Characteristics.
Anthrax is a zoonotic disease caused by Bacillus
anthracis. Under natural conditions,
humans become infected by contact with
infected animals or contaminated animal
products. Human anthrax is usually
manifested by cutaneous lesions.
A
biological attack with anthrax spores
delivered by aerosol would cause
inhalation anthrax, an extraordinarily
rare form of the naturally occurring
disease. Since Anthrax is a zoonotic
disease, deaths in cattle and sheep
coincident with human cases may indicate
an anthrax attack.
Clinical
Features. The disease begins after an
incubation period varying from 1-6 days, presumably
dependent upon the dose of inhaled organisms. Onset is
gradual and nonspecific, with fever, malaise, and
fatigue, sometimes in association with a nonproductive
cough and mild chest discomfort.
In
some cases, there may be a short period of improvement.
The initial symptoms are followed in 2-3 days by the
abrupt development of severe respiratory distress with
dyspnea, diaphoresis, stridor, and cyanosis. Physical
findings may include evidence of pleural effusions,
edema of the chest wall, and meningitis. Shock and
sudden death can occur within four hours of respiratory
symptom and fever onset.
Vaccine.
A licensed, fomalin-inactivated cellular
supernatant vaccine comprising the B.
anthracis protective antigen (PA)
has been shown to be effective in
preventing inhalation anthrax. Antibody
against protective antigent develops in
85-95% after initial 3 doses, and 100%
after 12-month dose. The vaccine should
be stored at refrigerator temperature
(not frozen).
Antibiotics.
If a biological attack is imminent or
cases have just been diagnosed,
prophylaxis with ciproflaxacin or
doxycycline is recommended. Effectiveness
of antibiotic use will depend on how
early treatment is started and the
antibiotic sensitivity of the organism.
Case-fatality rate is high following
onset of pulmonary signs and symptoms.
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Medical
Management of Biological Agent Patients
