What is anthrax?

Bacillus anthracis, the etiologic agent of anthrax, is a large, gram-positive, non-motile, spore-forming bacterial rod. The three virulence factors of B. anthracis are edema toxin, lethal toxin and a capsular antigen. Human anthrax has three major clinical forms: cutaneous, inhalation, and gastrointestinal. If left untreated, anthrax in all forms can lead to septicemia and death.

What is the case definition for anthrax?

A confirmed case of anthrax is defined as

1. a clinically compatible case of cutaneous, inhalational, or gastrointestinal illness that is laboratory-confirmed by isolation of B. anthracis from an affected tissue or site, or

2. a clinically compatible case of cutaneous, inhalational, or gastrointestinal disease with other laboratory evidence of B. anthracis infection based on at least two supportive laboratory tests.

How many anthrax cases have we had in the United States in the last 50 years?

From January 1955 to December 1999, there were 236 reported cases of anthrax, most of them cutaneous, in 30 states and the District of Columbia.

When was the last case of inhalational anthrax in the United States?

The last case of inhalational anthrax in the United States, before 2001, was in 1976 in California. A home craftsman, who worked with yarn, died. Bacillus anthracis was isolated from some of the imported yarns used by the patient. (MMWR 1976;25:33,34.)

When was the last case of cutaneous anthrax?

Can you list the most recent cases of anthrax in the Southeast of the United States?

Before October 2001, the last cases of anthrax, all cutaneous, were
 Florida, 1973
 South Carolina, 1974
 North Carolina, 1987

What are the signs and symptoms of anthrax?

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

Cutaneous anthrax is the most common naturally occurring type of infection (>95%) and usually occurs after skin contact with contaminated meat, wool, hides, or leather from infected animals. The incubation period ranges from 1-12 days. The skin infection begins as a small papule, progresses to a vesicle in 1-2 days followed by a necrotic ulcer. The lesion is usually painless, but patients also may have fever, malaise, headache, and regional lymphadenopathy. Most (about 95%) anthrax infections occur when the bacterium enters a cut of abrasion on the skin. Skin infection begins as a raised bump that resembles a spider bite, but (within 1-2 days) it 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 if patients are given appropriate antimicrobial therapy.

Inhalational anthrax is the most lethal form of anthrax. Anthrax spores must be aerosolized in order to cause inhalational anthrax. Studies show that 4,000 – 5,000 spores must be present to cause an infection. The incubation period of inhalational anthrax among humans is unclear, but it is reported to range from 1 to 7 days, possibly ranging up to 60 days. It resembles a viral respiratory illness and initial symptoms include sore throat, mild fever, muscle aches and malaise. These symptoms may progress to respiratory failure and shock with meningitis frequently developing.

Gastrointestinal anthrax usually follows the consumption of raw or undercooked contaminated meat and has an incubation period of 1-7 days. It is associated with severe abdominal distress followed by fever and signs of septicemia. The disease can take an oropharyngeal or abdominal form. Involvement of the pharynx is usually characterized by lesions at the base of the tongue, sore throat, dysphagia, fever, and regional lymphadenopathy. Lower bowel inflammation usually causes nausea, loss of appetite, vomiting and fever, followed by abdominal pain, vomiting blood, and bloody diarrhea.

What specific symptoms should I watch for?

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 inhalational 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 post-exposure 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.

What is the difference between exposure to anthrax and disease caused by anthrax?

A person can be said to be exposed to anthrax when that person comes in contact with the anthrax bacteria and a culture taken from that person is positive for anthrax. A person can be exposed without having disease. A person who might have come in contact with anthrax, but without a positive culture would be said to be potentially exposed. Disease caused by anthrax occurs when there is some sign of illness, such as the skin lesion that occurs with cutaneous anthrax.

A person who is exposed to anthrax but is given appropriate antibiotics can avoid developing disease.

Can I be exposed to anthrax via mail?

Letters containing Bacillus anthracis (anthrax) have been received by mail in several areas in the United States. In some instances, anthrax exposures have occurred, with several persons becoming infected. To prevent such exposures and subsequent infection, all persons should learn how to recognize a suspicious package or envelope and take appropriate steps to protect themselves and others.

What kind of mail should be considered suspicious?

Identifying Suspicious Packages and Envelopes
Some characteristics of suspicious packages and envelopes include the following:

 Inappropriate or unusual labeling
   - Excessive postage
   - Handwritten or poorly typed addresses
   - Misspellings of common words
   - Strange return address or no return address
   - Incorrect titles or title without a name
   - Not addressed to a specific person
   - Marked with restrictions, such as “Personal,” “Confidential,” or “Do not x-ray”
   - Marked with any threatening language
   - Postmarked from a city or state that does not match the return address

 Appearance
   - Powdery substance felt through or appearing on the package or envelope
   - Oily stains, discolorations, or odor
   - Lopsided or uneven envelope
   - Excessive packaging material such as masking tape, string, etc.

 Other suspicious signs
   - Excessive weight
   - Ticking sound
   - Protruding wires or aluminum foil

If a package or envelope appears suspicious, DO NOT OPEN IT.

What should people do who get a letter of package with powder?

Handling of Suspicious Packages or Envelopes*

 Do not shake or empty the contents of any suspicious package or envelope.
 Do not carry the package or envelope, show it to others or allow others to examine it.
 Put the package or envelope down on a stable surface; do not sniff, touch, taste, or look closely at it or at any contents which may have spilled.
 Alert others in the area about the suspicious package or envelope. Leave the area, close any doors, and take actions to prevent others from entering the area. If possible, shut off the ventilation system.
 WASH hands with soap and water to prevent spreading potentially infectious material to face or skin. Seek additional instructions for exposed or potentially exposed persons.
 If at work, notify a supervisor, a security officer, or a law enforcement official. If at home, contact the local law enforcement agency.
 If possible, create a list of persons who were in the room or area when this suspicious letter or package was recognized and a list of persons who also may have handled this package or letter. Give this list to both the local public health authorities and law enforcement officials.

Can anthrax spores be killed on letters in the mail by microwave, UV light, or ironing?

While some of these methods may kill some spores, it is not known what procedures to use (e.g., length of time, temperature, etc.). Furthermore, because of insufficient data on the efficacy of these methods in inactivating anthrax spores, CDC does not recommend these techniques for reliable decontamination.

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’ve been exposed to or carry it. The only way exposure can be determined is through a public health investigation. The tests that you hear or read about, such as nasal swabs and environmental tests, are not tests to determine whether an individual should be treated. These kinds of tests are used only to determine the extent of exposure in a given building or workplace.

If the patient is suspected of being exposed to anthrax, should he/she be quarantined or should other family members be tested?

Direct person-to-person spread of anthrax is extremely unlikely and anthrax is not contagious. 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.

Does CDC collect samples to test the bacteria?

CDC is engaging its partners in the Laboratory Response Network (LRN) in states all across the United States. The LRN is a collaborative partnership and multilevel system linking state and local public health laboratories with advanced capacity laboratories --including clinical, military, veterinary, agricultural, water, and food-testing laboratories -- to rapidly identify threat agents, including anthrax. Local clinical laboratory testing is confirmed at state and large metropolitan public health laboratories. CDC conducts the definitive or highly specialized testing for major threat agents. There are 100 laboratories in the network; none of them are commercials labs.

What's the turnaround time for an anthrax test in an environmental sample—for example, the time it takes to confirm that a substance in an envelope was indeed anthrax?

Before testing can begin, samples must be collected and arrive in the laboratory in a form suitable for testing. Testing itself is a two-step process. The initial screening tests may be positive within two hours if the sample is large and the concentration of bacteria is high. The confirmation tests take much longer, depending in part on how fast the bacteria grow, but are usually available 24-36 hours after the sample is received in the laboratory.

Does CDC recommend the use of home test kits for anthrax?

Hand-held assays (sometimes referred to as “Smart Tickets”) are sold commercially for the rapid detection of Bacillus anthracis. These assays are intended only for the screening of environmental samples. First responder and law enforcement communities are using these as instant screening devices and should forward any positive samples to authorities for more sensitive and specialized confirmatory testing. The results of these assays should not be used to make decisions about patient management or prophylaxis. The utility and validity of these assays are unknown.

At this time, CDC does not have enough scientific data to recommend the use of these assays. The analytical sensitivity of these assays is limited by the technology, and data provided by manufacturers indicate that a minimum of 10,000 spores is required to generate a positive signal. This number of spores would suggest a heavy contamination of the area (sample). Therefore a negative result does not rule out a lower level of contamination. Data collected from field use also indicate specificity problems with some of these assays. Some positive results have been obtained with spores of the non-anthrax Bacillus bacteria that may be found in the environment.

For these reasons, CDC has been asked to evaluate the sensitivity and specificity of the commercially available rapid, hand-held assays for B. anthracis. When this study is completed, results will be made available. Conclusions from this study are not expected in the near future.

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.

In patients with symptoms compatible with anthrax, providers should confirm the diagnosis by obtaining the appropriate laboratory specimens based on the clinical form of anthrax that is suspected (i.e., cutaneous, inhalational, or gastrointestinal).

What are the standard diagnostic tests used by the laboratories?

Presumptive identification to identify to Genus level (Bacillus family of organisms) requires Gram stain and colony identification.

Presumptive identification to identify to species level (B. anthracis) requires tests for motility, lysis by gamma phage, capsule production and visualization, hemolysis, wet mount and malachite green staining for spores.

Confirmatory identification of B. anthracis carried out by CDC may include phage lysis, capsular staining, and direct fluorescent antibody (DFA) testing on capsule antigen and cell wall polysaccharide.

When is a nasal swab indicated?

Nasal swabs and screening may assist in epidemiologic investigations, but should not be relied upon as a guide for prophylaxis or treatment. Epidemiologic investigation in response to threats of exposure to B. Anthracis may employ nasal swabs of potentially exposed persons as an adjunct to environmental sampling to determine the extent of exposure.

What is the therapy for preventing inhalational anthrax?

Interim recommendations for postexposure prophylaxis for prevention of inhalational anthrax after intentional exposure to B. anthracis may be found in the MMWR issue cited below:

What is cipro (ciprofloxacin)?

Ciprofloxacin, or cipro as it is commonly known, is a broad-spectrum, synthetic antimicrobial agent active against several microorganisms. The use of ciprofloxacin is warranted only under the strict supervision of a physician.

Does ciprofloxacin have an expiration date?

Yes. Antibiotics, just like all medicines, have expiration dates. If you received your ciprofloxacin through a pharmacist, the expiration date should be listed on the bottle. If you can’t find it or have questions about the expiration date, contact your pharmacist directly.

What are the side effects of Cipro?

Adverse health effects include vomiting, diarrhea, headaches, dizziness, sun sensitivity, and rash. Hypertension, blurred vision, and other central nervous system effects occur in <1% of patients and may be accentuated by caffeine or medications containing theophylline.

What are the guidelines for changing from ciprofloxacin to another antibiotic?

Should people buy and store antibiotics?

There is no need to buy or store antibiotics, and indeed, it can be detrimental to both the individual and to the community. First, only people who are exposed to anthrax should take antibiotics, and health authorities must make that determination. Second, individuals may not stockpile or store the correct antibiotics. Third, under emergency plans, the Federal government can ship appropriate antibiotics from its stockpile to wherever they are needed.

What is the treatment for patients with inhalational and cutaneous anthrax?

What if I develop side effects from the antibiotic?

If you develop side effects from the antibiotic, call your health care provider immediately. Depending on the type of side effects, you may be able to continue taking the medicine, or may be switched to an alternative antibiotic. If necessary, your physician may contact your State Department of Health for consultation on possible alternate antibiotics.

Has CDC tested the anthrax isolates for sensitivity to different antibiotics?

Yes. Antibiotic sensitivity testing performed at CDC has determined that the strain of anthrax was sensitive to a wide range of antibiotics, including penicillin and ciprofloxacin, giving public health officials important treatment information.

What are the risks of using tetracyclines and fluoroquinolones in children; are alternatives available?

Risks of using tetracyclines and fluroquinolones in children must be weighed carefully against the risk for developing a life-threatening disease due to B. anthracis. Both agents can have adverse health reactions in children. If adverse reactions are suspected, therapy may be changed to amoxicillin or penicillin.

Is the anthrax vaccine available to the public?

A vaccine has been developed for anthrax that is protective against invasive disease, but it is currently only recommended for high-risk populations. CDC and academic partners are continuing to support the development of the next generation of anthrax vaccines.

Who should be vaccinated against anthrax?

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

 Persons who work directly with the organism in the laboratory.
 Persons who work with imported animal hides or furs in areas where standards are insufficient to prevent exposure to anthrax spores.
 Persons who handle potentially infected animal products in high-incidence areas; while incidence is low in the United States, veterinarians who travel to work in other countries where incidence is higher should consider being vaccinated.
 Military personnel deployed to areas with high risk for exposure to the organism.

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.

What is the protocol for investigating and reporting possible anthrax exposures?

How is CDC responding to the anthrax reports?

The Federal government is coordinating the overall response to the anthrax reports. CDC continues to work with state and local health departments and other federal agencies to protect the public’s health and facilitate the epidemiologic investigations.

CDC has deployed a large number of epidemiologists, laboratorians, and other program staff to areas with possible anthrax exposures to assist local health professionals conducting these investigations. CDC also has professional staff in Atlanta working around the clock to track the exposures, process specimens, answer questions, and provide technical assistance and support.

What is CDC’s role on “rapid response teams”?

CDC teams are on stand-by and available to assist with investigations into outbreaks, confirmation of cases and exposures, and cleanup of B. anthracis and other biologic and chemical agents. These teams work closely with local health officials in the areas of laboratory capacity, epidemiologic response, disease surveillance, and communication.

What is the approach to cleanup of buildings?

The Environmental Protection Agency (EPA) has lead responsibility for issues related to environmental cleanup of hazardous materials and weapons of mass destruction with the assistance of 16 different federal agencies and departments including HHS/CDC working with the State and local agencies. The decision for a most efficient approach to cleanup will be defined based upon the sampling results, review of cleanup options, environmental media, etc.

Does CDC cooperate with international health organizations like the World Health Organization (WHO) to help in other countries with anthrax cases?

What are CDC’s recommendations for protecting mail handlers?

How long do anthrax spores live?

Anthrax spores can survive for decades in soil.

What is the importance of knowing the genetic information about anthrax?

Genetic information about B. anthracis, particularly to determine genetic similarity among strains, is an important part of a disease investigation, but it is not immediately required for taking action to prevent or treat anthrax in those who may have been exposed to or infected by B. anthracis. Genetic information is often used to determine the similarity of strains if a common source is suspected.

Does the similarity in strains from Florida, New York, and Washington, D.C. mean that they came from the same source or are these just the most common strains?

The strains of anthrax identified in Florida, New York, and Washington, D.C., are similar and consistent with a naturally occurring strain that shows no evidence of genetic alteration or bioengineering. All are sensitive and susceptible to the antibiotics recommended by CDC for those who have been exposed to or infected with B. anthracis.