Zoonotic Diseases and Bioterrorism

1
Zoonotic Diseases and Bioterrorism

• David A. Pegues, MD
• UCLA Medical Center
• Division of Infectious Diseases

2
Background/Outline

• Zoonoses
• diverse pathogenic microorganisms
• reside and cause disease in non-human animals
• Transmission
• direct contact, ingestion, inhalation, arthropod
  intermediates, and animal bites
• Selected zoonotic diseases
• anthrax, plague, tularemia
• Smallpox

3
Biological and Chemical Terrorism
Threat Agent of Concern Category A List

• Bacillus anthracis (anthrax)
• Variola virus (smallpox)
• Yersenia pestis (plague)
• Francisella tularensis (tularemia)
• Botulinum toxin (botulism)
• Viral hemorrhagic fever viruses
• Ebola, Marburg, Lassa

• These agents
• Are easy to disseminate
• Cause high mortality, with potential for major
  public health impact
• Cause public panic and social disruption
• Require special action for public health and
  hospital preparedness

4
Biological and Chemical Terrorism
Threat Agent of Concern Category B List

• Coxiella burnetti (Q fever)
• Brucella sp. (brucellosis)
• Burkholderia mallie (glanders)
• alpha viruses (VEE, EEE, WEE)
• ricin toxin (from castor beans)
• Epsiolon toxin of Clostridium perfringens
• Staphylococcal enterotoxin B
• Some food/waterborne pathogens

• These agents
• Are moderately easy to disseminate
• Cause moderate morbidity and low mortality
• require enhanced diagnostic capacity and disease
  surveillance

5
SARS

• T gt 100.5F (gt38 C) AND
• cough, shortness of breath, difficulty breathing,
  hypoxia, or pneumonia or ARDS AND
• Travel OR close contact within 10 days of onset
  of symptoms to a SARS area or a person known to
  be a suspect SARS case

6
West Nile Virus Transmission Cycle
Mosquito vector
Incidental infections
Avian reservoir
7
Anthrax

• Etiology
• Bacillus anthracis--spore forming, Gram bacillus
• zoonosis--sheep, goats and cattle ingest soil
• human infection--skin contact, inhalation, or
  ingestion
• person-to-person transmission is unlikely
• secondary cutaneous infection may occur
• Mode of transmission
• spores are very durable--may survive gt40 yrs
• cutaneous inoculation, inhalation, or ingestion
• spores germinate and disseminate via RE system
  may require up to 100 days to germinate

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Bacillus anthracis

• Large, Gram bacillus
• Encapsulated
• Non-motile
• Non-hemolytic
• 35oC O/N colonies 2-5mm in diameter
• Gray-white, flat or slightly convex
• 'Medusa-head' appearance
• Risk to microbiologists

9
Anthrax Virulence

• 3 plasmid-encoded genes
• poly-D-glutamate capsule
• resists phagocytosis
• Edema factor (EF)
• adenylate cyclase exotoxin
• ? intracellular cAMP
• Lethal factor (LF)
• Zn dependent protease
• ? macrophage oxidative burst and proinflammatory
  cytokines
• LF and EF must combine with protective antigen
  (PA) for virulence
• LF and EF resist PMN phagocytosis and oxidative
  killing

Colonial Growth of Bacillus anthracis on BAP
(Gram's stain, x1000). Bush LM, et al. NEJM
20013451607-10.
10
Dixon TC et al NEJM 1999341815-26
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Inhalation Anthrax

• Incubation period 1-6 days
• Prodrome--fever, malaise, fatigue, cough, mild CP
• Toxin production requires germination in lymph
  nodes
• Widened mediastinum often no pulmonary
  infiltrates
• Hemorrhagic mediastinitis and lymphadenitis
• 2-4 days after symptom onset--respiratory
  failure, sepsis, and meningitis (50)
• Death w/in 24-36 hrs of onset of severe symptoms
• Mortality 80-90 2001 outbreak--5/11 (44)

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MMWR 200150941-8
13
Bioterrorism-Related Inhalational Anthrax First
10 Cases Reported in the US

• Cases occurred from Oct. 4-Nov 2, 2001
• District of Columbia, New Jersey, New York
• All but one processed, handled, or received
  letters containing B. anthracis spores
• Median age 56 yrs (range, 43-72 yrs)
• Gender 70 male
• Median incubation period 4 days (range, 4-6
  days)
• Case fatality rate 40

Jernigan JA, et al. Emerg Infect Dis
20017933-44.
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Symptoms for 10 Patients with Bioterrorism-Related
Inhalational Anthrax, Oct. - Nov.2001

• Physical findings N10
• Fever (gt37.8C) 7
• Tachycardia 8
• Hypotension 1
• Laboratory results
• WBC (103/mm3) 9.8
• PMNsgt70 7
• Transaminitis 6
• Hypoxemia 6
• Metabolic acidosis 2

• Symptom N10
• Fever, chills 10
• Drenching sweats 7
• Fatigue, malaise 10
• Cough 9
• Nausea or vomiting 9
• Dyspnea 8
• Pleuritic chest pain 7

Jernigan JA, et al. Emerg Infect Dis
20017933-44.
15
Radiographic Findings for Patients with
Bioterrorism-Related Inhalational Anthrax

• Chest X-ray findings (N10)
• Any abnormality 10
• Mediastinal widening 7
• Infiltrates/consolidation 7
• Pleural effusion 8

• Chest CT findings (N8)
• Any abnormality 8
• Mediastinal widening 7
• Pleural effusion 8
• Infiltrates, consolidation 6

Jernigan JA, et al. Emerg Infect Dis
20017933-44.
16
Index Case of Fatal Inhalational Anthrax Due to
Bioterrorisum in the US
Bush LM, et al. NEJM 20013451607-10.
17
73 y.o Male Newspaper Mailroom Clerk with
Inhalational Anthrax, Case 2
Jernigan JA, et al. Emerg Infect Dis
20017933-44.
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Influenza vs. Inhalation Anthrax
Signs Symptoms Influenza
Inhalational Anthrax Onset Sudden Grad
ual Fever Present, gt 101?F Present, may improve
lasting 3 to 4 days before recurring Cough Nonpro
ductive can Nonproductive become
severe shortness of breath Headache Prominent Occa
sional Myalgia (aches and pains) Usual often
severe Occasional Fatigue weakness Can last up
to 2 to 3 weeks Prominent Extreme
exhaustion Early and prominent Early and
prominent Chest discomfort Common Pleuritic
pain Sore throat Sometimes Common Stuffy
nose Sometimes Rare Vomiting, abdominal
pain Rare Common Chest xray Normal Abnormal CBC No
rmal Elevated w/ left shift
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Cutaneous Anthrax

• 95 of naturally occurring infections
• Woolsorters disease
• Papule ? vesicle ? ulcer ? eschar w/in 2-6 days
• Mortality
• 10-20 if untreated
• lt1 with treatment

Dixon TC et al NEJM 1999341815-26
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Anthrax

• Gastrointestinal infection
• ingestion of insufficiently cooked meat from
  infected animals
• oral-pharyngeal and intestinal forms
• mucosal ulcers, regional lymphadenopathy, sepsis
• abdominal pain, nausea, vomiting, bloody
  diarrhea, sepsis
• gt50 mortality despite treatment
• Diagnosis
• clinical suspicion
• Gram stain and culture--nasal, respiratory,
  blood, CSF
• DFA detection of PA in clinical or environmental
  specimens
• DNA detection (Roche/Mayo Clinic)

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Management of Anthrax

• Treatment
• ciprofloxacin, doxycycline, penicillin G
• antimicrobial resistance uncommon but can be
  engineered
• current BT strain contains an inducible
  penicillinase
• combination therapy for serious illness
• antimicrobials of limited effectiveness late in
  illness
• supportive measures role for IVIG?
• Prophylaxis
• oral ciprofloxacin, doxycycline, or amoxacillin
• IF known, credible or imminent exposure
• 60 days therapy currently recommended
• animal data suggests that low numbers of spores
  remain viable up to 100 days.

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Clinical Evaluation of Persons with Possible
Inhalational Anthrax
MMWR 200150941-8
23
Clinical Evaluation of Persons with Possible
Cutaneous Anthrax
MMWR 200150941-8
24
Anthrax Vaccination

• Cell-free filtrate
• avirulent strain that expresses PA
• limited supply and modest production capacity
  (BioPort MI)
• 0.5mL SC--0, 2, 4 wks and then 6, 12, and 18
  mths annual booster
• Immune response
• mill worker trial--protected against cutaneous
  anthrax
• monkeys--2 doses (0 and 2 wk) 88 protective
  against inhalation anthrax at 2 yrs
• post-exposure --0, 2, 4 wks oral antimicrobial
  x 4wks
• Contraindications hypersensitivity, age lt18 or
  gt65
• Inoculation discomfort (30), rare serious
  reactions

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Plague--History and Significance

• Three great pandemics
• Justinian plague (6th C)
• Black Death (14th C)--killed 1/4 of the European
  population
• Modern pandemic (19th-20th C) 10 million
  deaths in India
• US worked w/ Y. pestis as a potential BT agent
  in 1950s-60s
• USSR 10 institutes worked w/ plague

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Plague

• Etiology
• aerobic, gram-negative, lactose-nonfermenting rod
• reservoir--wild rodents (ground squirrels) also
  rabbits, wild carnivores, domestic cats
• vector--flea (esp. Xenopsylla cheopis)
• Transmission
• human intrusion into zoonotic cycle
• SW US--2-15 cases per year
• handling tissue of infected animal
• aerosolization--human, cat, or bioterrorism act

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Yersenia pestis

• Safety pin morphology on stain
• Grows readily on most culture media
• Virulence factors
• LPS endotoxin
• fibrinolysin
• coagulase
• capsular antiphagocytic principle fraction I
  antigen
• plasmid-encoded V and W antigens

28
CDC
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Plague Syndromes

• Fever, chills, malaise, prostration, sore throat,
  headache
• Bubonic plague
• incubation 2-8 days mortality 60 untreated, lt5
  treated
• regional lymphadenitis--inguinal (90) gt
  axillary, cervical
• Septicemic plague
• 1/4 of bubonic cases--secondary bacteremia,
  sepsis, DIC, high mortality (Black Death)
• primary (10-25 present w/o buboes)
• Pneumonic plague
• secondary or primary pneumonia from
  aerosolization
• short incubation (1-3 days) survival unlikely if
  Rx delayed gt18 hours
• person-to-person transmission possible

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Patients with Naturally Occurring Plague

• A. Cervical bubo in patient with bubonic plague
• B. Petechiae and echymosis, septicemic plague
• C. Gangrene of digits, recovery phase of
  septicemic plague

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Chest Radiograph of Patient With Primary
Pneumonic Plague

• Infrequent cervical bubo
• Exudative pneumonitis
• lobar consolidation
• parenchymal necrosis
• Cough and dyspnea
• Chest pain
• Hemoptysis
• GI symptoms common
• nausea, vomiting, diarrhea, abdominal pain

32
Management of Plague

• Diagnosis
• clinical suspicion
• stain and culture--lymph node, sputum, blood, and
  CSF
• immunofluroescent staining
• Treatment 10-14 days
• streptomcycin 15 mg/kg IM Q12 hrs
• gentamicin 5 mg/kg IV Qday
• doxycycline 100 mg Q12 hrs quinolones may be
  effective
• Prophylaxis
• doxycycline 100 mg PO BID x 7 days
• no vaccine currently available

33
Tularemia

• Etiology
• Francisella tularensis--small, Gram-negative
  coccobacillus
• zoonosis-- rabbit fever and deerfly fever
• remains viable for weeks in water, soil,
  carcasses, hides
• resists freezing but easily killed by heat and
  disinfection
• most US cases occur in South-Central and Western
  states
• Mode of Transmission
• skin or mucous membrane contact with infected
  animal
• bite of infected tick, deerfly, or mosquito
• inhalation or ingestion
• no known human-to-human transmission

34
Tularemia--Signs and Symptoms

• Incubation 3-5 days (range, 1-21 days)
• 6 forms
• Typhoidal (5-15)
• inhalation (also intradermal or GI)
• fever, prostration, weight loss no
  lymphadenopathy
• pneumonia (80)--nonproductive cough
• mortality 35 in untreated disease
• Ulceroglandular (75-85)
• inoculation of skin and mucous membranes
• fever, chills, headache, malaise, ulcerative skin
  lesion (esp. fingers)
• painful regional lymphadenopathy mortality 5
• Glandular, oculoglandular, oropharyngeal,
  pneumonic

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Pulmonary Tularemia-- Chest
Radiographic Findings

• Radiographic signs maybe minimal or absent
• Peribronchial infiltrates
• Bronchopneumonia gt1 lobe
• Small, discrete pulmonary infiltrates
• Scattered granulomatous lesions
• Pleural effusions
• Hilar lymphadenopathy

JAMA 20012852763-73
36
Oropharyngeal Tularemia

• Acquired by drinking ingestion, or inhalation
• Exudative pharyngitis, tonsillitis or stomatitis
• Prominent cervical or retropharyngeal
  lymphadentitis

JAMA 20012852763-73
37
An Outbreak of Primary Pneumonic Tularemia on
Martha's Vineyard
2000
Feldman KA, et al. N Engl J Med 20013451601-6
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Tularemia--Diagnosis

• Differential Dx
• typhoidal syndromes (e.g., salmonella,
  rickettsia, malaria)
• pneumonic process (e.g., plague, mycoplasma,
  anthrax)
• CXR infiltrate (50), hilar adenopathy (isolated
  1), pleural effusion (15)
• Laboratory diagnosis
• recovery of organism difficult blood, ulcers,
  sputum, CSF
• laboratory biohazard (BSL-3 containment)
• serology--agglutination or ELISA titers max. in
  4-8 wks

39
Tularemia--Management

• Treatment 10-14 days
• gentamicin 3-5 mg/kg IV daily
• streptomycin 7.5-10 mg/kg Q12 h
• ciprofloxacin 400mg IV?500mg PO Q12 h or 750 mg
  PO
• chloramphenicol and tetracycline--significant
  relapse
• Prophylaxis
• investigational live-attenuated vaccine by
  scarification
• given to gt5000 persons prevents typhoidal,
  ameliorates OG forms
• ciprofloxacin, doxycycline, or tetracycline
• 2-wk course effective when given w/in 24 h of
  inhalation exposure

40
Gram Stain Smears of the Agents of Anthrax,
Plague, and Tularemia

• A. B. anthracis large, chain-forming,
  gram-positive rod that sporulates
• B. Y. pestis gram-negative, plump,
  non-spore-forming, bipolar-staining bacillus
• C. F. tularensis small, pleomorphic, poorly
  staining , gram-negative coccobacillus

41
Smallpox

• Etiology
• Orthopox virus variola
• variola major--mortality 20-40 in unvaccinated
• variola minor--mortality lt1
• Transmission
• risk of secondary transmission--from onset of
  exanthem until all scabs separate
• 50 secondary attack rate in unvaccinated
  population
• as many as 10-20 second-generation cases infected
  from a single case

42
Smallpox
Drazen JM. NEJM 20023461262-3 Breman JC,
Henderson DA. NEJM 20023461300-8.
43
Smallpox--History and Significance

• Endemic smallpox declared eradicated in 1980
• WHO-approved repositories--CDC (Atlanta) and
  Institute for Viral Preparations (Moscow)
• Stockpiles scheduled for destruction 30 June 2002
• US civilian vaccination stopped in early 1980s
  and military vaccination stopped in 1989
• British army gave contaminated blankets to Native
  Americans during French and Indian War
• Japan considered use of smallpox during WW II
• USSR reportedly stockpiled massive quantities of
  virus

44
Distribution of Smallpox Cases in Boston during
the Epidemic of 1901 - 1903
Albert et al. NEJM. 2001344375-9.
45
Smallpox-- Signs and Symptoms

• Incubation period 12 days (range, 7-19 days)
• Acute onset of malaise, fever, rigors, vomiting,
  headache and backache delirium (15)
• 2-3 days later enanthem and deep-seeded
  exanthem
• face, hands, upper arms--spreads centrally to
  trunk
• macule ? papule ? vesicle ? pustule ? scabs
• lesions favor ventral surfaces
• 8-14 days for scabs to form leave depressed
  depigmented scars
• Hemorrhagic smallpox
• 3 of infections death with hemorrhagic macules
• Variola without exanthem
• 30-50 of vaccinated contacts mild prodrome with
  conjunctivitis

46
Breman JC, Henderson DA. NEJM 20023461300-8.
47
Smallpox--Diagnosis

• Differential Dx
• chickenpox (varicella), erythema multiforme w/
  bullae, contact dermatitis, monkeypox
• Early lesions may be confused with varicella
• varicella lesions collapse, multiple stages,
  trunk
• smallpox non-collapsible lesions, single stage,
  extremities
• Diagnosis
• EM of vesicular scrapings
• Guarniere bodies--aggregates of virus under light
  microscopy
• PCR--differentiates smallpox, monkeypox, vaccinia

48
Smallpox vs. Chickenpox
49
Smallpox--Treatment

• Cidofovir
• nucleoside analog used to treat CMV infection
• in vitro activity and in vivo activity in animals
• SAEs nephrotoxicity, neutropenia, acidosis,
  iritis, uveitis
• consider use in patients with progressive
  vaccinia, severe eczema vaccinatum, generalized
  vaccinia or extensive autoinoculation
• Ribavirin
• in vitro activity
• one report of effectiveness in case of
  progressive vaccinia

50
Smallpox--Treatment

• Vaccination
• intradermal administration of vaccinia virus
  (scarification)
• 90 protective against disease if vaccinated
  before exposure
• may prevent/ameliorate disease if given w/in 7 d
• 42 of US population unvaccinated
• prior vaccination likely to ?severity
  transmission of infection
• Passive Immunoprophylaxis
• vaccinia immune globulin (VIG)--6000 U/kg IV
• treatment of vaccination complications
• lt7 d after exposure vaccination VIG
• gt7 d after exposure VIG vaccination

51
Vaccinia--Smallpox Vaccination

• Low grade fever
• Axillary adenopathy
• Secondary inoculation (6/10,000)
• Generalized vaccinia (3/10,000)
• Encephalitis (2/106)
• Contraindicated
• immunosuppresion
• eczema or history
• HIV infection

52
Complications of Smallpox Vaccination
JAMA 19992812127-37.
53
Adverse Events After Smallpox Vaccination,
04/24/03
54
Adverse Events After Smallpox Vaccination,
04/24/03
55
Ocular Vaccinia Following Contact Transmission
from a Vaccinee
Cell cultures inoculated with conjunctival
scrapings from patients right conjunctiva.
Appearance of the patients right eye on
2/26/03, before initiation of antiviral Rx