last smallpox victim on earth. prionsprotozoavirusesbacteria little nasty things amebae (dysentary)...
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PrionsProtozoa VirusesBacteria
Little Nasty Things
Amebae (dysentary)Plasmodium (malaria)
Mad Cow DiseaseVariant CJD
PrionsProtozoa VirusesBacteria
Little Nasty Things
Amebae (dysentary)Plasmodium (malaria)
Mad Cow DiseaseVariant CJD
E. coli
B. anthracis (Anthrax)
Y. pestis (Plague)
Influenza
Varicella (Chickenpox)
Variola (Smallpox)
RNA VirusesDNA Viruses
Little Nasty Things
(ortho)Pox Viruses
PrionsProtozoa VirusesBacteria
•Variola (smallpox)-Major & Minor
•Vaccinia/Cowpox•Monkeypox
Other Pox Viruses
•Molluscum•ORF (parapox)•Milker’s nodules• Tanapox, others
ManyOther
Viruses
Epidemiology
• Winter & Early spring – Like measles and chickenpox– Virus killed by heat and humidity
• Age Distribution– Historically affected younger children and
unvaccinated persons– Outbreak now would match age distribution of
population since there is little immunity
Transmission
• Person Person– Primarily droplet, or aerosol– No animal reservoir or vector
• Very contagious, but less than measles or chickenpox
– Less transmissible (lower 2° attack rates)
– Persons are very sick before contagious
Time Course of Infection
Entry through Oropharynx or Lungs
Virus Multiplies in Lymph Nodes
Spreads through Bloodstream (1° viremia)
Multiplies again in Lymph nodes, Spleen, Bone Marrow
Spreads through Bloodstream (2° viremia)Prodrome: Fever, Headache, Backache, SICK!
Multiplies in mouth and Dermis (deep layer of skin) Rash
NOT Infectious(12-14 d )
NOT Infectious(2-4 d)
VERY Infectious
Smallpox Lesions:
Start on Face, (fore)Arms, Mouth
Palms and Soles
Deeply Embedded into Skin
Similar Stage of Development
Occur in Very Sick Persons
Smallpox Complications• Hemorrhagic-type Smallpox: 1 in 20 cases
– More common in pregnant women
• Flat-type Smallpox: 1 in 20 cases
• Encephalitis– Variola major: 1 in 500 cases– Variola minor: 1 in 2000 cases
• Ocular Infection– Blindness in 1% of cases
• Infection transmitted to child in late pregnancy
Case Presentation• 20 y/o woman with Fever, Misery X 2 days• Today, rash appeared on face & arms• Temp 103oF Blood Pressure106/78
Pulse 116/minute Breathing Rate 18/minute• Mentally sound, Lungs clear
• Scattered macules (“spots”) and vesicles noted
• Diagnosis – Chicken pox (Varicella Zoster virus)
• Treatment – oral Acyclovir, recheck in 2 days
What if this wasn’t Chickenpox?
• Patient had history of chickenpox as a child– Unusually severe for atypical or second infection
• Need to Diagnose Smallpox ASAP
– “Needle in a haystack”
What if this wasn’t Chickenpox?
• Patient had history of chickenpox as a child– Unusually severe for atypical or second infection
• Need to Diagnose Smallpox ASAP
– “Match in a haystack”
Hospital Infection Control
•Respiratory Isolation Critical
•NOTIFY IMMEDIATELY
–Hospital Infection Control
–Local Health Department
Smallpox Response Plan
• Surveillance• Outbreak Investigation• Outbreak Containment
–Vaccination–Quarantine/Isolation
• Public/Media Communication
Smallpox Response Plan
• Surveillance• Outbreak Investigation• Outbreak Containment
–Vaccination–Quarantine/Isolation
• Public/Media Communication
Smallpox Response Plan
• Surveillance• Outbreak Investigation• Outbreak Containment
–Vaccination–Quarantine/Isolation
• Public/Media Communication
Smallpox Response Plan
• Surveillance• Outbreak Investigation• Outbreak Containment
–Vaccination–Isolation/Quarantine
• Public/Media Communication
Smallpox Response Plan
• Surveillance• Outbreak Investigation• Outbreak Containment
–Vaccination–Quarantine/Isolation
• Public/Media Communication
Surveillance• Pre-event (baseline) Rash Surveillance• Notification for suspected smallpox case,
outbreak, contamination or distribution: – Local Health Department– State Health Department CDC
• Emergency Preparedness and Response Branch • Bioterrorism Preparedness and Response Program• Poxvirus Section, Division of Viral and Rickettsial
Diseases
• Case Definitions and Clinical Appearance
Surveillance: Case Definition
• Major Criteria– Fever > 102°F before rash onset– Classical smallpox lesions– Lesions at same stage of development
• Minor Criteria– Patient is “toxic” or moribund– Rash began on forarms, face, or mouth– Rash includes palms and soles– Centrifugal distribution (extremities > trunk)– Slow evolution of rash
Surveillance:Smallpox Case Categories• Low Probability
– No Fever– Fever and no other major and <4 minor criteria
• Moderate Probability: Fever +– 1 other major, or– > 4minor criteria
• High Probability: all 3 major criteria
Outbreak Investigation• Active Surveillance for Smallpox
– Local, state, national, international
• Surveillance for Adverse Vaccine Reactions
• Epi Investigation of Cases
• Contact Tracing
• Specimen Collection & Transportation
• Laboratory Confirmation (at CDC )– Detecting Smallpox Directly in Tissues– Viral Culture– Molecular Fingerprinting using PCR
Outbreak Containment:Vaccination Activities
• CDC vaccine deployment strategy
• Set up vaccination clinics
• Educate a pool of vaccinators– Recognize vaccine “take”– Recognize and treat adverse events– Safe handling of vaccine
• MASS VS. TARGETED VACCINATION?
Outbreak Containment:Ring Vaccination
• Strategy used for smallpox elimination
• Avoids recurring cost of mass vaccination
• Avoids unacceptably high, recurring risk of mass vaccination
• Strengthen public health surveillance infrastructure for ALL infectious diseases– Smallpox vaccine prevents only smallpox
Outbreak Containment:Isolation Categories
• Isolation Units (smallpox hospitals): contagious persons
• Observation Units (for persons with fever but no rash after smallpox contact): possibly contagious persons awaiting triage
• Home Fever Surveillance with travel restriction: for exposed or vaccinated persons
Outbreak Containment:Levels of Quarantine
• Education/Notification
• Suspension of Gatherings
• Restriction on Travel
• Blockade (“cordon sanitaire”) and community-wide interventions
Communication• Training for Local/State Health Departments
– Webcasts– Workshops
• Direct public education
• During an Event: – Contact Information– Education of General Public– Media Relations
Final Thoughts• Smallpox can be recognized early in the
course of an outbreak, incumbent on:– Provider and public awareness– Public health surveillance capacity
• Outbreaks probably not avoidable, but could (theoretically) be contained– Prodromal symptoms– Rash identifiable– Contagious persons unlikely to travel extensively
Final Thoughts II• Public health agencies will play a critical role in
incident command (i.e., what do we do now?)– Important but political– Uncomfortable decisions
• Unprecedented (not yet available) public health “surge capacity” is crucial to early outbreak containment – Dual-use infrastructure may become
important method of efficiently using smallpox resources
Questions & Answers
Smallpox plan available at:
http://www.bt.cdc.gov/DocumentsApp/Smallpox/RPG/index.asp
Smallpox Vaccination Complications(a live virus vaccine)
• Disseminated vaccinia
• Eczema vaccinatum
Points:
• For each 1 million vaccinated, there were ~ 250 complications• Vaccine immune globulin (VIG) Rx is needed - short supply
Pre-AIDS!
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