Exposure
Recommendation Guidelines -
Health Care Professionals
Assess
the patient's risk of exposure to anthrax.
Factors
that can assist you in determining the patient's risk include
the credibility of the exposure and the route of potential exposure.
Certain things associated with the package or envelope can assist
in determining whether it contained anthrax or not. Law enforcement
personnel should make this determination, NOT healthcare providers.
Second, the rule of exposure should be assessed to determine whether
or not the patient would be at risk for cutaneous or inhalation
anthrax. To aid in this assessment, the following is provided:
Cutaneous
anthrax: Cutaneous anthrax is the most plausible form of anthrax
that could be caused by letters or packages - all one needs is
spores rubbed into the skin or cuts in the skin that were exposed
to the spores. Given its characteristic physical picture and good
prognosis when recognized and treated, potential exposures can
readily be managed by observation and treatment as indicated.
·Inhalation
anthrax: Inhalation anthrax generally requires a large dose of
fine powder - particles 1-5 micron in size - to establish an infection.
It is technologically difficult to get anthrax into a form where
it can be inhaled. Reaerosolization of particles on clothing and
on surfaces into particles of this size is nearly impossible.
Thus, visible, settled powders and letters or boxes that are opened
and contain powders are usually not serious threats for inhalation
anthrax. Thus, the immediate risk to people in these situations
is small. Inhalation anthrax would be of concern in the following
circumstances:
A. Asymptomatic patient WITHOUT known exposure
-
Provide reassurance to the patient about the rarity of infection
without known exposure
-
Recommend
the patient see a health care provider for further concerns
and/or diagnostic tests
-
Discourage
use of nasal swabs for diagnosis of exposure
-
(Nasal
swabs and blood serum tests are used as an epidemiological
tool to characterize an outbreak when there is a known biologic
agent.)
B. Asymptomatic
patient WITH potential exposure
-
Conduct
an individual risk assessment and refer to a health care
provider if post-exposure prophylaxis is necessary
-
Decontaminating
the patient, other than by washing with soap and water,
is not routinely recommended
Post-exposure
Prophylaxis (PEP) Recommendations Initial therapy Duration
Adults (including pregnant women and immunocompromised)
Ciprofloxacin 500 mg po BIS Or Doxycycline 100 mg po BID 60 days
Children 1, Ciprofloxacin 15-20 mg/kg po Q12 hrs Or Doxycycline:
>8 yrs and >45 kg: 100 mg po BID >8 yrs and = 45 kg: 2.2 mg/kg
po BID
= 8 yrs: 2.2 mg/kg po BID 60 days
Confirm the diagnosis by obtaining the appropriate laboratory
specimens based on the clinical form of anthrax that is suspected
(inhalational, gastrointestinal, or cutaneous)
-
Inhalational
anthrax: blood, CSF (if meningeal signs are present); chest
X-ray
-
Gastrointestinal
anthrax: blood
-
Cutaneous
anthrax: vesicular fluid and blood
-
Evaluation
of possible anthrax infection for individuals not connected
with the AMI incident in Florida should be performed through
standard laboratory test, following the Laboratory Response
Network (LRN) Level A Clinical Guidelines for rule-out and
presumptive testing http://www.bt.cdc.gov (follow link for
Resources: Agents/Diseases - Bacillus anthracis)
a. Presumptive identification criteria (level A LRN laboratory)
-
From
clinical samples, such as blood, CSF, or skin lesion (vesicular
fluid or eschar) material: encapsulated Gram-positive
rods
-
From growth on sheep blood agar: large Gram-positive rods
-
Non-motile
-
Non-hemolytic on sheep blood agar
Additional
LRN level B laboratory criteria for confirmation of B. anthracis
are available through State Public Health Laboratories and
involve:
b. Confirmatory criteria for identification of B. anthracis
(level B LRN laboratory)
Capsule
production (visualization of capsule), and
Lysis
by gamma-phage, or
Direct
fluorescent antibody assays (DFA)
Rapid screening assays, such as nucleic acid signatures
and antigen detection, which can be performed directly on
clinical specimens and environmental samples, are being
made available for restricted use in LRN B and C level laboratories.
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