Transcript Diseases of Bioterrorist Potential For Epidemiologists

Preparing for and Responding to
Bioterrorism:
Information for the Public Health
Workforce
Northwest Center for Public Health Practice
University of Washington School of Public Health and Community Medicine
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Acknowledgements
This presentation, and the accompanying instructor’s manual,
were prepared by Jennifer Brennan Braden, MD, MPH, at the
Northwest Center for Public Health Practice in Seattle, WA, for the
purpose of educating public health employees in the general aspects of
bioterrorism preparedness and response. Instructors are encouraged
to freely use all or portions of the material for its intended purpose.
The following people and organizations provided information and/or
support in the development of this curriculum. A complete list of
resources can be found in the accompanying instructor’s guide.
Patrick O’Carroll, MD, MPH
Project Coordinator
Centers for Disease Control and Prevention
Judith Yarrow
Design and Editing
Health Policy and Analysis; University of WA
Washington State Department of Health
Jeff Duchin, MD
Jane Koehler, DVM, MPH
Communicable Disease Control,
Epidemiology and Immunization Section
Public Health - Seattle and King County
Ed Walker, MD; University of WA
Department of Psychiatry
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Diseases of Bioterrorist Potential:
Anthrax
CDC, AFIP
UW Northwest Center for Public Health Practice
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Diseases of Bioterrorist Potential
Learning Objectives
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Describe the epidemiology, mode of
transmission and presenting symptoms of
disease caused by the CDC-defined Category A
agents
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Identify the infection control and prophylactic
measures to implement in the event of a
suspected or confirmed Category A case or
outbreak
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Anthrax
Overview
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Primarily a disease of herbivores
Hardy spore exists in soil reservoir
Humans “naturally” infected by
contact with infected animals or
contaminated animal products
In the early 1900s ~130 cases/yr in
U.S.
Woolsorter’s disease: inhalation
anthrax
Until 2001, 18 U.S.cases of inhalation
anthrax reported in the 20th century
Last naturally-occurring U.S. case of
inhalation anthrax in 1976
CDC
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Inhalational Anthrax
Acquisition of Infection
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Infectious dose in humans not precisely known
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Estimated 8-50,000 spores required for
inhalation anthrax
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May be less in the context of bioterrorism
May depend on host factors and bacterial strain
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Inhalational Anthrax
Acquisition of Infection
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Infectious aerosol particles >5 in size fall from
atmosphere and bond to surfaces
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Secondary aerosolization unlikely
Particles 1-5 behave like a gas and are
deposited in small air sacs of the lungs
 No environmental residue
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Anthrax
Case Definition
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An illness with acute onset characterized by
several distinct clinical forms
 Cutaneous: a skin lesion evolving during a
period of 2-6 days from a papule, through a
vesicular stage, to a depressed black eschar
 Inhalation*: a brief prodrome resembling a
viral respiratory illness, followed by
development of hypoxia and dyspnea, with
radiographic evidence of mediastinal
widening
*Presentation may vary in the context of bioterrorism
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MMWR 1997;46(RR-10)
Anthrax
Case Definition, cont.
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An illness with acute onset characterized by
several distinct clinical forms (continued)
 Intestinal: severe abdominal distress followed
by a fever and signs of septicemia
 Oropharyngeal: mucosal lesion in the oral
cavity or oropharynx, cervical adenopathy &
edema, & fever
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Confirmed case: Clinically compatible with
laboratory confirmation
MMWR 1997;46(RR-10) 9
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Anthrax
Laboratory Criteria for Diagnosis
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Isolation of B. anthracis from a clinical specimen
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Blood, lung fluid, spinal fluid, skin lesion OR
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Positive serology* (after symptom onset) OR
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Demonstration of B. anthracis in a clinical
specimen by immunofluorescence*
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Nasal swabs & serology – not useful for
clinicians, but can help determine the extent of
exposure in an epidemiologic investigation
*testing at state public health labs or CDC
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MMWR 1997;46(RR-10) 10
Inhalational Anthrax
Clinical Features
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Incubation period: 1 to 43 days or longer; may be
related to dose and host factors
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Initial symptoms typically appear in 2-5 days
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Nonspecific: fever, dry cough, chest discomfort,
muscle aches, malaise, profound fatigue, sweats
Gastrointestinal symptoms
Late symptoms
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Hemorrhagic mediastinitis, dyspnea
Some cases develop meningitis
Rapid progression to shock, death
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Inhalational Anthrax
Clinical Features
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No person-to-person transmission of inhalational
anthrax
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Mortality rate 100% despite aggressive Rx in
“advanced disease” but is lower with early
treatment
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6/11 cases in the 2001 outbreak survived with
early aggressive therapy
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Cutaneous Anthrax
Presentation and Course
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Most common form (95%)
under natural conditions
Portal of entry: break in skin
Incubation: hours - 12 days
Papule  vesicle 
ulcer/painless eschar
Significant edema surrounding
the lesion, and in nearby lymph
nodes
Fever, malaise, headache may
be present
Death 20% untreated; rare if
treated
CDC
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Cutaneous Anthrax
Clinical Progression
Day 5
Day 10-12
Day 7
Day 15
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CDC
Bioterrorism-Associated Anthrax
Epidemiologic Curve
Inhalation Case
NYC
FL
NJ*
DC
Cases
CT
5
4
3
2
NYC
letters*
Senate
letters*
1
0
9/17
9/21
9/25
9/29
*Postmarked date of known
contaminated letters.
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10/3
10/7
10/11
10/15
10/19 10/23 10/27 11/14
Date of Onset
*10/19 susp cutaneous case later removed
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Modified from: MMWR Nov 2, 2001; 50(43)
BT-related Inhalational Anthrax
Distinguishing Anthrax from Other Influenza-Like Illnesses
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MMWR. Nov 9, 2001;50(44)
2001 Anthrax Outbreak
Outcome
A n th ra x L e tte r C a se s
2 2 A n th ra x C a ses
1 1 C o n firm e d in ha la tio n al a n th rax
1 1 cu ta n e o u s a n th ra x ca ses
(7 co n firm e d , 4 su sp e cte d)
5 d e a ths
(4 5 % m o rta lity ra te)
N o d e a ths
MMWR Weekly 50(48);1077-9
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Anthrax
Treatment
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Antibiotics are effective against germinating or
vegetative B. anthracis but not against the spore
form
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Disease development can be prevented as long
as therapeutic levels of antibiotics are
maintained to kill germinating organisms, or until
spores are cleared or controlled by immune
defenses (duration unclear)
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Anthrax
Treatment and Prophylaxis
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Treatment of cases
 Antibiotics x 60 days
 Can treat cutaneous disease for 7-10 days, if
no potential aerosol exposure
 Standard precautions
 Cover cutaneous lesions, treat dressings as
biohazard waste
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Prophylaxis for those exposed
 Antibiotics for 60 – 100 days
 Possible role for vaccine in combination with
antibiotics
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Anthrax
Post-exposure Prophylaxis Beyond 60 days?
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Rationale:
 Viable spores demonstrated in mediastinal
lymph nodes of monkeys 100d post-exposure
 ACIP Recommendations (December, 2000):
If anthrax vaccine is available, antibiotics can
be discontinued after 3 doses of vaccine (0,
2, and 4 weeks) MMWR 49(RR-15)
Link to webcast 20
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Anthrax
Extension of PEP: CDC Options
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Earlier Recommendations – 60 days of
antibiotics + medical monitoring
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Additional Option 1 – 40 additional* days of
antibiotic treatment + medical monitoring
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Additional Option 2 – 40 additional* days of
antibiotic treatment + 3 doses of anthrax
vaccine over 4 weeks + medical monitoring
*Total=100days
UW Northwest Center for Public Health Practice
CDC Responds, Dec 21, 2001
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Anthrax Letters
Extension of PEP: CDC Options
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Both additional options investigational
 PEP approved by FDA for only 60 days
 Anthrax vaccine, 3-dose schedule and lot
number not approved for this particular use
Link to webcast
UW Northwest Center for Public Health Practice
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Anthrax Vaccine
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Current U.S. vaccine (FDA Licensed):
developed from attenuated strain of virus
 Protective against cutaneous (human data)
and possibly inhalational anthrax (animal
data)
 Injections at 0, 2, 4 wks & 6, 12, 18 mos;
yearly boosters
 3 dose schedule (0, 2, 4 wks) may be
effective post-exposure, when given
w/antibiotics
 83% serologic response after 3 doses,
 100% after 5
 Limited availability
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Anthrax Vaccine
Adverse Effects
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Safety profile similar to other licensed
vaccines
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Up to 30% with mild discomfort (tenderness,
redness, swelling, or itching) at inoculation
site for up to 72 hours
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<2% with more severe local reactions,
potentially limiting use of the arm for 1-2 days
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Systemic reactions uncommon
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Anthrax
Summary of Key Points
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The most likely presentation of anthrax in a BT
attack is inhalational disease; cutaneous
disease is also possible.
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Early in the course of illness, inhalational
anthrax is not easily distinguished from an
influenza-like illness due to other causes.
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Antibiotic prophylaxis can be used to prevent
development of disease in infected persons.
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Anthrax is not transmitted person to person.
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Case Reports
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Anthrax
AN EPIDEMIC OF INHALATION ANTHRAX:
THE FIRST IN THE TWENTIETH CENTURY
American Journal of Hygiene 72, 6-23, 1960
THE SVERDLOVSK ANTHRAX
OUTBREAK OF 1979
Science 266, 1202-1208, 1994
Anthrax Outbreak 2001 – UCLA SOPH website
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Resources
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Centers for Disease Control & Prevention
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Bioterrorism Web page: http://www.bt.cdc.gov/
CDC Office of Health and Safety Information System
(personal protective equipment)
http://www.cdc.gov/od/ohs/
USAMRIID -- includes link to on-line version of
Medical Management of Biological Casualties
Handbook http://www.usamriid.army.mil/
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Johns Hopkins Center for Civilian Biodefense
Studies http://www.hopkins-biodefense.org
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Resources
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Office of the Surgeon General: Medical
Nuclear, Biological and Chemical Information
http://www.nbc-med.org
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St. Louis University Center for the Study of
Bioterrorism and Emerging Infections
http://bioterrorism.slu.edu
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Public Health - Seattle & King County
http://www.metrokc.gov/health
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Resources
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Washington State Department of Health
http://www.doh.wa.gov
 Communicable
 (206)
 (877)
Disease Epidemiology
361-2914 OR
539-4344 (24 hour emergency)
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Association for Professionals in Infection
Control http://www.apic.org/bioterror
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MMWR Rec & Rep. Case definitions under
public health surveillance. 1997;46(RR-10):1-55
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