Anthrax: Risk

by CDC

(Page 9 of 10)

What is the risk for an individual if he or she is treated with antibiotics and is exposed to Bacillus anthracis again?

Because inhalation anthrax in humans is so rare, we cannot be certain about the risk of reinfection; therefore, CDC recommends that another course of antibiotic treatment be given promptly if a person is reexposed to Bacillus anthracis. In animal studies of inhalation anthrax, animals given anthrax vaccine and antibiotics after exposure did not develop anthrax when reexposed 4 months after the original exposures, while animals treated with antibiotics alone became ill when reexposed.

Can the spores that cause anthrax multiply outside of a human or animal host?

We do not think so, but we are not certain.

What are the odds of my getting anthrax? (What is the average risk of contracting anthrax in the United States?)

In an average year, the chance that any one individual in the United States will contract anthrax is extremely low - about one case in nearly 300 million. In 2001, even with the intentional release of Bacillus anthracis spores in some environments, the nationwide risk was still extremely low - about 23 cases in nearly 300 million people.

Can anthrax affect pregnancy? Should pregnant women exposed to anthrax take antibiotics?

Anthrax is a serious illness in all humans, including pregnant women. Inhalation anthrax has a high fatality rate, and cutaneous (skin) anthrax also is serious, but less frequently fatal. Because these infections are potentially fatal, it has been recommended that ciprofloxacin, or similar antibiotic drugs, be prescribed for pregnant women believed to have been exposed to anthrax. Clinical studies of the use of the ciprofloxacin in pregnant women have not been conducted, so ciprofloxacin and related drugs are not generally recommended for pregnant women with less serious illnesses.

Can anthrax be transmitted by handling money?

The Department of the Treasury sponsored a study to investigate this risk, and it revealed no evidence that anthrax can be spread by handling money.

What is the risk for anthrax in employees of a facility with a positive environmental sample?

The risk would depend on where the environmental sample was, the amount (quantity) of material, and if it was collected in an air sample or on a surface. The risk would also depend on the person's contact with the type of sample in terms of breathing or touching the sample.

Finding a positive surface or air sample does not mean that employees of a facility are at risk for anthrax. Heavily contaminated surfaces may pose a small risk for cutaneous anthrax, which can be minimized by clean-up. Laboratory test results of environmental surface samples should not be the only criterion for starting, continuing, or stopping preventive antibiotic therapy for inhalation disease.

Anthrax Signs and Symptoms

What are the types of anthrax infection?

Anthrax infection can occur in three forms: cutaneous (skin), inhalation, and gastrointestinal.

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. 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 anthrax: Initial symptoms may resemble a common cold - sore throat, mild fever, muscle aches and malaise. After several days, the symptoms may progress to severe breathing problems and shock. Inhalation anthrax is usually fatal.

Gastrointestinal anthrax: 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.

What are the symptoms for anthrax?

These symptoms can occur within 7 days of infection:

• Fever (temperature greater than 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 your face, arms or hands, that starts as a raised bump and develops into a painless ulcer with a black area in the center.

Is anthrax contagious?

No. Anthrax is not contagious; the illness cannot be transmitted from person to person.

What are the case fatality rates for the various forms of anthrax?

Early treatment of cutaneous anthrax is usually curative, and early treatment of all forms is important for recovery. Patients with cutaneous anthrax have reported case fatality rates of 20% without antibiotic treatment and less than 1% with it. Although case-fatality estimates for inhalation anthrax are based on incomplete information, the rate is extremely high, approximately 75%, even with all possible supportive care including appropriate antibiotics. Estimates of the impact of the delay in postexposure prophylaxis or treatment on survival are not known. For gastrointestinal anthrax, the case-fatality rate is estimated to be 25%-60% and the effect of early antibiotic treatment on that case-fatality rate is not defined.

Can the presence of Bacillus anthracis spores be detected by a characteristic appearance, odor, or taste?

Bacillus anthracis spores do not have a characteristic appearance (e.g., color), smell, or taste. Spores themselves are too small to be seen by the naked eye, but have been mixed with powder to transport them. The U.S. Postal Service advises that individuals be suspicious of letters or packages with any powdery substance on them, regardless of color.

What would be the approximate size of enough Bacillus anthracis spores to cause infection?

They could not be seen by the naked eye but could be seen under a microscope.

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.

If I have the flu, can I still get anthrax?

Yes, a person could theoretically get both the flu and anthrax, either at the same time or at different times.

About the Author

www.cdc.gov
The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.