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Fact Sheet: Anthrax Information for Health Care Providers

Cause Bacillus anthracis
  • Encapsulated, aerobic, gram-positive, spore-forming, rod-shaped (bacillus) bacterium
Systems Affected
Transmission
  • Skin: direct skin contact with spores; in nature, contact with infected animals or animal products (usually related to occupational exposure)
  • Respiratory tract: inhalation of aerosolized spores
  • GI: consumption of undercooked or raw meat products or dairy products from infected animals
  • NO person-to-person transmission of inhalation or GI anthrax
Reporting
  • Report suspected or confirmed anthrax cases immediately to your local or state department of health.

 

Cutaneous Anthrax
Incubation Period Usually an immediate response up to 1 day
Typical Signs/Symptoms
  • Local skin involvement after direct contact with spores or bacilli
  • Localized itching followed by 1) papular lesion that turns vesicular and 2) subsequent development of black eschar within 7–10 days of initial lesion
Treatment

(See Cutaneous Anthrax Treatment Protocol for specific therapy)
  • Obtain specimens for culture BEFORE initiating antimicrobial therapy.
  • Do NOT use extended-spectrum cephalosporins or trimethoprim/sulfamethoxazole because anthrax may be resistant to these drugs.
Precautions
  • Standard contact precautions. Avoid direct contact with wound or wound drainage.

 

Inhalation Anthrax
Incubation Period
  • Usually <1 week; may be prolonged for weeks (up to 2 months)
Typical Signs/Symptoms (often biphasic, but symptoms may progress rapidly) Initial phase
  • Non-specific symptoms such as low-grade fever, nonproductive cough, malaise, fatigue, myalgias, profound sweats, chest discomfort (upper respiratory tract symptoms are rare)
  • Maybe rhonchi on exam, otherwise normal
  • Chest X-ray:
    • mediastinal widening
    • pleural effusion (often)
    • infiltrates (rare)
Subsequent phase
  • 1–5 days after onset of initial symptoms
  • May be preceded by 1–3 days of improvement
  • Abrupt onset of high fever and severe respiratory distress (dyspnea, stridor, cyanosis)
  • Shock, death within 24–36 hours
Laboratory
  • Coordinate all aspects of testing, packaging, and transporting with public health laboratory/Laboratory Response Network (LRN).
  • Obtain specimens appropriate to system affected:
    • blood (essential)
    • pleural fluid
    • cerebral spinal fluid (CSF)
    • skin lesion
 Clues to diagnosis
  • Gram-positive bacilli on unspun peripheral blood smear or CSF
  • Aerobic blood culture growth of large, gram-positive bacilli provides preliminary identification of Bacillus species.
Treatment

(See Inhalational Anthrax Treatment Protocol for specific therapy)
  • Obtain specimens for culture BEFORE initiating antimicrobial therapy.
  • Initiate antimicrobial therapy immediately upon suspicion.
  • Do NOT use extended-spectrum cephalosporins or trimethoprim/sulfamethoxazole because anthrax may be resistant to these drugs.
  • Supportive care including controlling pleural effusions
Precautions
  • Standard contact precautions

 

Gastrointestinal Anthrax
Incubation Period
  • Usually 1–7 days
Typical Signs/Symptoms Initial phase
  • Nausea, anorexia, vomiting, and fever progressing to severe abdominal pain, hematemesis, and diarrhea that is almost always bloody
  • Acute abdomen picture with rebound tenderness may develop.
  • Mesenteric adenopathy on computed tomography (CT) scan likely. Mediastinal widening on chest X-ray has been reported
Subsequent phase
  • 2–4 days after onset of symptoms, ascites develops as abdominal pain decreases.
  • Shock, death within 2–5 days of onset
 Laboratory
  • Coordinate all aspects of testing, packaging, and transporting with public health laboratory/LRN.
  • Obtain specimens appropriate to system affected:
    • blood (essential)
    • ascitic fluid
 Clues to diagnosis
  • Gram-positive bacilli on unspun peripheral blood smear or ascitic fluid
  • Pharyngeal swab for pharyngeal form
  • Aerobic blood culture growth of large, gram-positive bacilli provides preliminary identification of Bacillus species.
Treatment

(See Inhalational Anthrax Treatment Protocol for specific therapy)
  • Obtain specimens for culture BEFORE initiating antimicrobial therapy.
  • Early (during initial phase) antimicrobial therapy is critical.
  • Do NOT use extended-spectrum cephalosporins or trimethoprim/sulfamethoxazole because anthrax may be resistant to these drugs.
Precautions
  • Standard precautions

 

Oropharyngeal Anthrax
Incubation Period
  • Usually 1–7 days
Typical Signs/Symptoms Initial phase
  • Fever and marked unilateral or bilateral neck swelling caused by regional lymphadenopathy
  • Severe throat pain and dysphagia
  • Ulcers at the base of the tongue, initially edematous and hyperemic
 Subsequent phase
  • Ulcers may progress to necrosis
  • Swelling can be severe enough to compromise the airway
 Laboratory
  • Coordinate all aspects of testing, packaging, and transporting with public health laboratory/LRN.
  • Obtain specimens appropriate to system affected:
    • blood (essential)
    • throat
 Clues to diagnosis
  • Aerobic blood culture growth of large, gram-positive bacilli provides preliminary identification of Bacillus species.
Treatment

(See Inhalational Anthrax Treatment Protocol for specific therapy)
  • Obtain specimens for culture BEFORE initiating antimicrobial therapy.
  • Do NOT use extended-spectrum cephalosporins or trimethoprim/sulfamethoxazole because anthrax may be resistant to these drugs.
  • Supportive care including controlling ascites
Precautions
  • Standard contact precautions
  • Page last updated March 8, 2002
  • Page last reviewed February 22, 2006
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
    24 Hours/Every Day
  • cdcinfo@cdc.gov
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348, 24 Hours/Every Day - cdcinfo@cdc.gov

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