Anthrax Information for Health Care Providers

Anthrax

• Caused by Bacillus anthracis, a large, encapsulated, gram-positive, aerobic, non-motile, spore-forming bacillus
• Transmission to humans usually occurs through occupational contact with infected animals or animal products
• Naturally acquired anthrax in humans most commonly involves the skin (cutaneous anthrax); inhalation anthrax and gastrointestinal (GI) anthrax are rare
• B. anthracis is considered one of the most likely biological warfare or terrorist threat agents
  Inhalation anthrax, caused by inhaling aerosolized spores, will be the most likely outcome of an intentional (bioterrorist) exposure
• Person-to-person transmission does NOT occur with inhalation or GI anthrax

Inhalation anthrax

Incubation: 1-5 days (may be as long as 60 days with low inoculum exposures)
Sign and Symptoms: Typically a bi-phasic illness:
Iitial Phase: Characterized by flu-like symptoms: Low grade fever, non-productive cough, malaise, fatigue, myalgias, mild chest discomfort. Rhonchi may be present, otherwise normal exam.
Acute Phase: Develops 1-5 days after initial symptoms. May be preceded by <1-3 days of improvement. Characterized by abrupt development of severe respiratory distress with dyspnea, stridor, cyanosis, and high fever. Shock and death usually follow within 24-36 hours after onset of respiratory distress. The average interval between onset of initial phase and death is 3 days.

Autopsy Clues: Hemorrhagic necrotizing mediastinitis and thoracic hemorrhagic necrotizing lymphadenitis. Hemorrhagic meningitis may also be present.

Laboratory Clues to Bacillus anthracis:

Peripheral blood smear: gram-positive bacilli on an unspun smear.
Microbiology: Aerobic blood culture growth of large, gram-positive bacilli with preliminary identification of Bacillus species

Laboratory Confirmation of Diagnosis

• Should be performed by the State Department of Health (DOH) Public Health Laboratory
  Appropriate clinical samples for testing at DOH include: blood (most important); pleural fluid and CSF may be helpful
• Transport and packaging of clinical specimens must be coordinated with local and State health departments
• DOH has the capacity to report some preliminary results within 2 to 4 hours

Treatment of Inhalation Anthrax

Early (during the initial phase) antibiotic treatment is essential. Mortality may still be high (~90%) after the onset of symptoms even with treatment
Natural strains of anthrax are resistant to extended-spectrum cephalosporins, sulfamethoxizol, and trimethoprim: these should not be used for treating (or prophylaxing for) anthrax
Physicians may be asked to get an informed consent signed for administration of certain medications supplied by the National Pharmaceutical Stockpile (NPS)

Anthrax Treatment Protocol (**indicated medications which
will be supplied as part of the NPS maintained at the CDC)

Therapy with ciprofloxacin may be initiated either as intravenous or oral dosage form. The pharmacokinetics are such that oral ciprofloxacin is rapidly and well absorbed from the GI tract with no substantial loss by first-pass metabolism. Maximum serum concentrations are attained 1-2 hours after oral dosing.

If susceptibility testing allows, therapy should be changed to IV penicillin for treatment or oral amoxicillin for post-exposure prophylaxis to continue therapy out 60 days. Ciprofloxacin dose should not exceed 1gram/day in children.

In 1991, the American Academy of Pediatrics amended their recommendation to allow treatment of young children with tetracyclines for serious infections, such as, Rocky Mountain Spotted Fever, for which doxycycline may be indicated. Doxycycline is preferred for its twice-a-day dosing low incidence of gastrointestinal side effects.

Although tetracyclines are not recommended during pregnancy, its use may be indicated for life-threatening illness. Adverse affects on developing teeth and bones are dose related, therefore, doxycycline might be used for a short course of therapy (7-14 days) prior to the 6th month of gestation. Please consult physician after the 6th month of gestation for recommendations.

Cutaneous Anthrax (a possible, though unlikely outcome of a terrorist release of B. anthracis)

• Local skin involvement after direct contact with spores or bacilli
• Commonly seen on exposed areas: face, neck, forearms, hands
• Localized itching, followed by a papular lesion that turns vesicular, followed by development of a black eschar within 7-10 days of onset of the initial lesion
• Usually non-fatal if treated with appropriate antibiotics for 7-10 days
• Wound or wound drainage may be contagious (direct contact): follow standard wound precautions

Gastrointestinal Anthrax(very unlikely outcome of a terrorist release of B. anthracis)

• Abdominal pain, nausea, vomiting, and fever following ingestion of contaminated food, usually meat
  Bloody diarrhea, hematemesis
• Gram-positive bacilli on blood or stool culture, usually after 2-3 days of illness
• Usually fatal after progression to septicemia
• Treatment is the same as for Inhalation Anthrax (see Inhalation Anthrax Treatment Protocol)

Post-Exposure Prophylaxis

• Antibiotic prophylaxis should be initiated when exposure to aerosolized anthrax spores is suspected
• Initiation of prophylaxis, especially in children, should be coordinated with the local health jurisdiction or the DOH
• Prophylaxis should continue for at least 60 days if the exposure is confirmed
• Physicians may be asked to get an informed consent signed for administration of certain medications supplied by the National Pharmaceutical Stockpile (NPS)

Post-Exposure Prophylaxis Protocol (**indicated medications which will be supplied as part of the NPS maintained at the CDC)

If susceptibility testing allows, therapy should be changed oral amoxicillin for post-exposure prophylaxis to continue therapy out to 60 days.

Although tetracyclines are not recommended during pregnancy, its use may be indicated for life-threatening illness. Adverse affects on developing teeth and bones are dose related, therefore, doxycycline might be used for a short course of therapy (7-14 days) prior to the 6th month of gestation. Please consult physician after the 6th month of gestation for recommendations.

Use of tetracyclines and fluoroquinolones in children has well-known adverse effects; these risks must be weighed carefully against the risk for developing life-threatening disease. If a release of B. anthracis is confirmed, children should be treated initially with ciprofloxacin or doxycycline as prophylaxis but therapy should be changed to oral amoxicillin 40 mg per kg of body mass per day divided every 8 hours (not to exceed 500 mg three times daily) as soon as penicillin susceptibility of the organism has been confirmed.

Ciprofloxacin dose should not exceed 1gram/day in children.

In 1991, the American Academy of Pediatrics amended their recommendation to allow treatment of young children with tetracyclines for serious infections, such as, Rocky Mountain Spotted Fever, for which doxycycline may be indicated. Doxycycline is preferred for its twice-a-day dosing low incidence of gastrointestinal side effects.

Anthrax Vaccine

• An inactivated cell-free vaccine that is used primarily by the military and those at occupational risk
• Is only licensed for use in healthy adults aged 18-65
• Anthrax vaccine should be administered at 0, 2 and 4 weeks following exposure.
• Supplies are very limited, however, and it is unlikely that the vaccine will be available for the general public in the future
• If vaccine is not available, antibiotic treatment should be continued for at least 30 days and possibly up to 60 days

Infection Control

Standard (Universal) Precautions for care and transport of patients and during post-mortem care

• Wound precautions for patients with cutaneous anthrax
• Isolation of patients is NOT necessary; however, the following extra precautions are advised:
• After an invasive procedure, instruments used should be autoclaved
• Contaminated clothing/bedding should be placed in labeled, plastic bags for later incineration or steam sterilization

Spills of potentially infected body fluid or tissue:

• Gently cover, then liberally apply 0.5% hypochlorite ( a 1:10 dilution of household bleach)
• Let sit for at least 20 minutes before cleaning up (work from perimeter to center)
• Any materials used in the clean-up must be autoclaved or incinerated
• Rinse off the concentrated bleach to avoid its caustic effects

Contamination of personnel

• Remove outer clothing carefully where spill occurred and place in a labeled, plastic bag
• Remove rest of clothing in the locker room and place in a labeled, plastic bag
• Shower thoroughly with soap and water

If exposure to contaminated sharps occurs:

Follow standard reporting procedures for sharps exposures

• Thoroughly irrigate site with soap and water and apply a disinfectant solution such as hypochlorite solution. DO NOT SCRUB AREA.
• Promptly begin therapy for cutaneous anthrax
• Recommended treatment for cutaneous exposure: prophylaxis with Ciprofloxacin 500 mg Po BID x 7-10 days
• Notify the DOH

Decontamination of environment

Use a decontamination solution , 0.5% hypochlorite ( a 1:10 dilution of household bleach) for surfaces
Let sit for at least 20 minutes before cleaning up (work from perimeter to center)
Routinely clean non-sterilizable equipment with a sterilizing solution
Cremation should be considered due to potential risks associated with embalming

References

• Inglesby TV, Henderson DA, Barlett JG, Ascher MS, et al. Anthrax as a biological weapon: Medical and public health management (consensus statement). JAMA, May 12, 1999;281(18):1735-1745.
• No authors listed. Biological warfare and terrorism: the military and public health response. U.S. Army, Public Health Training Network, Centers for Disease Control, and Food and Drug Administration Satellite broadcast, September 21-23, 1999.
• Physician’s Desk Reference, 53rd edition, 1999. Medical Economics Co., Montvale, NJ.
  WHO Guidelines
• Emerging Bacterial and Mycotic Disease Branch, DBMD, NCID, CDC: (February 12, 1999)
  AHFS Drug Information® 1999
• Drugs Facts and Comparisons® 2000
• 2000 Red Book, Report of Committee on Infectious Diseases, 25th Edition, American Academy of Pediatricians
• Mandell, Douglas, and Bennett’s, Principles and Practices of Infectious Diseases, 5th Edition
  Benenson AS. Control of Communicable Diseases Manual, American Public Health Association, Washington, DC 16th Edition, 1995.
• Abramson J, Jon S, Givner LB. Rocky Mountain Spotted Fever. [Review] Ped Inf Dis J. 18(6):539-540, June 1999.
• Centers for Disease Control and Prevention: Anthrax: Recommendations of the Immunization Practices Advisory Committee (ACIP), in press.