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 1

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 2

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Diseases of Bioterrorist Potential: Anthrax

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CDC, AFIP 3

Diseases of Bioterrorist Potential Learning Objectives

 Describe the epidemiology, mode of transmission and presenting symptoms of disease caused by the CDC-defined Category A agents  Identify the infection control and prophylactic measures to implement in the event of a suspected or confirmed Category A case or outbreak 4

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Anthrax

Overview        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 5

Inhalational Anthrax

Acquisition of Infection

 Infectious dose in humans not precisely known  Estimated 8-50,000 spores required for inhalation anthrax   May be less in the context of bioterrorism May depend on host factors and bacterial strain 6

Inhalational Anthrax

Acquisition of Infection

 Infectious aerosol particles >5  in size fall from atmosphere and bond to surfaces  Secondary aerosolization unlikely  Particles 1-5  behave like a gas and are deposited in small air sacs of the lungs  No environmental residue 7

Anthrax Case Definition

 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) 8

Anthrax Case Definition, cont.

 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  Confirmed case: Clinically compatible with laboratory confirmation MMWR 1997;46(RR-10) 9

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Anthrax Laboratory Criteria for Diagnosis

 Isolation of

B. anthracis

from a clinical specimen  Blood, lung fluid, spinal fluid, skin lesion

OR

 Positive serology* (after symptom onset)

OR

  Demonstration of

B. anthracis

in a clinical specimen by immunofluorescence* 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

 Incubation period : 1 to 43 days or longer; may be related to dose and host factors  Initial symptoms typically appear in 2-5 days  Nonspecific: fever, dry cough, chest discomfort, muscle aches, malaise, profound fatigue, sweats  Gastrointestinal symptoms  Late symptoms  Hemorrhagic mediastinitis, dyspnea  Some cases develop meningitis  Rapid progression to shock, death 11

Inhalational Anthrax

Clinical Features

 No person-to-person transmission of inhalational anthrax  Mortality rate 100% despite aggressive Rx in “advanced disease” but is lower with early treatment  6/11 cases in the 2001 outbreak survived with early aggressive therapy 12

Cutaneous Anthrax

Presentation and Course

       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 13

Cutaneous Anthrax

Clinical Progression

Day 5 Day 7

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Day 10-12 Day 15 14 CDC

Bioterrorism-Associated Anthrax Epidemiologic Curve

Inhalation Case NYC NJ*

CT

FL DC 5 4 3 2 1 0

NYC letters* Senate letters*

9/17 9/21 9/25 9/29

*Postmarked date of known contaminated letters.

UW Northwest Center for Public Health Practice 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 15 Modified from :

MMWR

Nov 2, 2001; 50(43)

BT-related Inhalational Anthrax

Distinguishing Anthrax from Other Influenza-Like Illnesses UW Northwest Center for Public Health Practice

16 MMWR. Nov 9, 2001;50(44)

2001 Anthrax Outbreak Outcome

Anthrax Letter Cases

22 Anthrax Cases 11 Confirmed inhalational anthrax 5 deaths (45% mortality rate) 11 cutaneous anthrax cases (7 confirmed, 4 suspected) No deaths MMWR Weekly 50(48);1077-9 17

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Anthrax Treatment

 Antibiotics are effective against germinating or vegetative

B. anthracis

but not against the spore form  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) 18

Anthrax Treatment and Prophylaxis

 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  Prophylaxis for those exposed  Antibiotics for 60 – 100 days  Possible role for vaccine in combination with antibiotics 19

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Anthrax

Post-exposure Prophylaxis Beyond 60 days?

 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

 Earlier Recommendations – 60 days of antibiotics + medical monitoring  Additional Option 1 – 40 additional* days of antibiotic treatment + medical monitoring  Additional Option 2 – 40 additional* days of antibiotic treatment + 3 doses of anthrax vaccine over 4 weeks + medical monitoring *Total=100days

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CDC Responds, Dec 21, 2001 21

Anthrax Letters Extension of PEP: CDC Options

 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 22

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Anthrax Vaccine

 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 23

Anthrax Vaccine

Adverse Effects

 Safety profile similar to other licensed vaccines  Up to 30% with mild discomfort (tenderness, redness, swelling, or itching) at inoculation site for up to 72 hours  <2% with more severe local reactions, potentially limiting use of the arm for 1-2 days  Systemic reactions uncommon 24

Anthrax Summary of Key Points

 The most likely presentation of anthrax in a BT attack is inhalational disease; cutaneous disease is also possible.

 Early in the course of illness, inhalational anthrax is not easily distinguished from an influenza-like illness due to other causes.  Antibiotic prophylaxis can be used to prevent development of disease in infected persons.

 Anthrax is not transmitted person to person.

25

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Case Reports



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 UW Northwest Center for Public Health Practice

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Resources

 Centers for Disease Control & Prevention   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 - Medical Management of Biological Casualties Handbook includes link to on-line version of http://www.usamriid.army.mil/  Johns Hopkins Center for Civilian Biodefense Studies http://www.hopkins-biodefense.org

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Resources

 Office of the Surgeon General: Medical Nuclear, Biological and Chemical Information http://www.nbc-med.org

 St. Louis University Center for the Study of Bioterrorism and Emerging Infections http://bioterrorism.slu.edu

 Public Health - Seattle & King County http://www.metrokc.gov/health 28

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Resources

 Washington State Department of Health http://www.doh.wa.gov

 Communicable Disease Epidemiology  (206) 361-2914

OR

 (877) 539-4344 (24 hour emergency)  Association for Professionals in Infection Control http://www.apic.org/bioterror  MMWR Rec & Rep. Case definitions under public health surveillance.

1997;46(RR-10):1-55 29

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