, Ascher MS, Eitzen E, Friedlander AM, Gerberding J, Hauer J, Hughes J, McDade J, Osterholm MT, , Parker G, Perl TM, Russell PK, Tonat K, Working Group on Civilian Bio-defense. Anthrax as a biological weapon, 2002: Updated recommendations for management.

    Journal of the American Medical Association 2002;287:2236-52.

    Journal of the American Medical Association specialty issue on biological warfare and biological terrorism: August 6, 1997.

    Sidell FR, Takafuji ET, Franz DR. Medical Aspects of Chemical & Biological Warfare. Washington, DC: Department of the Army, 1997.

    Turnbull PCB. Guidelines for the Surveillance and Control of Anthrax in Humans and Animals, 3rd ed., WHO Report WHO/EMC/ZDI/98.6.;jsessionid=FRZCbn15JMK9npLt12pBYDyZHTbdLSmz7Msn3Kvn1s1x75nCS8YR!736553971!-949856145!8091!-1